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Vitt JR, Loper NE, Mainali S. Multimodal and autoregulation monitoring in the neurointensive care unit. Front Neurol 2023; 14:1155986. [PMID: 37153655 PMCID: PMC10157267 DOI: 10.3389/fneur.2023.1155986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 04/04/2023] [Indexed: 05/10/2023] Open
Abstract
Given the complexity of cerebral pathology in patients with acute brain injury, various neuromonitoring strategies have been developed to better appreciate physiologic relationships and potentially harmful derangements. There is ample evidence that bundling several neuromonitoring devices, termed "multimodal monitoring," is more beneficial compared to monitoring individual parameters as each may capture different and complementary aspects of cerebral physiology to provide a comprehensive picture that can help guide management. Furthermore, each modality has specific strengths and limitations that depend largely on spatiotemporal characteristics and complexity of the signal acquired. In this review we focus on the common clinical neuromonitoring techniques including intracranial pressure, brain tissue oxygenation, transcranial doppler and near-infrared spectroscopy with a focus on how each modality can also provide useful information about cerebral autoregulation capacity. Finally, we discuss the current evidence in using these modalities to support clinical decision making as well as potential insights into the future of advanced cerebral homeostatic assessments including neurovascular coupling.
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Affiliation(s)
- Jeffrey R. Vitt
- Department of Neurological Surgery, UC Davis Medical Center, Sacramento, CA, United States
- Department of Neurology, UC Davis Medical Center, Sacramento, CA, United States
| | - Nicholas E. Loper
- Department of Neurological Surgery, UC Davis Medical Center, Sacramento, CA, United States
| | - Shraddha Mainali
- Department of Neurology, Virginia Commonwealth University, Richmond, VA, United States
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2
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Mankoo A, Roy S, Davies A, Panerai RB, Robinson TG, Brassard P, Beishon LC, Minhas JS. The role of the autonomic nervous system in cerebral blood flow regulation in stroke: A review. Auton Neurosci 2023; 246:103082. [PMID: 36870192 DOI: 10.1016/j.autneu.2023.103082] [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: 12/24/2021] [Revised: 11/22/2022] [Accepted: 02/22/2023] [Indexed: 03/02/2023]
Abstract
Stroke is a pathophysiological condition which results in alterations in cerebral blood flow (CBF). The mechanism by which the brain maintains adequate CBF in presence of fluctuating cerebral perfusion pressure (CPP) is known as cerebral autoregulation (CA). Disturbances in CA may be influenced by a number of physiological pathways including the autonomic nervous system (ANS). The cerebrovascular system is innervated by adrenergic and cholinergic nerve fibers. The role of the ANS in regulating CBF is widely disputed owing to several factors including the complexity of the ANS and cerebrovascular interactions, limitations to measurements, variation in methods to assess the ANS in relation to CBF as well as experimental approaches that can or cannot provide insight into the sympathetic control of CBF. CA is known to be impaired in stroke however the number of studies investigating the mechanisms by which this occurs are limited. This literature review will focus on highlighting the assessment of the ANS and CBF via indices derived from the analyses of heart rate variability (HRV), and baroreflex sensitivity (BRS), and providing a summary of both clinical and animal model studies investigating the role of the ANS in influencing CA in stroke. Understanding the mechanisms by which the ANS influences CBF in stroke patients may provide the foundation for novel therapeutic approaches to improve functional outcomes in stroke patients.
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Affiliation(s)
- Alex Mankoo
- University of Leicester, Department of Cardiovascular Sciences, Leicester, United Kingdom
| | - Sankanika Roy
- University of Leicester, Department of Cardiovascular Sciences, Leicester, United Kingdom.
| | - Aaron Davies
- University of Leicester, Department of Cardiovascular Sciences, Leicester, United Kingdom
| | - Ronney B Panerai
- University of Leicester, Department of Cardiovascular Sciences, Leicester, United Kingdom; NIHR Leicester Biomedical Research Centre, British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester, United Kingdom
| | - Thompson G Robinson
- University of Leicester, Department of Cardiovascular Sciences, Leicester, United Kingdom; NIHR Leicester Biomedical Research Centre, British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester, United Kingdom
| | - Patrice Brassard
- Department of Kinesiology, Faculty of Medicine, Université Laval, Québec, QC, Canada; Research center of the Institut universitaire de cardiologie et de pneumologie de Québec-Université Laval, Québec, QC, Canada
| | - Lucy C Beishon
- University of Leicester, Department of Cardiovascular Sciences, Leicester, United Kingdom
| | - Jatinder S Minhas
- University of Leicester, Department of Cardiovascular Sciences, Leicester, United Kingdom; NIHR Leicester Biomedical Research Centre, British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester, United Kingdom
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3
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Almudayni A, Alharbi M, Chowdhury A, Ince J, Alablani F, Minhas JS, Lecchini-Visintini A, Chung EML. Magnetic resonance imaging of the pulsing brain: a systematic review. MAGMA (NEW YORK, N.Y.) 2023; 36:3-14. [PMID: 36242710 PMCID: PMC9992013 DOI: 10.1007/s10334-022-01043-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 09/15/2022] [Accepted: 10/03/2022] [Indexed: 11/05/2022]
Abstract
OBJECTIVE To perform a systematic review of the literature exploring magnetic resonance imaging (MRI) methods for measuring natural brain tissue pulsations (BTPs) in humans. METHODS A prospective systematic search of MEDLINE, SCOPUS and OpenGrey databases was conducted by two independent reviewers using a pre-determined strategy. The search focused on identifying reported measurements of naturally occurring BTP motion in humans. Studies involving non-human participants, MRI in combination with other modalities, MRI during invasive procedures and MRI studies involving externally applied tests were excluded. Data from the retrieved records were combined to create Forest plots comparing brain tissue displacement between Chiari-malformation type 1 (CM-I) patients and healthy controls using an independent samples t-test. RESULTS The search retrieved 22 eligible articles. Articles described 5 main MRI techniques for visualisation or quantification of intrinsic brain motion. MRI techniques generally agreed that the amplitude of BTPs varies regionally from 0.04 mm to ~ 0.80 mm, with larger tissue displacements occurring closer to the centre and base of the brain compared to peripheral regions. Studies of brain pathology using MRI BTP measurements are currently limited to tumour characterisation, idiopathic intracranial hypertension (IIH), and CM-I. A pooled analysis confirmed that displacement of tissue in the cerebellar tonsillar region of CM-I patients was + 0.31 mm [95% CI 0.23, 0.38, p < 0.0001] higher than in healthy controls. DISCUSSION MRI techniques used for measurements of brain motion are at an early stage of development with high heterogeneity across the methods used. Further work is required to provide normative data to support systematic BTPs characterisation in health and disease.
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Affiliation(s)
- Alanoud Almudayni
- College of Applied Medical Sciences, Prince Sattam Bin Abdulaziz University, Al-Kharj, Saudi Arabia. .,Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Room 419, Robert Kilpatrick Building, Leicester Royal Infirmary, Infirmary Square, Leicester, LE1 5WW, UK.
| | - Meshal Alharbi
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Room 419, Robert Kilpatrick Building, Leicester Royal Infirmary, Infirmary Square, Leicester, LE1 5WW, UK.,College of Applied Medical Sciences, King Saud Bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
| | - Alimul Chowdhury
- University Hospitals of Leicester NHS Trust, Leicester, LE1 5WW, UK
| | - Jonathan Ince
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Room 419, Robert Kilpatrick Building, Leicester Royal Infirmary, Infirmary Square, Leicester, LE1 5WW, UK
| | - Fatmah Alablani
- College of Applied Medical Sciences, Prince Sattam Bin Abdulaziz University, Al-Kharj, Saudi Arabia.,Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Room 419, Robert Kilpatrick Building, Leicester Royal Infirmary, Infirmary Square, Leicester, LE1 5WW, UK
| | - Jatinder Singh Minhas
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Room 419, Robert Kilpatrick Building, Leicester Royal Infirmary, Infirmary Square, Leicester, LE1 5WW, UK.,National Institute for Health Research Leicester Biomedical Research Centre, University of Leicester, Leicester, LE5 4PW, UK
| | - Andrea Lecchini-Visintini
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Room 419, Robert Kilpatrick Building, Leicester Royal Infirmary, Infirmary Square, Leicester, LE1 5WW, UK.,School of Electronics and Computer Science, University of Southampton, Southampton, SO17 1BJ, UK
| | - Emma Ming Lin Chung
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Room 419, Robert Kilpatrick Building, Leicester Royal Infirmary, Infirmary Square, Leicester, LE1 5WW, UK. .,University Hospitals of Leicester NHS Trust, Leicester, LE1 5WW, UK. .,National Institute for Health Research Leicester Biomedical Research Centre, University of Leicester, Leicester, LE5 4PW, UK. .,School of Life Course and Population Sciences, King's College London, Room 3.25a, Shepherd's House, Guy's Campus, King's College London, London, SE1 7EH, UK.
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Beishon LC, Minhas JS. Cerebral Autoregulation and Neurovascular Coupling in Acute and Chronic Stroke. Front Neurol 2021; 12:720770. [PMID: 34539560 PMCID: PMC8446264 DOI: 10.3389/fneur.2021.720770] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 08/11/2021] [Indexed: 11/13/2022] Open
Affiliation(s)
- Lucy C. Beishon
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
| | - Jatinder S. Minhas
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
- National Institute for Health Research (NIHR) Leicester Biomedical Research Centre, British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester, United Kingdom
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Paschoal AM, Leoni RF, Foerster BU, Dos Santos AC, Pontes-Neto OM, Paiva FF. Contrast optimization in arterial spin labeling with multiple post-labeling delays for cerebrovascular assessment. MAGMA (NEW YORK, N.Y.) 2021; 34:119-131. [PMID: 32885356 DOI: 10.1007/s10334-020-00883-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 07/01/2020] [Accepted: 08/25/2020] [Indexed: 06/11/2023]
Abstract
OBJECTIVE Improving the readout for arterial spin labeling with multiple post-labeling delays (multi-PLD ASL) through a flip angle (FA) sweep towards increasing contrast-to-noise ratio for long PLD images. METHODS Images were acquired from 20 healthy subjects and 14 patients with severe, asymptomatic carotid artery stenosis (ACAS) in a 3T MRI scanner. Multi-PLD ASL images with conventional and proposed (FA sweep) readouts were acquired. For patients, magnetic resonance angiography was used to validate the multi-PLD ASL results. Perfusion values were calculated for brain regions irrigated by the main cerebral arteries and compared by analysis of variance. RESULTS For healthy subjects, better contrast was obtained for long PLDs when using the proposed multi-PLD method compared to the conventional. For both methods, no hemispheric difference of perfusion was observed. For patients, the proposed method facilitated the observation of delayed tissue perfusion, which was not visible for long PLD using the conventional multi-PLD ASL. CONCLUSION We successfully assessed brain perfusion of patients with asymptomatic CAS using multi-PLD ASL with FA sweep. We were able to show subtle individual differences. Moreover, prolonged arterial transit time in patients was observed, although they were considered asymptomatic, suggesting that it may not be an adequate term to characterize them.
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Affiliation(s)
- André Monteiro Paschoal
- Inbrain, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
- Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
| | - Renata Ferranti Leoni
- Inbrain, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
| | - Bernd Uwe Foerster
- Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador São-Carlense, 400, São Carlos, SP, 13566-590, Brazil
| | | | | | - Fernando Fernandes Paiva
- Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador São-Carlense, 400, São Carlos, SP, 13566-590, Brazil.
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He F, Sullender CT, Zhu H, Williamson MR, Li X, Zhao Z, Jones TA, Xie C, Dunn AK, Luan L. Multimodal mapping of neural activity and cerebral blood flow reveals long-lasting neurovascular dissociations after small-scale strokes. SCIENCE ADVANCES 2020; 6:eaba1933. [PMID: 32494746 PMCID: PMC7244270 DOI: 10.1126/sciadv.aba1933] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 03/10/2020] [Indexed: 06/02/2023]
Abstract
Neurovascular coupling, the close spatial and temporal relationship between neural activity and hemodynamics, is disrupted in pathological brain states. To understand the altered neurovascular relationship in brain disorders, longitudinal, simultaneous mapping of neural activity and hemodynamics is critical yet challenging to achieve. Here, we use a multimodal neural platform in a mouse model of stroke and realize long-term, spatially resolved tracking of intracortical neural activity and cerebral blood flow in the same brain regions. We observe a pronounced neurovascular dissociation that occurs immediately after small-scale strokes, becomes the most severe a few days after, lasts into chronic periods, and varies with the level of ischemia. Neuronal deficits extend spatiotemporally, whereas restoration of cerebral blood flow occurs sooner and reaches a higher relative value. Our findings reveal the neurovascular impact of ministrokes and inform the limitation of neuroimaging techniques that infer neural activity from hemodynamic responses.
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Affiliation(s)
- Fei He
- Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, TX 77005, USA
- Neuroengineering Initiative, Rice University, 6500 Main Street, Houston, TX 77005, USA
| | - Colin T. Sullender
- Department of Biomedical Engineering, The University of Texas at Austin, 107 E. Dean Keeton Street, 1 University Station, C0800, Austin, TX 78712, USA
| | - Hanlin Zhu
- Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, TX 77005, USA
| | - Michael R. Williamson
- Institute for Neuroscience, The University of Texas at Austin, 1 University Station, Stop C7000, Austin, TX 78712, USA
| | - Xue Li
- Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, TX 77005, USA
| | - Zhengtuo Zhao
- Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, TX 77005, USA
- Neuroengineering Initiative, Rice University, 6500 Main Street, Houston, TX 77005, USA
| | - Theresa A. Jones
- Department of Psychology, The University of Texas at Austin, 108 E. Dean Keeton Street, Stop A8000, SEA 6.106, Austin, TX 78712, USA
| | - Chong Xie
- Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, TX 77005, USA
- Neuroengineering Initiative, Rice University, 6500 Main Street, Houston, TX 77005, USA
- Department of Bioengineering, Rice University, 6100 Main Street, Houston, TX 77005, USA
| | - Andrew K. Dunn
- Department of Biomedical Engineering, The University of Texas at Austin, 107 E. Dean Keeton Street, 1 University Station, C0800, Austin, TX 78712, USA
| | - Lan Luan
- Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, TX 77005, USA
- Neuroengineering Initiative, Rice University, 6500 Main Street, Houston, TX 77005, USA
- Department of Bioengineering, Rice University, 6100 Main Street, Houston, TX 77005, USA
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7
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Ince J, Alharbi M, Minhas JS, Chung EM. Ultrasound measurement of brain tissue movement in humans: A systematic review. ULTRASOUND : JOURNAL OF THE BRITISH MEDICAL ULTRASOUND SOCIETY 2019; 28:70-81. [PMID: 32528543 DOI: 10.1177/1742271x19894601] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 11/07/2019] [Indexed: 11/15/2022]
Abstract
Introduction It has long been suggested that ultrasound could be used to measure brain tissue pulsations in humans, but potential clinical applications are relatively unexplored. The aim of this systematic review was to explore and synthesise available literature on ultrasound measurement of brain tissue motion in humans. Methods Our systematic review was designed to include predefined study selection criteria, quality evaluation, and a data extraction pro-forma, registered prospectively on PROSPERO (CRD42018114117). The systematic review was conducted by two independent reviewers. Results Ten studies were eligible for the evidence synthesis and qualitative evaluation. All eligible studies confirmed that brain tissue motion over the cardiac cycle could be measured using ultrasound; however, data acquisition, analysis, and outcomes varied. The majority of studies used tissue pulsatility imaging, with the right temporal window as the acquisition point. Currently available literature is largely exploratory, with measurements of brain tissue displacement over a narrow range of health conditions and ages. Explored health conditions include orthostatic hypotension and depression. Conclusion Further studies are needed to assess variability in brain tissue motion estimates across larger cohorts of healthy subjects and in patients with various medical conditions. This would be important for informing sample size estimates to ensure future studies are appropriately powered. Future research would also benefit from a consistent framework for data analysis and reporting, to facilitate comparative research and meta-analysis. Following standardisation and further healthy participant studies, future work should focus on assessing the clinical utility of brain tissue pulsation measurements in cerebrovascular disease states.
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Affiliation(s)
- Jonathan Ince
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHIASM) Cardiovascular Sciences Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
| | - Meshal Alharbi
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHIASM) Cardiovascular Sciences Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, UK.,College of Applied Medical Sciences, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
| | - Jatinder S Minhas
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHIASM) Cardiovascular Sciences Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, UK.,National Institute for Health Research Leicester Biomedical Research Centre, Leicester, UK
| | - Emma Ml Chung
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHIASM) Cardiovascular Sciences Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, UK.,National Institute for Health Research Leicester Biomedical Research Centre, Leicester, UK
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8
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Salinet AS, Silva NC, Caldas J, de Azevedo DS, de-Lima-Oliveira M, Nogueira RC, Conforto AB, Texeira MJ, Robinson TG, Panerai RB, Bor-Seng-Shu E. Impaired cerebral autoregulation and neurovascular coupling in middle cerebral artery stroke: Influence of severity? J Cereb Blood Flow Metab 2019; 39:2277-2285. [PMID: 30117360 PMCID: PMC6827118 DOI: 10.1177/0271678x18794835] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We aimed to assess cerebral autoregulation (CA) and neurovascular coupling (NVC) in stroke patients of differing severity comparing responses to healthy controls and explore the association between CA and NVC with functional outcome. Patients admitted with middle cerebral artery (MCA) stroke and healthy controls were recruited. Stroke severity was defined by the National Institutes of Health Stroke Scale (NIHSS) scores: ≤4 mild, 5-15 moderate and ≥16 severe. Transcranial Doppler ultrasound and Finometer recorded MCA cerebral blood flow velocity (CBFv) and blood pressure, respectively, over 5 min baseline and 1 min passive movement of the elbow to calculate the autoregulation index (ARI) and CBFv amplitude responses to movement. All participants were followed up for three months. A total of 87 participants enrolled in the study, including 15 mild, 27 moderate and 13 severe stroke patients, and 32 control subjects. ARI was lower in the affected hemisphere (AH) of moderate and severe stroke groups. Decreased NVC was seen bilaterally in all stroke groups. CA and NVC correlated with stroke severity and functional outcome. CBFv regulation is significantly impaired in acute stroke, and further compromised with increasing stroke severity. Preserved CA and NVC in the acute period were associated with improved three-month functional outcome.
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Affiliation(s)
- Angela Sm Salinet
- Neurology Department, School of Medicine, University of São Paulo, Hospital das Clinicas, São Paulo, Brazil.,Engineering, Modelling and Applied Social Sciences Centre, Federal ABC University, Sao Bernardo do Campo, Sao Paulo, Brazil
| | - Nathália Cc Silva
- Neurology Department, School of Medicine, University of São Paulo, Hospital das Clinicas, São Paulo, Brazil
| | - Juliana Caldas
- Neurology Department, School of Medicine, University of São Paulo, Hospital das Clinicas, São Paulo, Brazil
| | - Daniel S de Azevedo
- Neurology Department, School of Medicine, University of São Paulo, Hospital das Clinicas, São Paulo, Brazil
| | - Marcelo de-Lima-Oliveira
- Neurosurgical Division, Neurology Department, School of Medicine, University of São Paulo, Hospital das Clinicas, São Paulo, Brazil
| | - Ricardo C Nogueira
- Neurology Department, School of Medicine, University of São Paulo, Hospital das Clinicas, São Paulo, Brazil
| | - Adriana B Conforto
- Neurology Department, School of Medicine, University of São Paulo, Hospital das Clinicas, São Paulo, Brazil.,Brain Institute, Albert Einstein Israelite Hospital, São Paulo, Brazil
| | - Manoel J Texeira
- Engineering, Modelling and Applied Social Sciences Centre, Federal ABC University, Sao Bernardo do Campo, Sao Paulo, Brazil
| | - Thompson G Robinson
- Department of Cardiovascular Sciences, Cerebral Haemodynamics in Ageing and Stroke Medicine Research Group, University of Leicester, Leicester, UK.,NIHR Leicester Biomedical Research Centre, University of Leicester, Leicester, UK
| | - Ronney B Panerai
- Department of Cardiovascular Sciences, Cerebral Haemodynamics in Ageing and Stroke Medicine Research Group, University of Leicester, Leicester, UK.,NIHR Leicester Biomedical Research Centre, University of Leicester, Leicester, UK
| | - Edson Bor-Seng-Shu
- Neurosurgical Division, Neurology Department, School of Medicine, University of São Paulo, Hospital das Clinicas, São Paulo, Brazil
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Effects of Tai Chi on Cerebral Hemodynamics and Health-Related Outcomes in Older Community Adults at Risk of Ischemic Stroke: A Randomized Controlled Trial. J Aging Phys Act 2019; 27:678–687. [DOI: 10.1123/japa.2018-0232] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
This study investigated the effects of Tai Chi compared with no exercise control on the cerebral hemodynamic parameters and other health-related factors in community older adults at risk of ischemic stroke. A total of 170 eligible participants were randomly allocated to Tai Chi or control group. The cerebral hemodynamic parameters and physical fitness risk factors of cardiovascular disease were measured at baseline, 12 weeks, and 24 weeks. After the 12-week intervention, Tai Chi significantly improved the minimum of blood flow velocity (BFVmin); BFVmean; pulsatility index and resistance index of the right anterior cerebral artery; and BFVmax, BFVmin, and BFVmeanparameters of the right middle cerebral artery. Tai Chi training also decreased triglyceride, fasting blood glucose, and homocysteine levels, and improved balance ability. Therefore, the supervised 12-week Tai Chi exercise had potential beneficial effects on cerebral hemodynamics, plasma risk factors, and balance ability in older community adults at risk of ischemic stroke.
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Iyer PC, Rosenberg A, Baynard T, Madhavan S. Influence of neurovascular mechanisms on response to tDCS: an exploratory study. Exp Brain Res 2019; 237:2829-2840. [PMID: 31455998 DOI: 10.1007/s00221-019-05626-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 08/08/2019] [Indexed: 10/26/2022]
Abstract
The beneficial effects of transcranial direct current stimulation (tDCS) for stroke rehabilitation are limited by the variability in changes in corticomotor excitability (CME) after tDCS. Neuronal activity is closely related to cerebral blood flow; however, the cerebral hemodynamics of neuromodulation in relation to neural effects have been less explored. In this study, we examined the effects of tDCS on cerebral blood velocity (CBv) in chronic stroke survivors using transcranial Doppler (TCD) ultrasound in relation to changes in CME and described the neurovascular characteristics of tDCS responders. Middle cerebral artery (MCA) CBv, cerebrovascular resistance (CVRi) and other cerebral hemodynamics-related variables were continuously measured before and after 15 min of 1 mA anodal tDCS to the lesioned lower limb M1. tDCS did not modulate CBv in the whole group and upon TMS-based stratification of responders and non-responders. However, at baseline, responders demonstrated lower CME levels, lower CBv and higher CVRi as compared to non-responders. These results indicate a possible difference in baseline CME and CBv in tDCS responders that may influence their response to neuromodulation. Future trials with a large sample size and repeated baseline measurements may help validate these findings and establish a relationship between neuromodulation and neurovascular mechanisms in stroke.
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Affiliation(s)
- Pooja C Iyer
- Graduate Program in Rehabilitation Science, College of Applied Health Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | - Alexander Rosenberg
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, TX, USA.,Integrative Physiology Laboratory, College of Applied Health Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | - Tracy Baynard
- Integrative Physiology Laboratory, College of Applied Health Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | - Sangeetha Madhavan
- Brain Plasticity Laboratory, Department of Physical Therapy, College of Applied Health Sciences, University of Illinois at Chicago, 1919 West Taylor Street, Chicago, IL, 60612, USA.
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11
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Non-invasive brain stimulation in the modulation of cerebral blood flow after stroke: A systematic review of Transcranial Doppler studies. Clin Neurophysiol 2018; 129:2544-2551. [PMID: 30384025 DOI: 10.1016/j.clinph.2018.09.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 09/13/2018] [Accepted: 09/18/2018] [Indexed: 11/21/2022]
Abstract
OBJECTIVE Non-invasive brain stimulation (NIBS), such as repetitive TMS (rTMS) and transcranial direct current stimulation (tDCS), are promising neuromodulatory priming techniques to promote task-specific functional recovery after stroke. Despite promising results, clinical application of NIBS has been limited by high inter-individual variability. We propose that there is a possible influence of neuromodulation on cerebral blood flow (CBF), as neurons are spatially and temporally related to blood vessels. Transcranial Doppler (TCD), a clinically available non-invasive diagnostic tool, allows for evaluation of CBF velocity (CBFv). However, little is known about the role of neuromodulation on CBFv. METHODS A systematic review of literature to understand the effects of NIBS on CBFv using TCD in stroke was conducted. RESULTS Twelve studies fit our inclusion criteria and are included in this review. Our review suggested that CBFv and/or vasomotor reactivity maybe influenced by rTMS dosage (intensity and frequency) and the type of tDCS electrode montage. CONCLUSION There is limited evidence regarding the effects of NIBS on cerebral hemodynamics using TCD and the usefulness of TCD to capture changes in CBFv after NIBS is not evident from this review. We highlight the variability in the experimental protocols, differences in the applied neurostimulation protocols and discuss open questions that remain regarding CBF and neuromodulation. SIGNIFICANCE TCD, a clinically accessible tool, may potentially be useful to understand the interaction between cortical neuromodulation and CBFv.
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12
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Simon JJ, Welfringer A, Leifert-Fiebach G, Brandt T. Motor imagery in chronic neglect: An fMRI pilot study. J Clin Exp Neuropsychol 2018; 41:58-68. [PMID: 30080434 DOI: 10.1080/13803395.2018.1500527] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
AIM Previous studies indicate the effectiveness of motor imagery training in stroke patients. To determine whether patients showing chronic visuospatial neglect symptoms may profit from motor imagery training, it is important to assess how the brain implements motor imagery when cortical systems involved in attentional control are impaired. METHOD Therefore, in this pilot study, nine chronic neglect patients with right-hemispheric stroke performed motor imagery of a finger opposition task during functional magnetic resonance imaging (fMRI). RESULTS Imagery of unaffected hand movements was related to activations in the left primary somatosensory and premotor cortices as well as in the left supplementary motor area. During the imagery of the affected hand, patients displayed activations in the left premotor cortex and supplementary motor area as well as left dorsolateral prefrontal cortex. Furthermore, time since onset and visual imagery capacity were negatively related to activation in the supplementary motor area during the imagery of the affected hand. CONCLUSIONS These initial results demonstrate motor imagery capacity in patients with chronic neglect via compensatory neural processing during motor imagery of the affected hand in ipsilateral brain regions, since we found that the supplementary motor area appears to be specifically related to neglect severity. Although our results must be treated with caution due to the small sample size and missing control group, they indicate that neglect is not necessarily an exclusion criterion for motor imagery training per se.
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Affiliation(s)
- Joe J Simon
- a Department of General Internal Medicine and Psychosomatics, Centre for Psychosocial Medicine , University Hospital Heidelberg , Heidelberg , Germany.,b Department of Psychosomatic Medicine and Psychotherapy, Medical Faculty , Heinrich-Heine-University Düsseldorf , Düsseldorf , Germany
| | | | | | - Tobias Brandt
- d Department of Neurology , University of Heidelberg , Heidelberg , Germany.,e Suva, Insurance Medicine , Luzern , Switzerland
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Beishon L, Haunton VJ, Panerai RB, Robinson TG. Cerebral Hemodynamics in Mild Cognitive Impairment: A Systematic Review. J Alzheimers Dis 2018; 59:369-385. [PMID: 28671118 DOI: 10.3233/jad-170181] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
BACKGROUND The incidence of dementia is projected to rise over the coming decades, but with no sensitive diagnostic tests available. Vascular pathology precedes the deposition of amyloid and is an attractive early target. OBJECTIVE The aim of this review was to investigate the use of cerebral hemodynamics and oxygenation as a novel biomarker for mild cognitive impairment (MCI), focusing on transcranial Doppler ultrasonography (TCD) and near-infrared spectroscopy (NIRS). METHODS 2,698 articles were identified from Medline, Embase, PsychINFO, and Web of Science databases. 306 articles were screened and quality assessed independently by two reviewers; 26 met the inclusion criteria. Meta-analyses were performed for each marker with two or more studies and limited heterogeneity. RESULTS Eleven studies were TCD, 8 NIRS, 5 magnetic resonance imaging, and 2 positron/single photon emission tomography. Meta-analyses showed reduced tissue oxygenation index, cerebral blood flow and velocity, with higher pulsatility index, phase and cerebrovascular resistance in MCI compared to controls. The majority of studies found reduced CO2 reactivity in MCI, with mixed findings in neuroactivation studies. CONCLUSION Despite small sample sizes and heterogeneity, meta-analyses demonstrate clear abnormalities in cerebral hemodynamic and oxygenation parameters, even at an early stage of cognitive decline. Further work is required to investigate the use of cerebral hemodynamic and oxygenation parameters as a sensitive biomarker for dementia.
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Affiliation(s)
- Lucy Beishon
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
| | - Victoria J Haunton
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK.,NIHR Biomedical Research Unit in Cardiovascular Disease, British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester, UK
| | - Ronney B Panerai
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK.,NIHR Biomedical Research Unit in Cardiovascular Disease, British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester, UK
| | - Thompson G Robinson
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK.,NIHR Biomedical Research Unit in Cardiovascular Disease, British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester, UK
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14
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Caldas JR, Haunton VJ, Panerai RB, Hajjar LA, Robinson TG. Cerebral autoregulation in cardiopulmonary bypass surgery: a systematic review. Interact Cardiovasc Thorac Surg 2017; 26:494-503. [DOI: 10.1093/icvts/ivx357] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Accepted: 10/03/2017] [Indexed: 01/06/2023] Open
Affiliation(s)
- Juliana R Caldas
- Department of Anesthesia, Heart Institute, University of São Paulo, São Paulo, Brazil
- Hospital Sao Rafael, Salvador, Bahia, Brazil
| | - Victoria J Haunton
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
| | - Ronney B Panerai
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
- NIHR Leicester Biomedical Research Centre, University of Leicester, Leicester, UK
| | - Ludhmila A Hajjar
- Department of Anesthesia, Heart Institute, University of São Paulo, São Paulo, Brazil
- Department of Cardiopneumology, Heart Institute, University of São Paulo, Brazil
| | - Thompson G Robinson
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
- NIHR Leicester Biomedical Research Centre, University of Leicester, Leicester, UK
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15
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Tang Q, Lin J, Tsytsarev V, Erzurumlu RS, Liu Y, Chen Y. Review of mesoscopic optical tomography for depth-resolved imaging of hemodynamic changes and neural activities. NEUROPHOTONICS 2017; 4:011009. [PMID: 27990452 PMCID: PMC5108095 DOI: 10.1117/1.nph.4.1.011009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 10/19/2016] [Indexed: 05/18/2023]
Abstract
Understanding the functional wiring of neural circuits and their patterns of activation following sensory stimulations is a fundamental task in the field of neuroscience. Furthermore, charting the activity patterns is undoubtedly important to elucidate how neural networks operate in the living brain. However, optical imaging must overcome the effects of light scattering in the tissue, which limit the light penetration depth and affect both the imaging quantitation and sensitivity. Laminar optical tomography (LOT) is a three-dimensional (3-D) in-vivo optical imaging technique that can be used for functional imaging. LOT can achieve both a resolution of 100 to [Formula: see text] and a penetration depth of 2 to 3 mm based either on absorption or fluorescence contrast, as well as large field-of-view and high acquisition speed. These advantages make LOT suitable for 3-D depth-resolved functional imaging of the neural functions in the brain and spinal cords. We review the basic principles and instrumentations of representative LOT systems, followed by recent applications of LOT on 3-D imaging of neural activities in the rat forepaw stimulation model and mouse whisker-barrel system.
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Affiliation(s)
- Qinggong Tang
- University of Maryland, Fischell Department of Bioengineering, 2334 Jeong H. Kim Engineering Building, College Park, Maryland 20742, United States
| | - Jonathan Lin
- University of Maryland, Fischell Department of Bioengineering, 2334 Jeong H. Kim Engineering Building, College Park, Maryland 20742, United States
| | - Vassiliy Tsytsarev
- University of Maryland School of Medicine, Department of Anatomy and Neurobiology, 20 Penn Street, HSFII S251, Baltimore, Maryland 21201, United States
| | - Reha S. Erzurumlu
- University of Maryland School of Medicine, Department of Anatomy and Neurobiology, 20 Penn Street, HSFII S251, Baltimore, Maryland 21201, United States
| | - Yi Liu
- University of Maryland, Fischell Department of Bioengineering, 2334 Jeong H. Kim Engineering Building, College Park, Maryland 20742, United States
| | - Yu Chen
- University of Maryland, Fischell Department of Bioengineering, 2334 Jeong H. Kim Engineering Building, College Park, Maryland 20742, United States
- Address all correspondence to: Yu Chen, E-mail:
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Siegel JS, Snyder AZ, Ramsey L, Shulman GL, Corbetta M. The effects of hemodynamic lag on functional connectivity and behavior after stroke. J Cereb Blood Flow Metab 2016; 36:2162-2176. [PMID: 26661223 PMCID: PMC5363662 DOI: 10.1177/0271678x15614846] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 09/02/2015] [Accepted: 10/06/2015] [Indexed: 01/22/2023]
Abstract
Stroke disrupts the brain's vascular supply, not only within but also outside areas of infarction. We investigated temporal delays (lag) in resting state functional magnetic resonance imaging signals in 130 stroke patients scanned two weeks, three months and 12 months post stroke onset. Thirty controls were scanned twice at an interval of three months. Hemodynamic lag was determined using cross-correlation with the global gray matter signal. Behavioral performance in multiple domains was assessed in all patients. Regional cerebral blood flow and carotid patency were assessed in subsets of the cohort using arterial spin labeling and carotid Doppler ultrasonography. Significant hemodynamic lag was observed in 30% of stroke patients sub-acutely. Approximately 10% of patients showed lag at one-year post-stroke. Hemodynamic lag corresponded to gross aberrancy in functional connectivity measures, performance deficits in multiple domains and local and global perfusion deficits. Correcting for lag partially normalized abnormalities in measured functional connectivity. Yet post-stroke FC-behavior relationships in the motor and attention systems persisted even after hemodynamic delays were corrected. Resting state fMRI can reliably identify areas of hemodynamic delay following stroke. Our data reveal that hemodynamic delay is common sub-acutely, alters functional connectivity, and may be of clinical importance.
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Affiliation(s)
- Joshua S Siegel
- Departments of Neurology, Washington University School of Medicine, Washington University, St. Louis, MO, USA
| | - Abraham Z Snyder
- Departments of Neurology, Washington University School of Medicine, Washington University, St. Louis, MO, USA.,Mallinckrodt Institute of Radiology, Washington University School of Medicine, Washington University, St. Louis, MO, USA
| | - Lenny Ramsey
- Departments of Neurology, Washington University School of Medicine, Washington University, St. Louis, MO, USA
| | - Gordon L Shulman
- Departments of Neurology, Washington University School of Medicine, Washington University, St. Louis, MO, USA
| | - Maurizio Corbetta
- Departments of Neurology, Washington University School of Medicine, Washington University, St. Louis, MO, USA.,Mallinckrodt Institute of Radiology, Washington University School of Medicine, Washington University, St. Louis, MO, USA.,Anatomy & Neurobiology at Washington University School of Medicine, Washington University, St. Louis, MO, USA
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17
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Baldassarre A, Ramsey L, Rengachary J, Zinn K, Siegel JS, Metcalf NV, Strube MJ, Snyder AZ, Corbetta M, Shulman GL. Dissociated functional connectivity profiles for motor and attention deficits in acute right-hemisphere stroke. Brain 2016; 139:2024-38. [PMID: 27225794 DOI: 10.1093/brain/aww107] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 03/24/2016] [Indexed: 12/31/2022] Open
Abstract
Strokes often cause multiple behavioural deficits that are correlated at the population level. Here, we show that motor and attention deficits are selectively associated with abnormal patterns of resting state functional connectivity in the dorsal attention and motor networks. We measured attention and motor deficits in 44 right hemisphere-damaged patients with a first-time stroke at 1-2 weeks post-onset. The motor battery included tests that evaluated deficits in both upper and lower extremities. The attention battery assessed both spatial and non-spatial attention deficits. Summary measures for motor and attention deficits were identified through principal component analyses on the raw behavioural scores. Functional connectivity in structurally normal cortex was estimated based on the temporal correlation of blood oxygenation level-dependent signals measured at rest with functional magnetic resonance imaging. Any correlation between motor and attention deficits and between functional connectivity in the dorsal attention network and motor networks that might spuriously affect the relationship between each deficit and functional connectivity was statistically removed. We report a double dissociation between abnormal functional connectivity patterns and attention and motor deficits, respectively. Attention deficits were significantly more correlated with abnormal interhemispheric functional connectivity within the dorsal attention network than motor networks, while motor deficits were significantly more correlated with abnormal interhemispheric functional connectivity patterns within the motor networks than dorsal attention network. These findings indicate that functional connectivity patterns in structurally normal cortex following a stroke link abnormal physiology in brain networks to the corresponding behavioural deficits.
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Affiliation(s)
- Antonello Baldassarre
- 1 Department of Neurology, Washington University in St. Louis School of Medicine, 660 S Euclid Ave, St Louis, MO 63110, USA 2 Department of Neuroscience, Imaging, and Clinical Sciences, University of Chieti, via dei Vestini 33, 66013, Chieti, Italy 3 Institute for Advanced Biomedical Technologies, University of Chieti G. d'Annunzio, via dei Vestini 33, 66013, Chieti, Italy
| | - Lenny Ramsey
- 1 Department of Neurology, Washington University in St. Louis School of Medicine, 660 S Euclid Ave, St Louis, MO 63110, USA
| | - Jennifer Rengachary
- 1 Department of Neurology, Washington University in St. Louis School of Medicine, 660 S Euclid Ave, St Louis, MO 63110, USA
| | - Kristi Zinn
- 1 Department of Neurology, Washington University in St. Louis School of Medicine, 660 S Euclid Ave, St Louis, MO 63110, USA
| | - Joshua S Siegel
- 1 Department of Neurology, Washington University in St. Louis School of Medicine, 660 S Euclid Ave, St Louis, MO 63110, USA
| | - Nicholas V Metcalf
- 1 Department of Neurology, Washington University in St. Louis School of Medicine, 660 S Euclid Ave, St Louis, MO 63110, USA
| | - Michael J Strube
- 4 Department of Psychology, Washington University in St. Louis, 1 Brooking Dr., St Louis, MO, USA
| | - Abraham Z Snyder
- 5 Department of Radiology, Washington University in Saint Louis School of Medicine, 660 S Euclid Ave, St Louis, MO 63110, USA
| | - Maurizio Corbetta
- 1 Department of Neurology, Washington University in St. Louis School of Medicine, 660 S Euclid Ave, St Louis, MO 63110, USA 5 Department of Radiology, Washington University in Saint Louis School of Medicine, 660 S Euclid Ave, St Louis, MO 63110, USA 6 Department of Neuroscience, University of Padua, Via Giustiniani, 5 35128, Padova, Italy 7 Department of Anatomy and Neurobiology, Washington University in St. Louis, School of Medicine, 660 S Euclid Ave, St Louis, MO 63110, USA 8 Department of Bioengineering, Washington University in St. Louis, 660 S Euclid Ave, St Louis, MO 63110, USA
| | - Gordon L Shulman
- 1 Department of Neurology, Washington University in St. Louis School of Medicine, 660 S Euclid Ave, St Louis, MO 63110, USA
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Interpreting Intervention Induced Neuroplasticity with fMRI: The Case for Multimodal Imaging Strategies. Neural Plast 2015; 2016:2643491. [PMID: 26839711 PMCID: PMC4709757 DOI: 10.1155/2016/2643491] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 09/27/2015] [Indexed: 12/03/2022] Open
Abstract
Direct measurement of recovery from brain injury is an important goal in neurorehabilitation, and requires reliable, objective, and interpretable measures of changes in brain function, referred to generally as “neuroplasticity.” One popular imaging modality for measuring neuroplasticity is task-based functional magnetic resonance imaging (t-fMRI). In the field of neurorehabilitation, however, assessing neuroplasticity using t-fMRI presents a significant challenge. This commentary reviews t-fMRI changes commonly reported in patients with cerebral palsy or acquired brain injuries, with a focus on studies of motor rehabilitation, and discusses complexities surrounding their interpretations. Specifically, we discuss the difficulties in interpreting t-fMRI changes in terms of their underlying causes, that is, differentiating whether they reflect genuine reorganisation, neurological restoration, compensation, use of preexisting redundancies, changes in strategy, or maladaptive processes. Furthermore, we discuss the impact of heterogeneous disease states and essential t-fMRI processing steps on the interpretability of activation patterns. To better understand therapy-induced neuroplastic changes, we suggest that researchers utilising t-fMRI consider concurrently acquiring information from an additional modality, to quantify, for example, haemodynamic differences or microstructural changes. We outline a variety of such supplementary measures for investigating brain reorganisation and discuss situations in which they may prove beneficial to the interpretation of t-fMRI data.
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Abstract
SIGNIFICANCE The brain has high energetic requirements and is therefore highly dependent on adequate cerebral blood supply. To compensate for dangerous fluctuations in cerebral perfusion, the circulation of the brain has evolved intrinsic safeguarding measures. RECENT ADVANCES AND CRITICAL ISSUES The vascular network of the brain incorporates a high degree of redundancy, allowing the redirection and redistribution of blood flow in the event of vascular occlusion. Furthermore, active responses such as cerebral autoregulation, which acts to maintain constant cerebral blood flow in response to changing blood pressure, and functional hyperemia, which couples blood supply with synaptic activity, allow the brain to maintain adequate cerebral perfusion in the face of varying supply or demand. In the presence of stroke risk factors, such as hypertension and diabetes, these protective processes are impaired and the susceptibility of the brain to ischemic injury is increased. One potential mechanism for the increased injury is that collateral flow arising from the normally perfused brain and supplying blood flow to the ischemic region is suppressed, resulting in more severe ischemia. FUTURE DIRECTIONS Approaches to support collateral flow may ameliorate the outcome of focal cerebral ischemia by rescuing cerebral perfusion in potentially viable regions of the ischemic territory.
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Affiliation(s)
- Katherine Jackman
- Brain and Mind Research Institute, Weill Cornell Medical College , New York, New York
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Salinet ASM, Robinson TG, Panerai RB. Effects of cerebral ischemia on human neurovascular coupling, CO2 reactivity, and dynamic cerebral autoregulation. J Appl Physiol (1985) 2014; 118:170-7. [PMID: 25593216 DOI: 10.1152/japplphysiol.00620.2014] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Cerebral blood flow (CBF) regulation can be impaired in acute ischemic stroke but the combined effects of dynamic cerebral autoregulation (CA), CO2 cerebrovascular reactivity (CVR), and neurovascular coupling (NVC), obtained from simultaneous measurements, have not been described. CBF velocity in the middle cerebral artery (MCA) (CBFv, transcranial Doppler), blood pressure (BP, Finometer), and end-tidal Pco2 (PetCO2 , infrared capnography) were recorded during a 1-min passive movement of the arm in 27 healthy controls [mean age (SD) 61.4 (6.0) yr] and 27 acute stroke patients [age 63 (11.7) yr]. A multivariate autoregressive-moving average model was used to separate the contributions of BP, arterial Pco2 (PaCO2 ), and the neural activation to the CBFv responses. CBFv step responses for the BP, CO2, and stimulus inputs were also obtained. The contribution of the stimulus to the CBFv response was highly significant for the difference between the affected side [area under the curve (AUC) 104.5 (4.5)%] and controls [AUC 106.9 (4.3)%; P = 0.008]. CBFv step responses to CO2 [affected hemisphere 0.39 (0.7), unaffected 0.55 (0.8), controls 1.39 (0.9)%/mmHg; P = 0.01, affected vs. controls; P = 0.025, unaffected vs. controls] and motor stimulus inputs [affected hemisphere 0.20 (0.1), unaffected 0.22 (0.2), controls 0.37 (0.2) arbitrary units; P = 0.009, affected vs. controls; P = 0.02, unaffected vs. controls] were reduced in the stroke group compared with controls. The CBFv step responses to the BP input at baseline and during the paradigm were not different between groups (P = 0.07), but PetCO2 was lower in the stroke group (P < 0.05). These results provide new insights into the interaction of CA, CVR, and NVC in both health and disease states.
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Affiliation(s)
- Angela S M Salinet
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom; and
| | - Thompson G Robinson
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom; and National Institutes for Health Research (NIHR), Biomedical Research Unit in Cardiovascular Sciences, Glenfield Hospital, Leicester, United Kingdom
| | - Ronney B Panerai
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom; and National Institutes for Health Research (NIHR), Biomedical Research Unit in Cardiovascular Sciences, Glenfield Hospital, Leicester, United Kingdom
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Salinet ASM, Panerai RB, Robinson TG. The longitudinal evolution of cerebral blood flow regulation after acute ischaemic stroke. Cerebrovasc Dis Extra 2014; 4:186-97. [PMID: 25298773 PMCID: PMC4176407 DOI: 10.1159/000366017] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 07/20/2014] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Acute stroke is known to impair cerebral blood flow (CBF) regulation, but the longitudinal changes of these effects have been poorly reported. The main CBF regulatory mechanisms [cerebral autoregulation (CA) and neurovascular coupling (NVC)] were assessed over 3 months after acute ischaemic stroke. METHODS Recordings of CBF velocity (CBFv), blood pressure (BP), and end-tidal CO2 were performed during 5 min baseline and 1 min passive movement of the elbow. Stroke patients were assessed <72 h of stroke onset, and at 2 weeks, 1 and 3 months after stroke. RESULTS Fifteen acute stroke subjects underwent all 4 sessions and were compared to 22 control subjects. Baseline recordings revealed a significantly lower CBFv in the affected hemisphere within 72 h after stroke compared to controls (p = 0.02) and a reduction in CA index most marked at 2 weeks (p = 0.009). CBFv rise in response to passive arm movement was decreased bilaterally after stroke, particularly in the affected hemisphere (p < 0.01). Both alterations in CA and NVC returned to control levels during recovery. CONCLUSION The major novel finding of this study was that both CA and NVC regulatory mechanisms deteriorated initially following stroke onset, but returned to control levels during the recovery period. These findings are relevant to guide the timing of interventions to manipulate BP and potentially for the impact of intensive rehabilitation strategies that may precipitate acute physiological perturbations but require further exploration in a larger population that better reflects the heterogeneity of stroke. Further, they will also enable the potential influence of stroke subtype to be investigated.
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Affiliation(s)
- Angela S M Salinet
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
| | - Ronney B Panerai
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK ; National Institutes for Health Research, Biomedical Research Unit in Cardiovascular Sciences, Clinical Sciences Wing, Glenfield Hospital, Leicester, UK
| | - Thompson G Robinson
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK ; National Institutes for Health Research, Biomedical Research Unit in Cardiovascular Sciences, Clinical Sciences Wing, Glenfield Hospital, Leicester, UK
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Salinet ASM, Robinson TG, Panerai RB. Cerebral blood flow response to neural activation after acute ischemic stroke: a failure of myogenic regulation? J Neurol 2013; 260:2588-95. [PMID: 23824356 DOI: 10.1007/s00415-013-7022-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Revised: 06/17/2013] [Accepted: 06/23/2013] [Indexed: 12/19/2022]
Abstract
We tested two hypotheses: (1) neurovascular coupling is impaired after acute ischemic stroke, (2) subcomponent analysis of cerebral blood flow velocity can reveal significant differences between acute ischemic stroke and healthy controls. This was explored through the comparison of nineteen acute ischemic stroke patients with healthy controls. Recordings of cerebral blood flow velocity, blood pressure and end-tidal CO2 were obtained during 60s of passive elbow flexion. Cerebral blood flow velocity changes were decomposed into standardized subcomponents describing the contributions of blood pressure (V BP), resistance area product (V RAP) and critical closing pressure (V CrCP). The passive paradigm led to a bilateral cerebral blood flow velocity increase in both groups, but in acute ischemic stroke the magnitude of change was significantly lower. Blood pressure increases were shown to be an important contributor to cerebral blood flow velocity response throughout the paradigm in both groups, with no significant difference between groups. The V CrCP contribution was not different between groups or hemispheres; its continuous rise during activation indicating a vasodilatory effect. On the other hand, the V RAP contribution showed significant differences (p = 0.03), thus suggesting myogenic impairment in acute ischemic stroke. Cerebral blood flow velocity responses to passive elbow flexion suggest an impairment of neurovascular coupling in acute ischemic stroke. Subcomponent analysis suggests an impairment of the myogenic pathways, giving a greater insight into the different mechanisms contributing to neurovascular coupling. Further research is needed to assess the clinical value of subcomponent analysis of neurovascular coupling and the natural history of such changes following acute ischemic stroke.
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Affiliation(s)
- Angela S M Salinet
- Department of Cardiovascular Sciences, University of Leicester, Trent Stroke Research Network Office, Victoria Building, Leicester Royal Infirmary, LE1 5WW, Leicester, UK,
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Maggio P, Salinet ASM, Panerai RB, Robinson TG. Does hypercapnia-induced impairment of cerebral autoregulation affect neurovascular coupling? A functional TCD study. J Appl Physiol (1985) 2013; 115:491-7. [PMID: 23743398 DOI: 10.1152/japplphysiol.00327.2013] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Neurovascular coupling (NVC) and dynamic cerebral autoregulation (dCA) are both impaired in the acute phase of ischemic stroke, but their reciprocal interactions are difficult to predict. To clarify these aspects, the present study explored NVC in a healthy volunteer population during a surrogate state of impaired dCA induced by hypercapnia. This study aimed to test whether hypercapnia leads to a depression of NVC through an impairment of dCA. Continuous recordings of middle cerebral arteries cerebral blood flow velocity (CBFv), blood pressure (BP), heart rate, and end-tidal CO2 were performed in 19 right-handed subjects (aged >45 yr) before, during, and after 60 s of a passive paradigm during normocapnia and hypercapnia. The CBFv response was broken down into subcomponents describing the relative contributions of BP (VBP), critical closing pressure (VCrCP), and resistance area product (VRAP). VRAP reflects myogenic activity in response to BP changes, whereas VCrCP is more indicative of metabolic control. The results revealed that hypercapnia significantly affected NVC, with significant reductions in the relative contribution of VCrCP to the paradigm-induced increase in CBFv. The present study suggests that hypercapnia impairs both dCA and NVC, probably acting through an impairment of the metabolic component of CBF control.
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Affiliation(s)
- Paola Maggio
- Neurologia Clinica, Università Campus Bio-Medico, Rome, Italy
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