Effects of Using a Weighted or Pressure Vest for a Child with Autism By Aaron Rhinehardt Deris, Cynthia F DiCarlo

 

Children who are diagnosed with Autism Spectrum Disorder (ASD) often demonstrate decreased attention to task as a result of persistent self-stimulatory behaviors (Smith, Press, Koenig, & Kinnealey, 2005). Self-stimulatory behaviors can be defined as any behavior which is non-purposeful and repetitive, and may include rocking, twirling, spinning, arm or hand flapping, tapping, and squinting (American Psychiatric Association, 2000), which are believed to be a childs attempt to calm and modulate his or her arousal level during times of general over arousal (Helfin & Alaimo, 2007; King & Grandin, 1990; Mays, Beal-Alvarez, Jolivette, 2011; Yack, Aquilla, & Sutton, 2003). Self-stimulatory behaviors can interfere with a task as the childs focus is on the behavior and not the task at hand. For example, if the child is to be attending to a group activity but is spinning (self-stimulatory behavior) then the child will be missing out on the instruction of what is occurring. It is believed that a decrease in these self-stimulatory behaviors would result in improved attention.

Sensory integration therapy focuses on assisting individuals in calming and organizing input (see Vargas & Camilli, 1999, for a review). It has been suggested that proprioceptive input in the form of deep pressure calms children by modulating their central nervous system processing of sensory information (Edelson, Goldberg-Edelson, Kerr, & Grandin, 1999; Grandin, 1992; McClure & Holtz-Yotz, 1991). This calming and organizing of input helps to lower arousal levels in children to a more appropriate state, which is a standard of sensory integration (SI) therapy. The use of a pressure machine has been demonstrated to decrease tension and anxiety (Edelson et al. 1999) and a pressure garment has been found to reduce self-stimulatory behaviors in a child with autism (Zissermann, 1992), while other researchers (Reichow, Barton, Good, & Wolery, 2009) have not demonstrated increases in attention. Specifically, Reichow et al. examined the effects of wearing a pressure vest and found no differences when the vest was worn versus not worn in terms of engagement with materials. Similarly, weighted vests have also been used with mixed reviews with researchers finding both an increase and a non-effect on attention. Some research has demonstrated its effectiveness in both decreasing self-stimulatory behavior and increasing attention (Fertel-Daly, Bedell, & Hinojosa, 2001). Fertel-Daly et al. found an increase in attention to a fine motor task and decrease in distractions. Other researchers conducting similar studies have not (Kane, Luiselli, Dearorn, & Young, 2004: Reichow, Barton, Sewell, Good, & Wolery, 2010). Kane et al. found that the use of a weighted vest was not effective in increasing attention across three different conditions (no vest, vest with no weight, and weighted vest) and Reichow et al. (2010) found no differences in engagement across three conditions (no vest, vest with no weight, and weighted vest).

While researchers have voiced concerns over the use of SI therapy for children with autism (Lang et al., 2012), it continues to be a common practice for occupational therapists to use weighted vests and pressure garments during the course of treatment for sensory processing disorders. One possible implication is that these vests are still being used is based on clinical opinion, which is often not based on data. The rationale for the present study was to further the literature in this area through the systematic examination the effects of using a weighted vest or a pressure garment on a preschooler who has autism and other disabilities.

Method

Subject and Setting

The participant in this study was a four-year-old boy, Kyle, who had a diagnosis of Autism Spectrum Disorder. Additionally, Kyle has strabismus in both eyes. Strabismus is a condition in which both of the eyes do not properly align and is commonly referred to as cross-eyed (American Optometric Association, 2013). He exhibited self-stimulatory behaviors including mouthing of his hand or objects, jumping up and down, and tapping either objects or himself. In light of the current literature in the field, the intervention was aimed at both giving Kyle the sensory input he seemed to desire, in order to help him attend to instruction in his early childhood classroom. Kyle attended class in a self-contained setting for children with autism and other sensory processing impairments in a private school. Including Kyle, there were six children in the classroom.

Participant Protection

Prior to conducting this research, IRB approval was obtained as well as approval by the board of directors from the school Kyle was attending. Informed consent was obtained from the school staff (teacher and paraprofessionals) as well as from Kyles parents.

Materials

Weighted vest. The weighted vest used in this study was the Bear Hug Vest with the addition of the Bear Hug Weighted Wrap by Southpaw Enterprises. The Bear Hug Weighted Wrap distributes pound weights in 16 sections of the vest across the chest region. Using recommended practices in the field of occupational therapy and according to Kashman and Mora (2002) and VandenBerg (2001), the total amount of weight used in the vest was 3 pounds or at 10% of his body weight (i.e., he weighed 32 pounds). The vest was worn for 30-minute increments every 2 hours over the entire school day. Kyle was assessed after having worn the vest for at least 15 minutes in one of the 30-minute increments.

Pressure vest. The pressure vest used in this study was the Bear Hug Vest by Southpaw Enterprises. The pressure vest was used to apply pressure to Kyles torso area and also had two straps that went over his shoulders. The vest applied pressure to this area of his body, the same areas that were affected by the weighted vest. The vest was worn for 30-minute increments every 2 hours over the entire school day. Kyle was assessed after having worn the vest for at least 15 minutes in one of the 30-minute increments.

Behavior Definition

Two dependent variables were identified for this study: attention to task and self-stimulatory behaviors. Attention was defined as either answering a question that was asked of him, participating in the academic activity with behavior that is appropriate to the context, and/or having his eyes oriented to the leader of the activity for at least 10 seconds of the 15-second interval. Self-stimulatory behaviors were broken down and defined in the following categories: fingers breaking the plane of the mouth and being left in the mouth for more than 2 seconds (i.e., one thousand one, one thousand two), commonly known as mouthing; tapping or hitting objects (defined as using hands or objects to tap another object or to tap against himself) for more than two seconds (i.e., one thousand one, one thousand two); repetitively jumping up and down more than once when not appropriate to the context.

Observation Procedure

Baseline.

The goal of baseline data collection was to determine Kyles current level of attention during circle time, as well as the self-stimulatory behaviors exhibited. Kyle was observed for 10-minute intervals during morning circle time prior. Circle time consisted of teacher-led songs and other activities to enhance skills development, such as calendar, counting activities, or shapes. The children in the classroom took turns selecting the next activity in circle time when offered choices by the teacher. Teachers were not given any instructions on what to do with Kyle or the other students, they were asked to conduct circle time as they would normally and use the same routine as any other day

Alternating Treatment Vest Intervention.

The intervention consisted of alternating treatments of wearing a weighted vest, a pressure vest, and no vest during the morning circle time activity. Teachers were provided with a schedule of which days to put the weighted or pressure vest on Kyle, and which days to not put a vest on him. Kyle was given the vest (weighted or pressure) 30 minutes prior to the beginning of circle time and it was removed immediately prior to the activity. As noted in previous research there is believed to be long lasting effects after the vest is removed (Olson & Moulton, 2004; Fertel-Daly et al. 2001). Teachers were given no other instructions about their own behavior, again they were asked to conduct circle time as it would be in their normal routine of the day.

Observation system.

Observers were trained through written instructions, practice, and feedback prior to beginning observations. All of the observational sessions were videotaped and a stopwatch was used to time intervals. Attention to task and self-stimulatory behaviors were recorded for a 10-minute period on a partial interval basis and non-occurrence was measured on a whole interval basis (Cooper, 1987). An event was defined as an opportunity for the child to exhibit attention to task. An opportunity began when the academic activity begins and ends 15 seconds after the onset of the interval.

Inter-observer Agreement

Inter-observer agreement was calculated between the lead author and a graduate assistant during live observations of circle time. Inter-observer agreement was calculated for 20% of the sessions across both baseline and the alternating treatment intervention. For reliability purposes, the 10-minute sessions were divided into 40, 15-second intervals. The formula used to calculate inter-observer agreement for occurrence was number of agreements divided by number of agreements plus number of disagreements multiplied by 100%. Inter-observer agreement for occurrences of attention was 83% (range: 73% to 93%). Inter-observer agreement for non-occurrence of self-stimulatory behavior was 86% (range: 73% to 94%) and inter-observer agreement for occurrences of self-stimulatory behaviors was 91% (range: 88% to 95%).

Experimental Design

An alternating treatment design (Alberto & Troutman, 2012) was used to measure the effects of the intervention, specifically, the use of a weighted vest versus a pressure vest versus no vest to increase attention and decrease self-stimulatory behaviors. Tokens were used prior to circle time to indicate which condition (weighted vest, pressure vest, or no vest) prior to circle time for the teacher to decide which to use Teachers were to not use the same condition as what was used the day before. This design was chosen because it is well suited for examining the effectiveness of more than one treatment on a behavior. The alternating treatment design does not establish a functional relationship between the interventions and any change in behavior; instead, the design can identify if one treatment is more effective than another treatment (fractionation).

Results

Figure 1 shows the percentage of observed intervals with self-stimulatory behaviors across baseline and the alternating treatment vest intervention. Self-stimulatory behavior occurred during 70% of the observed intervals during the baseline condition. Self-stimulatory behavior remained unchanged when the weighted vest intervention was applied (71%), as well as when the pressure vest was used (69%). Self-stimulatory behavior was observed 77% of the time when no vest was used during the alternating treatment intervention.

Figure 2 shows the percentage of observed intervals with attention to task. Attention to task increased from an average of 32% during baseline to an average of 45% when the weighted vest intervention was used (an increase of 13 percentage points). When the pressure vest was introduced, attention to task increased to 50% (an increase of 18 percentage points). During the no vest condition, attention to task averaged 40% (an increase of 8 percentage points).

Discussion

This study sought to measure the utility of a sensory integrative intervention to decrease self-stimulatory behavior and increase child attention during instruction. Neither the use of the weighted vest nor the pressure vest appeared to be beneficial for Kyle to decrease his self-stimulatory behavior. A very modest increase was observed in his attention to task when these vests were used. There are several reasons that may account for results of this study.

First, no formal protocol for the amount of weight used in vests was found to be uniformly accepted in the literature. The amount of weight varies in published research from a minimum of one pound to a maximum of 15% of the childs body weight (Fertel-Daly et al., 2001; Kashman & Mora, 2002; Reichow et al., 2010; VandenBerg, 2001). This intervention used the formula of 10% of Kyles weight, or 3 pounds. Other interventions have utilized other formulas for determining the weight of the vest. The amount of weight used in this study may not have been sufficient to produce an effect.

Secondly, the time period for wearing the vest varies from study to study. Wearing times varies through the research and from recommended practices from a minimum of 20-30 minutes to a maximum of wearing the vest for 2-hour periods (Fertel-Daly et al., 2001; Kashman & Mora, 2002; Reichow, 2010; VandenBerg, 2001). Kyle wore the weighted vest or the pressure vest for 30 minutes prior to the observed activity. The amount of time he wore the vest may have been insufficient to produce an effect. Additionally, while previous researchers have noted that there is a lasting effect after removing the vest, and in this study the activity was conducted immediately after wearing the vest, this study may add evidence that a lasting effect of wearing the vest does not exist.

An additional factor was Kyles visual problems (strabismus). This may have interfered with the data collectors ability to determine Kyles attention by examining his eye gaze, although reliability was satisfactory (83%). Future studies focusing on children with visual problems should involve direct participation in hands-on activities, not a group activity, with verbal, as well as physical, responses.

The results of this study should be interpreted with caution. Because only one participant was observed, these results should not be generalized. The use of weighted vests and pressure vests continued to be used as part of sensory integration (SI) therapy. Children with autism have a right to effective treatment; it is our ethical responsibility as professionals to ensure that interventions used with this population have demonstrated effectiveness. This study is a beginning attempt to standardize intervention procedures and build the literature base in sensory integrative therapy.

References

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Figure Captions

Figure 1. Percentage of observed intervals with self-stimulatory behavior.

Figure 2. Percentage of observed intervals with attention to task.

Figure 1 top

Figure 2 top