Pilot Study for Measuring Sensitivity to Social Touch in School-Age Children with Autism Spectrum Disorders

Background: A variety of anomalous sensitivities to touch have been described anecdotally in children with autism spectrum disorders (ASD).  Reports of these behaviors cover a wide range of responses, including (but not limited to) undersensitivity to pain, oversensitivity to light touch, preference for deep pressure, and atypical reaction to social touch.  Most of these reports have been qualitative, however, and there are few studies with direct, quantitative measurements of sensitivity to touch in individuals with ASD.  And to our knowledge, there have been no studies that directly measure sensitivity to social touch in children with ASD.

Objectives: To measure selective sensitivity to contingent social touch in school-age children with autism spectrum disorders in comparison with matched, typically-developing peers.  Control conditions will measure sensitivity to mechanical (non-social) touch and sensitivity to non-contingent social touch.  We will test the hypothesis that children with ASD exhibit reduced sensitivity to contingent social, but not mechanical, touch.

Methods: We designed and built a novel device for measuring haptic interaction between two individuals or between one individual and a pre-recorded touch signal.  The device consists of horizontal rollers, linked remotely, that can be turned by either of two participants.  The rollers of each participant are coupled electromechanically, so that if one participant moves a roller, the other participant will feel that movement on his own roller; if both participants move their rollers, the resulting motion of each roller will be proportional to the force applied to both.  The force applied by the test participant in response to varying input signals (contingent social, non-contingent social, and mechanical) is the dependent variable for measuring haptic sensitivity.  

Results: Preliminary results demonstrate the utility and effectiveness of the interface for measuring social touch.  In pilot development, typical participants report a keen sensation of feeling another person’s actions during the contingent social touch condition, and a clear sense of non-social touch during the mechanical touch condition.  

Conclusions: Large amounts of previous research with individuals with ASD have documented atypical processing, particularly during social interaction, in the domains of hearing and vision, but the sense of touch has not been closely studied.  Typically-developing individuals are highly sensitized to recognize certain kinds of touch as social, and to react and respond in kind.  Developing research platforms for the quantification of response to social touch will be an important part of understanding atypical behavioral and neural specialization in individuals with ASD.