Weighted blankets, weighted vests, compression garments, and in general, deep pressure therapy has worked its way into the mainstream commercial world. Think of the hype around the “Gravity Blanket,” a weighted blanket that raised $3 million on Kickstarter. Or what about “Thunder Shirts,” which are basically just compression vests for anxious dogs?
I don’t mean to brag, but occupational therapists have been using the theory behind these products since before it was cool, specifically in our work with sensory processing disorders. While we tend to hear big claims about their benefits, do weighted blankets really work?
Why Therapists Recommend Weighted Blankets
According to Sensory Integration Theory, deep pressure input has a calming effect on the nervous system. There has also been research to suggest that deep pressure input (i.e. from massage) can influence biochemistry by decreasing the release of the stress hormone cortisol, and increasing the release of serotonin and dopamine (Field et al., 2005).
For many of the children we work with in occupational therapy, interaction with sensory input such as light touch, noise, smells, or movement can leave them feeling under or over stimulated. This difficulty with sensory processing frequently interferes with their engagement in childhood “occupations” such as learning, self-care skills, and social interactions.
Therapists will commonly recommend weighted blankets for children that have difficulty falling or staying asleep due to their sensory processing difficulties. You’ll also find weighted or compression vests, shirts, or backpacks used in a school setting to assist a child with attention or decreasing self-stimulation and sensory seeking behaviors. According to theory, if we provide a child with the necessary regulating stimulation through deep pressure input, then they won’t have to distract themselves by seeking it elsewhere by, for example, rocking in their chairs or walking around the room.
What Therapists and Parents Have to Say About
Therapists make recommendations for weighted blankets or vests, and continue to do so, based on the positive feedback we receive from both parents and children. Children typically tolerate them very well and often request their use at home and school. We hear (and observe) that children seem to sit without fidgeting as much, appear calmer and more regulated, and parents often report that their child can’t go to sleep without their heavy blanket. We use this fairly consistent anecdotal evidence to support our recommendations.
So, case closed; they work, right?
I’m afraid it’s not quite that easy in a world demanding evidence based practice, especially when it comes to interventions based in Sensory Integration Theory. As I’ve mentioned before when talking about goal writing, (How do You Write your Sensory Integration Goals?) insurance often denies sensory integration intervention as “experimental” and Sensory Processing Disorder did not make it into the DSM-5 as an official diagnosis. It can be difficult to find solid, strong studies that back this intervention, even though so many people rely on this approach for their child.
Losinski, Cook, Hirsch, & Sanders (2017) reminded us that even though research often refutes our claims of sensory integration’s effectiveness, this type of intervention has a “wide advocacy base,” which is so incredibly true. Even as I write this, I know I’ll have a group of therapists, parents, and even children that would strongly stand by this theory and what we do, even when the research studies don’t quite match up with what we’re seeing in the clinic. (And why can’t research replicate the results we see as therapists in our day to day practice? I have lots of thoughts about that, but I’ll save it for another day…)
What the Research Says About Weighted Blankets and Vests
While we can say with confidence that children and parents typically enjoy weighted blankets, research, on the other hand, doesn’t appear to have our backs on the subject. Here’s what I found after a review of five research studies:
The Recommendations Aren’t Consistent
How much weight is safe, but still effective? How long should the child be wearing the weight? I’ve heard of using 10% of a child’s weight, but many studies used just 5%. Some researchers simply used the same fixed weight on everyone. As far as a “rule of thumb” for a wearing schedule for weighted vests, I’ve always been told to use 20 minutes on, 20 minutes off to avoid habituation, but that was completely different in every study as well. Some were wearing the weight all day, some a few hours, some a few minutes. With no set protocol or basis for our intervention recommendations, how will we ever be sure we are making a difference?
Studies Aren’t High Quality
In the research realm, there are studies that carry more weight than others based on the way they were carried out. Small sample sizes, inconsistent recommendations, and potential researcher bias may have muddied the available research results on this particular subject. Studies that did find positive outcomes have been criticized for their poor research designs and conflicts of interest. Many studies didn’t even have a clear control group to compare the results against. This introduces subjective rating bias and unclear results.
No Conclusive Evidence of Positive Outcomes
This one stings the most. I immediately think of the children that LOVE their blankets. Surely it’s having a positive impact on their arousal level, their anxiety, and their self-regulation! But in that same breath, I’ve also had plenty of items returned, parents saying, “Maybe this will help someone else, but it didn’t help us.” Are we simply being influenced by a placebo effect? The idea that something feels “good,” so it must be working?
In all of the studies I searched, (and I really, really tried to find some good ones) there weren’t any strong, statistically significant positive outcomes. My husband can attest to these disappointing findings as I was shouting, “Aw man, come on!” while reading these studies at the kitchen table.
Gringras et al. (2014) stated that weighted blankets didn’t help children on the autism spectrum fall asleep faster, sleep longer, or wake up any less often than a control blanket. They did, however, report that children and parents liked the weighted blankets more than the control.
When Lew, Stein, & Gibbard (2010) looked at the impact of weighted vests on social attention in toddlers on the autism spectrum, they found that the vests “do not affect rates of competing behaviours or joint attention for toddlers…” (However, they did point out that maybe the vests they used weren’t providing enough deep pressure touch input.)
Hodgetts, Magill-Evans, & Misiaszek (2011) looked to see if weighted vests had an impact on stereotyped behaviors (rocking, hand flapping, spinning objects, etc.). As I mentioned previously, therapists often recommend weighted vests in classroom or other settings when they feel like behaviors such as these are interfering with learning. The researchers concluded that that their results did not support the use of weighted vests to decrease these behaviors.
Another group that compared deep-pressure therapies (DPTs) including weighted blankets and compression vests against exercise suggested that their study “…reinforces findings in previous reviews on the ineffectiveness of DPTs…” (Losinki, Cook, Hirsch, & Sanders, 2017).
In their review of the available literature on the subject, Stephenson & Carter (2008) stated that, “Until such time as well-conducted studies can provide replicated evidence to the contrary, weighted vests cannot be recommended for clinic application.”
Wow. That’s certainly a conclusive statement – How many occupational therapists have read that before?
Should We Stop Recommending Weighted Blankets or Vests?
Based on the available evidence, perhaps therapists and companies can’t necessarily claim that a weighted blanket or vest is a definitive treatment for children with sensory processing difficulties. In fact, according to an article in Scientific American, the makers of the popular Gravity Blanket had to change the language on their website from claiming their weighted blankets can “treat” anxiety, insomnia, etc. to the fact that they can be “used” for these conditions. A small, but very distinctive difference.
In the midst of this review, let’s not overlook the importance of what positive outcomes were found in a few of these studies. Is it still significant to see that many parents and children preferred the weighted products, and even expressed a positive morale boost in relation to their use? (Lew, Stein, & Gibbard, 2010) If therapists can promote positive outcomes through improved parent and child interactions, weighted products might still be a powerful tool in our realm of treatment.
Also, just to play devil’s advocate, maybe the weight used in the studies wasn’t enough to stimulate the positive effects of deep pressure on the nervous system. However, what’s the “safe” amount that won’t be harmful or dangerous to sleep with, or cause other issues such as muscle or joint pain? There are many unanswered questions; I feel all of us as therapists should, at the very least, be questioning our recommendations.
Regardless of all of this relatively disappointing research, it’s still very difficult to throw this one out of our therapy toolbox all together. I have to equate this intervention to the Wilbarger Brushing Protocol that I have written about before (10 Realities of the OT Brushing Protocol). Even though the research evidence to support this intervention wasn’t conclusive, I still had a number of people comment on how life changing it was for their child.
So therein lies the challenge of our profession. We toe the line between what we see in the clinic day after day and what the research suggests. We feel compelled to provide parents with all of the options and resources available, because we don’t definitively know what might be the one thing to make all the difference for their child. A pretty heavy task, indeed.
Field, T., Hernandez-Reif, M., Diego, M., Schanberg, S., & Kuhn, C. (2005). Cortisol decreases and serotonin and dopamine increase following massage therapy, International Journal of Neuroscience, 115:10, 1397-1413.
Gringras, P., Green, D., Wright, B., Rush, C., Sparrowhawk, M., Pratt, K., Allgar, V., Hooke, N., Moore, D., Zaiwalla, Z., Wiggs, L. (2014). Weighted blankets and sleep in autistic children – A randomized controlled trial. Pediatrics, 134(2), 298.
Hodgetts, S., Magill-evans, J., & Misiaszek, J. E. (2011). Weighted vests, stereotyped behaviors and arousal in children with autism. Journal of Autism and Developmental Disorders, 41(6), 805-14.
Leew, S. V., Stein, N. G., & Gibbard, W. B. (2010). Weighted vests’ effect on social attention for toddlers with autism spectrum disorders. The Canadian Journal of Occupational Therapy, 77(2), 113-24.
Losinski, M., Cook, K., Hirsch, S., & Sanders, S. (2017). The effects of deep pressure therapies and antecedent exercise on stereotypical behaviors of students with autism spectrum disorders. Behavioral Disorders, 42(4), 196-208.
Stephenson, J., & Carter, M. (2009). The use of weighted vests with children with autism spectrum disorders and other disabilities. Journal of Autism and Developmental Disorders, 39(1), 105-14.