Behavioral and physiological effects of deep pressure on children with autism: a pilot study evaluating the efficacy of Grandin's Hug Machine

Am J Occup Ther. 1999 Mar-Apr;53(2):145-52. doi: 10.5014/ajot.53.2.145.


Objective: One symptom common to many persons with autism is a high arousal or anxiety level. This study investigated the effects of deep pressure on arousal and anxiety reduction in autism with Grandin's Hug Machine, a device that allows self-administration of lateral body pressure.

Method: Twelve children with autism were randomly assigned to either an experimental group (receiving deep pressure) or a placebo group (not receiving deep pressure but in the disengaged Hug Machine). All children received two 20-min sessions a week over a 6-week period. Arousal was measured behaviorally with the Conners Parent Rating Scale and physiologically with galvanic skin response (GSR) readings.

Results: Behavioral results indicated a significant reduction in tension and a marginally significant reduction in anxiety for children who received the deep pressure compared with the children who did not. Additionally, children in the experimental group, whose GSR measures decreased, on average, after deep pressure, were somewhat more likely to have higher GSR arousal a priori.

Conclusion: These preliminary findings support the hypothesis that deep pressure may have a calming effect for persons with autism, especially those with high levels of arousal or anxiety.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptation, Physiological
  • Adolescent
  • Anxiety / physiopathology*
  • Arousal / physiology
  • Autistic Disorder / diagnosis
  • Autistic Disorder / physiopathology
  • Autistic Disorder / prevention & control
  • Autistic Disorder / rehabilitation*
  • Child
  • Child Behavior / physiology
  • Child, Preschool
  • Equipment Design
  • Female
  • Humans
  • Male
  • Occupational Therapy / instrumentation*
  • Pilot Projects
  • Pressure*
  • Reference Values
  • Sensitivity and Specificity