Modulation of N400 in chronic non-fluent aphasia using low frequency Repetitive Transcranial Magnetic Stimulation (rTMS)

Caroline H S Barwood*, Bruce E. Murdoch, Brooke Mai Whelan, David Lloyd, Stephan Riek, John D. O'Sullivan, Alan Coulthard, Andrew Wong

*Corresponding author for this work

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26 Citations (Scopus)

Abstract

Low frequency Repetitive Transcranial Magnetic Stimulation (rTMS) has previously been applied to language homologues in non-fluent populations of persons with aphasia yielding significant improvements in behavioral language function up to 43. months post stimulation. The present study aimed to investigate the electrophysiological correlates associated with the application of rTMS through measurement of the semantic based N400 Event-related brain potentials (ERP) component. Low frequency (1. Hz) rTMS was applied to the anterior portion of the homologue to Broca's area (pars triangularis), for 20. min per day for 10. days, using a stereotactic neuronavigational system. Twelve non-fluent persons with aphasia, 2-6. years post stroke were stimulated. Six participants were randomly assigned to receive real stimulation and six participants were randomly assigned to receive a blind sham control condition. ERP measures were recorded at baseline, 1. week and 2. months subsequent to stimulation. The findings demonstrate treatment related changes observed in the stimulation group when compared to the placebo control group at 2. months post stimulation indicating neuromodulation of N400 as a result of rTMS. No treatment related changes were identified in the stimulation group, when compared to the sham group from baseline to 1. week post stimulation. The electrophysiological results represent the capacity of rTMS to modulate neural language networks and measures of lexical-semantic function in participants with non-fluent aphasia and suggest that time may be an important factor in brain reorganization subsequent to rTMS.

Original languageEnglish
Pages (from-to)125-135
Number of pages11
JournalBrain and Language
Volume116
Issue number3
DOIs
Publication statusPublished - Mar 2011
Externally publishedYes

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Barwood, C. H. S., Murdoch, B. E., Whelan, B. M., Lloyd, D., Riek, S., O'Sullivan, J. D., ... Wong, A. (2011). Modulation of N400 in chronic non-fluent aphasia using low frequency Repetitive Transcranial Magnetic Stimulation (rTMS). Brain and Language, 116(3), 125-135. https://doi.org/10.1016/j.bandl.2010.07.004