Although differences in processing external sensory inputs are widely reported and increasingly studied in ASD, little is known about the ability of children with ASD to attend to and perceive sensory signals from within their own bodies. The insula is important for perception of bodily signals and has been implicated in empathy as well as affect-based direction of attention as part of the salience network, both of which have relevance for ASD. Although interoception is linked with empathy and thus may be predicted to be impaired in ASD, our hypothesis was that children with ASD would show enhanced interoception. This prediction was based on a model positing that internal sensory cues may compete with external cues for salience in ASD.
To measure interoceptive ability in a group of children with ASD, compared to a matched group of children with typical development.
10 children with ASD and 15 typically developing children (ages 8-17) were monitored for heart rate using a pulse oximeter over four intervals: 25, 35, 45, and 100 seconds. Participants were asked to focus on their heartbeat and count the number of heartbeats during each interval. An error rate was calculated as the absolute value of the difference between perceived and actual heartbeats, expressed as a percentage of the actual number of heartbeats. Effects of group and interval were assessed with a repeated measures ANOVA.
There was a significant group*interval interaction, which follow-up tests indicated was driven by significantly better performance by the ASD group at the longest interval. There was a trend for a main effect of group, with the ASD group performing better overall (lower error rate) on the task.
We found interoceptive ability to be enhanced in a sample of children with ASD, particularly over a long time interval for which typically developing children performed most poorly. This may point to heightened salience of internal sensory cues, which is consistent with sensorimotor studies suggesting aberrant reliance on proprioceptive relative to visual cues. Future work will investigate the role of the insula in enhanced interoception in ASD.
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