Repetitive transcranial magnetic stimulation (rTMS) improves movement-related cortical potentials in autism spectrum disorders

Background Motor impairments are common in autism spectrum disorders (ASD). Electrophysiologic studies reveal abnormalities in the preparation of movement; repetitive transcranial magnetic stimulation (rTMS) to key motor cortical sites may therefore be a useful technique for improving motor function in ASD. Objective To examine whether rTMS can improve electrophysiologic and behavioral indices of motor activity. Methods Eleven participants with ASD completed three sessions in which they were administered one of three rTMS conditions (left M1, supplementary motor area [SMA], sham) at 1 Hz for 15 minutes. Movement-related cortical potentials (MRCPs) were assessed before and after rTMS. Results rTMS to the SMA was associated with a gradient increase to the early component of MRCPs, whereas rTMS to left M1 produced a stronger gradient in the late component. Conclusions rTMS appears to improve movement-related electrophysiologic activity in ASD, perhaps through an influence on cortical inhibitory processes.