University of Louisville
Autonomic Nervous System Dysfunctions in Children with Autism
Institution
University of Louisville
Faculty Advisor/ Mentor
Ayman El-Baz; Tato Sokhadze; Lonnie Sears
Abstract
Many children with autism exhibit symptoms associated with autonomic dysfunction. The main findings of autonomic abnormalities studies in Autistic Spectrum Disorders (ASD) point to reduced baseline parasympathetic activity in association with evidence of increased baseline sympathetic tone. We investigated autonomic nervous system activity in 14 children with ASD (mean age 14.3 years) and 16 typically developing subjects (17.8 years). Physiological activity measures such as skin conductance level (SCL), heart rate (HR), HR variability (HRV), and skin temperature (SKT) were recorded during resting state with a C-2 J&J Engineering Inc psychophysiological monitor. Analysis of autonomic measures during 5 min long resting baseline revealed higher HR (95.6 beats/min in ASD vs. 80.8 beats/min in controls, F=7.98, p=0.009), higher SCL (7.4 microSiemens vs. 4.3 microSiemens in controls, F=4.49, p=0.043), and a tendency (p=0.068) to reduced respiratory sinus arrhythmia reflected in lower power of high frequency (HF) component of HRV in autism. High basal tonic electrodermal activity (SCL) and accelerated HR in association with lower HRV index found in children with autism are indicators of excessive sympathetic and reduced parasympathetic activation in ASD resulting in a limited psychophysiological flexibility. Beside comparison of autonomic measures between autism and control groups we investigated changes in autonomic activity during a repetitive magnetic transcranial stimulation (rTMS) course in the same children with autism. Post-rTMS measurements showed a decrease of low frequency (LF) component of HRV without statistical changes in HR, SCL, and SKT. Assessment of autonomic balance in autism is important for understanding neurobiological mechanisms of this neurodevelopmental disorder.
Autonomic Nervous System Dysfunctions in Children with Autism
Many children with autism exhibit symptoms associated with autonomic dysfunction. The main findings of autonomic abnormalities studies in Autistic Spectrum Disorders (ASD) point to reduced baseline parasympathetic activity in association with evidence of increased baseline sympathetic tone. We investigated autonomic nervous system activity in 14 children with ASD (mean age 14.3 years) and 16 typically developing subjects (17.8 years). Physiological activity measures such as skin conductance level (SCL), heart rate (HR), HR variability (HRV), and skin temperature (SKT) were recorded during resting state with a C-2 J&J Engineering Inc psychophysiological monitor. Analysis of autonomic measures during 5 min long resting baseline revealed higher HR (95.6 beats/min in ASD vs. 80.8 beats/min in controls, F=7.98, p=0.009), higher SCL (7.4 microSiemens vs. 4.3 microSiemens in controls, F=4.49, p=0.043), and a tendency (p=0.068) to reduced respiratory sinus arrhythmia reflected in lower power of high frequency (HF) component of HRV in autism. High basal tonic electrodermal activity (SCL) and accelerated HR in association with lower HRV index found in children with autism are indicators of excessive sympathetic and reduced parasympathetic activation in ASD resulting in a limited psychophysiological flexibility. Beside comparison of autonomic measures between autism and control groups we investigated changes in autonomic activity during a repetitive magnetic transcranial stimulation (rTMS) course in the same children with autism. Post-rTMS measurements showed a decrease of low frequency (LF) component of HRV without statistical changes in HR, SCL, and SKT. Assessment of autonomic balance in autism is important for understanding neurobiological mechanisms of this neurodevelopmental disorder.