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Ross DA, Shinde AB, Lerud KD, Schlaug G. Multielectrode Network Stimulation (ME-NETS) demonstrated by concurrent tDCS and fMRI. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.13.544867. [PMID: 37398497 PMCID: PMC10312777 DOI: 10.1101/2023.06.13.544867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Non-invasive transcranial direct current stimulation (tDCS) can modulate activity of targeted brain regions. Whether tDCS can reliably and repeatedly modulate intrinsic connectivity of entire brain networks is unclear. We used concurrent tDCS-MRI to investigate the effect of high dose anodal tDCS on resting state connectivity within the Arcuate Fasciculus (AF) network, which spans the temporal, parietal, and frontal lobes and is connected via a structural backbone, the Arcuate Fasciculus (AF) white matter tract. Effects of high-dose tDCS (4mA) delivered via a single electrode placed over one of the AF nodes (single electrode stimulation, SE-S) was compared to the same dose split between multiple electrodes placed over AF-network nodes (multielectrode network stimulation, ME-NETS). While both SE-S and ME-NETS significantly modulated connectivity between AF network nodes (increasing connectivity during stimulation epochs), ME-NETS had a significantly larger and more reliable effect than SE-S. Moreover, comparison with a control network, the Inferior Longitudinal Fasciculus (ILF) network suggested that the effect of ME-NETS on connectivity was specific to the targeted AF-network. This finding was further supported by the results of a seed-to-voxel analysis wherein we found ME-NETS primarily modulated connectivity between AF-network nodes. Finally, an exploratory analysis looking at dynamic connectivity using sliding window correlation found strong and immediate modulation of connectivity during three stimulation epochs within the same imaging session.
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Marchina S, Norton A, Schlaug G. Effects of melodic intonation therapy in patients with chronic nonfluent aphasia. Ann N Y Acad Sci 2023; 1519:173-185. [PMID: 36349876 PMCID: PMC10262915 DOI: 10.1111/nyas.14927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Patients with large left-hemisphere lesions and post-stroke aphasia often remain nonfluent. Melodic intonation therapy (MIT) may be an effective alternative to traditional speech therapy for facilitating recovery of fluency in those patients. In an open-label, proof-of-concept study, 14 subjects with nonfluent aphasia with large left-hemisphere lesions (171 ± 76 cc) underwent two speech/language assessments before, one at the midpoint, and two after the end of 75 sessions (1.5 h/session) of MIT. Functional MR imaging was done before and after therapy asking subjects to vocalize the same set of 10 bi-syllabic words. We found significant improvements in speech output after a period of intensive MIT (75 sessions for a total of 112.5 h) compared to two pre-therapy assessments. Therapy-induced gains were maintained 4 weeks post-treatment. Imaging changes were seen in a right-hemisphere network that included the posterior superior temporal and inferior frontal gyri, inferior pre- and postcentral gyri, pre-supplementary motor area, and supramarginal gyrus. Functional changes in the posterior right inferior frontal gyri significantly correlated with changes in a measure of fluency. Intense training of intonation-supported auditory-motor coupling and engaging feedforward/feedback control regions in the unaffected hemisphere improves speech-motor functions in subjects with nonfluent aphasia and large left-hemisphere lesions.
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Affiliation(s)
- Sarah Marchina
- Department of Neurology, Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, Massachusetts, USA
| | - Andrea Norton
- Department of Neurology, Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, Massachusetts, USA
| | - Gottfried Schlaug
- Department of Neurology, Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, Massachusetts, USA
- Department of Neurology, Music, Neuroimaging and Stroke Recovery Laboratories, University of Massachusetts Chan Medical School – Baystate Campus, Springfield, Massachusetts, USA
- Department of Biomedical Engineering and Institute of Applied Life Sciences, University of Massachusetts, Amherst, Amherst, Massachusetts, USA
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Integrity of the Left Arcuate Fasciculus Segments Significantly Affects Language Performance in Individuals with Acute/Subacute Post-Stroke Aphasia: A Cross-Sectional Diffusion Tensor Imaging Study. Brain Sci 2022; 12:brainsci12070907. [PMID: 35884714 PMCID: PMC9313217 DOI: 10.3390/brainsci12070907] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 07/05/2022] [Accepted: 07/08/2022] [Indexed: 01/05/2023] Open
Abstract
Objective: To investigate the correlation between the left arcuate fasciculus (AF) segments and acute/subacute post-stroke aphasia (PSA). Methods: Twenty-six patients underwent language assessment and MRI scanning. The integrity of the AF based on a three-segment model was evaluated using diffusion tensor imaging. All patients were classified into three groups according to the reconstruction of the left AF: completely reconstructed (group A, 8 cases), non-reconstructed (group B, 6 cases), and partially reconstructed (group C, 12 cases). The correlations and intergroup differences in language performance and diffusion indices were comprehensively estimated. Results: A correlation analyses showed that the lesion load of the language areas and diffusion indices on the left AF posterior and long segments was significantly related to some language subsets, respectively. When controlled lesion load was variable, significant correlations between diffusion indices on the posterior and long segments and comprehension, repetition, naming, and aphasia quotient were retained. Multiple comparison tests revealed intergroup differences in diffusion indices on the left AF posterior and long segments, as well as these language subsets. No significant correlation was found between the anterior segment and language performance. Conclusions: The integrity of the left AF segments, particularly the posterior segment, is crucial for the residual comprehension and repetition abilities in individuals with acute/subacute PSA, and lesion load in cortical language areas is an important factor that should be taken into account when illustrating the contributions of damage to special fiber tracts to language impairments.
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Prillwitz CC, David B, Schlaug G, Deller T, Schramm J, Lindenberg R, Hattingen E, Weber B, Surges R, Elger CE, Rüber T. Functional redundancy of the premotor network in hemispherotomy patients. Ann Clin Transl Neurol 2021; 8:1796-1808. [PMID: 34351075 PMCID: PMC8419409 DOI: 10.1002/acn3.51427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 06/30/2021] [Indexed: 11/08/2022] Open
Abstract
OBJECTIVE Using multimodal imaging, we tested the hypothesis that patients after hemispherotomy recruit non-primary motor areas and non-pyramidal descending motor fibers to restore motor function of the impaired limb. METHODS Functional and structural MRI data were acquired in a group of 25 patients who had undergone hemispherotomy and in a matched group of healthy controls. Patients' motor impairment was measured using the Fugl-Meyer Motor Assessment. Cortical areas governing upper extremity motor-control were identified by task-based functional MRI. The resulting areas were used as nodes for functional and structural connectivity analyses. RESULTS In hemispherotomy patients, movement of the impaired upper extremity was associated to widespread activation of non-primary premotor areas, whereas movement of the unimpaired one and of the control group related to activations prevalently located in the primary motor cortex (all p ≤ 0.05, FWE-corrected). Non-pyramidal tracts originating in premotor/supplementary motor areas and descending through the pontine tegmentum showed relatively higher structural connectivity in patients (p < 0.001, FWE-corrected). Significant correlations between structural connectivity and motor impairment were found for non-pyramidal (p = 0.023, FWE-corrected), but not for pyramidal connections. INTERPRETATION A premotor/supplementary motor network and non-pyramidal fibers seem to mediate motor function in patients after hemispherotomy. In case of hemispheric lesion, the homologous regions in the contralesional hemisphere may not compensate the resulting motor deficit, but the functionally redundant premotor network.
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Affiliation(s)
| | - Bastian David
- Department of EpileptologyUniversity of Bonn Medical CenterBonnGermany
| | - Gottfried Schlaug
- Stroke Recovery LaboratoryBeth Israel Deaconess Medical CenterHarvard Medical SchoolBostonMassachusettsUSA
| | - Thomas Deller
- Institute of Clinical NeuroanatomyNeuroscience CenterGoethe‐University FrankfurtFrankfurt am MainGermany
| | | | - Robert Lindenberg
- Department of History, Philosophy and Ethics of MedicineCenter for Health and SocietyHeinrich‐Heine‐UniversityDüsseldorfGermany
| | - Elke Hattingen
- Department of NeuroradiologyGoethe‐University FrankfurtFrankfurt am MainGermany
| | - Bernd Weber
- Institute of Experimental Epileptology and Cognition ResearchUniversity of Bonn Medical CenterBonnGermany
| | - Rainer Surges
- Department of EpileptologyUniversity of Bonn Medical CenterBonnGermany
| | | | - Theodor Rüber
- Department of EpileptologyUniversity of Bonn Medical CenterBonnGermany
- Department of NeurologyEpilepsy Center Frankfurt Rhine‐MainGoethe‐University FrankfurtFrankfurt am MainGermany
- Center for Personalized Translational Epilepsy Research (CePTER)Goethe‐University FrankfurtFrankfurt am MainGermany
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Wilmskoetter J, Marebwa B, Basilakos A, Fridriksson J, Rorden C, Stark BC, Johnson L, Hickok G, Hillis AE, Bonilha L. Long-range fibre damage in small vessel brain disease affects aphasia severity. Brain 2020; 142:3190-3201. [PMID: 31501862 DOI: 10.1093/brain/awz251] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 06/02/2019] [Accepted: 06/25/2019] [Indexed: 12/13/2022] Open
Abstract
We sought to determine the underlying pathophysiology relating white matter hyperintensities to chronic aphasia severity. We hypothesized that: (i) white matter hyperintensities are associated with damage to fibres of any length, but to a higher percentage of long-range compared to mid- and short-range intracerebral white matter fibres; and (ii) the number of long-range fibres mediates the relationship between white matter hyperintensities and chronic post-stroke aphasia severity. We measured the severity of periventricular and deep white matter hyperintensities and calculated the number and percentages of short-, mid- and long-range white matter fibres in 48 individuals with chronic post-stroke aphasia. Correlation and mediation analyses were performed to assess the relationship between white matter hyperintensities, connectome fibre-length measures and aphasia severity as measured with the aphasia quotient of the Western Aphasia Battery-Revised (WAB-AQ). We found that more severe periventricular and deep white matter hyperintensities correlated with a lower proportion of long-range fibres (r = -0.423, P = 0.003 and r = -0.315, P = 0.029, respectively), counterbalanced by a higher proportion of short-range fibres (r = 0.427, P = 0.002 and r = 0.285, P = 0.050, respectively). More severe periventricular white matter hyperintensities also correlated with a lower proportion of mid-range fibres (r = -0.334, P = 0.020), while deep white matter hyperintensities did not correlate with mid-range fibres (r = -0.169, P = 0.250). Mediation analyses revealed: (i) a significant total effect of periventricular white matter hyperintensities on WAB-AQ (standardized beta = -0.348, P = 0.008); (ii) a non-significant direct effect of periventricular white matter hyperintensities on WAB-AQ (P > 0.05); (iii) significant indirect effects of more severe periventricular white matter hyperintensities on worse aphasia severity mediated in parallel by fewer long-range fibres (effect = -6.23, bootstrapping: standard error = 2.64, 95%CI: -11.82 to -1.56) and more short-range fibres (effect = 4.50, bootstrapping: standard error = 2.59, 95%CI: 0.16 to 10.29). We conclude that small vessel brain disease seems to affect chronic aphasia severity through a change of the proportions of long- and short-range fibres. This observation provides insight into the pathophysiology of small vessel brain disease, and its relationship with brain health and chronic aphasia severity.
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Affiliation(s)
- Janina Wilmskoetter
- Department of Neurology, College of Medicine, Medical University of South Carolina, Charleston, SC, USA
| | - Barbara Marebwa
- Department of Neurology, College of Medicine, Medical University of South Carolina, Charleston, SC, USA
| | - Alexandra Basilakos
- Department of Communication Sciences and Disorders, University of South Carolina, Columbia, SC, USA
| | - Julius Fridriksson
- Department of Communication Sciences and Disorders, University of South Carolina, Columbia, SC, USA
| | - Chris Rorden
- Department of Psychology, University of South Carolina, Columbia, SC, USA
| | - Brielle C Stark
- Department of Speech and Hearing Sciences, Indiana University, IN, USA
| | - Lisa Johnson
- Department of Communication Sciences and Disorders, University of South Carolina, Columbia, SC, USA
| | - Gregory Hickok
- Department of Cognitive Sciences, University of California, Irvine, CA, USA
| | - Argye E Hillis
- Department of Neurology, Johns Hopkins University, Baltimore, MD, USA
| | - Leonardo Bonilha
- Department of Neurology, College of Medicine, Medical University of South Carolina, Charleston, SC, USA
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Osa García A, Brambati SM, Brisebois A, Désilets-Barnabé M, Houzé B, Bedetti C, Rochon E, Leonard C, Desautels A, Marcotte K. Predicting Early Post-stroke Aphasia Outcome From Initial Aphasia Severity. Front Neurol 2020; 11:120. [PMID: 32153496 PMCID: PMC7047164 DOI: 10.3389/fneur.2020.00120] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 02/03/2020] [Indexed: 12/11/2022] Open
Abstract
Background: The greatest degree of language recovery in post-stroke aphasia takes place within the first weeks. Aphasia severity and lesion measures have been shown to be good predictors of long-term outcomes. However, little is known about their implications in early spontaneous recovery. The present study sought to determine which factors better predict early language outcomes in individuals with post-stroke aphasia. Methods: Twenty individuals with post-stroke aphasia were assessed <72 h (acute) and 10-14 days (subacute) after stroke onset. We developed a composite score (CS) consisting of several linguistic sub-tests: repetition, oral comprehension and naming. Lesion volume, lesion load and diffusion measures [fractional anisotropy (FA) and axial diffusivity (AD)] from both arcuate fasciculi (AF) were also extracted using MRI scans performed at the same time points. A series of regression analyses were performed to predict the CS at the second assessment. Results: Among the diffusion measures, only FA from right AF was found to be a significant predictor of early subacute aphasia outcome. However, when combined in two hierarchical models with FA, age and either lesion load or lesion size, the initial aphasia severity was found to account for most of the variance (R 2 = 0.678), similarly to the complete models (R 2 = 0.703 and R 2 = 0.73, respectively). Conclusions: Initial aphasia severity was the best predictor of early post-stroke aphasia outcome, whereas lesion measures, though highly correlated, show less influence on the prediction model. We suggest that factors predicting early recovery may differ from those involved in long-term recovery.
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Affiliation(s)
- Alberto Osa García
- Centre de Recherche du Centre Intégré Universitaire de Santé et de Services Sociaux du Nord-de-l'Île-de-Montréal, Montreal, QC, Canada
- École d'Orthophonie et d'Audiologie, Université de Montréal, Montreal, QC, Canada
| | - Simona Maria Brambati
- Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal, Montreal, QC, Canada
- Département de Psychologie, Université de Montréal, Montreal, QC, Canada
| | - Amélie Brisebois
- Centre de Recherche du Centre Intégré Universitaire de Santé et de Services Sociaux du Nord-de-l'Île-de-Montréal, Montreal, QC, Canada
- École d'Orthophonie et d'Audiologie, Université de Montréal, Montreal, QC, Canada
| | - Marianne Désilets-Barnabé
- Centre de Recherche du Centre Intégré Universitaire de Santé et de Services Sociaux du Nord-de-l'Île-de-Montréal, Montreal, QC, Canada
- École d'Orthophonie et d'Audiologie, Université de Montréal, Montreal, QC, Canada
| | - Bérengère Houzé
- Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal, Montreal, QC, Canada
| | - Christophe Bedetti
- Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal, Montreal, QC, Canada
| | - Elizabeth Rochon
- Department of Speech-Language Pathology, University of Toronto, Toronto, ON, Canada
- Toronto Rehabilitation Institute, Toronto, ON, Canada
- Heart and Stroke Foundation, Canadian Partnership for Stroke Recovery, Ottawa, ON, Canada
- Rehabilitation Sciences Institute, University of Toronto, Toronto, ON, Canada
| | - Carol Leonard
- Department of Speech-Language Pathology, University of Toronto, Toronto, ON, Canada
- Heart and Stroke Foundation, Canadian Partnership for Stroke Recovery, Ottawa, ON, Canada
- School of Rehabilitation Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Alex Desautels
- Centre de Recherche du Centre Intégré Universitaire de Santé et de Services Sociaux du Nord-de-l'Île-de-Montréal, Montreal, QC, Canada
- Département de Neurosciences, Université de Montréal, Montreal, QC, Canada
- Centre d'Études Avancées en Médecine du Sommeil, Hôpital du Sacré-Cœur de Montréal, Montreal, QC, Canada
| | - Karine Marcotte
- Centre de Recherche du Centre Intégré Universitaire de Santé et de Services Sociaux du Nord-de-l'Île-de-Montréal, Montreal, QC, Canada
- École d'Orthophonie et d'Audiologie, Université de Montréal, Montreal, QC, Canada
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Right Structural and Functional Reorganization in Four-Year-Old Children with Perinatal Arterial Ischemic Stroke Predict Language Production. eNeuro 2019; 6:ENEURO.0447-18.2019. [PMID: 31383726 PMCID: PMC6749144 DOI: 10.1523/eneuro.0447-18.2019] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 04/24/2019] [Accepted: 06/03/2019] [Indexed: 11/21/2022] Open
Abstract
Brain imaging methods have contributed to shed light on the mechanisms of recovery after early brain insult. The assumption that the unaffected right hemisphere can take over language functions after left perinatal stroke is still under debate. Here, we report how patterns of brain structural and functional reorganization were associated with language outcomes in a group of four-year-old children with left perinatal arterial ischemic stroke (PAIS). Specifically, we gathered specific fine-grained developmental measures of receptive and productive aspects of language as well as standardized measures of cognitive development. We also collected structural neuroimaging data as well as functional activations during a passive listening story-telling fMRI task and a resting state session (rs-fMRI). Children with a left perinatal stroke showed larger lateralization indices of both structural and functional connectivity of the dorsal language pathway towards the right hemisphere that, in turn, were associated with better language outcomes. Importantly, the pattern of structural asymmetry was significantly more right-lateralized in children with a left perinatal brain insult than in a group of matched healthy controls. These results strongly suggest that early lesions of the left dorsal pathway and the associated perisylvian regions can induce the interhemispheric transfer of language functions to right homolog regions. This study provides combined evidence of structural and functional brain reorganization of language networks after early stroke with strong implications for neurobiological models of language development.
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Rüber T, Schlaug G. Repair after brainstem ischemia involves neurogenesis and the rubrospinal system. Ann Neurol 2019; 83:1069-1071. [PMID: 29908075 DOI: 10.1002/ana.25265] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 05/19/2018] [Accepted: 05/21/2018] [Indexed: 12/19/2022]
Affiliation(s)
- Theodor Rüber
- Department of Epileptology, University of Bonn Medical Center, Bonn, Germany
| | - Gottfried Schlaug
- Department of Neurology Division of Stroke Recovery and Neurorestoration and Division of Cerebrovascular Diseases, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA
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Carlson HL, Sugden C, Brooks BL, Kirton A. Functional connectivity of language networks after perinatal stroke. Neuroimage Clin 2019; 23:101861. [PMID: 31141787 PMCID: PMC6536856 DOI: 10.1016/j.nicl.2019.101861] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 04/17/2019] [Accepted: 05/19/2019] [Indexed: 02/06/2023]
Abstract
Successful language acquisition during development is imperative for lifelong function. Complex language networks develop throughout childhood. Perinatal stroke may cause significant language disabilities but function can also be remarkably normal. Studying such very early brain injury populations may inform developmental plasticity models of language networks. We examined functional connectivity (FC) of language networks in children with arterial and venous perinatal stroke and typically developing controls (TDC) in a population-based, controlled, cohort study. Resting state functional MRI was performed at 3 T (TR/TE = 2000/30 ms, 150 volumes, 3.6mm3 voxels). Seed-based analyses used bilateral inferior frontal and superior temporal gyri. A subset of stroke participants completed clinical language testing. Sixty-six children participated (median age: 12.85±3.8y, range 6-19; arterial N = 17; venous N = 15; TDC N = 34]. Children with left hemisphere strokes had comparable FC in their right hemispheres compared to TDC. Inter- and intra-hemispheric connectivity strengths were similar between TDC and PVI but lower for AIS. Reduced FC was associated with poorer language comprehension. Language networks can be estimated using resting-state fMRI in children with perinatal stroke. Altered connectivity may occur in both hemispheres, is more pronounced with arterial lesions, and is associated with clinical function. Our results have implications for therapeutic language interventions after early stroke.
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Affiliation(s)
- Helen L Carlson
- Calgary Pediatric Stroke Program, Alberta Children's Hospital, Calgary, AB, Canada; Alberta Children's Hospital Research Institute (ACHRI), Calgary, AB, Canada; Department of Pediatrics, University of Calgary, Calgary, AB, Canada.
| | - Cole Sugden
- Calgary Pediatric Stroke Program, Alberta Children's Hospital, Calgary, AB, Canada
| | - Brian L Brooks
- Alberta Children's Hospital Research Institute (ACHRI), Calgary, AB, Canada; Department of Pediatrics, University of Calgary, Calgary, AB, Canada; Neuropsychology Service, Alberta Children's Hospital, Calgary, AB, Canada; Department of Psychology, University of Calgary, Calgary, AB, Canada
| | - Adam Kirton
- Calgary Pediatric Stroke Program, Alberta Children's Hospital, Calgary, AB, Canada; Alberta Children's Hospital Research Institute (ACHRI), Calgary, AB, Canada; Department of Pediatrics, University of Calgary, Calgary, AB, Canada; Department of Clinical Neurosciences, University of Calgary, Calgary, AB, Canada; Department of Radiology, University of Calgary, Calgary, AB, Canada; Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
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Anderlini D, Wallis G, Marinovic W. Language as a Predictor of Motor Recovery: The Case for a More Global Approach to Stroke Rehabilitation. Neurorehabil Neural Repair 2019; 33:167-178. [PMID: 30757952 DOI: 10.1177/1545968319829454] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Stroke is the third leading cause of death in the developed world and the primary cause of adult disability. The most common site of stroke is the middle cerebral artery (MCA), an artery that supplies a range of areas involved in both language and motor function. As a consequence, many stroke patients experience a combination of language and motor deficits. Indeed, those suffering from Broca's aphasia have an 80% chance of also suffering hemiplegia. Despite the prevalence of multifaceted disability in patients, the current trend in both clinical trials and clinical practice is toward compartmentalization of dysfunction. In this article, we review evidence that aphasia and hemiplegia do not just coexist, but that they interact. We review a number of clinical reports describing how therapies for one type of deficit can improve recovery in the other and vice versa. We go on to describe how language deficits should be seen as a warning to clinicians that the patient is likely to experience motor impairment and slower motor recovery, aiding clinicians to optimize their choice of therapy. We explore these findings and offer a tentative link between language and arm function through their shared need for sequential action, which we term fluency. We propose that area BA44 (part of Broca's area) acts as a hub for fluency in both movement and language, both in terms of production and comprehension.
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Affiliation(s)
- Deanna Anderlini
- 1 The University of Queensland, St Lucia, Queensland, Australia.,2 Royal Brisbane and Women's Hospital, Brisbane, Queensland, Australia
| | - Guy Wallis
- 1 The University of Queensland, St Lucia, Queensland, Australia
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