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Neuromodulation with TMS Effects On Heart Rate Variability in Children with Autism

Thursday, 2 May 2013: 14:00-18:00
Banquet Hall (Kursaal Centre)
M. K. Hensley1, E. M. Sokhadze2, A. S. El-Baz1 and M. F. Casanova2, (1)Bioengineering, University of Louisville, Louisville, KY, (2)Psychiatry and Behavioral Sciences, University of Louisville, Louisville, KY

Autism spectrum disorder (ASD) is a pervasive developmental disorder marked by difficulty in social interaction, lack of communication, and restricted range of interests. Many children with autism exhibit symptoms associated with autonomic dysfunction. The main findings of autonomic abnormalities studies in autism point at reduced parasympathetic activity in association with increased sympathetic tone resulting in autonomic disbalance which affects physiological functions and manifests in heart rate variability (HRV) measures. 


Objective of the study study was to investigate cardiac rhythm measures reflecting autonomic nervous system activity in children with autism undergoing treatment using 1 Hz  repetitive Transcranial Magnetic Stimulation (rTMS). Our hypothesis was that as weekly rTMS sessions continued, individuals would display a decrease in heart rate (HR) and increase in HRV, indicative of enhanced parasympathetic nervous system activity and/or decreased sympathetic activity.


Twenty individuals with ASD were enrolled in the study. EKG-based HR and HRV were recorded  with a C-2 J&J monitor. HR analysis was done using Kubios software. We investigated changes in HR and  HRV during  rTMS course with 18 weekly sessions.


Post-rTMS outcomes showed slower HR accompanied by decrease of low frequency (LF), increase of high frequency (HF) component of HRV, and lower LF/HF ratio. Our findings show reduced sympathetic activation after TMS resulting in lower HR predominantly through withdrawal of sympathetic tone (LF of HRV) rather than increase of parasympathetic (vagus) cardiac neural control activity post 12  rTMS sessions, but higher HF component after 18 sessions.


Prefrontal rTMS activates inhibitory tone of the frontal cortex resulting in a lower excitation of the autonomic system probably through the inhibitory fronto-limbic circuits. We found that weekly rTMS sessions increase parasympathetic nervous system activity and decrease sympathetic nervous system activity, and is therefore a promising candidate for treatment of ASD.

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