1
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Msheik A, Fares Y, Mohanna M, Aoude A, Shkeir M, Chehade F, Kanj A, Mohanna A. Middle meningeal artery embolisation: The review of a new treatment for chronic subdural hematomas. Surg Neurol Int 2023; 14:66. [PMID: 36895214 PMCID: PMC9990792 DOI: 10.25259/sni_1096_2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 02/03/2023] [Indexed: 02/26/2023] Open
Abstract
Background This is a literature review aiming to provide an update about the recent findings related to the efficacy of middle meningeal artery embolization (MMAE) in the treatment of chronic subdural hematomas (cSDHs), comparison with conventional therapy and deduction of the current recommendations and indications. Methods The literature is reviewed using a search through the PubMed index using keywords. Studies are then screened, skimmed, and thoroughly read. 32 studies fulfilled the inclusion criteria and are included in the study. Results Five indications for the application of MMA embolization (MMAE) are deducted from the literature. The usage as a preventive measure after surgical treatment of symptomatic cSDHs in patients with a high risk of recurrence and the usage as a standalone procedure has been the most common reasons for indication of this procedure. Rates of failures for the aforementioned indications have been 6.8% and 3.8%, respectively. Conclusion The safety of MMAE as a procedure is regarded as a general theme in the literature and can be considered for future applications. Usage of this procedure in clinical trials with more patient segregation and timeframe assessment relative to surgical intervention are recommendations of this literature review.
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Affiliation(s)
- Ali Msheik
- Department of Neurological Surgery, Lebanese University, Faculty of Medical Sciences
| | - Youssef Fares
- Department of Neurological Surgery, Neuroscience Research Center, Faculty of Medical Sciences, Lebanese University, Lebanon
| | - Mohammad Mohanna
- Department of Oncology, Cleveland Clinic, Weston, Florida, United States
| | - Ahmad Aoude
- Department of Neurological Surgery, Al Rassoul Al-Azam Hospital
| | - Mohamad Shkeir
- Head of Radiology Department, Zahraa Hospital University Medical Center
| | - Feras Chehade
- Department of Nuclear Medicine Radiobiology Radiopathology, Faculty of Medical Sciences, Lebanese University
| | - Ali Kanj
- Radiology Department, Bahman Hospital, Faculty of Medicine, Lebanese University
| | - Assaad Mohanna
- Head of Department of Radiology, Faculty of Medicine, Lebanese University, Bahman Hospital, Centre Hospitalier Vallee de la Maurienne-France, Beirut, Lebanon
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2
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Carrabba G, Fiore G, Di Cristofori A, Bana C, Borellini L, Zarino B, Conte G, Triulzi F, Rocca A, Giussani C, Caroli M, Locatelli M, Bertani G. Diffusion tensor imaging, intra-operative neurophysiological monitoring and small craniotomy: Results in a consecutive series of 103 gliomas. Front Oncol 2022; 12:897147. [PMID: 36176387 PMCID: PMC9513471 DOI: 10.3389/fonc.2022.897147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 07/14/2022] [Indexed: 11/13/2022] Open
Abstract
Diffusion tensor imaging (DTI) allows visualization of the main white matter tracts while intraoperative neurophysiological monitoring (IONM) represents the gold standard for surgical resection of gliomas. In recent years, the use of small craniotomies has gained popularity thanks to neuronavigation and to the low morbidity rates associated with shorter surgical procedures. The aim of this study was to review a series of patients operated for glioma using DTI, IONM, and tumor-targeted craniotomies. The retrospective analysis included patients with supratentorial glioma who met the following inclusion criteria: preoperative DTI, intraoperative IONM, tumor-targeted craniotomy, pre- and postoperative MRI, and complete clinical charts. The DTI was performed on a 3T scanner. The IONM included electroencephalography (EEG), transcranial (TC) and/or cortical motor-evoked potentials (MEP), electrocorticography (ECoG), and direct electrical stimulation (DES). Outcomes included postoperative neurological deficits, volumetric extent of resection (EOR), and overall survival (OS). One hundred and three patients (61 men, 42 women; mean age 54 ± 14 years) were included and presented the following WHO histologies: 65 grade IV, 19 grade III, and 19 grade II gliomas. After 3 months, only three patients had new neurological deficits. The median postoperative volume was 0cc (IQR 3). The median OS for grade IV gliomas was 15 months, while for low-grade gliomas it was not reached. In our experience, a small craniotomy and a tumor resection supported by IONM and DTI permitted to achieve satisfactory results in terms of neurological outcomes, EOR, and OS for glioma patients.
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Affiliation(s)
- Giorgio Carrabba
- Neurosugery, Azienda Socio Sanitaria Territoriale Monza - Ospedale San Gerardo di Monza, Monza, Italy
- Dipartimento di Medicina e Chirurgia, Università degli Studi di Milano-Bicocca, Milan, Italy
- *Correspondence: Giorgio Carrabba,
| | - Giorgio Fiore
- Neurosurgery, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Università degli Studi di Milano, Milan, Italy
| | - Andrea Di Cristofori
- Neurosugery, Azienda Socio Sanitaria Territoriale Monza - Ospedale San Gerardo di Monza, Monza, Italy
| | - Cristina Bana
- Neurophysiopathology, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Università degli Studi di Milano, Milano, Italy
| | - Linda Borellini
- Neurophysiopathology, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Università degli Studi di Milano, Milano, Italy
| | - Barbara Zarino
- Neurosurgery, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Università degli Studi di Milano, Milan, Italy
| | - Giorgio Conte
- Neuroradiology, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, University of Milano, Milano, Italy
| | - Fabio Triulzi
- Neuroradiology, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, University of Milano, Milano, Italy
| | - Alessandra Rocca
- Neurosugery, Azienda Socio Sanitaria Territoriale Monza - Ospedale San Gerardo di Monza, Monza, Italy
- Dipartimento di Medicina e Chirurgia, Università degli Studi di Milano-Bicocca, Milan, Italy
| | - Carlo Giussani
- Neurosugery, Azienda Socio Sanitaria Territoriale Monza - Ospedale San Gerardo di Monza, Monza, Italy
- Dipartimento di Medicina e Chirurgia, Università degli Studi di Milano-Bicocca, Milan, Italy
| | - Manuela Caroli
- Neurosurgery, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Università degli Studi di Milano, Milan, Italy
| | - Marco Locatelli
- Neurosurgery, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Università degli Studi di Milano, Milan, Italy
- Department of Medical-Surgical Physiopathology and Transplantation, University of Milan, Milan, Italy
| | - Giulio Bertani
- Neurosurgery, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Università degli Studi di Milano, Milan, Italy
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3
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Zahnert F, Kräling G, Melms L, Belke M, Kleinholdermann U, Timmermann L, Hirsch M, Jansen A, Mross P, Menzler K, Habermehl L, Knake S. Diffusion magnetic resonance imaging connectome features are predictive of functional lateralization of semantic processing in the anterior temporal lobes. Hum Brain Mapp 2022; 44:496-508. [PMID: 36098483 PMCID: PMC9842893 DOI: 10.1002/hbm.26074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 07/22/2022] [Accepted: 08/18/2022] [Indexed: 01/25/2023] Open
Abstract
Assessment of regional language lateralization is crucial in many scenarios, but not all populations are suited for its evaluation via task-functional magnetic resonance imaging (fMRI). In this study, the utility of structural connectome features for the classification of language lateralization in the anterior temporal lobes (ATLs) was investigated. Laterality indices for semantic processing in the ATL were computed from task-fMRI in 1038 subjects from the Human Connectome Project who were labeled as stronger rightward lateralized (RL) or stronger leftward to bilaterally lateralized (LL) in a data-driven approach. Data of unrelated subjects (n = 432) were used for further analyses. Structural connectomes were generated from diffusion-MRI tractography, and graph theoretical metrics (node degree, betweenness centrality) were computed. A neural network (NN) and a random forest (RF) classifier were trained on these metrics to classify subjects as RL or LL. After classification, comparisons of network measures were conducted via permutation testing. Degree-based classifiers produced significant above-chance predictions both during cross-validation (NN: AUC-ROC[CI] = 0.68[0.64-0.73], accuracy[CI] = 68.34%[63-73.2%]; RF: AUC-ROC[CI] = 0.7[0.66-0.73], accuracy[CI] = 64.81%[60.9-68.5]) and testing (NN: AUC-ROC[CI] = 0.69[0.53-0.84], accuracy[CI] = 68.09[53.2-80.9]; RF: AUC-ROC[CI] = 0.68[0.53-0.84], accuracy[CI] = 68.09[55.3-80.9]). Comparison of network metrics revealed small effects of increased node degree within the right posterior middle temporal gyrus (pMTG) in subjects with RL, while degree was decreased in the right posterior cingulate cortex (PCC). Above-chance predictions of functional language lateralization in the ATL are possible based on diffusion-MRI connectomes alone. Increased degree within the right pMTG as a right-sided homologue of a known semantic hub, and decreased hubness of the right PCC may form a structural basis for rightward-lateralized semantic processing.
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Affiliation(s)
- Felix Zahnert
- Epilepsy Center Hesse, Department for NeurologyUniversity Hospital Marburg, Philipps University MarburgMarburgGermany
| | - Gunter Kräling
- Department of Medical TechnologyUniversity Hospital MarburgMarburgGermany
| | - Leander Melms
- Institute for Artificial IntelligenceUniversity Hospital Marburg, Philipps University MarburgMarburgGermany
| | - Marcus Belke
- Epilepsy Center Hesse, Department for NeurologyUniversity Hospital Marburg, Philipps University MarburgMarburgGermany,LOEWE Center for Personalized Translational Epilepsy Research (CePTER)Goethe‐University FrankfurtFrankfurt Am MainGermany
| | - Urs Kleinholdermann
- Department for NeurologyUniversity Hospital Marburg, Philipps University MarburgMarburgGermany
| | - Lars Timmermann
- Department for NeurologyUniversity Hospital Marburg, Philipps University MarburgMarburgGermany,Center for Mind, Brain and Behavior (CMBB)Philipps‐University MarburgMarburgGermany,Core Facility Brainimaging, Faculty of MedicineUniversity of MarburgMarburgGermany
| | - Martin Hirsch
- Institute for Artificial IntelligenceUniversity Hospital Marburg, Philipps University MarburgMarburgGermany
| | - Andreas Jansen
- Center for Mind, Brain and Behavior (CMBB)Philipps‐University MarburgMarburgGermany,Core Facility Brainimaging, Faculty of MedicineUniversity of MarburgMarburgGermany,Department for Psychiatry and PsychotherapyUniversity Hospital Marburg, Philipps University MarburgMarburgGermany
| | - Peter Mross
- Epilepsy Center Hesse, Department for NeurologyUniversity Hospital Marburg, Philipps University MarburgMarburgGermany
| | - Katja Menzler
- Epilepsy Center Hesse, Department for NeurologyUniversity Hospital Marburg, Philipps University MarburgMarburgGermany,Center for Mind, Brain and Behavior (CMBB)Philipps‐University MarburgMarburgGermany,Core Facility Brainimaging, Faculty of MedicineUniversity of MarburgMarburgGermany
| | - Lena Habermehl
- Epilepsy Center Hesse, Department for NeurologyUniversity Hospital Marburg, Philipps University MarburgMarburgGermany
| | - Susanne Knake
- Epilepsy Center Hesse, Department for NeurologyUniversity Hospital Marburg, Philipps University MarburgMarburgGermany,LOEWE Center for Personalized Translational Epilepsy Research (CePTER)Goethe‐University FrankfurtFrankfurt Am MainGermany,Center for Mind, Brain and Behavior (CMBB)Philipps‐University MarburgMarburgGermany,Core Facility Brainimaging, Faculty of MedicineUniversity of MarburgMarburgGermany
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4
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Wu D, Zhang M, Geng J, Chen X. Noninvasive Prediction of Language Lateralization Through Arcuate Fasciculus Tractography in Patients With Low-Grade Gliomas: Correlation With The Wada Test. Front Oncol 2022; 12:936228. [PMID: 35936675 PMCID: PMC9354698 DOI: 10.3389/fonc.2022.936228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 06/15/2022] [Indexed: 11/13/2022] Open
Abstract
Language lateralization is unique to humans, so clarifying dominant side is helpful for removing gliomas involving language areas. This study investigated the arcuate fasciculus (AF) reconstructed by diffusion tensor imaging–based tractography (DTT) in predicting language lateralization in patients with low-grade gliomas. Wada test was performed to determine the language Dominant Hemisphere (DH) and the Contralateral Hemisphere. DTI data [1.5-T magnetic resonance imaging (MRI)] was used to reconstruct AF by two independent operators using a DTT method. Fiber number, volume, and fractional anisotropy (FA) of bilateral reconstructed AF were measured. Lateralization indexes (LIs), including Number Index (NI), Volume Index (VI), and FA Index (FI), were accordingly calculated by mean values. A total of 21 patients with WHO Grade II gliomas in the left hemisphere were included. Every patient received a successful Wada test and reconstruction of bilateral AF. DTT metrics of reconstructed AF, such as fiber number, volume, and FA, showed significantly asymmetric between hemispheres. All the LI (NI, VI, and FI) values were statistically higher in the DH determined by the Wada test. No discrepancy was found between the prediction using the cutoff values of DTT metrics and the results of WADA test. The Kappa values were 0.829, 0.696, and 0.611, indicating NI and VI as more reliable predictor than FI although FI itself may also be feasible. Compared with the Wada test, we consider that DTT of AF is a non-invasive, simple, relatively accurate, and feasible method in predicting language lateralization in patients with low-grade gliomas.
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Affiliation(s)
- Dongdong Wu
- Department of Neurosurgery, Chinese People's Liberation Army (PLA) General Hospital, Beijing, China
| | - Meng Zhang
- Department of Neurosurgery, The Second Hospital of Southern Theater of Chinese Navy, Sanya, China
| | - Jiefeng Geng
- Department of Neurosurgery, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Xiaolei Chen
- Department of Neurosurgery, Chinese People's Liberation Army (PLA) General Hospital, Beijing, China
- *Correspondence: Xiaolei Chen,
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5
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Di Cristofori A, Remida P, Patassini M, Piergallini L, Buonanno R, Bruno R, Carrabba G, Pavesi G, Iaccarino C, Giussani CG. Middle meningeal artery embolization for chronic subdural hematomas. A systematic review of the literature focused on indications, technical aspects, and future possible perspectives. Surg Neurol Int 2022; 13:94. [PMID: 35399896 PMCID: PMC8986643 DOI: 10.25259/sni_911_2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 02/14/2022] [Indexed: 12/20/2022] Open
Abstract
Background: Chronic subdural hematoma (CSDH) is one of the most common neurosurgical diseases that affect elderly and fragile patients and as a consequence, management can be challenging. Surgery represents the standard treatment; however, alternative options are under investigation. Middle meningeal artery (MMA) embolization is considered a minimally invasive treatment although with poor evidence. In this review, we tried to summarize the findings about MMA embolization as a treatment for a CSDH to provide a useful guidance for clinical practice and for future speculative aspects. Methods: Literature review on PubMed until March 2021 was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Statement. We conducted a research on PubMed with a various combinations of the keywords “CSDH” and “middle meningeal artery” and “embolization,” “refractory subdural hematoma,” and then we reviewed the references of the relevant studies as additional source of eligible articles. Results: Among the 35 studies eligible for this review, 22 were case series, 11 were case reports, one was a technical note, and 1 was a randomized trial. A total of 746 patients were found in the literature. Failure rate of MMA embolization was between 3.9 and 8.9% of the cases according the indication to treat CSDH (upfront vs. after surgery). Conclusion: The global impression deriving from the data available and the literature is that MMA embolization is a safe procedure with very low complications and with a low failure rate, both when associated with surgery or in case of a standalone treatment.
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Affiliation(s)
- Andrea Di Cristofori
- Unit of Neurosurgery, Azienda Socio SanitariaTerritoriale - Monza, Ospedale San Gerardo,
| | - Paolo Remida
- Unit of Neuroradiology, Azienda Socio Sanitaria Territoriale - Monza, Ospedale San Gerardo, Monza,
| | - Mirko Patassini
- Unit of Neuroradiology, Azienda Socio Sanitaria Territoriale - Monza, Ospedale San Gerardo, Monza,
| | - Lorenzo Piergallini
- Unit of Neuroradiology, Azienda Socio Sanitaria Territoriale - Monza, Ospedale San Gerardo, Monza,
| | - Raffaella Buonanno
- Unit of Neurosurgery, Azienda Socio SanitariaTerritoriale - Monza, Ospedale San Gerardo,
- Unit of Neurosurgery, School of Medicine and Surgery, Department of Medicine and Surgery, Università degli Studi Milano Bicocca, Milan,
| | - Raffaele Bruno
- Unit of Neurosurgery, Azienda Socio SanitariaTerritoriale - Monza, Ospedale San Gerardo,
- Unit of Neurosurgery, School of Medicine and Surgery, Department of Medicine and Surgery, Università degli Studi Milano Bicocca, Milan,
| | - Giorgio Carrabba
- Unit of Neurosurgery, Azienda Socio SanitariaTerritoriale - Monza, Ospedale San Gerardo,
- Unit of Neurosurgery, School of Medicine and Surgery, Department of Medicine and Surgery, Università degli Studi Milano Bicocca, Milan,
| | - Giacomo Pavesi
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia,
- Neurosurgery Division, University Hospital of Modena, Modena, Italy
| | - Corrado Iaccarino
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia,
- Neurosurgery Division, University Hospital of Modena, Modena, Italy
| | - Carlo Giorgio Giussani
- Unit of Neurosurgery, Azienda Socio SanitariaTerritoriale - Monza, Ospedale San Gerardo,
- Unit of Neurosurgery, School of Medicine and Surgery, Department of Medicine and Surgery, Università degli Studi Milano Bicocca, Milan,
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6
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Species and individual differences and connectional asymmetry of Broca's area in humans and macaques. Neuroimage 2021; 244:118583. [PMID: 34562577 DOI: 10.1016/j.neuroimage.2021.118583] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 09/11/2021] [Accepted: 09/15/2021] [Indexed: 01/03/2023] Open
Abstract
To reveal the connectional specialization of the Broca's area (or its homologue), voxel-wise inter-species and individual differences, and inter-hemispheric asymmetry were respectively inspected in humans and macaques at both whole-brain connectivity and single tract levels. It was discovered that the developed connectivity blueprint approach is able to localize connectionally comparable voxels between the two species in Broca's area, whereas the quantitative differences between blueprints of locationally or connectionally corresponding voxels enable us to generate inter-hemispheric, inter-subject, and inter-species connectional variabilities, respectively. More importantly, the inter-species and inter-subject variabilities exhibited positive correlation in both two primates, and relatively higher variabilities were detected in the anatomically defined pars triangularis. By contrast, negative relationship was identified between the inter-species variability and hemispheric asymmetry in human brain. In particular, relatively higher asymmetry was revealed in the anatomically defined pars opercularis. Therefore, our novel findings demonstrated that pars triangularis, as compared to pars opercularis, might be a more active area during primate evolution, in which the brain connectivity and possible functions of pars triangularis show relatively higher degree in species specialization, yet lower in hemispheric specialization. Meanwhile, brain connectivity and possible functions of pars opercularis manifested an opposite pattern. At the tract level, functional roles related to the ventral stream in speech comprehension were relatively conservative and bilaterally organized, while those related to the dorsal stream in speech production show relatively higher species and hemispheric specializations.
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7
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Porto de Oliveira JVM, Raquelo-Menegassio AF, Maldonado IL. What's your name again? A review of the superior longitudinal and arcuate fasciculus evolving nomenclature. Clin Anat 2021; 34:1101-1110. [PMID: 34218465 DOI: 10.1002/ca.23764] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 05/25/2021] [Accepted: 06/18/2021] [Indexed: 11/11/2022]
Abstract
Studies of the superior longitudinal fasciculus (SLF) have multiplied in recent decades owing to methodological advances, but the absence of a convention for nomenclature remains a source of confusion. Here, we have reviewed existing nomenclatures in the context of the research studies that generated them and we have identified their agreements and disagreements. A literature search was conducted using PubMed/MEDLINE, Web-of-Science, Embase, and a review of seminal publications, without restrictions regarding publication date. Our search revealed that diffusion imaging, autoradiography, and fiber dissection have been the main methods contributing to tract designation. The first two have been particularly influential in systematizing the horizontal elements distant from the lateral sulcus. Twelve approaches to naming were identified, eight of them differing considerably from each other. The terms SLF and arcuate fasciculus (AF) were often used as synonyms until the second half of the 20th century. During the last 15 years, this has ceased to be the case in a growing number of publications. The term AF has been used to refer to the assembly of three different segments, or exclusively to long frontotemporal fibers. Similarly, the term SLF has been employed to denote the whole superior longitudinal associative system, or only the horizontal frontoparietal parts. As only partial correspondence can be identified among the available nomenclatures, and in the absence of an official designation of all anatomical structures that can be encountered in clinical practice, a high level of vigilance regarding the effectiveness of every oral or written act of communication is mandatory.
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Affiliation(s)
| | | | - Igor Lima Maldonado
- UMR Inserm U1253, iBrain, Université de Tours, Tours, France.,CHRU de Tours, Tours, France.,Departamento de Biomorfologia, Instituto de Ciências da Saúde, Universidade Federal da Bahia, Salvador, Brazil.,Programa de Pós-Graduação em Medicina e Saúde, Universidade Federal da Bahia, Salvador, Brazil
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8
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Gerrits R, Verhelst H, Dhollander T, Xiang L, Vingerhoets G. Structural perisylvian asymmetry in naturally occurring atypical language dominance. Brain Struct Funct 2021; 227:573-586. [PMID: 34173870 DOI: 10.1007/s00429-021-02323-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 06/14/2021] [Indexed: 01/15/2023]
Abstract
Functional and anatomical hemispheric asymmetries abound in the neural language system, yet the relationship between them remains elusive. One attractive proposal is that structural interhemispheric differences reflect or even drive functional language laterality. However, studies on structure-function couplings either find that left and right language dominant individuals display similar leftward structural asymmetry or yield inconsistent results. The current study aimed to replicate and extend prior work by comparing structural asymmetries between neurologically healthy left-handers with right hemispheric language dominance (N = 24) and typically lateralized left-handed controls (N = 39). Based on structural MRI data, anatomical measures of six 'language-related' perisylvian structures were derived, including the surface area of five gray matter regions with known language functions and the FDC (combined fiber density and fiber-bundle cross-sectional area) of the arcuate fasciculus. Only the surface area of the pars triangularis and the anterior insula differed significantly between participant groups, being on average leftward asymmetric in those with typical dominance, but right lateralized in volunteers with atypical language specialization. However, these findings did not survive multiple testing correction and the asymmetry of these structures demonstrated much inter-individual variability in either subgroup. By integrating our findings with those reported previously we conclude that while some perisylvian anatomical asymmetries may differ subtly between typical and atypical speech dominants at the group level, they serve as poor participant-specific predictors of hemispheric language specialization.
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Affiliation(s)
- Robin Gerrits
- Department of Experimental Psychology, Ghent University, Ghent, Belgium.
| | - Helena Verhelst
- Department of Experimental Psychology, Ghent University, Ghent, Belgium
| | - Thijs Dhollander
- Developmental Imaging, Murdoch Children's Research Institute, Melbourne, Australia
| | - Li Xiang
- Centre for Reproductive Health, University of Edinburgh, Edinburgh, EH16 4TJ, UK
| | - Guy Vingerhoets
- Department of Experimental Psychology, Ghent University, Ghent, Belgium
- Ghent Institute for Functional and Metabolic Imaging (GIfMI), Ghent University, Ghent, Belgium
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9
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Di Cristofori A, Basso G, de Laurentis C, Mauri I, Sirtori MA, Ferrarese C, Isella V, Giussani C. Perspectives on (A)symmetry of Arcuate Fasciculus. A Short Review About Anatomy, Tractography and TMS for Arcuate Fasciculus Reconstruction in Planning Surgery for Gliomas in Language Areas. Front Neurol 2021; 12:639822. [PMID: 33643213 PMCID: PMC7902861 DOI: 10.3389/fneur.2021.639822] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 01/05/2021] [Indexed: 11/13/2022] Open
Abstract
Gliomas are brain tumors that are treated with surgical resection. Prognosis is influenced by the extent of resection and postoperative neurological status. As consequence, given the extreme interindividual and interhemispheric variability of subcortical white matter (WM) surgical planning requires to be patient's tailored. According to the “connectionist model,” there is a huge variability among both cortical areas and subcortical WM in all human beings, and it is known that brain is able to reorganize itself and to adapt to WM lesions. Brain magnetic resonance imaging diffusion tensor imaging (DTI) tractography allows visualization of WM bundles. Nowadays DTI tractography is widely available in the clinical setting for presurgical planning. Arcuate fasciculus (AF) is a long WM bundle that connects the Broca's and Wernicke's regions with a complex anatomical architecture and important role in language functions. Thus, its preservation is important for the postoperative outcome, and DTI tractography is usually performed for planning surgery within the language-dominant hemisphere. High variability among individuals and an asymmetrical pattern has been reported for this WM bundle. However, the functional relevance of AF in the contralateral non-dominant hemisphere in case of tumoral or surgical lesion of the language-dominant AF is unclear. This review focuses on AF anatomy with special attention to its asymmetry in both normal and pathological conditions and how it may be explored with preoperative tools for planning surgery on gliomas in language areas. Based on the findings available in literature, we finally speculate about the potential role of preoperative evaluation of the WM contralateral to the surgical site.
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Affiliation(s)
| | - Gianpaolo Basso
- Neurosurgery Unit, San Gerardo Hospital, ASST Monza, Monza, Italy.,School of Medicine and Surgery, University of Milano-Bicocca, Milan, Italy.,Neuroradiology Unit, San Gerardo Hospital, ASST Monza, Monza, Italy
| | - Camilla de Laurentis
- Neurosurgery Unit, San Gerardo Hospital, ASST Monza, Monza, Italy.,School of Medicine and Surgery, University of Milano-Bicocca, Milan, Italy
| | - Ilaria Mauri
- Neurology Unit, San Gerardo Hospital, ASST Monza, Monza, Italy
| | | | - Carlo Ferrarese
- School of Medicine and Surgery, University of Milano-Bicocca, Milan, Italy.,Neurology Unit, San Gerardo Hospital, ASST Monza, Monza, Italy
| | - Valeria Isella
- School of Medicine and Surgery, University of Milano-Bicocca, Milan, Italy.,Neurology Unit, San Gerardo Hospital, ASST Monza, Monza, Italy
| | - Carlo Giussani
- Neurosurgery Unit, San Gerardo Hospital, ASST Monza, Monza, Italy.,School of Medicine and Surgery, University of Milano-Bicocca, Milan, Italy
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10
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Delgado-Fernández J, García-Pallero MÁ, Manzanares-Soler R, Martín-Plasencia P, Blasco G, Frade-Porto N, Navas-García M, Pulido P, Sola RG, Torres CV. Language hemispheric dominance analyzed with magnetic resonance DTI: correlation with the Wada test. J Neurosurg 2020; 134:1703-1710. [PMID: 32707542 DOI: 10.3171/2020.4.jns20456] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Accepted: 04/22/2020] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Language lateralization is a major concern in some patients with pharmacoresistant epilepsy who will face surgery; in these patients, hemispheric dominance testing is essential to avoid further complications. The Wada test is considered the gold standard examination for language localization, but is invasive and requires many human and material resources. Functional MRI and tractography with diffusion tensor imaging (DTI) have demonstrated that they could be useful for locating language in epilepsy surgery, but there is no evidence of the correlation between the Wada test and DTI MRI in language dominance. METHODS The authors performed a retrospective review of patients who underwent a Wada test before epilepsy surgery at their institution from 2012 to 2017. The authors retrospectively analyzed fractional anisotropy (FA), number and length of fibers, and volume of the arcuate fasciculus and uncinate fasciculus, comparing dominant and nondominant hemispheres. RESULTS Ten patients with temporal lobe epilepsy were reviewed. Statistical analysis showed that the mean FA of the arcuate fasciculus in the dominant hemisphere was higher than in the nondominant hemisphere (0.369 vs 0.329, p = 0.049). Also, the number of fibers in the arcuate fasciculus was greater in the dominant hemisphere (881.5 vs 305.4, p = 0.003). However, no differences were found in the FA of the uncinate fasciculus or number of fibers between hemispheres. The length of fibers of the uncinate fasciculus was longer in the dominant side (74.4 vs 50.1 mm, p = 0.05). Volume in both bundles was more prominent in the dominant hemisphere (12.12 vs 6.48 cm3, p = 0.004, in the arcuate fasciculus, and 8.41 vs 4.16 cm3, p = 0.018, in the uncinate fasciculus). Finally, these parameters were compared in patients in whom the seizure focus was situated in the dominant hemisphere: FA (0.37 vs 0.30, p = 0.05), number of fibers (114.4 vs 315.6, p = 0.014), and volume (12.58 vs 5.88 cm3, p = 0.035) in the arcuate fasciculus were found to be statistically significantly higher in the dominant hemispheres. Linear discriminant analysis of FA, number of fibers, and volume of the arcuate fasciculus showed a correct discrimination in 80% of patients (p = 0.024). CONCLUSIONS The analysis of the arcuate fasciculus and other tract bundles by DTI could be a useful tool for language location testing in the preoperative study of patients with refractory epilepsy.
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Affiliation(s)
| | | | | | | | - Guillermo Blasco
- 4Department of Neurosurgery, University Hospital La Princesa, Madrid
| | | | | | - Paloma Pulido
- 4Department of Neurosurgery, University Hospital La Princesa, Madrid
| | - Rafael G Sola
- 5Department of Innovation in Neurosurgery, Universidad Autonoma de Madrid; and.,6Department of Neurosurgery, Hospital del Rosario, Madrid, Spain
| | - Cristina V Torres
- 4Department of Neurosurgery, University Hospital La Princesa, Madrid
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11
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Kalyvas A, Koutsarnakis C, Komaitis S, Karavasilis E, Christidi F, Skandalakis GP, Liouta E, Papakonstantinou O, Kelekis N, Duffau H, Stranjalis G. Mapping the human middle longitudinal fasciculus through a focused anatomo-imaging study: shifting the paradigm of its segmentation and connectivity pattern. Brain Struct Funct 2019; 225:85-119. [PMID: 31773331 DOI: 10.1007/s00429-019-01987-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 11/14/2019] [Indexed: 12/11/2022]
Abstract
Τhe middle longitudinal fasciculus (MdLF) was initially identified in humans as a discrete subcortical pathway connecting the superior temporal gyrus (STG) to the angular gyrus (AG). Further anatomo-imaging studies, however, proposed more sophisticated but conflicting connectivity patterns and have created a vague perception on its functional anatomy. Our aim was, therefore, to investigate the ambiguous structural architecture of this tract through focused cadaveric dissections augmented by a tailored DTI protocol in healthy participants from the Human Connectome dataset. Three segments and connectivity patterns were consistently recorded: the MdLF-I, connecting the dorsolateral Temporal Pole (TP) and STG to the Superior Parietal Lobule/Precuneus, through the Heschl's gyrus; the MdLF-II, connecting the dorsolateral TP and the STG with the Parieto-occipital area through the posterior transverse gyri and the MdLF-III connecting the most anterior part of the TP to the posterior border of the occipital lobe through the AG. The lack of an established termination pattern to the AG and the fact that no significant leftward asymmetry is disclosed tend to shift the paradigm away from language function. Conversely, the theory of "where" and "what" auditory pathways, the essential relationship of the MdLF with the auditory cortex and the functional role of the cortical areas implicated in its connectivity tend to shift the paradigm towards auditory function. Allegedly, the MdLF-I and MdLF-II segments could underpin the perception of auditory representations; whereas, the MdLF-III could potentially subserve the integration of auditory and visual information.
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Affiliation(s)
- Aristotelis Kalyvas
- Athens Microneurosurgery Laboratory, Evangelismos Hospital, Athens, Greece.,Department of Neurosurgery, Evangelismos Hospital, National and Kapodistrian University of Athens, Athens, Greece.,Department of Anatomy, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Christos Koutsarnakis
- Athens Microneurosurgery Laboratory, Evangelismos Hospital, Athens, Greece. .,Department of Neurosurgery, Evangelismos Hospital, National and Kapodistrian University of Athens, Athens, Greece. .,Department of Anatomy, Medical School, National and Kapodistrian University of Athens, Athens, Greece.
| | - Spyridon Komaitis
- Athens Microneurosurgery Laboratory, Evangelismos Hospital, Athens, Greece.,Department of Neurosurgery, Evangelismos Hospital, National and Kapodistrian University of Athens, Athens, Greece.,Department of Anatomy, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Efstratios Karavasilis
- Second Department of Radiology, Attikon Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Foteini Christidi
- First Department of Neurology, Aeginition Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Georgios P Skandalakis
- Athens Microneurosurgery Laboratory, Evangelismos Hospital, Athens, Greece.,Department of Anatomy, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Evangelia Liouta
- Athens Microneurosurgery Laboratory, Evangelismos Hospital, Athens, Greece.,Hellenic Center for Neurosurgical Research, "PetrosKokkalis", Athens, Greece
| | - Olympia Papakonstantinou
- Second Department of Radiology, Attikon Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Nikolaos Kelekis
- Second Department of Radiology, Attikon Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Hugues Duffau
- Department of Neurosurgery, Montpellier University Medical Center, Gui de Chauliac Hospital, Montpellier, France
| | - George Stranjalis
- Athens Microneurosurgery Laboratory, Evangelismos Hospital, Athens, Greece.,Department of Neurosurgery, Evangelismos Hospital, National and Kapodistrian University of Athens, Athens, Greece.,Hellenic Center for Neurosurgical Research, "PetrosKokkalis", Athens, Greece
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12
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Bernal B, Guillen M, Korman B. Nontask-Related Brain Lateralization Biomarkers in Children: The Asymmetry of Language Areas on Functional Connectivity Functional Magnetic Resonance Imaging. Brain Connect 2019; 8:321-332. [PMID: 30124344 DOI: 10.1089/brain.2017.0553] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In this work, we will test the hypothesis that the connectivity of language areas in normal children is asymmetric between the hemispheres. Intrahemispheric region of interest (ROI)-to-ROI connectivity was assessed in 40 normal right-handed children. Asymmetries were assessed (1) between the hemispheres (global language connectivity); (2) between Brodmann areas (BAs) pairs (pairwise connectivity); and (3) between two homotopic BA (Global BA connectivity). Sixteen BAs were selected: 6, 7, 9, 19, 21, 22, 37, 38, 39, 40, 41, 42, 44, 45, 46, and 47. T scores for connectivity of each BA pair were ascertained using the MATLAB toolbox CONN. Lateralization index (LI) scores based on T-values were obtained. Only LIs with 2SD above the mean were considered as significant. Comparisons between T-value groups (per side and per BA) were performed utilizing double-sided T-tests. Null hypothesis was rejected for p < 0.05. There was not a statistical difference between global left and right connectivity strength (p = 0.40). There was significant pairwise connectivity asymmetry for the following pairs: BA7-BA44 (LI = 0.662); BA21-BA42 (LI = -0.616); BA21-BA40 (LI = -0.595); BA38-BA44 (LI = 0.470); BA39-BA44 (LI = -0.903); and BA42-BA47 (LI = -0.445). Language-related brain connectivity asymmetries have been demonstrated in a group of children and young adolescents. Two pairs related to Broca's area were left dominant (BA44-BA38 and BA44-BA7) and four pairs right dominant (BA42-BA47, BA39-BA44, BA21-BA40, and BA21-BA42).
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Affiliation(s)
- Byron Bernal
- 1 Brain Institute , Nicklaus Children's Hospital, Miami, Florida.,2 Department of Radiology, Florida International University , Miami, Florida.,3 Nicklaus Children's Hospital and Florida International University , Miami, Florida
| | - Magno Guillen
- 2 Department of Radiology, Florida International University , Miami, Florida.,3 Nicklaus Children's Hospital and Florida International University , Miami, Florida
| | - Brandon Korman
- 1 Brain Institute , Nicklaus Children's Hospital, Miami, Florida.,3 Nicklaus Children's Hospital and Florida International University , Miami, Florida
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13
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Bain JS, Yeatman JD, Schurr R, Rokem A, Mezer AA. Evaluating arcuate fasciculus laterality measurements across dataset and tractography pipelines. Hum Brain Mapp 2019; 40:3695-3711. [PMID: 31106944 DOI: 10.1002/hbm.24626] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 04/18/2019] [Accepted: 05/01/2019] [Indexed: 11/11/2022] Open
Abstract
The arcuate fasciculi are white-matter pathways that connect frontal and temporal lobes in each hemisphere. The arcuate plays a key role in the language network and is believed to be left-lateralized, in line with left hemisphere dominance for language. Measuring the arcuate in vivo requires diffusion magnetic resonance imaging-based tractography, but asymmetry of the in vivo arcuate is not always reliably detected in previous studies. It is unknown how the choice of tractography algorithm, with each method's freedoms, constraints, and vulnerabilities to false-positive and -negative errors, impacts findings of arcuate asymmetry. Here, we identify the arcuate in two independent datasets using a number of tractography strategies and methodological constraints, and assess their impact on estimates of arcuate laterality. We test three tractography methods: a deterministic, a probabilistic, and a tractography-evaluation (LiFE) algorithm. We extract the arcuate from the whole-brain tractogram, and compare it to an arcuate bundle constrained even further by selecting only those streamlines that connect to anatomically relevant cortical regions. We test arcuate macrostructure laterality, and also evaluate microstructure profiles for properties such as fractional anisotropy and quantitative R1. We find that both tractography choice and implementing the cortical constraints substantially impact estimates of all indices of arcuate laterality. Together, these results emphasize the effect of the tractography pipeline on estimates of arcuate laterality in both macrostructure and microstructure.
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Affiliation(s)
- Jonathan S Bain
- The Edmond & Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Jason D Yeatman
- Institute for Learning & Brain Sciences and Department of Speech and Hearing Science, The University of Washington, Seattle, Washington, USA
| | - Roey Schurr
- The Edmond & Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Ariel Rokem
- The University of Washington eScience Institute, The University of Washington, Seattle, Washington, USA
| | - Aviv A Mezer
- The Edmond & Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
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14
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Kuhn T, Gullett JM, Boutzoukas AE, Bohsali A, Mareci TH, FitzGerald DB, Carney PR, Bauer RM. Temporal lobe epilepsy affects spatial organization of entorhinal cortex connectivity. Epilepsy Behav 2018; 88:87-95. [PMID: 30243111 PMCID: PMC6294293 DOI: 10.1016/j.yebeh.2018.06.038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 06/18/2018] [Accepted: 06/20/2018] [Indexed: 12/15/2022]
Abstract
Evidence for structural connectivity patterns within the medial temporal lobe derives primarily from postmortem histological studies. In humans and nonhuman primates, the parahippocampal gyrus (PHg) is subdivided into parahippocampal (PHc) and perirhinal (PRc) cortices, which receive input from distinct cortical networks. Likewise, their efferent projections to the entorhinal cortex (ERc) are distinct. The PHc projects primarily to the medial ERc (M-ERc). The PRc projects primarily to the lateral portion of the ERc (L-ERc). Both M-ERc and L-ERc, via the perforant pathway, project to the dentate gyrus and hippocampal (HC) subfields. Until recently, these neural circuits could not be visualized in vivo. Diffusion tensor imaging algorithms have been developed to segment gray matter structures based on probabilistic connectivity patterns. However, these algorithms have not yet been applied to investigate connectivity in the temporal lobe or changes in connectivity architecture related to disease processes. In this study, this segmentation procedure was used to classify ERc gray matter based on PRc, ERc, and HC connectivity patterns in 7 patients with temporal lobe epilepsy (TLE) without hippocampal sclerosis (mean age, 14.86 ± 3.34 years) and 7 healthy controls (mean age, 23.86 ± 2.97 years). Within samples paired t-tests allowed for comparison of ERc connectivity between epileptogenic and contralateral hemispheres. In healthy controls, there were no significant within-group differences in surface area, volume, or cluster number of ERc connectivity-defined regions (CDR). Likewise, in line with histology results, ERc CDR in the control group were well-organized, uniform, and segregated via PRc/PHc afferent and HC efferent connections. Conversely, in TLE, there were significantly more PRc and HC CDR clusters in the epileptogenic than the contralateral hemisphere. The surface area of the PRc CDR was greater, and that of the HC CDRs was smaller, in the epileptogenic hemisphere as well. Further, there was no clear delineation between M-ERc and L-ERc connectivity with PRc, PHc or HC in TLE. These results suggest a breakdown of the spatial organization of PHg-ERc-HC connectivity in TLE. Whether this breakdown is the cause or result of epileptic activity remains an exciting research question.
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Affiliation(s)
- Taylor Kuhn
- Department of Clinical and Health Psychology, University of Florida, Gainesville, FL, United States of America; Department of Physical Therapy, University of Florida, Gainesville, FL, United States of America.
| | - Joseph M Gullett
- Department of Clinical and Health Psychology, University of Florida, Gainesville, FL, United States of America; Department of VA Brain Rehabilitation Research Center, Malcolm Randall VA Center Gainesville, FL, United States of America
| | - Angelique E Boutzoukas
- Department of Clinical and Health Psychology, University of Florida, Gainesville, FL, United States of America
| | - Anastasia Bohsali
- Department of Neurology, University of Florida, Gainesville, FL, United States of America
| | - Thomas H Mareci
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL, United States of America
| | - David B FitzGerald
- Department of VA Brain Rehabilitation Research Center, Malcolm Randall VA Center Gainesville, FL, United States of America
| | - Paul R Carney
- Department of Pediatrics, University of Florida, Gainesville, FL, United States of America; Department of Neurology, University of Florida, Gainesville, FL, United States of America; Department of Neuroscience, University of Florida, Gainesville, FL, United States of America; J. Crayton Pruitt Department of Biomedical Engineering, University of Florida, Gainesville, FL, United States of America; B.J. and Eve Wilder Epilepsy Center Excellence, University of Florida, Gainesville, FL, United States of America
| | - Russell M Bauer
- Department of Clinical and Health Psychology, University of Florida, Gainesville, FL, United States of America; Department of VA Brain Rehabilitation Research Center, Malcolm Randall VA Center Gainesville, FL, United States of America
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15
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Mürner-Lavanchy IM, Kelly CE, Reidy N, Doyle LW, Lee KJ, Inder T, Thompson DK, Morgan AT, Anderson PJ. White matter microstructure is associated with language in children born very preterm. Neuroimage Clin 2018; 20:808-822. [PMID: 30268990 PMCID: PMC6169247 DOI: 10.1016/j.nicl.2018.09.020] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2018] [Revised: 08/23/2018] [Accepted: 09/21/2018] [Indexed: 12/21/2022]
Abstract
Very preterm birth is associated with altered white matter microstructure and language difficulties, which may compromise communication, social function and academic achievement, but the relationship between these two factors is unclear. The aim of this study was to explore associations between white matter microstructure and language domains of semantics, grammar and phonological awareness at 7-years of age on a whole-brain level and within the arcuate fasciculus, an important language pathway, in very preterm and term-born children. Language was assessed in 145 very preterm-born (<30 weeks' gestation and/or <1250 g birth weight) and 33 term-born children aged 7 years. Fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD), mean diffusivity (MD), axon orientation dispersion and axon density were estimated from diffusion magnetic resonance images also obtained at 7 years. The correlation between diffusion values and language was assessed using Tract-Based Spatial Statistics (TBSS). The arcuate fasciculus was delineated using constrained spherical deconvolution tractography and diffusion parameters from this tract were related to language measures using linear regression. While there was evidence for widespread associations between white matter microstructure and language, there was little evidence of differences in these associations between very preterm and term-born groups. TBSS analyses revealed that higher FA and lower AD, RD, and MD in major fibre tracts, including those subserving language, were associated with better semantic, grammar and phonological awareness performance. Higher axon density in widespread fibre tracts was also associated with better semantic performance. The tractography analyses of the arcuate fasciculus showed some evidence for associations between white matter microstructure and language outcomes. White matter microstructural organisation in widespread fibre tracts, including language-relevant pathways, was associated with language performance in whole-brain and tract-based analyses. The associations were similar for very preterm and term-born groups, despite very preterm children performing more poorly across language domains.
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Affiliation(s)
- Ines M Mürner-Lavanchy
- Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Australia; Murdoch Children's Research Institute, Melbourne, Australia; University Hospital of Child and Adolescent Psychiatry and Psychotherapy, University of Bern, Bern, Switzerland..
| | - Claire E Kelly
- Murdoch Children's Research Institute, Melbourne, Australia
| | - Natalie Reidy
- Murdoch Children's Research Institute, Melbourne, Australia
| | - Lex W Doyle
- Murdoch Children's Research Institute, Melbourne, Australia; Department of Obstetrics and Gynaecology, University of Melbourne, Melbourne, Victoria, Australia; Department of Paediatrics, University of Melbourne, Melbourne, Australia; Research Office, The Royal Women's Hospital, Melbourne, Australia
| | - Katherine J Lee
- Murdoch Children's Research Institute, Melbourne, Australia; Department of Paediatrics, University of Melbourne, Melbourne, Australia
| | | | - Deanne K Thompson
- Murdoch Children's Research Institute, Melbourne, Australia; Florey Institute of Neuroscience and Mental Health, Melbourne, Australia; Department of Paediatrics, University of Melbourne, Melbourne, Australia
| | - Angela T Morgan
- Murdoch Children's Research Institute, Melbourne, Australia; Department of Paediatrics, University of Melbourne, Melbourne, Australia; Department of Audiology and Speech Pathology, University of Melbourne, Melbourne, Australia
| | - Peter J Anderson
- Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Australia; Murdoch Children's Research Institute, Melbourne, Australia.
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16
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Keller SS, Roberts N, Baker G, Sluming V, Cezayirli E, Mayes A, Eldridge P, Marson AG, Wieshmann UC. A voxel-based asymmetry study of the relationship between hemispheric asymmetry and language dominance in Wada tested patients. Hum Brain Mapp 2018; 39:3032-3045. [PMID: 29569808 PMCID: PMC6055618 DOI: 10.1002/hbm.24058] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 03/08/2018] [Accepted: 03/13/2018] [Indexed: 01/08/2023] Open
Abstract
Determining the anatomical basis of hemispheric language dominance (HLD) remains an important scientific endeavor. The Wada test remains the gold standard test for HLD and provides a unique opportunity to determine the relationship between HLD and hemispheric structural asymmetries on MRI. In this study, we applied a whole‐brain voxel‐based asymmetry (VBA) approach to determine the relationship between interhemispheric structural asymmetries and HLD in a large consecutive sample of Wada tested patients. Of 135 patients, 114 (84.4%) had left HLD, 10 (7.4%) right HLD, and 11 (8.2%) bilateral language representation. Fifty‐four controls were also studied. Right‐handed controls and right‐handed patients with left HLD had comparable structural brain asymmetries in cortical, subcortical, and cerebellar regions that have previously been documented in healthy people. However, these patients and controls differed in structural asymmetry of the mesial temporal lobe and a circumscribed region in the superior temporal gyrus, suggesting that only asymmetries of these regions were due to brain alterations caused by epilepsy. Additional comparisons between patients with left and right HLD, matched for type and location of epilepsy, revealed that structural asymmetries of insula, pars triangularis, inferior temporal gyrus, orbitofrontal cortex, ventral temporo‐occipital cortex, mesial somatosensory cortex, and mesial cerebellum were significantly associated with the side of HLD. Patients with right HLD and bilateral language representation were significantly less right‐handed. These results suggest that structural asymmetries of an insular‐fronto‐temporal network may be related to HLD.
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Affiliation(s)
- Simon S Keller
- Department of Molecular and Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom.,The Walton Centre NHS Foundation Trust, Liverpool, United Kingdom
| | - Neil Roberts
- Edinburgh Imaging, The Queens Medical Research Institute (QMRI), School of Clinical Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Gus Baker
- Department of Molecular and Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom.,The Walton Centre NHS Foundation Trust, Liverpool, United Kingdom
| | - Vanessa Sluming
- Department of Psychological Sciences, Institute of Psychology, Health and Society, University of Liverpool, Liverpool, United Kingdom
| | - Enis Cezayirli
- School of Medicine, University of St Andrews, Scotland, United Kingdom
| | - Andrew Mayes
- School of Psychological Sciences, University of Manchester, Manchester, United Kingdom
| | - Paul Eldridge
- The Walton Centre NHS Foundation Trust, Liverpool, United Kingdom
| | - Anthony G Marson
- Department of Molecular and Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom.,The Walton Centre NHS Foundation Trust, Liverpool, United Kingdom
| | - Udo C Wieshmann
- The Walton Centre NHS Foundation Trust, Liverpool, United Kingdom
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17
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Wilkinson M, Lim AR, Cohen AH, Galaburda AM, Takahashi E. Detection and Growth Pattern of Arcuate Fasciculus from Newborn to Adult. Front Neurosci 2017; 11:389. [PMID: 28769741 PMCID: PMC5509799 DOI: 10.3389/fnins.2017.00389] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2017] [Accepted: 06/21/2017] [Indexed: 11/13/2022] Open
Abstract
Fractional anisotropy (FA) threshold is commonly used to perform diffusion MRI tractography. However, FA threshold may be one aspect of tractography that needs additional scrutiny in accurately assessing pathways in immature, developing brains, as well as in adult brains. Using high-angular resolution diffusion MRI (HARDI) tractography without an FA threshold, we identified the arcuate fasciculus (AF) of 83 healthy subjects ranging in age from 40 gestational weeks (GW) (newborns) to 28-year-old adults. The AF was identified in both hemispheres in all subjects with high inter-rater reliability. The detected AF included regions with very low FA values. The entire AF was segmented into anterior, posterior, and long tracts. Growth and laterality patterns were investigated using tract count (number of detected streamlines), total volume of imaging voxels (touched by the detected streamlines), mean length, mean FA, and mean apparent diffusion coefficient (ADC). Comparison of subjects under 3 years old, to those that were older, revealed the three AF tracts that took different developmental courses. As expected, the anterior and long tracts showed lower ADC values in subjects over 3 years old, while the posterior tract showed higher ADC in that same age range. The posterior tract did not show age-related effect in terms of FA, tract count, length, and volume. These results suggest that the posterior AF tract shows a matured state, indexed by most of the used measurements in early postnatal developmental ages, and ADC is a measurement that can detect further maturation of the posterior tract. Interestingly, in all tracts, hemispheric asymmetries were found in raw (left<right), and in whole brain (WB)-normalized (left>right) tract count, as well as in raw volume (left<right). In raw, and in WB-normalized length, as well as in WB-normalized volume, rightward asymmetry (left<right) was found only in the anterior tract; other tracts were not significantly affected by hemisphere. Although many previous studies have observed a leftward asymmetry in the AF, rightward asymmetry has also been reported in other studies, and together with the present report, the results in the literature are likely to reflect differences in the methods used.
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Affiliation(s)
- Molly Wilkinson
- Department of Behavioral Neuroscience, Northeastern UniversityBoston, MA, United States.,Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital, Harvard Medical SchoolBoston, MA, United States
| | - Ashley R Lim
- Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital, Harvard Medical SchoolBoston, MA, United States.,Department of Psychology, Northeastern UniversityBoston, MA, United States
| | - Andrew H Cohen
- Department of Behavioral Neuroscience, Northeastern UniversityBoston, MA, United States.,Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital, Harvard Medical SchoolBoston, MA, United States
| | - Albert M Galaburda
- Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical SchoolBoston, MA, United States
| | - Emi Takahashi
- Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital, Harvard Medical SchoolBoston, MA, United States
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18
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Yamao Y, Suzuki K, Kunieda T, Matsumoto R, Arakawa Y, Nakae T, Nishida S, Inano R, Shibata S, Shimotake A, Kikuchi T, Sawamoto N, Mikuni N, Ikeda A, Fukuyama H, Miyamoto S. Clinical impact of intraoperative CCEP monitoring in evaluating the dorsal language white matter pathway. Hum Brain Mapp 2017; 38:1977-1991. [PMID: 28112455 DOI: 10.1002/hbm.23498] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 12/07/2016] [Indexed: 11/09/2022] Open
Abstract
In order to preserve postoperative language function, we recently proposed a new intraoperative method to monitor the integrity of the dorsal language pathway (arcuate fasciculus; AF) using cortico-cortical evoked potentials (CCEPs). Based on further investigations (20 patients, 21 CCEP investigations), including patients who were not suitable for awake surgery (five CCEP investigations) or those without preoperative neuroimaging data (eight CCEP investigations including four with untraceable tractography due to brain edema), we attempted to clarify the clinical impact of this new intraoperative method. We monitored the integrity of AF by stimulating the anterior perisylvian language area (AL) by recording CCEPs from the posterior perisylvian language area (PL) consecutively during both general anesthesia and awake condition. After tumor resection, single-pulse electrical stimuli were also applied to the floor of the removal cavity to record subcortico-cortical evoked potentials (SCEPs) at AL and PL in 12 patients (12 SCEP investigations). We demonstrated that (1) intraoperative dorsal language network monitoring was feasible even when patients were not suitable for awake surgery or without preoperative neuroimaging studies, (2) CCEP is a dynamic marker of functional connectivity or integrity of AF, and CCEP N1 amplitude could even become larger after reduction of brain edema, (3) a 50% CCEP N1 amplitude decline might be a cut-off value to prevent permanent language dysfunction due to impairment of AF, (4) a correspondence (<2.0 ms difference) of N1 onset latencies between CCEP and the sum of SCEPs indicates close proximity of the subcortical stimulus site to AF (<3.0 mm). Hum Brain Mapp 38:1977-1991, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Yukihiro Yamao
- Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Kengo Suzuki
- Department of Neurosurgery, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Takeharu Kunieda
- Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto, Japan.,Department of Neurosurgery, Ehime University Graduate School of Medicine, Toon, Ehime, Japan
| | - Riki Matsumoto
- Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Yoshiki Arakawa
- Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Takuro Nakae
- Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Sei Nishida
- Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Rika Inano
- Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Sumiya Shibata
- Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Akihiro Shimotake
- Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Takayuki Kikuchi
- Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Nobukatsu Sawamoto
- Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan.,Department of Human Health Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Nobuhiro Mikuni
- Department of Neurosurgery, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Akio Ikeda
- Department of Epilepsy, Movement Disorders and Physiology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Hidenao Fukuyama
- Human Brain Research Center, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Susumu Miyamoto
- Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto, Japan
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Cichocka M, Kozub J, Karcz P, Urbanik A. Differences in Metabolite Concentrations Between the Hemispheres of the Brain in Healthy Children: A Proton Magnetic Resonance Spectroscopy Study (1HMRS). J Child Neurol 2016; 31:1296-301. [PMID: 27364739 DOI: 10.1177/0883073816653784] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 05/09/2016] [Indexed: 12/11/2022]
Abstract
The aim of this (1)HMRS study was to identify hemispheric asymmetries in metabolismus in healthy children. The study group consisted of children of both sexes aged 6 to 15. Concentrations of 6 metabolites occurring in the brain were determined for 6 locations: hippocampus, frontal lobe, and basal ganglia in the left and right hemispheres. There were no hemispheric differences in the metabolites' concentrations in the brain in children when the variable of sex was disregarded. Only in the group of boys and in the group of girls did the findings show few discrepancies. In none of these groups, relative concentrations to creatine concentration were found to be significantly different between hemispheres. In clinical practice, concentrations of specific metabolites are most frequently determined relative to the concentration of creatine. Consequently, the analysis of standard (1)HMRS examinations in children does not need to take into account interhemispheric differences.
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Affiliation(s)
- Monika Cichocka
- Department of Radiology, Collegium Medicum, Jagiellonian University, Krakow, Poland
| | - Justyna Kozub
- Department of Radiology, Collegium Medicum, Jagiellonian University, Krakow, Poland
| | - Paulina Karcz
- Department of Electroradiology, Collegium Medicum, Jagiellonian University, Krakow, Poland
| | - Andrzej Urbanik
- Department of Radiology, Collegium Medicum, Jagiellonian University, Krakow, Poland
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Nowell M, Vos SB, Sidhu M, Wilcoxen K, Sargsyan N, Ourselin S, Duncan JS. Meyer's loop asymmetry and language lateralisation in epilepsy. J Neurol Neurosurg Psychiatry 2016; 87:836-42. [PMID: 26384513 PMCID: PMC4975828 DOI: 10.1136/jnnp-2015-311161] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 09/01/2015] [Indexed: 01/03/2023]
Abstract
OBJECTIVES Several studies have suggested an asymmetry in Meyer's loop in individuals, with the left loop anterior to the right. In this study we test the hypothesis that there is an association between Meyer's loop asymmetry (MLA) and language lateralisation. METHODS 57 patients with epilepsy were identified with language functional MRI (fMRI) and diffusion MRI acquisition. Language lateralisation indices from fMRI(LI) and optic radiation and arcuate fasciculus probabilistic tractography was performed for each subject. The subjects were divided into left language dominant (LI>0.4) and non-left language groups (LI<0.4) according to their LI. RESULTS A negative linear correlation was identified between language lateralisation and MLA, with greater left lateralised language associated with more anteriorly placed left Meyer's loops (R value -0.34, p=0.01). There was a significant difference in mean MLA between the two groups, with the left loop being anterior to the right loop in the LI>0.4 group and posterior to the right loop in the LI<0.4 group (p=0.003). No correlation was found between language lateralisation and arcuate fasciculus volume. CONCLUSIONS This study suggests an association between the extent of Meyer's loop asymmetry and the lateralisation of language determined by fMRI in patients with epilepsy. Further studies should be carried out to evaluate this association in control subjects and with other measures of language lateralisation.
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Affiliation(s)
- Mark Nowell
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK MRI Unit, Epilepsy Society, Chalfont St Peter, UK
| | - Sjoerd B Vos
- MRI Unit, Epilepsy Society, Chalfont St Peter, UK Translational Imaging Group, Centre of Medical Imaging and Computing, UCL, London, UK
| | - Meneka Sidhu
- MRI Unit, Epilepsy Society, Chalfont St Peter, UK
| | | | | | - Sebastien Ourselin
- Translational Imaging Group, Centre of Medical Imaging and Computing, UCL, London, UK
| | - John S Duncan
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK MRI Unit, Epilepsy Society, Chalfont St Peter, UK
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21
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Ocklenburg S, Friedrich P, Güntürkün O, Genç E. Intrahemispheric white matter asymmetries: the missing link between brain structure and functional lateralization? Rev Neurosci 2016; 27:465-80. [DOI: 10.1515/revneuro-2015-0052] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 11/29/2015] [Indexed: 01/01/2023]
Abstract
AbstractHemispheric asymmetries are a central principle of nervous system architecture and shape the functional organization of most cognitive systems. Structural gray matter asymmetries and callosal interactions have been identified as contributing neural factors but always fell short to constitute a full explanans. Meanwhile, recent advances in in vivo white matter tractography have unrevealed the asymmetrical organization of many intrahemispheric white matter pathways, which might serve as the missing link to explain the substrate of functional lateralization. By taking into account callosal interactions, gray matter asymmetries and asymmetrical interhemispheric pathways, we opt for a new triadic model that has the potential to explain many observations which cannot be elucidated within the current frameworks of lateralized cognition.
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Affiliation(s)
- Sebastian Ocklenburg
- 1Institute of Cognitive Neuroscience, Biopsychology, Department of Psychology, Ruhr University of Bochum, D-44780 Bochum, Germany
| | - Patrick Friedrich
- 1Institute of Cognitive Neuroscience, Biopsychology, Department of Psychology, Ruhr University of Bochum, D-44780 Bochum, Germany
| | - Onur Güntürkün
- 1Institute of Cognitive Neuroscience, Biopsychology, Department of Psychology, Ruhr University of Bochum, D-44780 Bochum, Germany
| | - Erhan Genç
- 1Institute of Cognitive Neuroscience, Biopsychology, Department of Psychology, Ruhr University of Bochum, D-44780 Bochum, Germany
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22
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Chen Z, Tie Y, Olubiyi O, Rigolo L, Mehrtash A, Norton I, Pasternak O, Rathi Y, Golby AJ, O'Donnell LJ. Reconstruction of the arcuate fasciculus for surgical planning in the setting of peritumoral edema using two-tensor unscented Kalman filter tractography. NEUROIMAGE-CLINICAL 2015; 7:815-22. [PMID: 26082890 PMCID: PMC4459040 DOI: 10.1016/j.nicl.2015.03.009] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 02/19/2015] [Accepted: 03/13/2015] [Indexed: 11/19/2022]
Abstract
Background Diffusion imaging tractography is increasingly used to trace critical fiber tracts in brain tumor patients to reduce the risk of post-operative neurological deficit. However, the effects of peritumoral edema pose a challenge to conventional tractography using the standard diffusion tensor model. The aim of this study was to present a novel technique using a two-tensor unscented Kalman filter (UKF) algorithm to track the arcuate fasciculus (AF) in brain tumor patients with peritumoral edema. Methods Ten right-handed patients with left-sided brain tumors in the vicinity of language-related cortex and evidence of significant peritumoral edema were retrospectively selected for the study. All patients underwent 3-Tesla magnetic resonance imaging (MRI) including a diffusion-weighted dataset with 31 directions. Fiber tractography was performed using both single-tensor streamline and two-tensor UKF tractography. A two-regions-of-interest approach was applied to perform the delineation of the AF. Results from the two different tractography algorithms were compared visually and quantitatively. Results Using single-tensor streamline tractography, the AF appeared disrupted in four patients and contained few fibers in the remaining six patients. Two-tensor UKF tractography delineated an AF that traversed edematous brain areas in all patients. The volume of the AF was significantly larger on two-tensor UKF than on single-tensor streamline tractography (p < 0.01). Conclusions Two-tensor UKF tractography provides the ability to trace a larger volume AF than single-tensor streamline tractography in the setting of peritumoral edema in brain tumor patients. We compared two tractography methods in datasets from 10 brain tumor patients. All patients had peritumoral edema affecting the arcuate fasciculus (AF), a fiber tract related to language function. AF volume from unscented Kalman filter (UKF) two-tensor tractography was larger than in standard DTI tractography. Two-tensor UKF tractography may trace the AF more completely in patients with peritumoral edema.
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Affiliation(s)
- Zhenrui Chen
- Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
- Department of Neurosurgery, Jinling Hospital, Southern Medical University, Nanjing, Jiangsu 210002, China
| | - Yanmei Tie
- Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Olutayo Olubiyi
- Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Laura Rigolo
- Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Alireza Mehrtash
- Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Isaiah Norton
- Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Ofer Pasternak
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
- Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Yogesh Rathi
- Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Alexandra J. Golby
- Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
- Correspondence to: A. Golby, Department of Neurosurgery, Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, USA. Tel.: +1 617 525 7373; fax: +1 617 713 3050.
| | - Lauren J. O'Donnell
- Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
- Correspondence to: L. O'Donnell, 1249 Boylston St., Room #210, Boston, MA 02215, USA. Tel.: +1 617 525 6074.
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Chen JL, Kumar S, Williamson VJ, Scholz J, Griffiths TD, Stewart L. Detection of the arcuate fasciculus in congenital amusia depends on the tractography algorithm. Front Psychol 2015; 6:9. [PMID: 25653637 PMCID: PMC4300860 DOI: 10.3389/fpsyg.2015.00009] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 01/05/2015] [Indexed: 12/30/2022] Open
Abstract
The advent of diffusion magnetic resonance imaging (MRI) allows researchers to virtually dissect white matter fiber pathways in the brain in vivo. This, for example, allows us to characterize and quantify how fiber tracts differ across populations in health and disease, and change as a function of training. Based on diffusion MRI, prior literature reports the absence of the arcuate fasciculus (AF) in some control individuals and as well in those with congenital amusia. The complete absence of such a major anatomical tract is surprising given the subtle impairments that characterize amusia. Thus, we hypothesize that failure to detect the AF in this population may relate to the tracking algorithm used, and is not necessarily reflective of their phenotype. Diffusion data in control and amusic individuals were analyzed using three different tracking algorithms: deterministic and probabilistic, the latter either modeling two or one fiber populations. Across the three algorithms, we replicate prior findings of a left greater than right AF volume, but do not find group differences or an interaction. We detect the AF in all individuals using the probabilistic 2-fiber model, however, tracking failed in some control and amusic individuals when deterministic tractography was applied. These findings show that the ability to detect the AF in our sample is dependent on the type of tractography algorithm. This raises the question of whether failure to detect the AF in prior studies may be unrelated to the underlying anatomy or phenotype.
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Affiliation(s)
- Joyce L Chen
- Department of Physical Therapy and Graduate Department of Rehabilitation Sciences, Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute, University of Toronto Toronto, ON, Canada
| | - Sukhbinder Kumar
- Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London London, UK ; Institute of Neuroscience, University of Newcastle Upon Tyne Newcastle Upon Tyne, UK
| | | | - Jan Scholz
- Mouse Imaging Centre, The Hospital for Sick Children Toronto, ON, Canada
| | - Timothy D Griffiths
- Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London London, UK ; Institute of Neuroscience, University of Newcastle Upon Tyne Newcastle Upon Tyne, UK
| | - Lauren Stewart
- Department of Psychology, Goldsmiths, University of London London, UK
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Patterson DK, Van Petten C, Beeson PM, Rapcsak SZ, Plante E. Bidirectional iterative parcellation of diffusion weighted imaging data: separating cortical regions connected by the arcuate fasciculus and extreme capsule. Neuroimage 2014; 102 Pt 2:704-16. [PMID: 25173414 DOI: 10.1016/j.neuroimage.2014.08.032] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Revised: 07/01/2014] [Accepted: 08/20/2014] [Indexed: 10/24/2022] Open
Abstract
This paper introduces a Bidirectional Iterative Parcellation (BIP) procedure designed to identify the location and size of connected cortical regions (parcellations) at both ends of a white matter tract in diffusion weighted images. The procedure applies the FSL option "probabilistic tracking with classification targets" in a bidirectional and iterative manner. To assess the utility of BIP, we applied the procedure to the problem of parcellating a limited set of well-established gray matter seed regions associated with the dorsal (arcuate fasciculus/superior longitudinal fasciculus) and ventral (extreme capsule fiber system) white matter tracts in the language networks of 97 participants. These left hemisphere seed regions and the two white matter tracts, along with their right hemisphere homologues, provided an excellent test case for BIP because the resulting parcellations overlap and their connectivity via the arcuate fasciculi and extreme capsule fiber systems are well studied. The procedure yielded both confirmatory and novel findings. Specifically, BIP confirmed that each tract connects within the seed regions in unique, but expected ways. Novel findings included increasingly left-lateralized parcellations associated with the arcuate fasciculus/superior longitudinal fasciculus as a function of age and education. These results demonstrate that BIP is an easily implemented technique that successfully confirmed cortical connectivity patterns predicted in the literature, and has the potential to provide new insights regarding the architecture of the brain.
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Affiliation(s)
- Dianne K Patterson
- The University of Arizona, Department of Speech, Language, and Hearing Sciences, Tucson, AZ, USA.
| | - Cyma Van Petten
- Binghamton University, Department of Psychology, Binghamton, NY, USA
| | - Pélagie M Beeson
- The University of Arizona, Department of Speech, Language, and Hearing Sciences, Tucson, AZ, USA; The University of Arizona, Department of Neurology, Tucson, AZ, USA
| | - Steven Z Rapcsak
- The University of Arizona, Department of Neurology, Tucson, AZ, USA
| | - Elena Plante
- The University of Arizona, Department of Speech, Language, and Hearing Sciences, Tucson, AZ, USA
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25
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Forkel SJ, Thiebaut de Schotten M, Dell'Acqua F, Kalra L, Murphy DGM, Williams SCR, Catani M. Anatomical predictors of aphasia recovery: a tractography study of bilateral perisylvian language networks. ACTA ACUST UNITED AC 2014; 137:2027-39. [PMID: 24951631 DOI: 10.1093/brain/awu113] [Citation(s) in RCA: 192] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Stroke-induced aphasia is associated with adverse effects on quality of life and the ability to return to work. For patients and clinicians the possibility of relying on valid predictors of recovery is an important asset in the clinical management of stroke-related impairment. Age, level of education, type and severity of initial symptoms are established predictors of recovery. However, anatomical predictors are still poorly understood. In this prospective longitudinal study, we intended to assess anatomical predictors of recovery derived from diffusion tractography of the perisylvian language networks. Our study focused on the arcuate fasciculus, a language pathway composed of three segments connecting Wernicke's to Broca's region (i.e. long segment), Wernicke's to Geschwind's region (i.e. posterior segment) and Broca's to Geschwind's region (i.e. anterior segment). In our study we were particularly interested in understanding how lateralization of the arcuate fasciculus impacts on severity of symptoms and their recovery. Sixteen patients (10 males; mean age 60 ± 17 years, range 28-87 years) underwent post stroke language assessment with the Revised Western Aphasia Battery and neuroimaging scanning within a fortnight from symptoms onset. Language assessment was repeated at 6 months. Backward elimination analysis identified a subset of predictor variables (age, sex, lesion size) to be introduced to further regression analyses. A hierarchical regression was conducted with the longitudinal aphasia severity as the dependent variable. The first model included the subset of variables as previously defined. The second model additionally introduced the left and right arcuate fasciculus (separate analysis for each segment). Lesion size was identified as the only independent predictor of longitudinal aphasia severity in the left hemisphere [beta = -0.630, t(-3.129), P = 0.011]. For the right hemisphere, age [beta = -0.678, t(-3.087), P = 0.010] and volume of the long segment of the arcuate fasciculus [beta = 0.730, t(2.732), P = 0.020] were predictors of longitudinal aphasia severity. Adding the volume of the right long segment to the first-level model increased the overall predictive power of the model from 28% to 57% [F(1,11) = 7.46, P = 0.02]. These findings suggest that different predictors of recovery are at play in the left and right hemisphere. The right hemisphere language network seems to be important in aphasia recovery after left hemispheric stroke.
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Affiliation(s)
- Stephanie J Forkel
- 1 Research Department of Clinical, Educational, and Health Psychology (RDCEHP), Division of Psychology and Language Sciences, Faculty of Brain Sciences, University College London, UK2 Natbrainlab, Department of Neuroimaging, Institute of Psychiatry, King's College London, UK
| | - Michel Thiebaut de Schotten
- 3 Natbrainlab, Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, King's College London, London, UK4 Inserm U1127; UPMC-Paris6, UMR_S 1127; CNRS UMR 7225, Centre de Recherche de l'Institut du Cerveau et de la Moelle épinière, Groupe Hospitalier Pitié-Salpêtrière, 75013 Paris, France
| | - Flavio Dell'Acqua
- 2 Natbrainlab, Department of Neuroimaging, Institute of Psychiatry, King's College London, UK5 NIHR Biomedical Research Centre for Mental Health at South London and Maudsley NHS Foundation Trust and King's College London, London, UK
| | - Lalit Kalra
- 6 Department of Clinical Neuroscience, Institute of Psychiatry, King's College London, London, UK
| | - Declan G M Murphy
- 7 Sackler Institute for Translational Neurodevelopment and Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, King's College London, UK
| | - Steven C R Williams
- 2 Natbrainlab, Department of Neuroimaging, Institute of Psychiatry, King's College London, UK5 NIHR Biomedical Research Centre for Mental Health at South London and Maudsley NHS Foundation Trust and King's College London, London, UK
| | - Marco Catani
- 3 Natbrainlab, Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, King's College London, London, UK
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Altered microstructural connectivity of the superior cerebellar peduncle is related to motor dysfunction in children with autistic spectrum disorders. THE CEREBELLUM 2014; 12:645-56. [PMID: 23564050 DOI: 10.1007/s12311-013-0475-x] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Many studies have reported motor impairments in autistic spectrum disorders (ASD). However, the brain mechanism underlying motor impairment in ASD remains unclear. Recent neuroimaging studies have suggested that underconnectivity between the cerebellum and other brain regions contributes to the features of ASD. In this study, we investigated the microstructural integrity of the cerebellar pathways, including the superior, middle, and inferior cerebellar peduncles, of children with and without ASD by using diffusion tensor imaging (DTI) tractography to determine whether the microstructural integrity of the cerebellar pathways is related to motor function in children with ASD. Thirteen children with ASD and 11 age-, gender-, handedness-, and IQ-matched typically developing (TD) controls were enrolled in this study. DTI outcome measurements, such as fractional anisotropy (FA), axial diffusivity (AD), and radial diffusivity (RD), for the cerebellar pathways were calculated. The Movement Assessment Battery for Children 2 (M-ABC 2) was used for assessing motor functions. There were no significant differences between the two groups in RD. However, compared to the TD subjects, patients with ASD had a significantly lower FA in the right superior cerebellar peduncle and lower AD in the left superior cerebellar peduncle, in addition to a significantly lower score in ball skills and the total test score of M-ABC 2. There was a significant positive correlation between the total test score of M-ABC 2 and FA in the right superior cerebellar peduncle in the ASD group. These findings suggest that the altered microstructural integrity of the superior cerebellar peduncle may be related to motor impairment in ASD.
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27
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Yamao Y, Matsumoto R, Kunieda T, Arakawa Y, Kobayashi K, Usami K, Shibata S, Kikuchi T, Sawamoto N, Mikuni N, Ikeda A, Fukuyama H, Miyamoto S. Intraoperative dorsal language network mapping by using single-pulse electrical stimulation. Hum Brain Mapp 2014; 35:4345-61. [PMID: 24615889 DOI: 10.1002/hbm.22479] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 11/27/2013] [Accepted: 01/21/2014] [Indexed: 11/09/2022] Open
Abstract
The preservation of language function during brain surgery still poses a challenge. No intraoperative methods have been established to monitor the language network reliably. We aimed to establish intraoperative language network monitoring by means of cortico-cortical evoked potentials (CCEPs). Subjects were six patients with tumors located close to the arcuate fasciculus (AF) in the language-dominant left hemisphere. Under general anesthesia, the anterior perisylvian language area (AL) was first defined by the CCEP connectivity patterns between the ventrolateral frontal and temporoparietal area, and also by presurgical neuroimaging findings. We then monitored the integrity of the language network by stimulating AL and by recording CCEPs from the posterior perisylvian language area (PL) consecutively during both general anesthesia and awake condition. High-frequency electrical stimulation (ES) performed during awake craniotomy confirmed language function at AL in all six patients. Despite an amplitude decline (≤32%) in two patients, CCEP monitoring successfully prevented persistent language impairment. After tumor removal, single-pulse ES was applied to the white matter tract beneath the floor of the removal cavity in five patients, in order to trace its connections into the language cortices. In three patients in whom high-frequency ES of the white matter produced naming impairment, this "eloquent" subcortical site directly connected AL and PL, judging from the latencies and distributions of cortico- and subcortico-cortical evoked potentials. In conclusion, this study provided the direct evidence that AL, PL, and AF constitute the dorsal language network. Intraoperative CCEP monitoring is clinically useful for evaluating the integrity of the language network.
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Affiliation(s)
- Yukihiro Yamao
- Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto, Japan
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Axer H, Klingner CM, Prescher A. Fiber anatomy of dorsal and ventral language streams. BRAIN AND LANGUAGE 2013; 127:192-204. [PMID: 22632814 DOI: 10.1016/j.bandl.2012.04.015] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2012] [Revised: 04/05/2012] [Accepted: 04/23/2012] [Indexed: 06/01/2023]
Abstract
Recent advances in neuroimaging have led to new insights into the organization of language related networks. Increasing evidence supports the model of dorsal and ventral streams of information flow between language-related areas. Therefore, a review of the descriptions of language-related fiber anatomy in the human and monkey brain was performed. In addition, case studies of macroscopical fiber dissection and polarized light imaging (PLI) with special focus on the ventral stream were done. Several fiber structures can be identified to play a role in language, i.e. the arcuate fasciculus as a part of the superior longitudinal fasciculus, the middle longitudinal fasciculus, the inferior fronto-occipital fasciculus, and extreme and external capsules. Substantial differences between human and monkey fiber architecture have been identified. Despite inconsistencies based on different terminologies used, there can be no doubt that dorsal and ventral language streams have a clear correlation in the structure of white matter tracts.
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Affiliation(s)
- Hubertus Axer
- Hans Berger Department of Neurology, Jena University Hospital, Jena, Germany.
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29
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De-Torres I, Dávila G, Berthier ML, Walsh SF, Moreno-Torres I, Ruiz-Cruces R. Repeating with the right hemisphere: reduced interactions between phonological and lexical-semantic systems in crossed aphasia? Front Hum Neurosci 2013; 7:675. [PMID: 24151460 PMCID: PMC3798981 DOI: 10.3389/fnhum.2013.00675] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Accepted: 09/26/2013] [Indexed: 11/13/2022] Open
Abstract
Knowledge on the patterns of repetition amongst individuals who develop language deficits in association with right hemisphere lesions (crossed aphasia) is very limited. Available data indicate that repetition in some crossed aphasics experiencing phonological processing deficits is not heavily influenced by lexical-semantic variables (lexicality, imageability, and frequency) as is regularly reported in phonologically-impaired cases with left hemisphere damage. Moreover, in view of the fact that crossed aphasia is rare, information on the role of right cortical areas and white matter tracts underpinning language repetition deficits is scarce. In this study, repetition performance was assessed in two patients with crossed conduction aphasia and striatal/capsular vascular lesions encompassing the right arcuate fasciculus (AF) and inferior frontal-occipital fasciculus (IFOF), the temporal stem and the white matter underneath the supramarginal gyrus. Both patients showed lexicality effects repeating better words than non-words, but manipulation of other lexical-semantic variables exerted less influence on repetition performance. Imageability and frequency effects, production of meaning-based paraphrases during sentence repetition, or better performance on repeating novel sentences than overlearned clichés were hardly ever observed in these two patients. In one patient, diffusion tensor imaging disclosed damage to the right long direct segment of the AF and IFOF with relative sparing of the anterior indirect and posterior segments of the AF, together with fully developed left perisylvian white matter pathways. These findings suggest that striatal/capsular lesions extending into the right AF and IFOF in some individuals with right hemisphere language dominance are associated with atypical repetition patterns which might reflect reduced interactions between phonological and lexical-semantic processes.
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Affiliation(s)
- Irene De-Torres
- Unit of Cognitive Neurology and Aphasia, Centro de Investigaciones, Médico-Sanitarias, University of MálagaMalaga, Spain
- Unit of Physical Medicine and Rehabilitation, Carlos Haya University HospitalMalaga, Spain
| | - Guadalupe Dávila
- Unit of Cognitive Neurology and Aphasia, Centro de Investigaciones, Médico-Sanitarias, University of MálagaMalaga, Spain
- Psychobiology Area, Faculty of Psychology, University of MálagaMalaga, Spain
| | - Marcelo L. Berthier
- Unit of Cognitive Neurology and Aphasia, Centro de Investigaciones, Médico-Sanitarias, University of MálagaMalaga, Spain
| | - Seán Froudist Walsh
- Unit of Cognitive Neurology and Aphasia, Centro de Investigaciones, Médico-Sanitarias, University of MálagaMalaga, Spain
- Department of Psychosis Studies, Institute of Psychiatry, King's Health PartnersKing's College London, UK
| | | | - Rafael Ruiz-Cruces
- Unit of Cognitive Neurology and Aphasia, Centro de Investigaciones, Médico-Sanitarias, University of MálagaMalaga, Spain
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Vandermosten M, Poelmans H, Sunaert S, Ghesquière P, Wouters J. White matter lateralization and interhemispheric coherence to auditory modulations in normal reading and dyslexic adults. Neuropsychologia 2013; 51:2087-99. [PMID: 23872049 DOI: 10.1016/j.neuropsychologia.2013.07.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2012] [Revised: 07/04/2013] [Accepted: 07/10/2013] [Indexed: 10/26/2022]
Abstract
Neural activation of slow acoustic variations that are important for syllable identification is more lateralized to the right hemisphere than activation of fast acoustic changes that are important for phoneme identification. It has been suggested that this complementary function at different hemispheres is rooted in a different degree of white matter myelination in the left versus right hemisphere. The present study will investigate this structure-function relationship with Diffusion Tensor Imaging (DTI) and Auditory Steady-State Responses (ASSR), respectively. With DTI we examined white matter lateralization in the cortical auditory and language regions (i.e. posterior region of the superior temporal gyrus and the arcuate fasciculus) and white matter integrity in the splenium of the corpus callosum. With ASSR we examined interhemispheric coherence to slow, syllabic-rate (i.e. 4 Hz) and fast, phonemic-rate (i.e. 20 Hz) modulations. These structural and functional techniques were applied in a group of normal reading adults and a group of dyslexic adults for whom previously reduced functional interhemispheric connectivity at 20 Hz has been reported (Poelmans et al. (2012). Ear and Hearing, 33, 134-143). This sample was chosen since it is hypothesized that in dyslexic readers insufficient hemispheric asymmetry in myelination might relate to their auditory and phonological problems. Results demonstrate reduced white matter lateralization in the posterior superior temporal gyrus and the arcuate fasciculus in the dyslexic readers. Additionally, white matter lateralization in the posterior superior temporal gyrus and white matter integrity in the splenium of the corpus callosum related to interhemispheric coherence to phonemic-rate modulations (i.e. 20 Hz). Interestingly, this correlation pattern was opposite in normal versus dyslexic readers. These results might imply that less pronounced left white matter dominance in dyslexic adults might relate to their problems to process phonemic-rate acoustic information and to integrate them into the phonological system.
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Affiliation(s)
- Maaike Vandermosten
- ExpORL, Department of Neurosciences, KU Leuven, Herestraat 49, 3000 Leuven, Belgium; Parenting and Special Education Research Unit, KU Leuven, Leopold Vanderkelenstraat 32, PO Box 3765, 3000 Leuven, Belgium; Radiology Section, KU Leuven, Herestraat 49, 3000 Leuven, Belgium.
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Kundu B, Penwarden A, Wood JM, Gallagher TA, Andreoli MJ, Voss J, Meier T, Nair VA, Kuo JS, Field AS, Moritz C, Meyerand ME, Prabhakaran V. Association of functional magnetic resonance imaging indices with postoperative language outcomes in patients with primary brain tumors. Neurosurg Focus 2013; 34:E6. [PMID: 23544412 PMCID: PMC3954579 DOI: 10.3171/2013.2.focus12413] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT Functional MRI (fMRI) has the potential to be a useful presurgical planning tool to treat patients with primary brain tumor. In this study the authors retrospectively explored relationships between language-related postoperative outcomes in such patients and multiple factors, including measures estimated from task fMRI maps (proximity of lesion to functional activation area, or lesion-to-activation distance [LAD], and activation-based language lateralization, or lateralization index [LI]) used in the clinical setting for presurgical planning, as well as other factors such as patient age, patient sex, tumor grade, and tumor volume. METHODS Patient information was drawn from a database of patients with brain tumors who had undergone preoperative fMRI-based language mapping of the Broca and Wernicke areas. Patients had performed a battery of tasks, including word-generation tasks and a text-versus-symbols reading task, as part of a clinical fMRI protocol. Individually thresholded task fMRI activation maps had been provided for use in the clinical setting. These clinical imaging maps were used to retrospectively estimate LAD and LI for the Broca and Wernicke areas. RESULTS There was a relationship between postoperative language deficits and the proximity between tumor and Broca area activation (the LAD estimate), where shorter LADs were related to the presence of postoperative aphasia. Stratification by tumor location further showed that for posterior tumors within the temporal and parietal lobes, more bilaterally oriented Broca area activation (LI estimate close to 0) and a shorter Wernicke area LAD were associated with increased postoperative aphasia. Furthermore, decreasing LAD was related to decreasing LI for both Broca and Wernicke areas. Preoperative deficits were related to increasing patient age and a shorter Wernicke area LAD. CONCLUSIONS Overall, LAD and LI, as determined using fMRI in the context of these paradigms, may be useful indicators of postsurgical outcomes. Whereas tumor location may influence postoperative deficits, the results indicated that tumor proximity to an activation area might also interact with how the language network is affected as a whole by the lesion. Although the derivation of LI must be further validated in individual patients by using spatially specific statistical methods, the current results indicated that fMRI is a useful tool for predicting postoperative outcomes in patients with a single brain tumor.
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Affiliation(s)
- Bornali Kundu
- School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin, USA.
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Kim H, Harrison A, Kankirawatana P, Rozzelle C, Blount J, Torgerson C, Knowlton R. Major white matter fiber changes in medically intractable neocortical epilepsy in children: A diffusion tensor imaging study. Epilepsy Res 2013; 103:211-20. [PMID: 22917916 DOI: 10.1016/j.eplepsyres.2012.07.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Revised: 07/25/2012] [Accepted: 07/30/2012] [Indexed: 11/25/2022]
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33
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Altered hemispheric symmetry found in left-sided mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE/HS) but not found in right-sided MTLE/HS. Magn Reson Imaging 2013; 31:53-9. [DOI: 10.1016/j.mri.2012.06.030] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Revised: 05/27/2012] [Accepted: 06/25/2012] [Indexed: 11/19/2022]
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Reliability of the corticospinal tract and arcuate fasciculus reconstructed with DTI-based tractography: implications for clinical practice. Eur Radiol 2012; 23:28-36. [DOI: 10.1007/s00330-012-2589-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Accepted: 06/29/2012] [Indexed: 10/28/2022]
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35
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Berthier ML, Lambon Ralph MA, Pujol J, Green C. Arcuate fasciculus variability and repetition: The left sometimes can be right. Cortex 2012; 48:133-43. [DOI: 10.1016/j.cortex.2011.06.014] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Revised: 06/01/2011] [Accepted: 06/14/2011] [Indexed: 11/24/2022]
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36
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Abdul-Kareem IA, Stancak A, Parkes LM, Al-Ameen M, Alghamdi J, Aldhafeeri FM, Embleton K, Morris D, Sluming V. Plasticity of the superior and middle cerebellar peduncles in musicians revealed by quantitative analysis of volume and number of streamlines based on diffusion tensor tractography. THE CEREBELLUM 2012; 10:611-23. [PMID: 21503593 DOI: 10.1007/s12311-011-0274-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
This work was conducted to study the plasticity of superior (SCP) and middle (MCP) cerebellar peduncles in musicians. The cerebellum is well known to support several musically relevant motor, sensory and cognitive functions. Previous studies reported increased cerebellar volume and grey matter (GM) density in musicians. Here, we report on plasticity of white matter (WM) of the cerebellum. Our cohort included 10/10 gender and handedness-matched musicians and controls. Using diffusion tensor imaging, fibre tractography of SCP and MCP was performed. The fractional anisotropy (FA), number of streamlines and volume of streamlines of SCP/MCP were compared between groups. Automatic measurements of GM and WM volumes of the right/left cerebellar hemispheres were also compared. Musicians have significantly increased right SCP volume (p = 0.02) and number of streamlines (p = 0.001), right MCP volume (p = 0.004) and total WM volume of the right cerebellum (p = 0.003). There were no significant differences in right MCP number of streamlines, left SCP/MCP volume and number of streamlines, SCP/MCP FA values, GM volume of the right cerebellum and GM/WM volumes of the left cerebellum. We propose that increased volume and number of streamlines of the right cerebellar peduncles represent use-dependent structural adaptation to increased sensorimotor and cognitive functional demands on the musician's cerebellum.
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Affiliation(s)
- Ihssan A Abdul-Kareem
- Department of Molecular and Cellular Biology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK.
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37
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Tiwari VN, Jeong JW, Asano E, Rothermel R, Juhasz C, Chugani HT. A sensitive diffusion tensor imaging quantification method to detect language laterality in children: correlation with the Wada test. J Child Neurol 2011; 26:1516-21. [PMID: 21652590 PMCID: PMC3673532 DOI: 10.1177/0883073811409225] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Using diffusion tensor imaging tractography and color-coded anisotropy map quantification, we investigated asymmetry of the arcuate fasciculus to determine language laterality in children and compared it with the Wada test. Arcuate fasciculus volume and fractional anisotropy were measured after tractography. We also quantified the fiber orientation distribution in the arcuate fasciculus region, ie, the fraction of arcuate fasciculus fibers oriented in the anteroposterior and mediolateral directions. A Laterality Index was calculated for each of the measured parameters. Volumetric analysis of the arcuate fasciculus showed asymmetry favoring the language dominant hemisphere (P = .02), while fractional anisotropy showed no significant asymmetry (P = .07). The mean anteroposterior and mediolateral components on the language dominant side were significantly higher than on the nondominant side (P = .003 and .002, respectively). The Laterality Index values were concordant with the Wada test results except for 1 case. Fractional anisotropy also falsely lateralized language in 1 case.
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Affiliation(s)
- Vijay Narayan Tiwari
- Department of Pediatrics, Children’s Hospital of Michigan, Wayne State University, Detroit, Michigan,PET Center, Children’s Hospital of Michigan, Wayne State University, Detroit, Michigan
| | - Jeong-Won Jeong
- Department of Pediatrics, Children’s Hospital of Michigan, Wayne State University, Detroit, Michigan,PET Center, Children’s Hospital of Michigan, Wayne State University, Detroit, Michigan
| | - Eishi Asano
- Department of Pediatrics, Children’s Hospital of Michigan, Wayne State University, Detroit, Michigan,PET Center, Children’s Hospital of Michigan, Wayne State University, Detroit, Michigan,Department of Neurology, Children’s Hospital of Michigan, Wayne State University, Detroit, Michigan
| | - Robert Rothermel
- Department of Psychiatry, Children’s Hospital of Michigan, Wayne State University, Detroit, Michigan
| | - Csaba Juhasz
- Department of Pediatrics, Children’s Hospital of Michigan, Wayne State University, Detroit, Michigan,PET Center, Children’s Hospital of Michigan, Wayne State University, Detroit, Michigan,Department of Neurology, Children’s Hospital of Michigan, Wayne State University, Detroit, Michigan
| | - Harry T. Chugani
- Department of Pediatrics, Children’s Hospital of Michigan, Wayne State University, Detroit, Michigan,PET Center, Children’s Hospital of Michigan, Wayne State University, Detroit, Michigan,Department of Neurology, Children’s Hospital of Michigan, Wayne State University, Detroit, Michigan
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McDonald CR, Taylor J, Hamberger M, Helmstaedter C, Hermann BP, Schefft B. Future directions in the neuropsychology of epilepsy. Epilepsy Behav 2011; 22:69-76. [PMID: 21795122 DOI: 10.1016/j.yebeh.2011.06.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Accepted: 06/05/2011] [Indexed: 11/17/2022]
Abstract
Two important themes for future clinical research in the neuropsychology of epilepsy are proposed: (1) the neurobiological abnormalities that underlie neuropsychological impairment in people with epilepsy, and (2) neuropsychological status of persons with new-onset epilepsy.
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Affiliation(s)
- Carrie R McDonald
- Multimodal Imaging Laboratory, Department of Psychiatry, University of California, San Diego, San Diego, CA, USA
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Wrench JM, Matsumoto R, Inoue Y, Wilson SJ. Current challenges in the practice of epilepsy surgery. Epilepsy Behav 2011; 22:23-31. [PMID: 21482197 DOI: 10.1016/j.yebeh.2011.02.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Accepted: 02/10/2011] [Indexed: 10/18/2022]
Abstract
The accurate prediction of individual outcomes after epilepsy surgery represents a key challenge facing clinicians. It requires a precise understanding of surgical candidacy and the optimal timing of surgery to maximize a range of outcomes, including medical, psychosocial, cognitive, and psychiatric outcomes. We promote careful consideration of how epilepsy has affected an individual's developmental trajectory as key to constructing more differentiated profiles of postsurgical risk or resilience across multiple outcome measures. This life span approach conceives surgery as a crucial "turning point" in an individual's development from which varied outcome trajectories may follow. This helps clinicians understand the expectations patients and families bring to surgery, and emphasizes the interplay of factors that determine a patient's outcome. It also promotes comprehensive, longitudinal assessment of outcome using data analytical techniques that capture individual differences and identify subgroups with similar trajectories. An ongoing challenge facing clinicians is the development of an outcome classification system that incorporates outcomes other than seizures. We illustrate two emerging areas of research shaping how we define surgical candidacy and predict outcome: (1) using cortico-cortical evoked potentials to identify pathways of seizure propagation and cortico-cortical networks mediating cortical functions, and (2) predicting postoperative depression using a model that incorporates psychosocial and neurobiological factors. The latter research points to the importance of routine follow-up and postoperative psychosocial rehabilitation, particularly in patients deemed at "high risk" for poor outcomes so that early treatment interventions can be implemented. Significantly more research is needed to characterize those patients with poor outcomes who may require re-surgery.
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Affiliation(s)
- Joanne M Wrench
- Psychological Sciences, University of Melbourne, Melbourne, Australia
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40
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Kang X, Herron TJ, Woods DL. Regional variation, hemispheric asymmetries and gender differences in pericortical white matter. Neuroimage 2011; 56:2011-23. [PMID: 21397700 DOI: 10.1016/j.neuroimage.2011.03.016] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Revised: 02/06/2011] [Accepted: 03/04/2011] [Indexed: 10/18/2022] Open
Abstract
Brain white matter tissue composition can be quantified using Diffusion Tensor Imaging (DTI) and Magnetization Transfer Imaging (MTI). Fractional Anisotropy (FA), derived from DTI, indexes the integrity, density and organization of axons. Magnetization Transfer Ratio (MTR), derived from MTI, indexes to the presence of cell membranes and myelin. The combined use of FA and MTR provides a more complete picture of white matter structure than either imaging modality in isolation. Here we describe the regional distribution of FA and MTR measurements of pericortical white matter in 56 young, healthy right-handed subjects. Significant regional and lobar differences are seen for both measures along with a significant gender difference in FA. Highly consistent hemispheric asymmetries in FA and MTR were observed, suggesting that the greater fiber coherence and increased myelination of fibers in left hemisphere perisylvian regions may provide a structural basis for left-hemisphere language dominance.
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Affiliation(s)
- Xiaojian Kang
- Human Cognitive Neurophysiology Lab, VA Research Service, VA-NCHCS, 150 Muir Road, Martinez, CA 94553, USA.
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41
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Bell B, Lin JJ, Seidenberg M, Hermann B. The neurobiology of cognitive disorders in temporal lobe epilepsy. Nat Rev Neurol 2011; 7:154-64. [PMID: 21304484 DOI: 10.1038/nrneurol.2011.3] [Citation(s) in RCA: 308] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Cognitive impairment, particularly memory disruption, is a major complicating feature of epilepsy. This Review will begin with a focus on the problem of memory impairment in temporal lobe epilepsy (TLE). We present a brief overview of anatomical substrates of memory disorders in TLE, followed by a discussion of how our understanding of these disorders has been improved by studying the outcomes of anterior temporal lobectomy. The clinical efforts made to predict which patients are at greatest risk of experiencing adverse cognitive outcomes following epilepsy surgery are also considered. Finally, we examine the vastly changing view of TLE, including findings demonstrating that anatomical abnormalities extend far outside the temporal lobe, and that cognitive impairments extend beyond memory function. Linkage between these distributed cognitive and anatomical abnormalities point to a new understanding of the anatomical architecture of cognitive impairment in epilepsy. Clarifying the origin of these cognitive and anatomical abnormalities, their progression over time and, most importantly, methods for protecting cognitive and brain health in epilepsy, present a challenge to neurologists.
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Affiliation(s)
- Brian Bell
- Department of Neurology, University of Wisconsin School of Medicine and Public Health, 600 North Highland Avenue, Madison, WI 53792, USA
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42
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Abstract
Medically refractory focal epilepsy is potentially curable by surgery. This Review considers the application of recent advances in structural and functional brain imaging to increase the number of patients with epilepsy who are treated surgically, and to reduce the risk of complications arising from such intervention. Current optimal MRI of brain structure can identify previously undetectable lesions, with voxel-based and quantitative analyses further increasing the diagnostic yield. If MRI proves unremarkable, PET (with (18)F-fluorodeoxyglucose) and single-photon emission CT of ictal-interictal cerebral blood flow might identify the brain region that contains the epileptic focus. Magnetoencephalography plus simultaneous EEG and functional MRI can map the location of interictal epileptic discharges, thereby facilitating placement of intracranial recording electrodes to define the site of seizure onset. Functional MRI can also lateralize language and localize primary motor, somatosensory and language areas, and shows promise for predicting the effects of temporal lobe resection on memory. Tractography can visualize the main cerebral white matter tracts, thereby predicting and reducing surgery risk. Currently, displays of the optic radiation and pyramidal tracts are the most relevant for epilepsy surgery. Reliable integration of structural and functional data into surgical image-guidance systems is being pursued, and promises safer neurosurgery for epilepsy in the future.
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Affiliation(s)
- John S Duncan
- National Society for Epilepsy, Department of Clinical and Experimental Epilepsy, University College London Institute of Neurology, Queen Square, London, UK.
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43
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Thiebaut de Schotten M, Ffytche DH, Bizzi A, Dell'Acqua F, Allin M, Walshe M, Murray R, Williams SC, Murphy DGM, Catani M. Atlasing location, asymmetry and inter-subject variability of white matter tracts in the human brain with MR diffusion tractography. Neuroimage 2010; 54:49-59. [PMID: 20682348 DOI: 10.1016/j.neuroimage.2010.07.055] [Citation(s) in RCA: 506] [Impact Index Per Article: 36.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2010] [Revised: 06/18/2010] [Accepted: 07/25/2010] [Indexed: 11/24/2022] Open
Abstract
The purpose of this study is to create a white matter atlas of the human brain using diffusion tensor imaging (DTI) tractography and to describe the constant and variable features of the major pathways. DTI was acquired from 40 healthy right-handed adults and reconstructed tracts mapped within a common reference space (MNI). Group effect maps of each tract defined constant anatomical features while overlap maps were generated to study inter-subject variability and to compare DTI derived anatomy with a histological atlas. Two patients were studied to assess the localizing validity of the atlas. The DTI-derived maps are overall consistent with a previously published histological atlas. A statistically significant leftward asymmetry was found for the volume and number of streamlines of the cortico-spinal tract and the direct connections between Broca's and Wernicke's territories (long segment). A statistically significant rightward asymmetry was found for the inferior fronto-occipital fasciculus and the fronto-parietal connections (anterior segment) of the arcuate fasciculus. Furthermore, males showed a left lateralization of the fronto-temporal segment of the arcuate fasciculus (long segment), while females had a more bilateral distribution. In two patients with brain lesions, DTI was acquired and tractography used to show that the tracts affected by the lesions were correctly identified by the atlas. This study suggests that DTI-derived maps can be used together with a previous histological atlas to establish the relationship of focal lesions with nearby tracts and improve clinico-anatomical correlation.
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Affiliation(s)
- Michel Thiebaut de Schotten
- Natbrainlab, Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, King's College London, London, UK.
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De Witt Hamer PC, Moritz-Gasser S, Gatignol P, Duffau H. Is the human left middle longitudinal fascicle essential for language? A brain electrostimulation study. Hum Brain Mapp 2010; 32:962-73. [PMID: 20578169 DOI: 10.1002/hbm.21082] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2009] [Revised: 03/13/2010] [Accepted: 03/26/2010] [Indexed: 11/07/2022] Open
Abstract
Human brain pathways required for language processing are poorly known. A new white matter tract in humans, the middle longitudinal fascicle, has recently been anatomically determined by diffusion tensor imaging and suggested to be essential for language. Our aim is to determine the importance of the middle longitudinal fascicle for language processing. This study is based on 8 patients with glioma resection at least involving the superior temporal gyrus of the left dominant hemisphere. Language is systematically examined pre- and postoperatively at 3 months. Intraoperative electrostimulation is used to map cortical and subcortical structures as functional boundaries of the glioma resection, including those essential for language processing. The resections are extensive (on average 62 ml, ranging from 21 to 111 ml) and include a large part of the middle longitudinal fascicle in all patients. Intraoperatively, no interference with picture naming is observed by electrostimulation of the middle longitudinal fascicle, while in all patients the inferior fronto-occipital fascicle is identified by eliciting semantic paraphasia as functional boundary. Postoperatively, no new permanent language deficits are detected by systematic language examination. Therefore, we suggest that the middle longitudinal fascicle may participate but is not essential for language processing.
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Affiliation(s)
- Philip C De Witt Hamer
- Neurosurgical Center Amsterdam, VU University Medical Center, Amsterdam, The Netherlands
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45
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Propper RE, O'Donnell LJ, Whalen S, Tie Y, Norton IH, Suarez RO, Zollei L, Radmanesh A, Golby AJ. A combined fMRI and DTI examination of functional language lateralization and arcuate fasciculus structure: Effects of degree versus direction of hand preference. Brain Cogn 2010; 73:85-92. [PMID: 20378231 DOI: 10.1016/j.bandc.2010.03.004] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2009] [Revised: 03/11/2010] [Accepted: 03/12/2010] [Indexed: 10/19/2022]
Abstract
The present study examined the relationship between hand preference degree and direction, functional language lateralization in Broca's and Wernicke's areas, and structural measures of the arcuate fasciculus. Results revealed an effect of degree of hand preference on arcuate fasciculus structure, such that consistently-handed individuals, regardless of the direction of hand preference, demonstrated the most asymmetric arcuate fasciculus, with larger left versus right arcuate, as measured by DTI. Functional language lateralization in Wernicke's area, measured via fMRI, was related to arcuate fasciculus volume in consistent-left-handers only, and only in people who were not right hemisphere lateralized for language; given the small sample size for this finding, future investigation is warranted. Results suggest handedness degree may be an important variable to investigate in the context of neuroanatomical asymmetries.
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Affiliation(s)
- Ruth E Propper
- Golby Neurosurgical Brain Mapping Laboratory, Departments of Neurosurgery and Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
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Bizzi A. Presurgical mapping of verbal language in brain tumors with functional MR imaging and MR tractography. Neuroimaging Clin N Am 2010; 19:573-96. [PMID: 19959006 DOI: 10.1016/j.nic.2009.08.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Functional magnetic resonance (fMR) imaging and diffusion MR tractography have emerged as valuable tools in the evaluation of verbal language in brain tumor patients, and have changed the way neurosurgeons look at patients with a mass in the dominant hemisphere. The techniques have obtained recognition as valuable presurgical clinical tools in the determination of hemispheric dominance and in the selection of candidates who may benefit from awake craniotomy. In the near future fMRI and diffusion MR Tractography may contribute to elucidate mechanisms of brain plasticity and may provide predictors of favorable postoperative clinical outcome. The functional anatomy of the language network and the role of fMR imaging and diffusion MR tractography in the evaluation of patients with a brain tumor are the focus of this article.
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Affiliation(s)
- Alberto Bizzi
- Neuroradiology Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, 201133 Milan, Italy.
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Lebel C, Beaulieu C. Lateralization of the arcuate fasciculus from childhood to adulthood and its relation to cognitive abilities in children. Hum Brain Mapp 2010; 30:3563-73. [PMID: 19365801 DOI: 10.1002/hbm.20779] [Citation(s) in RCA: 212] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The arcuate fasciculus is a major white matter tract involved in language processing that has also been repeatedly implicated in intelligence and reasoning tasks. Language in the human brain is lateralized in terms of both function and structure, and while the arcuate fasciculus reflects this asymmetry, its pattern of lateralization is poorly understood in children and adolescents. We used diffusion tensor imaging (DTI) and tractography to examine arcuate fasciculus lateralization in a large (n = 183) group of healthy right-handed volunteers aged 5-30 years; a subset of 68 children aged 5-13 years also underwent cognitive assessments. Fractional anisotropy and number of streamlines of the arcuate fasciculus were both significantly higher in the left hemisphere than the right hemisphere in most subjects, although some subjects (10%) were right lateralized. Age and gender effects on lateralization were not significant. Children receiving cognitive assessments were divided into three groups: a "left-only" group in whom only the left side of the arcuate fasciculus could be tracked, a left-lateralized group, and a right-lateralized group. Scores on the Peabody Picture Vocabulary Test (PPVT) and NEPSY Phonological Processing task differed significantly among groups, with left-only subjects outperforming the right-lateralized group on the PPVT, and the left-lateralized children scoring significantly better than the right-lateralized group on phonological processing. In summary, DTI tractography demonstrates leftward arcuate fasciculus lateralization in children, adolescents, and young adults, and reveals a relationship between structural white matter lateralization and specific cognitive abilities in children.
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Affiliation(s)
- Catherine Lebel
- Department of Biomedical Engineering, University of Alberta, Alberta, Canada
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Hermann BP, Lin JJ, Jones JE, Seidenberg M. The emerging architecture of neuropsychological impairment in epilepsy. Neurol Clin 2009; 27:881-907. [PMID: 19853214 PMCID: PMC2811050 DOI: 10.1016/j.ncl.2009.08.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
A new literature is now under way, one linking cognitive abnormalities directly to indices of structural, functional, metabolic, and other neurobiologic markers of cerebral integrity, independent of their association with clinical epilepsy characteristics. These trends are reviewed in this article. The focus is on temporal lobe epilepsy (TLE) as a model with which to address the core points because this form of localization-related epilepsy has been very carefully studied from both a cognitive and imaging standpoint. Some pertinent historical issues are touched on first, followed by more detailed reviews of the cognitive and neuroimaging abnormalities that have been found in TLE, followed by an overview of studies examining direct structure-function relationships in TLE and other epilepsies.
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Affiliation(s)
- Bruce P Hermann
- Department of Neurology, University of Wisconsin School of Medicine and Public Health, 600 North Highland Avenue, Madison, WI 53792, USA.
| | - Jack J Lin
- Department of Neurology, University of California-Irvine, Irvine, CA 92697, USA
| | - Jana E Jones
- Department of Neurology, University of Wisconsin School of Medicine and Public Health, 600 North Highland Avenue, Madison, WI 53792, USA
| | - Michael Seidenberg
- Department of Psychology, Rosalind Franklin School of Medicine and Science, 3333 N. Green Bay Road, North Chicago, IL 60064, USA
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Ellmore TM, Beauchamp MS, Breier JI, Slater JD, Kalamangalam GP, O'Neill TJ, Disano MA, Tandon N. Temporal lobe white matter asymmetry and language laterality in epilepsy patients. Neuroimage 2009; 49:2033-44. [PMID: 19874899 DOI: 10.1016/j.neuroimage.2009.10.055] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2009] [Revised: 10/02/2009] [Accepted: 10/19/2009] [Indexed: 11/16/2022] Open
Abstract
Recent studies using diffusion tensor imaging (DTI) have advanced our knowledge of the organization of white matter subserving language function. It remains unclear, however, how DTI may be used to predict accurately a key feature of language organization: its asymmetric representation in one cerebral hemisphere. In this study of epilepsy patients with unambiguous lateralization on Wada testing (19 left and 4 right lateralized subjects; no bilateral subjects), the predictive value of DTI for classifying the dominant hemisphere for language was assessed relative to the existing standard-the intra-carotid Amytal (Wada) procedure. Our specific hypothesis is that language laterality in both unilateral left- and right-hemisphere language dominant subjects may be predicted by hemispheric asymmetry in the relative density of three white matter pathways terminating in the temporal lobe implicated in different aspects of language function: the arcuate (AF), uncinate (UF), and inferior longitudinal fasciculi (ILF). Laterality indices computed from asymmetry of high anisotropy AF pathways, but not the other pathways, classified the majority (19 of 23) of patients using the Wada results as the standard. A logistic regression model incorporating information from DTI of the AF, fMRI activity in Broca's area, and handedness was able to classify 22 of 23 (95.6%) patients correctly according to their Wada score. We conclude that evaluation of highly anisotropic components of the AF alone has significant predictive power for determining language laterality, and that this markedly asymmetric distribution in the dominant hemisphere may reflect enhanced connectivity between frontal and temporal sites to support fluent language processes. Given the small sample reported in this preliminary study, future research should assess this method on a larger group of patients, including subjects with bi-hemispheric dominance.
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Affiliation(s)
- Timothy M Ellmore
- Department of Neurosurgery, The University of Texas Medical School at Houston, 6431 Fannin St, MSB Suite G550, Houston, TX 77030, USA.
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Bernal B, Altman N. The connectivity of the superior longitudinal fasciculus: a tractography DTI study. Magn Reson Imaging 2009; 28:217-25. [PMID: 19695825 DOI: 10.1016/j.mri.2009.07.008] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2009] [Revised: 07/01/2009] [Accepted: 07/04/2009] [Indexed: 11/17/2022]
Abstract
PURPOSE The left superior longitudinal fasciculus (SLF) has been felt to link receptive with expressive language areas. The latter is located in the pars opercularis (Broca's area) of the left inferior frontal gyrus. We report the findings with tractography of the SLF in a group of normal volunteers. METHODS AND MATERIALS The data and subsidiary results of 12 normal right-handed volunteers who participated in an institutional review board-approved diffusion tensor imaging study were evaluated. The SLF fibers were obtained bilaterally placing a region of interest at the triangular-shaped region lateral to each of the corticospinal tracts, in a coronal plane along the rostral aspect of the corpus callosum. A sagittal fractional anisotropy image was used to determine the rostral endpoint of the SLF fibers in the white matter pertaining to specific gyri or pars of the frontal lobe. The SLF projection to Broca's area was ranked qualitatively as none, minimal, most or all. Findings are presented in descriptive statistics. RESULTS The SLF projection to Broca's areas was absent in seven subjects (58.3%) and minimal in five (41.6%). SLF's rostral end points were found uniquely or mainly in the precentral gyrus in 100% of cases. CONCLUSION The SLF was found connecting the posterior language areas to the precentral gyrus and only marginally in some cases to the canonical Broca's area. This finding is consistent with reports describing lack of correlation between lateralization of the SLF and language areas. The understanding of language circuitry is beginning to emerge with the use of tractography.
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Affiliation(s)
- Byron Bernal
- Department of Radiology, Miami Children's Hospital, Miami, FL 33155, USA.
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