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Weighted Items and Autism Ranking: Insufficient/Mixed evidence

Current Research

Current Research Studies

We have identified eleven* studies of the use of weighted items on children and adolescents on the autism spectrum published in peer-reviewed journals published in English. We have been unable to identify any studies on adults.  These studies included more than 100 participants aged from 2 to 16 years old, although 67 of these were from the only study (Gringras et al, 2014).
 
Most of the studies looked at weighted vests, one study looked at weighted blankets (Gringras et al, 2014) and one study looked at weighted blankets and weighted vests (Losinski et al, 2017).
 
  • The study by Gringras compared weighted blankets to non-weighted blankets and found no benefits from either type of blanket.
  • The study by Losinski compared weighted blankets with pressure vests and with physical exercise. It found that neither the weighted blankets nor the pressure vests provided any benefits, although physical exercise provided some benefits for two of the three participants.
  • A majority of studies which looked at weighted vests found no benefits for the participants and some even found some increases in problem behaviours.
  • A minority of studies which looked at weighted vests found some benefits for some participants (such as an increase in attention to task and a decrease in self-stimulatory behaviours).
  • The studies which compared weighted vests to non-weighted vests found no benefits from either type of vest.
* Please note: We have not included studies with less than three participants, studies in which weighted items were one part of a multi-component intervention (such as sensory integrative therapy) or studies of other types of vest or blanket.

Status of Current Research Studies

There have been a number of literature reviews published in peer reviewed journals on the subject of weighted items, which identified a number of limitations to all of the research studies published to date. For example,
  • Morrison (2007) noted the lack of a standardised protocol for determining the weight of vests and the duration of their use, which makes it difficult to assess the effect, if any, they might have had across different studies.
  • Stephenson and Carter (2008) noted that some studies did not provide information on how the participants were selected; did not provide formal diagnosis for some participants; did not provide information about the characteristics of some participants (such as their IQs); did not provide sufficient information about the interventions used (such as length of treatment, weight of vests etc.); did not provide outcome data for some participants; did not provide information about the reliability of the observation and recording methods used; made incorrect assumptions about the problem behaviours identified e.g. repetitive behaviour. They also noted that most of the studies were single case designs and many of these used very basic methodologies (such as simple ABA designs).
We have identified a number of other limitations beyond those listed above.
 
The study by Hodgetts et al (2011) was a randomised controlled trial but it only had six participants.
  • The study by Gringras et al (2014) was a large, multi-centre randomised controlled trial. However the authors noted a number of limitations including the relatively high number of participants who were either unable to tolerate actigraphy or in whom actigraphy equipment failed; their decision to use 60 minutes additional sleep time as the measure of success (the children gained 20 minutes a night on average, which some people would say is a success); their definition of a sleep disorder did not vary across the age range of children included, potentially meaning that younger children experienced greater deviation from sleeping habit norms than older children.
  • None of the studies appeared to involve people on the autism spectrum in the design, development and evaluation of those studies.

For a comprehensive list of potential flaws in research studies, please see Why some autism research studies are flawed

Updated
12 Jun 2018
Last Review
31 May 2018
Next Review
31 May 2021