Brain Network Plasticity in Aphasic Patients Associated With Combined Speech Therapy and Transcranial Direct Current Stimulation

The efficacy of conventional speech therapy alone for aphasia recovery is inconclusive. The prospective study will monitor the effects of combined language therapy and tDCS through structural and functional MRI.

This randomized, placebo-controlled, double-blinded pilot study will recruit ten chronic stroke patients with Broca's Aphasia randomly assigned either to sham or an anodal tDCS groups. Following speech and language assessment, all the participants will receive 20 minutes of individualized language therapy daily for ten days in two consecutive weeks. Simultaneously, the treatment group will receive 20 minutes of 2mA anodal HD-tDCS over the left IFG, while the sham group will receive the 30s of 2mA anodal HD-tDCS. Structural, resting state and task activated functional MRI will be performed. Data acquisition will be performed before, immediately after and two months after the treatment.

Repeated measure ANOVA for changes in picture-naming accuracy and response time will be performed as a within-subject factor between sham and anodal tDCS. Pearson's correlation coefficient of left IFG and its homolog in the right hemisphere through Independent component analysis (ICA) of low-frequency fluctuations in resting-state and task activated state will be compared for functional connectivity analysis for IFG and other major languages hubs for oral language production between groups.