Seven studies (n=20) were included in the review. None of the studies had a control group. Studies included one to five participants. The authors stated that the primary studies had a number of weaknesses, including inadequate or missing information on inter-observer reliability in more than half of the studies, lack of blinded assessment and short observation periods over short time spans.
The included studies reported that weighted vests were associated with a reduction of the stereotypic behaviour for five children and a highest attention or engagement in a task for 10 children, but had no effect on the problem behaviour for one child.
Two studies reported the positive effects for weighted vests on children's problems of attention to task and stereotypic behaviours, but one study found mixed results. Four studies showed no effects for weighted vests on children's inattentiveness and stereotypic behaviours.