TY - JOUR

T1 - Hemispheric contributions to language reorganisation

T2 - An MEG study of neuroplasticity in chronic post stroke aphasia

AU - Mohr, Bettina

AU - MacGregor, Lucy J.

AU - Difrancesco, Stephanie

AU - Harrington, Karen

AU - Pulvermüller, Friedemann

AU - Shtyrov, Yury

PY - 2016/12/1

Y1 - 2016/12/1

N2 - Previous studies have demonstrated that efficient neurorehabilitation in post stroke aphasia leads to clinical language improvements and promotes neuroplasticity. Brain areas frequently implicated in functional restitution of language after stroke comprise perilesional sites in the left hemisphere and homotopic regions in the right hemisphere. However, the neuronal mechanisms underlying therapy-induced language restitution are still largely unclear. In this study, magnetoencephalography was used to investigate neurophysiological changes in a group of chronic aphasia patients who underwent intensive language action therapy (ILAT), also known as constraint-induced aphasia therapy (CIAT). Before and immediately after ILAT, patients’ language and communication skills were assessed and their brain responses were recorded during a lexical magnetic mismatch negativity (MMNm) paradigm, presenting familiar spoken words and meaningless pseudowords. After the two-week therapy interval, patients showed significant clinical improvements of language and communication skills. Spatio-temporal dynamics of neuronal changes revealed a significant increase in word-specific neuro-magnetic MMNm activation around 200 ms after stimulus identification points. This enhanced brain response occurred specifically for words and was most pronounced over perilesional areas in the left hemisphere. Therapy-related changes in neuromagnetic activation for words in both hemispheres significantly correlated with performance on a clinical language test. The findings indicate that functional recovery of language in chronic post stroke aphasia is associated with neuroplastic changes in both cerebral hemispheres, with stronger left-hemispheric contribution during automatic stages of language processing.

AB - Previous studies have demonstrated that efficient neurorehabilitation in post stroke aphasia leads to clinical language improvements and promotes neuroplasticity. Brain areas frequently implicated in functional restitution of language after stroke comprise perilesional sites in the left hemisphere and homotopic regions in the right hemisphere. However, the neuronal mechanisms underlying therapy-induced language restitution are still largely unclear. In this study, magnetoencephalography was used to investigate neurophysiological changes in a group of chronic aphasia patients who underwent intensive language action therapy (ILAT), also known as constraint-induced aphasia therapy (CIAT). Before and immediately after ILAT, patients’ language and communication skills were assessed and their brain responses were recorded during a lexical magnetic mismatch negativity (MMNm) paradigm, presenting familiar spoken words and meaningless pseudowords. After the two-week therapy interval, patients showed significant clinical improvements of language and communication skills. Spatio-temporal dynamics of neuronal changes revealed a significant increase in word-specific neuro-magnetic MMNm activation around 200 ms after stimulus identification points. This enhanced brain response occurred specifically for words and was most pronounced over perilesional areas in the left hemisphere. Therapy-related changes in neuromagnetic activation for words in both hemispheres significantly correlated with performance on a clinical language test. The findings indicate that functional recovery of language in chronic post stroke aphasia is associated with neuroplastic changes in both cerebral hemispheres, with stronger left-hemispheric contribution during automatic stages of language processing.

KW - Aphasia

KW - Intensive language action therapy

KW - Language

KW - MEG

KW - Mismatch negativity

KW - Neuroplasticity

UR - http://www.scopus.com/inward/record.url?scp=84963591446&partnerID=8YFLogxK

U2 - 10.1016/j.neuropsychologia.2016.04.006

DO - 10.1016/j.neuropsychologia.2016.04.006

M3 - Article

C2 - 27063061

AN - SCOPUS:84963591446

VL - 93

SP - 413

EP - 424

JO - Neuropsychologia

JF - Neuropsychologia

SN - 0028-3932

ER -