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Weighted Items and Autism Ranking: Insufficient/Mixed evidence

Weighted vest

Weighted items are any items (such as blankets or vests) which have been made heavier by adding small weights. Those weights can either be stitched into the fabric or put into specially designed pockets.

Weighted items can be bought from specialist suppliers, bought second hand or made at home. 

Some people believe that specially weighted items can help children on the autism spectrum cope better with a wide range of problems, such as poor motor skills, hyperactivity and sleeplessness.

They believe that the pressure of the weights helps to calm autistic children by changing how they process sensory information and by allowing them to better feel their movements and understand where their bodies are in space.   

Our Opinion

There is a very small amount of high quality research evidence (one large controlled trial and one small controlled trial) and a small amount of low quality research (nine single-case design studies with three or more participants) into the use of weighted items for children and young people on the autism spectrum.

There is insufficient evidence to determine if weighted items provide any benefits to children and young people on the autism spectrum. There is no evidence to determine if weighted items provide any benefits to adults on the autism spectrum. 

There is a need for more research into weighted items which uses scientifically robust, experimental methodologies with larger numbers of more diverse participants. That research should investigate whether weighted items are more or less effective than other interventions designed to help with sensory issues (such as physical exercise) and whether specific individuals are more likely to benefit from weighted items than other individuals.

There is also a need for a set of agreed protocols on how weighted items should be used, for example, how much they should weigh, how long they should be used and under what circumstances.

Disclaimer

Please read our Disclaimer on Autism Interventions

Audience

According to Stephenson and Carter (2008), weighted items like weighted vests are designed for people with sensory problems (such as sensory integration dysfunction) or for people with posture and balance problems (such as people with cerebral palsy).

Some people believe that individuals with sensory problems may be easily distracted, hyperactive and lacking in concentration, have poor hearing and speaking skills, have sleep difficulties, or have poor proprioception (awareness of their body), anxiety or stress.

According to Stephenson and Carter (2008), weighted items have been used with a wide range of children including
“…  children with Autism Spectrum Disorder, ADHD, sensory integrative disorder, cerebral palsy, developmental delay, Down syndrome and traumatic brain injury.”

Weighted items are mostly used with pre-school children and primary school aged children, but they may also be used by older children and adults.

Aims and Claims

Aims

The aim of using weighted items is to apply deep pressure to the body. Some people think that the pressure of the weights helps to calm people with sensory problems by changing how they process sensory information, allowing them to better feel their movements and understand where their bodies are in space. For example, according to Morrison (2007), 

“The use of a weighted vest is based on the sensory integrative frame of reference. It is argued that the weight in the vest provides proprioception (deep pressure), which provides calming input to the central nervous system by promoting the production of neurotransmitters such as serotonin and dopamine.”

Some people believe that using weighted items to calm autistic children can in turn help them with a wide range of other problems such as poor motor skills, hyperactivity and sleeplessness etc.

Claims 

There have been various claims made for weighted vests and blankets. For example, 

  • Fertel-Daly et al (2001) claimed that the use of a weighted vest resulted in an increase in attention to task and decrease in self-stimulatory behaviors in five pre-schoolers with pervasive developmental disorders.
  • Olson and Moulton (2004) claimed that 82% of respondents to a survey of school-based occupational therapists were using weighted vests with autistic students. These therapists reported some decreased behaviours which they considered to be negative (flapping, hitting, rocking, tantrums, covering face, wandering) and some increased behaviours which they considered to be positive (attention, eye contact, staying on task, purposeful requests, following instructions, and balance and stability).

Key Features

Weighted items are any items (such as blankets, vests, belts, lap pads, and shoulder wraparounds) which have been made heavier by adding small weights. Those weights can either be stitched into the fabric or put into specially designed pockets. Weighted items can be bought from specialist suppliers, bought second hand or made at home. 

However there are no widely agreed standards about what to use as weights, where to put the weights, how much weight to use or for how long to use the weighted item. For example, according to Olson and Moulton (2004) who conducted a survey of school-based occupational therapists using weighted vests, some of the therapists reported using 2%-10% of the participant's body weight, while others used weights of between 1-2 kilograms / 2-4 lbs. Some of the participants wore the vests for 10 minutes, while others wore them for 45 minutes or longer.  

Blankets

Weighted blankets may weigh anything up to 12 kilograms / 24 pounds. The weights are usually sewn into the fabric of the blanket.  They are sometimes used to help with sleep difficulties or to help calm a child from over stimulation or a tantrum. 

Vests

Weighted vests may weigh anything up to 6 kilograms / 12 pounds. The weights may be sewn into the fabric of the vest or placed in special pockets. Pressure vests are similar to weighted vests but are designed to provide greater pressure more evenly over the entire trunk. The weighted vest is worn depending on the individual child, his or her behaviours and his or her response to wearing it. As it may be designed and tailored to suit the individual child it can be worn unobtrusively. Weights can be adjusted and the vest can be introduced as part of play or activity.

Belts

Belts may weigh up to 1.5 kilograms / 3 pounds. The weights may be sewn into the fabric of the belt or placed in special pockets.  Belts are sometimes used instead of vests, especially for younger children or for children who will not allow anything to be placed over them.

Shoulder wraparounds.

Shoulder wraparounds may weigh up to 3.5 kilograms / 7 pounds and are worn around the shoulders. They are used to calm children who display anxiety and stress.

Lap pads

Lap pads may weigh up to 6 kilograms / 12 pounds. They are placed on the child's lap and can be used at mealtimes, at school, whilst travelling and at social events.

Cost and Time

Cost

The cost of weighted items varies enormously, depending on the supplier, the size of the item, the materials used, whether you buy new or second-hand, or whether you have the item specially made for you or make it yourself. The following costs for new items were taken from a variety of UK websites in September 2017. 

  • Weighted blankets, approximately £45-£525.
  • Weighted vests, approximately £38-£90.
  • Weighted belts, approximately £10-£60.  
  • Shoulder wraps, approximately £15-£29.
  • Lap pads, approximately £35-£55.

Time

There is no general agreement on the frequency or length of time that weighted item should be used. 

In practice, weighted blankets tend to be used all night, every night. Weighted vests, on the other hand, are sometimes worn for 10 minute periods, for 45 minute periods or sometimes for most of the school day. 

Risks and Safety

Hazards

There are a number of potential hazards involved in the use of weighted items, such as blankets and vests.

Weighted blankets

On April 18th 2008 Gabriel Poirier, a young autistic boy, died in the province of Quebec after being wrapped in a weighted blanket by a teacher in a classroom. Following this tragedy, Coroner Catherine Rudel-Tessier, made the following recommendations,

“Because the therapeutic value of weight blankets does not seem to be proven scientifically, and because of the fact that they pose a risk for children's lives, we could be tempted to prohibit their use altogether. However, I believe that it is possible to manage usage in a strict manner in order to minimize the danger. I believe that certain ground rules must be respected by those who wish to use this sensory pressure technique, namely:

  • A health professional's advice must be obtained to ensure that the use of the blanket is suitable for the child
  • The weight of the blanket must be in proportion of the child's physique and weight
  • The child's head must never be, or be able to be, covered by the blanket
  • Vital signs should always be observable
  • The child must never be rolled in a blanket (unless a therapist is constantly at his or her side)
  • A child must never be left unsupervised
  • The child must be able to easily slip out of the blanket if he or she wishes to do so (it is not a confinement)
  • The child must express his or her consent to this, even if it is not verbal.”
Weighted vests

Stephenson and Carter (2008) expressed some concerns about the potential harm from wearing weighted vests for prolonged periods, suggesting that the effects are unknown.

“The effect of prolonged wearing of a weighted vest needs to be considered. It is recommended that children carry no more than 10-15% of their body weight in a backpack and recent research evidence indicates that 10% is a safer limit. While the weight in a vest is more evenly distributed than in a backpack, the maximum weight used in the studies was at the upper end of the safe range. While a vest was worn for a maximum of 2 h at a time in studies in the current review, it has been reported that they can be worn for up to 4 h at a time and for most of the school day. Clearly, these are much longer periods than a backpack would typically be carried by a child. One issue that does need consideration is the effect per se of carrying this amount of weight, suspended above the centre of gravity, particularly for an extended period of time. If vests do have effects, and the evidence on this point remains unconvincing at this stage, it is possible that these may be artifacts of fatigue and unrelated to purported sensory integrative mechanisms.”

Contraindications

There are no known contraindications for weighted items - something which makes a particular treatment or procedure potentially inadvisable for a specific group of people. 

Suppliers and Availability

Suppliers 

Weighted items, new and second-hand, are widely available from a variety of suppliers in a number of countries, including the UK and the USA.  It is also possible to make some of these items at home, either from scratch or using patterns provided by suppliers.

Credentials

There are a number of specialist suppliers of weighted products but there does not appear to be any industry standard that applies worldwide or even within specific countries like the UK or the USA. For this reason, we strongly recommend that you should consult an appropriately qualified health care professional (such as an occupational therapist or a physiotherapist) before using any weighted items.

History

According to Olson and Moulton (2004), the use of weighted items as a supplement to occupational therapy grew out of the work of therapists (such as Ayres, Baranek and Dunn) who were using a sensory integration theoretical and treatment framework in the 1980s and 1990s.  

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

Ongoing Research

Research Studies Currently Underway

We have been unable to identify any studies into weighted items that are currently underway.  If you know of any other studies we should include please email info@researchautism.net with the details. Thank you.

Future Research

Summary of Existing Research

There is a very small amount of high quality research evidence (one large controlled trial and one small controlled trial) and a small amount of low quality research (nine single-case design studies with three or more participants) into the use of weighted items for children and young people on the autism spectrum.

There is insufficient evidence to determine if weighted items provide any benefits to children and young people on the autism spectrum. There is no evidence to determine if weighted items provide any benefits to adults on the autism spectrum. 

Recommendations for Future Research

Various authors have made recommendations about the need for future research into weighted items. For example, Stephenson and Carter (2008) made a number of recommendations on future research into weighted vests.

“While it should be acknowledged there is only a limited body of research, on balance, indications are that weighted vests are ineffective. There may be an arguable case for continued research on this intervention but future investigators need to ensure that: criteria for participant selection are replicable and justifiable; participants are adequately described; interobserver reliability is satisfactorily established; observers are blinded to the presence of weight in the vests; results are appropriately interpreted with consideration of the functional magnitude of changes; more stringent research designs (such as alternating treatment or multiple baseline designs) are employed.”

We agree and would also suggest that there is a need for more research into weighted items which uses scientifically robust, experimental methodologies with larger numbers of more diverse participants. That research should investigate whether weighted items are more or less effective than other interventions designed to help with sensory issues (such as physical exercise) and whether specific individuals are more likely to benefit from weighted items than other individuals.

That research should also involve people on the autism spectrum in the design, development and evaluation of the studies. 

There is also a need for a set of agreed protocols on how weighted items should be used, for example, how much they should weigh, how long they should be used for and under what circumstances.

Studies and Trials

This section provides details of scientific studies into the effectiveness of this intervention for people on the autism spectrum which have been published in English-language, peer-reviewed journals. If you know of any other studies we should include please email info@researchautism.net with the details. Thank you.

Please note that we are unable to supply publications unless we are listed as the publisher. However, if you are a UK resident you may be able to obtain them from your local public library, your college library or direct from the publisher.

Other Reading

This section provides details of other publications on this topic. If you know of any other publications we should include please email info@researchautism.net with the details. Thank you.

Please note that we are unable to supply publications unless we are listed as the publisher. However, if you are a UK resident you may be able to obtain them from your local public library, your college library or direct from the publisher.

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