Transcranial Magnetic Stimulation in Autism Spectrum Disorders: Modulating Brainwave Abnormalities and Behaviors

Neuropathological studies in autism spectrum disorder (ASD) suggest the presence of a neuronal migrational disorder that alters the excitatory–inhibitory bias of the cerebral cortex. More specifically, in ASD, there appears to be widespread loss of parvalbumin (PV)-positive interneurons manifested as abnormalities in gamma oscillations (neural network instabilities), epileptogenesis, and impaired cognitive functions. Transcranial magnetic stimulation (TMS) is one of the first treatment to target this putative core pathological feature of ASD. Studies show that low-frequency TMS over the dorsolateral prefrontal cortex (DLPC) of individuals with ASD decreases the power of gamma activity while improving both executive function skills related to self-monitoring behaviors as well as the ability to apply corrective actions. Studies from our group have also shown that low-frequency TMS in ASD provides a reduction of stimulus-bound behaviors and diminished sympathetic arousal. Results become more significant with an increasing number of sessions and bear synergism when used along with neurofeedback.