Friday, November 18, 2011

Thoughts about use of weighted vests to promote attending behaviors in children

Please reference an entry earlier this year about seat cushions.

I am essentially re-posting that earlier entry but replacing 'seat cushions' with 'weighted vests.' Let me start this post with congratulations for Amy Collins and Rosalind J. Dworkin who wrote an excellent article in this month's American Journal of Occupational Therapy.

Here comes some mildly edited cutting and pasting from the previous entry - and I will take the liberty of copying my own writing because the issue is identical and this entry will likely be searched separately than the seat cushion entry!

I encourage everyone to open up the current American Journal of Occupational Therapy and read 'Pilot Study of the Effectiveness of Weighted Vests.' This is a fantastic article that looks at the issue of whether or not weighted vests were effective at promoting attending behavior.

I think this is a fantastic study because it take a very common OT intervention and puts it to the test. For many years OTs have been dispensing weighted vests to children in classrooms based on the thought that the vests provided calming/organizing sensory stimulation that would promote attention . This has been done for so many years in so many settings that it becomes a common request from teachers who don't know what to do with children who have attending difficulties. How many OTs hear the request "Can we try to see if a weighted vest will help?"

We have precious little evidence that weighted vests do anything at all for children - and the lack of evidence is reflected in the fact that this intervention is barely mentioned in some common pediatric occupational therapy texts. However, given the formulaic and mythical popularity of the intervention you might think there would be more supporting research!! Now we have a series of recently published articles that when considered in total indicate very little evidence for using weighted vests.

For additional background reading please also reference Hodgetts, Magill-Evans, & Misiaszek (2011); Leew, Stein, & Gibbard (2010); and Stephenson & Carter (2009).

In the AJOT study the authors Collins and Dworkin used an intervention and control group in a blinded and randomly assigned design to measure the impact of wearing a weighted vest on attending behaviors. They used a clever model of removing the weights from the vests in the control group and inserting insignificantly weighted Styrofoam that replicated the appearance of the weighted vests for the data collectors.

The authors were unable to find evidence that weighted vests had any effectiveness for improving attending behaviors. The study was limited because of small sample size and a need for ensuring consistency in coding/recording methods. These limitations are significant enough to warrant the label of 'pilot study.'

The findings of this pilot study are consistent with previous studies and although there are some limitations in the research design there are some other strengths of the study and its confirmation of previous studies is compelling.

My analysis of this is that we should probably make attempts to confirm this with a more tightly controlled design and a larger sample, but based on these results and the consistency of these results with previous studies there is very little support for using weighted vests with the expressed purpose of trying to improve attending behaviors.


References:

Collins, A. & Dworkin, R.J. (2011). Pilot Study of the Effectiveness of Weighted Vests. American Journal of Occupational Therapy, 65(6), 688-694.

Hodgetts, S., Magill-Evans, J., & Misiaszek, J. (2011). Weighted vests, stereotyped behaviors and arousal in children with autism. Journal Of Autism And Developmental Disorders, 41(6), 805-814.

Leew, S., Stein, N., & Gibbard, W. (2010). Weighted vests' effect on social attention for toddlers with Autism Spectrum Disorders. Canadian Journal Of Occupational Therapy. Revue Canadienne D'ergothérapie, 77(2), 113-124.

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), 105-114.

7 comments:

TherExtras said...

I love your debunking of a good sensory myth, Chris!

Barbara

Your Therapy Source Inc said...

I certainly agree with your thoughts that the weighted vest appears to be ineffective. In this study it made no difference on the attention span of the 10 second graders with attention difficulties. But I do not think that a generalization can be made yet due to such a small sample size. I am in complete agreement that somehow many strategies have popped up that have no research to back up the suggested intervention. Therapists need to do a better job of documenting what works for each child. Therefore, if you try a weighted vest on a student please establish a data collection system to determine if it is effective. If it is not discontinue the intervention. It irks me to see students wearing weighted or compression vests for the entire school year and then you ask the teacher if it does anything and they shake their head no. Also irks me when I see students wearing the vests for prolonged periods of time.

Chris said...

It was a small sample size but I feel comfortable letting this intervention go because of all the other studies that have yielded similar results, as well as my own clinical experience where it doesn't seem that they make much of a difference. It is interesting though how teachers in these studies routinely think that attending behaviors increase even though recorded observations indicate otherwise. This speaks to the amazing power of the placebo.

Loren Shlaes said...

Thank you for posting this. I have never used weighted vests in my practice. Except for inflatable cushions, I don't use interventions that act as a bandage on symptoms and behaviors, preferring instead to spend my energy on correcting the underlying problems causing the issues in the first place. A child who can't sit still has some combination of sensory defensiveness, low trunk strength, poor nutritional status, shallow respiration, high vestibular threshold combined with not enough exercise and time spent outside, and retained postural and primitive reflexes. When those issues are addressed and rectified, the ability to sit and attend increases dramatically.

Edie said...

Every child is unique. My son has SPD. When he used a weighted vest for the first time in his OT's office, he was like a completely different child! His printing was neat and legible and he was able to print for more than just a couple of minutes. He's never been able to do this before. He's used it at school as well with very positive results. His teacher borrowed a vest he'd outgrown to lend to another student - and it helped him to regulate and stay on task. Obviously the vests don't work for every child, but please remember that they DO work for some children.

Christopher Alterio said...

I am very glad that your son's writing improved. You describe a transformation that is very uncommon.

The problem that we have as therapists is in trying to determine why something improves. If weighted vests were this effective, even on a slightly occasional basis, there would be less controversy. The controversy exists because they are used with many children and there are no measurable changes in many cases. Research supports this conclusion.

We would like to be able to draw linkages between the things we use in intervention to the direct outcomes that occur. When we take an approach to try things that MIGHT work on an infrequent basis we spend a lot of time and resources - and this is something that we probably should not be doing because it is potentially harmful to do this in many health care contexts.

Certainly, weighted vests are not a life and death issue - but we are still responsible for appropriate utilization of resources. Should we make our children wear weighted vests or alter their schedules and remove them from normal instructional time for therapies that MIGHT work some of the time? As a parent you probably have a right to much more specificity than something that MIGHT work - and the point here is that we do research on these things to inform us whether or not it is worth trying these kinds of interventions by default or as a matter of course. We want to spend our therapy time and all of our resources (which are really your resources!) wisely. It is a tough balancing act.

Christopher Alterio said...

And yet more evidence...
http://www.ncbi.nlm.nih.gov/pubmed/23278839