Interhemispheric Plasticity following Intermittent Theta Burst Stimulation in Chronic Poststroke Aphasia

The effects of noninvasive neurostimulation on brain structure and function in chronic poststroke aphasia are poorly understood. We investigated the effects of intermittent theta burst stimulation (iTBS) applied to residual language-responsive cortex in chronic patients using functional and anatomic...

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Main Authors:	Griffis, Joseph C., Nenert, Rodolphe, Allendorfer, Jane B., Szaflarski, Jerzy P.
Format:	Online
Language:	English
Published:	Hindawi Publishing Corporation 2016
Online Access:	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4736997/

id	pubmed-4736997
recordtype	oai_dc
spelling	pubmed-47369972016-02-15 Interhemispheric Plasticity following Intermittent Theta Burst Stimulation in Chronic Poststroke Aphasia Griffis, Joseph C. Nenert, Rodolphe Allendorfer, Jane B. Szaflarski, Jerzy P. Research Article The effects of noninvasive neurostimulation on brain structure and function in chronic poststroke aphasia are poorly understood. We investigated the effects of intermittent theta burst stimulation (iTBS) applied to residual language-responsive cortex in chronic patients using functional and anatomical MRI data acquired before and after iTBS. Lateralization index (LI) analyses, along with comparisons of inferior frontal gyrus (IFG) activation and connectivity during covert verb generation, were used to assess changes in cortical language function. Voxel-based morphometry (VBM) was used to assess effects on regional grey matter (GM). LI analyses revealed a leftward shift in IFG activity after treatment. While left IFG activation increased, right IFG activation decreased. Changes in right to left IFG connectivity during covert verb generation also decreased after iTBS. Behavioral correlations revealed a negative relationship between changes in right IFG activation and improvements in fluency. While anatomical analyses did not reveal statistically significant changes in grey matter volume, the fMRI results provide evidence for changes in right and left IFG function after iTBS. The negative relationship between post-iTBS changes in right IFG activity during covert verb generation and improvements in fluency suggests that iTBS applied to residual left-hemispheric language areas may reduce contralateral responses related to language production and facilitate recruitment of residual language areas after stroke. Hindawi Publishing Corporation 2016 2016-01-10 /pmc/articles/PMC4736997/ /pubmed/26881111 http://dx.doi.org/10.1155/2016/4796906 Text en Copyright © 2016 Joseph C. Griffis et al. https://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
repository_type	Open Access Journal
institution_category	Foreign Institution
institution	US National Center for Biotechnology Information
building	NCBI PubMed
collection	Online Access
language	English
format	Online
author	Griffis, Joseph C. Nenert, Rodolphe Allendorfer, Jane B. Szaflarski, Jerzy P.
spellingShingle	Griffis, Joseph C. Nenert, Rodolphe Allendorfer, Jane B. Szaflarski, Jerzy P. Interhemispheric Plasticity following Intermittent Theta Burst Stimulation in Chronic Poststroke Aphasia
author_facet	Griffis, Joseph C. Nenert, Rodolphe Allendorfer, Jane B. Szaflarski, Jerzy P.
author_sort	Griffis, Joseph C.
title	Interhemispheric Plasticity following Intermittent Theta Burst Stimulation in Chronic Poststroke Aphasia
title_short	Interhemispheric Plasticity following Intermittent Theta Burst Stimulation in Chronic Poststroke Aphasia
title_full	Interhemispheric Plasticity following Intermittent Theta Burst Stimulation in Chronic Poststroke Aphasia
title_fullStr	Interhemispheric Plasticity following Intermittent Theta Burst Stimulation in Chronic Poststroke Aphasia
title_full_unstemmed	Interhemispheric Plasticity following Intermittent Theta Burst Stimulation in Chronic Poststroke Aphasia
title_sort	interhemispheric plasticity following intermittent theta burst stimulation in chronic poststroke aphasia
description	The effects of noninvasive neurostimulation on brain structure and function in chronic poststroke aphasia are poorly understood. We investigated the effects of intermittent theta burst stimulation (iTBS) applied to residual language-responsive cortex in chronic patients using functional and anatomical MRI data acquired before and after iTBS. Lateralization index (LI) analyses, along with comparisons of inferior frontal gyrus (IFG) activation and connectivity during covert verb generation, were used to assess changes in cortical language function. Voxel-based morphometry (VBM) was used to assess effects on regional grey matter (GM). LI analyses revealed a leftward shift in IFG activity after treatment. While left IFG activation increased, right IFG activation decreased. Changes in right to left IFG connectivity during covert verb generation also decreased after iTBS. Behavioral correlations revealed a negative relationship between changes in right IFG activation and improvements in fluency. While anatomical analyses did not reveal statistically significant changes in grey matter volume, the fMRI results provide evidence for changes in right and left IFG function after iTBS. The negative relationship between post-iTBS changes in right IFG activity during covert verb generation and improvements in fluency suggests that iTBS applied to residual left-hemispheric language areas may reduce contralateral responses related to language production and facilitate recruitment of residual language areas after stroke.
publisher	Hindawi Publishing Corporation
publishDate	2016
url	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4736997/
_version_	1613532212290912256

Interhemispheric Plasticity following Intermittent Theta Burst Stimulation in Chronic Poststroke Aphasia

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