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Casilio M, Kasdan AV, Schneck SM, Entrup JL, Levy DF, Crouch K, Wilson SM. Situating word deafness within aphasia recovery: A case report. Cortex 2024; 173:96-119. [PMID: 38387377 PMCID: PMC11073474 DOI: 10.1016/j.cortex.2023.12.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 10/02/2023] [Accepted: 12/26/2023] [Indexed: 02/24/2024]
Abstract
Word deafness is a rare neurological disorder often observed following bilateral damage to superior temporal cortex and canonically defined as an auditory modality-specific deficit in word comprehension. The extent to which word deafness is dissociable from aphasia remains unclear given its heterogeneous presentation, and some have consequently posited that word deafness instead represents a stage in recovery from aphasia, where auditory and linguistic processing are affected to varying degrees and improve at differing rates. Here, we report a case of an individual (Mr. C) with bilateral temporal lobe lesions whose presentation evolved from a severe aphasia to an atypical form of word deafness, where auditory linguistic processing was impaired at the sentence level and beyond. We first reconstructed in detail Mr. C's stroke recovery through medical record review and supplemental interviewing. Then, using behavioral testing and multimodal neuroimaging, we documented a predominant auditory linguistic deficit in sentence and narrative comprehension-with markedly reduced behavioral performance and absent brain activation in the language network in the spoken modality exclusively. In contrast, Mr. C displayed near-unimpaired behavioral performance and robust brain activations in the language network for the linguistic processing of words, irrespective of modality. We argue that these findings not only support the view of word deafness as a stage in aphasia recovery but also further instantiate the important role of left superior temporal cortex in auditory linguistic processing.
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Affiliation(s)
| | - Anna V Kasdan
- Vanderbilt University Medical Center, Nashville, TN, USA; Vanderbilt Brain Institute, TN, USA
| | | | | | - Deborah F Levy
- Vanderbilt University Medical Center, Nashville, TN, USA
| | - Kelly Crouch
- Vanderbilt University Medical Center, Nashville, TN, USA
| | - Stephen M Wilson
- Vanderbilt University Medical Center, Nashville, TN, USA; School of Health and Rehabilitation Sciences, University of Queensland, Brisbane, QLD, Australia
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Levy DF, Entrup JL, Schneck SM, Onuscheck CF, Rahman M, Kasdan A, Casilio M, Willey E, Davis LT, de Riesthal M, Kirshner HS, Wilson SM. Multivariate lesion symptom mapping for predicting trajectories of recovery from aphasia. Brain Commun 2024; 6:fcae024. [PMID: 38370445 PMCID: PMC10873140 DOI: 10.1093/braincomms/fcae024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 12/05/2023] [Accepted: 01/30/2024] [Indexed: 02/20/2024] Open
Abstract
Individuals with post-stroke aphasia tend to recover their language to some extent; however, it remains challenging to reliably predict the nature and extent of recovery that will occur in the long term. The aim of this study was to quantitatively predict language outcomes in the first year of recovery from aphasia across multiple domains of language and at multiple timepoints post-stroke. We recruited 217 patients with aphasia following acute left hemisphere ischaemic or haemorrhagic stroke and evaluated their speech and language function using the Quick Aphasia Battery acutely and then acquired longitudinal follow-up data at up to three timepoints post-stroke: 1 month (n = 102), 3 months (n = 98) and 1 year (n = 74). We used support vector regression to predict language outcomes at each timepoint using acute clinical imaging data, demographic variables and initial aphasia severity as input. We found that ∼60% of the variance in long-term (1 year) aphasia severity could be predicted using these models, with detailed information about lesion location importantly contributing to these predictions. Predictions at the 1- and 3-month timepoints were somewhat less accurate based on lesion location alone, but reached comparable accuracy to predictions at the 1-year timepoint when initial aphasia severity was included in the models. Specific subdomains of language besides overall severity were predicted with varying but often similar degrees of accuracy. Our findings demonstrate the feasibility of using support vector regression models with leave-one-out cross-validation to make personalized predictions about long-term recovery from aphasia and provide a valuable neuroanatomical baseline upon which to build future models incorporating information beyond neuroanatomical and demographic predictors.
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Affiliation(s)
- Deborah F Levy
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Jillian L Entrup
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Sarah M Schneck
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Caitlin F Onuscheck
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Maysaa Rahman
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Anna Kasdan
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Marianne Casilio
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Emma Willey
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - L Taylor Davis
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Michael de Riesthal
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Howard S Kirshner
- Vanderbilt Stroke and Cerebrovascular Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Stephen M Wilson
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- School of Health and Rehabilitation Sciences, University of Queensland, Brisbane, QLD 4072, Australia
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Brito AC, Levy DF, Schneck SM, Entrup JL, Onuscheck CF, Casilio M, de Riesthal M, Davis LT, Wilson SM. Leukoaraiosis Is Not Associated With Recovery From Aphasia in the First Year After Stroke. Neurobiol Lang (Camb) 2023; 4:536-549. [PMID: 37946731 PMCID: PMC10631799 DOI: 10.1162/nol_a_00115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 06/28/2023] [Indexed: 11/12/2023]
Abstract
After a stroke, individuals with aphasia often recover to a certain extent over time. This recovery process may be dependent on the health of surviving brain regions. Leukoaraiosis (white matter hyperintensities on MRI reflecting cerebral small vessel disease) is one indication of compromised brain health and is associated with cognitive and motor impairment. Previous studies have suggested that leukoaraiosis may be a clinically relevant predictor of aphasia outcomes and recovery, although findings have been inconsistent. We investigated the relationship between leukoaraiosis and aphasia in the first year after stroke. We recruited 267 patients with acute left hemispheric stroke and coincident fluid attenuated inversion recovery MRI. Patients were evaluated for aphasia within 5 days of stroke, and 174 patients presented with aphasia acutely. Of these, 84 patients were evaluated at ∼3 months post-stroke or later to assess longer-term speech and language outcomes. Multivariable regression models were fit to the data to identify any relationships between leukoaraiosis and initial aphasia severity, extent of recovery, or longer-term aphasia severity. We found that leukoaraiosis was present to varying degrees in 90% of patients. However, leukoaraiosis did not predict initial aphasia severity, aphasia recovery, or longer-term aphasia severity. The lack of any relationship between leukoaraiosis severity and aphasia recovery may reflect the anatomical distribution of cerebral small vessel disease, which is largely medial to the white matter pathways that are critical for speech and language function.
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Affiliation(s)
| | - Deborah F. Levy
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Sarah M. Schneck
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Jillian L. Entrup
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Caitlin F. Onuscheck
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Marianne Casilio
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Michael de Riesthal
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - L. Taylor Davis
- Department of Radiology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Stephen M. Wilson
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Radiology, Vanderbilt University Medical Center, Nashville, TN, USA
- School of Health and Rehabilitation Sciences, University of Queensland, Brisbane, Australia
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Philips M, Schneck SM, Levy DF, Wilson SM. Modality-Specificity of the Neural Correlates of Linguistic and Non-Linguistic Demand. Neurobiol Lang (Camb) 2023; 4:516-535. [PMID: 37841966 PMCID: PMC10575553 DOI: 10.1162/nol_a_00114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 06/28/2023] [Indexed: 10/17/2023]
Abstract
Imaging studies of language processing in clinical populations can be complicated to interpret for several reasons, one being the difficulty of matching the effortfulness of processing across individuals or tasks. To better understand how effortful linguistic processing is reflected in functional activity, we investigated the neural correlates of task difficulty in linguistic and non-linguistic contexts in the auditory modality and then compared our findings to a recent analogous experiment in the visual modality in a different cohort. Nineteen neurologically normal individuals were scanned with fMRI as they performed a linguistic task (semantic matching) and a non-linguistic task (melodic matching), each with two levels of difficulty. We found that left hemisphere frontal and temporal language regions, as well as the right inferior frontal gyrus, were modulated by linguistic demand and not by non-linguistic demand. This was broadly similar to what was previously observed in the visual modality. In contrast, the multiple demand (MD) network, a set of brain regions thought to support cognitive flexibility in many contexts, was modulated neither by linguistic demand nor by non-linguistic demand in the auditory modality. This finding was in striking contradistinction to what was previously observed in the visual modality, where the MD network was robustly modulated by both linguistic and non-linguistic demand. Our findings suggest that while the language network is modulated by linguistic demand irrespective of modality, modulation of the MD network by linguistic demand is not inherent to linguistic processing, but rather depends on specific task factors.
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Affiliation(s)
- Mackenzie Philips
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Sarah M. Schneck
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Deborah F. Levy
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Stephen M. Wilson
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
- School of Health and Rehabilitation Sciences, University of Queensland, Brisbane, Australia
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Levy DF, Silva AB, Scott TL, Liu JR, Harper S, Zhao L, Hullett PW, Kurteff G, Wilson SM, Leonard MK, Chang EF. Apraxia of speech with phonological alexia and agraphia following resection of the left middle precentral gyrus: illustrative case. J Neurosurg Case Lessons 2023; 5:CASE22504. [PMID: 37014023 PMCID: PMC10550577 DOI: 10.3171/case22504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 01/23/2023] [Indexed: 03/29/2023]
Abstract
BACKGROUND Apraxia of speech is a disorder of speech-motor planning in which articulation is effortful and error-prone despite normal strength of the articulators. Phonological alexia and agraphia are disorders of reading and writing disproportionately affecting unfamiliar words. These disorders are almost always accompanied by aphasia. OBSERVATIONS A 36-year-old woman underwent resection of a grade IV astrocytoma based in the left middle precentral gyrus, including a cortical site associated with speech arrest during electrocortical stimulation mapping. Following surgery, she exhibited moderate apraxia of speech and difficulty with reading and spelling, both of which improved but persisted 6 months after surgery. A battery of speech and language assessments was administered, revealing preserved comprehension, naming, cognition, and orofacial praxis, with largely isolated deficits in speech-motor planning and the spelling and reading of nonwords. LESSONS This case describes a specific constellation of speech-motor and written language symptoms-apraxia of speech, phonological agraphia, and phonological alexia in the absence of aphasia-which the authors theorize may be attributable to disruption of a single process of "motor-phonological sequencing." The middle precentral gyrus may play an important role in the planning of motorically complex phonological sequences for production, independent of output modality.
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Affiliation(s)
- Deborah F. Levy
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, California
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California
| | - Alexander B. Silva
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, California
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California
- University of California Berkeley - University of California San Francisco Graduate Program in Bioengineering, Berkeley, California
- Medical Scientist Training Program, University of California, San Francisco, California
| | - Terri L. Scott
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, California
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California
| | - Jessie R. Liu
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, California
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California
- University of California Berkeley - University of California San Francisco Graduate Program in Bioengineering, Berkeley, California
| | - Sarah Harper
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, California
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California
| | - Lingyun Zhao
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, California
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California
| | - Patrick W. Hullett
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, California
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California
| | - Garret Kurteff
- Department of Speech, Language, and Hearing Sciences, University of Texas Austin, Austin, Texas; and
| | - Stephen M. Wilson
- Department of Hearing and Speech Sciences, Vanderbilt University, Nashville, Tennessee
| | - Matthew K. Leonard
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, California
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California
| | - Edward F. Chang
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, California
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California
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Andrews JP, Cahn N, Speidel BA, Chung JE, Levy DF, Wilson SM, Berger MS, Chang EF. Dissociation of Broca's area from Broca's aphasia in patients undergoing neurosurgical resections. J Neurosurg 2023; 138:847-857. [PMID: 35932264 PMCID: PMC9899289 DOI: 10.3171/2022.6.jns2297] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 06/15/2022] [Indexed: 02/07/2023]
Abstract
OBJECTIVE Broca's aphasia is a syndrome of impaired fluency with retained comprehension. The authors used an unbiased algorithm to examine which neuroanatomical areas are most likely to result in Broca's aphasia following surgical lesions. METHODS Patients were prospectively evaluated with standardized language batteries before and after surgery. Broca's area was defined anatomically as the pars opercularis and triangularis of the inferior frontal gyrus. Broca's aphasia was defined by the Western Aphasia Battery language assessment. Resections were outlined from MRI scans to construct 3D volumes of interest. These were aligned using a nonlinear transformation to Montreal Neurological Institute brain space. A voxel-based lesion-symptom mapping (VLSM) algorithm was used to test for areas statistically associated with Broca's aphasia when incorporated into a resection, as well as areas associated with deficits in fluency independent of Western Aphasia Battery classification. Postoperative MRI scans were reviewed in blinded fashion to estimate the percentage resection of Broca's area compared to areas identified using the VLSM algorithm. RESULTS A total of 289 patients had early language evaluations, of whom 19 had postoperative Broca's aphasia. VLSM analysis revealed an area that was highly correlated (p < 0.001) with Broca's aphasia, spanning ventral sensorimotor cortex and supramarginal gyri, as well as extending into subcortical white matter tracts. Reduced fluency scores were significantly associated with an overlapping region of interest. The fluency score was negatively correlated with fraction of resected precentral, postcentral, and supramarginal components of the VLSM area. CONCLUSIONS Broca's aphasia does not typically arise from neurosurgical resections in Broca's area. When Broca's aphasia does occur after surgery, it is typically in the early postoperative period, improves by 1 month, and is associated with resections of ventral sensorimotor cortex and supramarginal gyri.
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Affiliation(s)
- John P. Andrews
- Department of Neurological Surgery, University of California, San Francisco, School of Medicine, San Francisco, California; and
| | - Nathan Cahn
- Department of Neurological Surgery, University of California, San Francisco, School of Medicine, San Francisco, California; and
| | - Benjamin A. Speidel
- Department of Neurological Surgery, University of California, San Francisco, School of Medicine, San Francisco, California; and
| | - Jason E. Chung
- Department of Neurological Surgery, University of California, San Francisco, School of Medicine, San Francisco, California; and
| | - Deborah F. Levy
- Department of Neurological Surgery, University of California, San Francisco, School of Medicine, San Francisco, California; and
| | - Stephen M. Wilson
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Mitchel S. Berger
- Department of Neurological Surgery, University of California, San Francisco, School of Medicine, San Francisco, California; and
| | - Edward F. Chang
- Department of Neurological Surgery, University of California, San Francisco, School of Medicine, San Francisco, California; and
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Wilson SM, Entrup JL, Schneck SM, Onuscheck CF, Levy DF, Rahman M, Willey E, Casilio M, Yen M, Brito AC, Kam W, Davis LT, de Riesthal M, Kirshner HS. Recovery from aphasia in the first year after stroke. Brain 2023; 146:1021-1039. [PMID: 35388420 PMCID: PMC10169426 DOI: 10.1093/brain/awac129] [Citation(s) in RCA: 25] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 03/02/2022] [Accepted: 03/27/2022] [Indexed: 11/13/2022] Open
Abstract
Most individuals who experience aphasia after a stroke recover to some extent, with the majority of gains taking place in the first year. The nature and time course of this recovery process is only partially understood, especially its dependence on lesion location and extent, which are the most important determinants of outcome. The aim of this study was to provide a comprehensive description of patterns of recovery from aphasia in the first year after stroke. We recruited 334 patients with acute left hemisphere supratentorial ischaemic or haemorrhagic stroke and evaluated their speech and language function within 5 days using the Quick Aphasia Battery (QAB). At this initial time point, 218 patients presented with aphasia. Individuals with aphasia were followed longitudinally, with follow-up evaluations of speech and language at 1 month, 3 months, and 1 year post-stroke, wherever possible. Lesions were manually delineated based on acute clinical MRI or CT imaging. Patients with and without aphasia were divided into 13 groups of individuals with similar, commonly occurring patterns of brain damage. Trajectories of recovery were then investigated as a function of group (i.e. lesion location and extent) and speech/language domain (overall language function, word comprehension, sentence comprehension, word finding, grammatical construction, phonological encoding, speech motor programming, speech motor execution, and reading). We found that aphasia is dynamic, multidimensional, and gradated, with little explanatory role for aphasia subtypes or binary concepts such as fluency. Patients with circumscribed frontal lesions recovered well, consistent with some previous observations. More surprisingly, most patients with larger frontal lesions extending into the parietal or temporal lobes also recovered well, as did patients with relatively circumscribed temporal, temporoparietal, or parietal lesions. Persistent moderate or severe deficits were common only in patients with extensive damage throughout the middle cerebral artery distribution or extensive temporoparietal damage. There were striking differences between speech/language domains in their rates of recovery and relationships to overall language function, suggesting that specific domains differ in the extent to which they are redundantly represented throughout the language network, as opposed to depending on specialized cortical substrates. Our findings have an immediate clinical application in that they will enable clinicians to estimate the likely course of recovery for individual patients, as well as the uncertainty of these predictions, based on acutely observable neurological factors.
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Affiliation(s)
- Stephen M Wilson
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Jillian L Entrup
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Sarah M Schneck
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Caitlin F Onuscheck
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Deborah F Levy
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Maysaa Rahman
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Emma Willey
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Marianne Casilio
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Melodie Yen
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | | | - Wayneho Kam
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.,Vanderbilt Stroke and Cerebrovascular Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - L Taylor Davis
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Michael de Riesthal
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Howard S Kirshner
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.,Vanderbilt Stroke and Cerebrovascular Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
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Silva AB, Liu JR, Zhao L, Levy DF, Scott TL, Chang EF. A Neurosurgical Functional Dissection of the Middle Precentral Gyrus during Speech Production. J Neurosci 2022; 42:8416-8426. [PMID: 36351829 PMCID: PMC9665919 DOI: 10.1523/jneurosci.1614-22.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 08/30/2022] [Indexed: 11/17/2022] Open
Abstract
Classical models have traditionally focused on the left posterior inferior frontal gyrus (Broca's area) as a key region for motor planning of speech production. However, converging evidence suggests that it is not critical for either speech motor planning or execution. Alternative cortical areas supporting high-level speech motor planning have yet to be defined. In this review, we focus on the precentral gyrus, whose role in speech production is often thought to be limited to lower-level articulatory muscle control. In particular, we highlight neurosurgical investigations that have shed light on a cortical region anatomically located near the midpoint of the precentral gyrus, hence called the middle precentral gyrus (midPrCG). The midPrCG is functionally located between dorsal hand and ventral orofacial cortical representations and exhibits unique sensorimotor and multisensory functions relevant for speech processing. This includes motor control of the larynx, auditory processing, as well as a role in reading and writing. Furthermore, direct electrical stimulation of midPrCG can evoke complex movements, such as vocalization, and selective injury can cause deficits in verbal fluency, such as pure apraxia of speech. Based on these findings, we propose that midPrCG is essential to phonological-motoric aspects of speech production, especially syllabic-level speech sequencing, a role traditionally ascribed to Broca's area. The midPrCG is a cortical brain area that should be included in contemporary models of speech production with a unique role in speech motor planning and execution.
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Affiliation(s)
- Alexander B Silva
- Department of Neurological Surgery, University of California, San Francisco, California, 94158
- Weill Institute for Neurosciences, University of California, San Francisco, California, 94158
- Medical Scientist Training Program, University of California, San Francisco, California, 94158
- Graduate Program in Bioengineering, University of California, Berkeley, California 94720, & University of California, San Francisco, California, 94158
| | - Jessie R Liu
- Department of Neurological Surgery, University of California, San Francisco, California, 94158
- Weill Institute for Neurosciences, University of California, San Francisco, California, 94158
- Graduate Program in Bioengineering, University of California, Berkeley, California 94720, & University of California, San Francisco, California, 94158
| | - Lingyun Zhao
- Department of Neurological Surgery, University of California, San Francisco, California, 94158
- Weill Institute for Neurosciences, University of California, San Francisco, California, 94158
| | - Deborah F Levy
- Department of Neurological Surgery, University of California, San Francisco, California, 94158
- Weill Institute for Neurosciences, University of California, San Francisco, California, 94158
| | - Terri L Scott
- Department of Neurological Surgery, University of California, San Francisco, California, 94158
- Weill Institute for Neurosciences, University of California, San Francisco, California, 94158
| | - Edward F Chang
- Department of Neurological Surgery, University of California, San Francisco, California, 94158
- Weill Institute for Neurosciences, University of California, San Francisco, California, 94158
- Graduate Program in Bioengineering, University of California, Berkeley, California 94720, & University of California, San Francisco, California, 94158
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Levy DF, Kasdan AV, Bryan KM, Wilson SM, de Riesthal M, Herrington DP. Designing and Implementing a Community Aphasia Group: An Illustrative Case Study of the Aphasia Group of Middle Tennessee. Perspect ASHA Spec Interest Groups 2022; 7:1-11. [PMID: 36311052 PMCID: PMC9615148 DOI: 10.1044/2022_persp-22-00006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
PURPOSE Community aphasia groups serve an important purpose in enhancing the quality of life and psychosocial well-being of individuals with chronic aphasia. Here, we describe the Aphasia Group of Middle Tennessee, a community aphasia group with a 17-year (and continuing) history, housed within Vanderbilt University Medical Center in Nashville, Tennessee. METHOD We describe in detail the history, philosophy, design, curriculum, and facilitation model of this group. We also present both quantitative and qualitative outcomes from group members and their loved ones. RESULTS Group members and their loved ones alike indicated highly positive assessments of the format and value of the Aphasia Group of Middle Tennessee. CONCLUSION By characterizing in detail the successful Aphasia Group of Middle Tennessee, we hope this can serve as a model for clinicians interested in starting their own community aphasia groups, in addition to reaching individuals living with chronic aphasia and their loved ones through the accessible and aphasia-friendly materials provided with this clinical focus article.
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Affiliation(s)
- Deborah F. Levy
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN
- Curb Center for Art, Enterprise, and Public Policy, Nashville, TN
- Department of Neurological Surgery, University of California, San Francisco
| | - Anna V. Kasdan
- Curb Center for Art, Enterprise, and Public Policy, Nashville, TN
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN
| | - Katherine M. Bryan
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN
| | - Stephen M. Wilson
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN
| | - Michael de Riesthal
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN
| | - Dominique P. Herrington
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN
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Solomon EA, Sperling MR, Sharan AD, Wanda PA, Levy DF, Lyalenko A, Pedisich I, Rizzuto DS, Kahana MJ. Theta-burst stimulation entrains frequency-specific oscillatory responses. Brain Stimul 2021; 14:1271-1284. [PMID: 34428553 PMCID: PMC9161680 DOI: 10.1016/j.brs.2021.08.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 08/12/2021] [Accepted: 08/17/2021] [Indexed: 10/26/2022] Open
Abstract
BACKGROUND Brain stimulation has emerged as a powerful tool in human neuroscience, becoming integral to next-generation psychiatric and neurologic therapeutics. Theta-burst stimulation (TBS), in which electrical pulses are delivered in rhythmic bouts of 3-8 Hz, seeks to recapitulate neural activity seen endogenously during cognitive tasks. A growing literature suggests that TBS can be used to alter or enhance cognitive processes, but little is known about how these stimulation events influence underlying neural activity. OBJECTIVE Our study sought to investigate the effect of direct electrical TBS on mesoscale neural activity in humans by asking (1) whether TBS evokes persistent theta oscillations in cortical areas, (2) whether these oscillations occur at the stimulated frequency, and (3) whether stimulation events propagate in a manner consistent with underlying functional and structural brain architecture. METHODS We recruited 20 neurosurgical epilepsy patients with indwelling electrodes and delivered direct cortical TBS at varying locations and frequencies. Simultaneous iEEG was recorded from non-stimulated electrodes and analyzed to understand how TBS influences mesoscale neural activity. RESULTS We found that TBS rapidly evoked theta rhythms in widespread brain regions, preferentially at the stimulation frequency, and that these oscillations persisted for hundreds of milliseconds post stimulation offset. Furthermore, the functional connectivity between recording and stimulation sites predicted the strength of theta response, suggesting that underlying brain architecture guides the flow of stimulation through the brain. CONCLUSIONS By demonstrating that cortical TBS induces frequency-specific oscillatory responses, our results suggest this technology can be used to directly and predictably influence the activity of cognitively-relevant brain networks.
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Affiliation(s)
- Ethan A Solomon
- University of Pennsylvania, Perelman School of Medicine, Philadelphia PA 19104, USA; University of Pennsylvania, Department of Psychology, Philadelphia PA 19104, USA.
| | - Michael R Sperling
- Thomas Jefferson University Hospital, Department of Neurology, Philadelphia PA 19107, USA
| | - Ashwini D Sharan
- Thomas Jefferson University Hospital, Department of Neurosurgery, Philadelphia PA 19107, USA
| | - Paul A Wanda
- University of Pennsylvania, Department of Psychology, Philadelphia PA 19104, USA
| | - Deborah F Levy
- University of Pennsylvania, Department of Psychology, Philadelphia PA 19104, USA
| | - Anastasia Lyalenko
- University of Pennsylvania, Department of Psychology, Philadelphia PA 19104, USA
| | - Isaac Pedisich
- University of Pennsylvania, Department of Psychology, Philadelphia PA 19104, USA
| | - Daniel S Rizzuto
- University of Pennsylvania, Department of Psychology, Philadelphia PA 19104, USA; Nia Therapeutics Inc., Bala Cynwyd, PA 19004, USA
| | - Michael J Kahana
- University of Pennsylvania, Department of Psychology, Philadelphia PA 19104, USA.
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Levy DF, Wilson SM. Categorical Encoding of Vowels in Primary Auditory Cortex. Cereb Cortex 2021; 30:618-627. [PMID: 31241149 DOI: 10.1093/cercor/bhz112] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 04/05/2019] [Accepted: 05/02/2019] [Indexed: 11/14/2022] Open
Abstract
Speech perception involves mapping from a continuous and variable acoustic speech signal to discrete, linguistically meaningful units. However, it is unclear where in the auditory processing stream speech sound representations cease to be veridical (faithfully encoding precise acoustic properties) and become categorical (encoding sounds as linguistic categories). In this study, we used functional magnetic resonance imaging and multivariate pattern analysis to determine whether tonotopic primary auditory cortex (PAC), defined as tonotopic voxels falling within Heschl's gyrus, represents one class of speech sounds-vowels-veridically or categorically. For each of 15 participants, 4 individualized synthetic vowel stimuli were generated such that the vowels were equidistant in acoustic space, yet straddled a categorical boundary (with the first 2 vowels perceived as [i] and the last 2 perceived as [i]). Each participant's 4 vowels were then presented in a block design with an irrelevant but attention-demanding level change detection task. We found that in PAC bilaterally, neural discrimination between pairs of vowels that crossed the categorical boundary was more accurate than neural discrimination between equivalently spaced vowel pairs that fell within a category. These findings suggest that PAC does not represent vowel sounds veridically, but that encoding of vowels is shaped by linguistically relevant phonemic categories.
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Affiliation(s)
- Deborah F Levy
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Stephen M Wilson
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, USA
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Fisher JM, Dick FK, Levy DF, Wilson SM. Neural representation of vowel formants in tonotopic auditory cortex. Neuroimage 2018; 178:574-582. [PMID: 29860083 DOI: 10.1016/j.neuroimage.2018.05.072] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 05/29/2018] [Accepted: 05/30/2018] [Indexed: 11/25/2022] Open
Abstract
Speech sounds are encoded by distributed patterns of activity in bilateral superior temporal cortex. However, it is unclear whether speech sounds are topographically represented in cortex, or which acoustic or phonetic dimensions might be spatially mapped. Here, using functional MRI, we investigated the potential spatial representation of vowels, which are largely distinguished from one another by the frequencies of their first and second formants, i.e. peaks in their frequency spectra. This allowed us to generate clear hypotheses about the representation of specific vowels in tonotopic regions of auditory cortex. We scanned participants as they listened to multiple natural tokens of the vowels [ɑ] and [i], which we selected because their first and second formants overlap minimally. Formant-based regions of interest were defined for each vowel based on spectral analysis of the vowel stimuli and independently acquired tonotopic maps for each participant. We found that perception of [ɑ] and [i] yielded differential activation of tonotopic regions corresponding to formants of [ɑ] and [i], such that each vowel was associated with increased signal in tonotopic regions corresponding to its own formants. This pattern was observed in Heschl's gyrus and the superior temporal gyrus, in both hemispheres, and for both the first and second formants. Using linear discriminant analysis of mean signal change in formant-based regions of interest, the identity of untrained vowels was predicted with ∼73% accuracy. Our findings show that cortical encoding of vowels is scaffolded on tonotopy, a fundamental organizing principle of auditory cortex that is not language-specific.
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Affiliation(s)
- Julia M Fisher
- Department of Linguistics, University of Arizona, Tucson, AZ, USA; Statistics Consulting Laboratory, BIO5 Institute, University of Arizona, Tucson, AZ, USA
| | - Frederic K Dick
- Department of Psychological Sciences, Birkbeck College, University of London, UK; Birkbeck-UCL Center for Neuroimaging, London, UK; Department of Experimental Psychology, University College London, UK
| | - Deborah F Levy
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Stephen M Wilson
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN, USA.
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