Neuromodulation based on rTMS affects behavioral measures and autonomic nervous system activity in children with autism

Many children with autism spectrum disorder (ASD) exhibit symptoms associated with autonomic nervous system (ANS) dysfunction indicative of low psychophysiological flexibility.  It is suggested that ASD symptoms are associated with generalized abnormalities in the central nervous system, including structures and networks involved in the top-down regulation of the ANS. Repetitive transcranial magnetic stimulation (rTMS) has been suggested as a possible therapy to target ANS regulation deficits in ASD. In the current study we used neuromodulation based on rTMS over the dorsolateral prefrontal cortex (DLPFC) to reduce sympathetic arousal and increase parasympathetic activity in children with ASD. In a study on 27 children with autism we administered weekly 0.5 Hz rTMS bilaterally over the DLPFC with concurrent recording of autonomic activity.  Statistical analysis of time and frequency domain heart rate variability (HRV) indices and skin conductance level (SCL) revealed a strong linear regression of most HRV and SCL measures. Several parental behavioral rating scores improved post-TMS and showed a correlation with autonomic outcomes, in particular parasympathetic indices of HRV negatively correlated with repetitive and stereotyped behaviors, while sympathetic arousal indices showed positive correlation with the same behaviors.  The paper discusses potential neurobiological mechanisms involved in post-TMS autonomic balance and aberrant behavior improvements.