Objective. One symptom common to many persons with Behavioral and autism is a high arousal or anxiety level. This study investi- gated the effects of deep pressure on arousal and anxiety Physiological Effects of 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 Deep Pressure on assigned to either an experimental group (receiving deep pressure) or a placebo group (not receiving deep pressure but Children With Autism: in the disengaged Hug Machine). All children received two 20-min sessions a week over a 6-week period. Arousal was A Pilot Study Evaluating measured behaviorally with the Conners Parent Rating Scale and physiologically with galvanic skin response (GSR) readings. the Efficacy of Grandin's Results. Behavioral results indicated a significant reduction in tension and a marginally significant reduction Hug Machine in anxiety for children who received the deep pressure com- pared 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 flndings support the Stephen M. Edelson, Meredyth Goldberg hypothesis that deep pressure may have a calming effect for Edelson, David C. R. Kerr, Temple Grandin persons with autism, especially those with high levels of arousal or anxiety. Key Words: anxiety arousal (physiologic) Edelson, S. M., Edelson, M. G., Kerr, D. C. R., & Grandin, T. (1999). Behavioral and physiological effects of deep pressure on children with autism: A pilot study evaluating the efficacy of Grandin's Hug Machine. AmericanJournal of Occupational Therapy, 53, 145-152. ersons with autism are often described as having rel- p atively high arousal or anxiety levels (Hardy, 1990; Sands & Ratey, 1986; Wing, 1989). Hutt, Hutt, Lee, and Ounsted (1965) noted that children with autism demonstrate a desynchronized electroencephalogram pat- tern, indicating high levels of arousal. This desynchronization was related to increased environmental stimulation and increased stereotyped (i.e., repetitive) behavior. The underlying reason for the high levels of arousal in some persons with autism is not entirely known. Some researchers suggested that a high level of arousal may be Stephen M. Edelson, PhD, is Research Associate, Autism due to neurological dysfunction, such as sensory processing Research Institute, San Diego, California. problems (Delacato, 1974; Grandin, 1995); others posited that the problem relates to faulty information processing Meredyth Goldberg Edelson, PhD, is Associate Professor of (Ornitz, 1985); and others suggested that a myelination Psychology,Willamette University, 900 State Street, Salem, defect might lead to increased neuronal arousal (McClelland, Oregon 97031. land, Eyre, Watson, Calvert, & Sherrard, 1992). One method clinicians use to lessen anxiety and David C. R. Kerr, was Student and Research Assistant, arousal in persons with autism is the application of deep Willamette University, Salem, Oregon, at the time of this study. pressure. For example, Ayres (1979) and King (1989) Temple Grandin, PhD, is Assistant Professor of Animal Sciences, reported that wrapping a child with autism in a gym mat Colorado State University, Fort Collins, Colorado. produces a calming effect. Persons with autism also have been known to provide themselves with deep pressure in an This article was acceptedfor publication August 27, 1998. attempt to calm themselves (Grandin, 1992; Grandin & Downloaded From: http://ajot.aota.org/ on 08/19/2014 Terms of Use: http://AOTA.org/terms Scariano, 1986) and often prefer to provide this stimula- movementson each of the following areas: head/neck, arms/ tion themselves, frequently avoiding tactile stimulation hands, torso, and legs/feet" (p. 334). The results indicated controlled by others (Delacato, 1974). increases in attention to multiple tasks, social and relating There has been little empirical research on the efficacy behavior, and initiating behavior, and a decrease in general of deep pressure on persons with autism. Inamura, Wiss, sensory problems. It should be noted that although touch and Parham (1990a, 1990b) investigated the effects of therapy provides tactile stimulation, it is not deep pressure. Grandin's Hug Machine, a device that provides deep pres- Two case studies reported dramatic behavioral changes sure to the lateral parts of the body, on the behavior of nine as a result of other forms of tactile stimulation that more children with autism. Temple Grandin, a woman with closely resemble deep pressure. In one study, foam arm autism, developed the Hug Machine after observing that splints were placed on a child with autism, resulting in a cattle showed a dramatic decrease in anxiety when receiv- decrease in self-injurious behavior and an increase in social ing deep pressure from a cattle chute, a device used during interaction (McClure & Holtz-Yotz, 1991). In another branding. Grandin modeled the Hug Machine on the cat- study, a reduction in stereotypic, self-stimulatory behaviors de chute but modified the design for human use (Grandin was observed after frequent back rubs and hugs from a ther- & Scariano, 1986). She proposed that persons with rela- apist (Zissermann, 1992). When the child also wore tight- tively high levels of anxiety or arousal are more likely to fitting gloves and a weighted vest, which provided contin- benefit from the Hug Machine than those with moderate uous pressure, stereotypic behaviors and hand slapping to low levels of anxiety or arousal. were further reduced. As clinical reports, these case studies Inamura et al. (1990a, 1990b) noted that, in general, did not empirically test the efficacy of deep pressure. the children in their study did not consistently use the Finally, Krauss (1987) investigated the effects of deep Hug Machine, with duration of use being less than 2 min pressure on college students using a device called the per session. However, greater use seemed to be related to Hug'm Apparatus. Anxiety level was determined with a decreased hyperactive behavior in some children. physiological measure (heart rate) and a self-report measure Although these findings are encouraging, Inamura et al. (State-Trait Anxiety Inventory). Although there was no sig- did not use a control group, did not use physiological nificant change in heart rate as a result of the deep pressure, measures to see whether there were concomitant physio- the State-Trait Anxiety Inventory indicated a greater re- logical changes due to deep pressure, and did not analyze duction in anxiety levels in the experimental group than in their data statistically. the control group. However, this difference was not signif- In an open clinical study, Creedon (1994) found that icant. Krauss speculated that initial low levels of state anx- children with autism who used the Hug Machine for iety may, in part, explain the limited change in anxiety after longer periods and with more sustained pressure on days deep pressure noted in the experimental group. that were associated with behavior problems made fewer The aim of the present study was to provide a more aimless actions, made more adaptive movements, and were controlled empirical investigation of the effects of deep able to sit more calmly than children who did not use the pressure, using Grandin's Hug Machine, on children with Hug Machine regularly. Similar to Inamura et al.'s (1990a, autism. In contrast to Inamura et al.'s (1990a, 1990b) 1990b) study, Creedon's report was based on clinical rather study, we used an experimental group receiving deep pres- than statistical data. sure and a matched (a priori on observable indicators of Another type of intervention involving deep pressure is anxiety, such as jitteriness, shakiness, etc.) placebo group holding therapy (Welch, 1988). This treatment involves that did not. Unlike the clinical reports of Creedon (1994), holding the person for long periods while providing deep McClure and Holtz-Yotz (1991), and Zissermann (1992), pressure. Because the person does not control the deep we specifically wished to conduct statistical comparisons of pressure, one criticism of holding therapy is that he or she children who did and did not receive deep pressure to see may not desire the pressure or the amount of pressure whether any observed changes would meet the criteria of applied. Additionally, children often resist the initial hold- significance. Finally, similar to Krauss's (1987) study with ing therapy sessions, which can lead to considerable stress college students, we wanted to investigate the relationship for the child. Therefore, the calming effects noted by Welch between behavioral and physiological indicators of arousal may be due to learned helplessness rather than the tactile before and after deep pressure in children with autism. stimulation. We are unaware of scientific studies assessing The specific goals of the present study were to deter- the efficacy of this intervention. mine whether (a) deep pressure affected behavioral indexes Field et al. (1997) investigated the use of touch therapy of anxiety, (b) deep pressure affected physiological indexes on 22 preschool children with autism, half of whom received of anxiety; and (c) there were unintended side effects of touch treatment and the other half a placebo intervention. deep pressure. It should be noted that because of our small The form