Language Changes Following Stimulation of Inferior Frontal Cortex in Adolescents With Autism Spectrum Disorder: A Preliminary Report

Background: Treatment with transcranial direct current stimulation (tDCS) has resulted in language improvements in a variety of populations. Objective: To determine the feasibility of tDCS in adolescents with autism spectrum disorder (ASD) and to examine fMRI activation changes associated with tDCS. To provide preliminary information on whether the left or right inferior frontal gyrus (IFG) is a better target for language improvement. Methods: We applied anodal tDCS to the left or right IFG in eight adolescents (11–17 years) with ASD and examined changes in fluency and fMRI activation during a semantic task. Results: tDCS was well tolerated and all participants were able to complete the session. Of the participants who received right tDCS, 67% (2/3) showed improvements in letter and category fluency. None of the participants who received left tDCS showed improvement in both letter and category fluency. We were unable to collect two usable fMRI scans forhalf of the participants. Individual fMRI activation data did not produce reliable results regarding tDCS-induced changes. Conclusion: Our preliminary results add to findings suggesting tDCS is feasible in adolescents with ASD, including those with severely impaired language abilities. Right IFG stimulation should be investigated in a larger population, as our pilot findings suggest slightly greater improvement in language fluency relative to left IFG stimulation. It may not be practical or reliable to use fMRI to evaluate the effectiveness of tDCS in individuals with ASD.