Developing Innovative Ways to Measure and Communicate Autonomic Arousal in Autism Spectrum Disorders

Background: The Autonomic Nervous System (ANS) is a control system in the body with far-reaching influences, including maintenance of heart rate, digestion, respiration rate, and perspiration that mediates regulation of emotion, shifting of attention, sleep, signaling of anticipation and salience, biasing of memory, and more. A number of investigators over the past 30 years have recorded ANS activity in individuals with Autism Spectrum Disorders (ASD) to assess physiological responsivity during attention and habituation tasks, while exposed to social and sensory stimuli, and when engaged in self-injurious and repetitive behaviors. Unfortunately, however, there are several methodological issues associated with these studies that cast doubt on the reliability, validity, and generalizability of the data obtained. For instance, the majority of ANS studies to date use obtrusive equipment that require individuals to sit still while multiple wires are adhered to their chest or fingers, limiting the number of participants who can comply with the procedures and thus contribute data to a study. ANS observations are also undertaken primarily in unfamiliar research laboratories that are potentially stress inducing, and are often limited to short intervals of measurement that may or may not represent a person’s true ANS patterns when going about everyday activities. Data from these studies are also often averaged across persons so that no individual profiles are retained, obscuring the heterogeneity of response patterns across individuals.

Objectives: This presentation will briefly discuss the clinical utility of recording ANS responsivity in ASD, review findings to date in this area, describe the abovementioned methodological issues, and demonstrate a novel platform being developed in the MIT Media Lab for sensing sympathetic and parasympathetic autonomic data comfortably off the wrist and ankle without wires or boxes.

Methods: The wireless autonomic recording system captures: (1) Electrodermal activity, which provides a sensitive measure of changes in sympathetic arousal associated with emotion, cognition and attention; (2) Heart rate and heart rate variability that provides information related to the sympathetic and parasympathetic branches of the ANS; (3) Temperature; and (4) Motor movement and posture changes through 3-axis accelerometery. The 3-axis accelerometer and temperature sensors provide information about a person’s activity and account for the influence of motion and environmental temperature on electrodermal and cardiovascular signals.

Results: & Conclusions: Monitoring autonomic reactivity using comfortable, wireless, wearable packages could enable new in situ experimental paradigms and address some of the shortcomings associated with traditional methods of recording the ANS in persons with ASD. For instance, these sensors could enable longitudinal studies of individuals that yield data beyond the traditional “snapshot” timeframe, providing new insights on within-person, within-group, and across-group differences over time, and capturing phenomena of interest that are hard to replicate in laboratory settings, e.g., panic attacks. Measuring and communicating ANS patterns that precede, co-occur, and follow an event could also provide rich data enabling new ways to anticipate, intervene on, and ultimately prevent problem behaviors.