The Effectiveness of Weighted Vests Vs. Standard

Weighted Vests Vs. Standard
Occupational Therapy on
On-Task Behavior in Children
with Autism Spectrum Disorders
Brittney Schorr, MOTS
Methodological Quality of Studies
Implications for OT Practitioners
Implications for Future Research
On-Task Behavior
Sensory Integration
• Regulates behavior through sensory systems:
– Tactile
– Proprioceptive
– Vestibular
• SI treatments:
– weighted vests
– pressured vests
– weighted blankets
Weighted Vests
• Commonly cloth vests with pockets in the
front and back
• Weights in the pockets
• Weights can be made of any material
Occupational Therapy
Treatment as Usual
• Includes:
Music Therapy
Therapy Ball Chairs
Picture Activity Schedules
Hug Machine
Picture Activity Schedule
Hug Machine
• To examine the extent to which the research
literature supports weighted vests as
compared to treatment as usual as a more
effective approach to improving on-task
behavior in children with ASD
Search Terms
• Autism
• Weighted vest
• Therapy
• On-task behavior
• Attention
• Developmental Disorder
Types of Studies
• Controlled Clinical Trials
• Mixed Study Designs
• Experimental Research
• Single Subject
• Children with:
– Attention deficit hyperactive disorders (ADHD)
– Developmental delays
• 2 to 13 years old
• 45 boys, 11 girls (56 total)
Diagnoses & Interventions
Weighted Vest
4 Autism and PDD
Fertel-Daly et al.,
Hodgetts et al.,
Kane et al., 2005
Leew et al., 2009
VandenBerg, 2001
1 Developmental
Reichow et al., 2009
Diagnoses & Interventions
Therapy as Usual
(all children with autism)
1 Music Therapy
Kim et al., 2008
1 Hug Machine
Edelson, et al., 1998
1 Picture Activity
Bryan & Gast, 2000
1 Therapy Ball Chairs
Bagatell et al., 2010
Inclusion Criteria
Confirmed physician diagnosis
Between 2 and 13 years old
Korean Childhood Autism Rating Scale
Problematic behaviors interfering with ADLs
65 or above on Conners’ Teacher Rating Scale
Exclusion Criteria
• Diagnoses not confirmed by physicians
• Over 13 and younger than 2 years old
• Current therapy (OT, PT, SLP) in 9 studies
• Co-morbid diagnoses
Sample Sizes
• Range: 1 child to 12 children
• Average: 6 children per study
Weighted Vest Intervention:
ABA Withdrawal Design
• Initial baseline phases (A)
– Classroom fine-motor activity
• Intervention phases (B)
Classroom fine-motor activity
2 studies: Vests worn six 20-30 minute sessions
1 study: Vests worn 2 hrs. per day, 3x/wk for 12 wks
1 study: Vests worn 45 minutes during 14 sessions
• Withdrawal phases (A)
– Classroom fine-motor activity
– Removal of vests
Weighted Vest Intervention:
ABC Withdrawal Design
• Baseline phase (A):
– Classroom fine-motor activity
• Experimental phase (B):
– Vests worn without weight 20-30 mins./day for 2
• Experimental phase (C):
– Vests worn with weight 20-30 mins./day for 2 wks
Treatment as Usual: Hug Machine
• Two 20 min. sessions/wk. for 6 wks.
• Experimental group:
– Lie in Hug Machine
– Lever provided deep pressure
• Control group:
– Lie in the Hug Machine
– Lever disengaged
Treatment as Usual: Therapy Ball Chairs
• Baseline phase:
– 15 minute classroom “Circle Time”
– No therapy ball chairs
• Intervention phase:
– Utilized therapy ball chairs during “Circle Time”
Treatment as Usual:
Picture Activity Schedules
• Baseline phase:
– Classroom activity 45 mins./day for 5 days
– No picture activity schedule
• Intervention phase:
– Picture activity books
– 4 step activity
Treatment as Usual: Music Therapy
• Baseline phase:
– Observed engagement during normal play
– 30 mins./day for 12 weeks
• Intervention phase:
– Observed during normal play incorporating music
– 30 mins./day for 12 weeks
Outcome Measures
• Data sheets (10 studies)
• Data collection:
Videotaped recordings
Researcher observations
Conner’s Parent Rating Scale
Parenting Morale Index
Pre-tests and post-tests
• Pervasive Developmental Disorder Behavior Inventory-C
Data Analysis
• Repeated measures ANOVA
• 2-standard deviation
• Celeration line approach
– Predicted an increase or decrease in on-task
Methodological Quality of Studies
• Natural environments
– Classroom
– Home
• Randomization in 5 studies
• Blinding in 5 studies
Controlling for Threats to Validity
• Same diagnoses
• Did not include scores of 3 children who dropped out
• Served as own control
• Inter-rater reliability
• Controlled for maturation by conducting the studies
within weeks
• Small number of participants
• Only male participants in four studies
• Only one facility when recruiting participants
• Unequal groups in 4 studies:
– Group numbers
– 1 child had previous experiences with weighted vests
– Experimental group rated higher on the Tension and
Anxiety Scale than control group
• Poorly defined procedures:
– Did not state the frequency, duration, or intensity of OT
• Undisclosed treatment environment
• No means of controlling environmental distractions
– Disruptive classmates
– Loud noises
• No randomization in group assignments in 5 studies
• No experimenter blinding in 5 studies
• No psychometric properties of tests were
disclosed in 5 studies
• Hawthorne effect
– Children knew they were being observed
Results: Treatment as Usual
• Hug Machine:
– Experimental group lower tension levels on the Tension
Scale than control group
• t(10)= 3.124, p<.05
– Lower on Anxiety Scale than the control group
• t(10)=1.959, p<10
• Therapy Ball Chairs:
– Positive effects during “Circle Time”
– Decreased number of minutes spent out of chair
– No p values given
Results: Treatment as Usual
• Picture Activity Schedule:
– Children remained on-task and on-schedule when
using the books
– No p values given
• Music therapy:
– Increased eye contact (p<0.0001).
– Medium effect on on-task behavior (d=.63)
Results: Weighted Vests
– Significant change (p<.05) from baseline to
– Increase in on-task behavior (18% - 25%)
• Developmental Delays:
– No improvement in on-task behavior
– Greater incidences of problematic behavior
– No p values
Results: Weighted Vests
• PDD:
– 1st study
• Decrease in number of distractions
• Increase in focused attention
• No p values
– 2nd study (PDD & autism)
• No increase in on-task behavior
• No p values
Results: Weighted Vests
• Autism:
– 1st study
• No overall improvement in on-task behavior
• Slight increase in on-task behavior in one child, but not
• No p values
– 2nd study
• No increase in on-task behavior
• No p values
• Evidence suggests that weighted vests are not
a more effective intervention than OT as usual
for increasing on-task behavior in children
with Developmental Delays and ASD (autism,
• Weighted vests appeared to temporarily
improve on-task behavior in one child with
– Long term effects not evaluated
– Child received OT throughout the study
– Unable to determine whether the results were
contributed to the vests or from OT
• Weighted vests appeared to have significant
effects on children with ADHD
• Only included 4 children
– Convenience sampling recruitment method
– Long term effects not evaluated
• OT as usual is noted to be a more effective method
for promoting on-task behavior in children with
• Therapy ball chairs
– Positive effects on in-seat and on-task behavior
• Music therapy
– Effective intervention
• Hug Machine
– Deep pressure can contribute to an increase in ontask behavior
– Extensive measures to control for threats
• Picture activity schedules
– Children’s performance increased by 100%
• Efficacy of weighted vests depends on the
child and his or her diagnosis
• OT as usual appears to be a more reliable
option for improving on-task behavior in
children with ASD
Implications for OT Practice
• Weighted vests may provide short-term calming
effects on children with ADHD, but long-term
effects have not been evaluated
• OTs should not generalize the results to adults
and diagnoses outside of the study
• OTs who use weighted vests must proceed with
caution until further evidence can be established
Implications for Future Research
• Replicating in other contexts
• Long term effects
• Longer intervention period
• Examining other protocols
• Larger sample sizes
• Boys and girls
• Increasing amounts of weight in vests
Bagatell, N., Mirigliani, G., Patterson, C., Reyes, Y., & Test, L. (2010). Effectiveness of therapy ball chairs on classroom participation in children
with autism spectrum disorders. American Journal of Occupational Therapy, 64, 895–903.
Bryan, L., & Gast, D. (2000). Teaching on-task and on-schedule behaviors to high-functioning children with autism via picture activity schedules.
Journal of Autism and Developmental Disorders, 30(6), 553-567.
Edelson, S., Edelson, M., Kerr, D., & Grandin, T. (1999). Behavioral and physiological effects of deep pressure on children with autism: a pilot
study evaluating the efficacy of grandin's hug machine. The American Journal of Occupational Therapy, 53(2), 145-152.
Fertel-Daly, D., Bedell, G., & Hinojosa, J. (2001). Effects of a weighted vest on attention to
task and self-stimulatory behaviors in
preschoolers with pervasive developmental disorders. The American Journal of Occupational Therapy, 55(6), 629-640. Retrieved from
Hodgetts, S., Magill-Evans, J., & Misiaszek, J. (2010). Weighted vests, stereotyped behaviors and arousal in children with autism. Journal of
Autism and Developmental Disorders, 41, 805-814.
Kane, A., Luiselli, J., Dearborn, S., & Young, N. (2004). Wearing a weighted vest as intervention for children with autism/pervasive
developmental disorder. The Scientific Review of Mental Health Practice, 3(2), 19-24.
Kim, J., Wigram, T., & Gold, C. (2008). The effects of improvisational music therapy on joint attention behaviors in autistic children: a
randomized controlled study. Journal of Autism and Developmental Disorders, 38, 1758-1766.
Krebs, M, McDaniel, M, & Neely, R. (2011). The effects of peer training on the social interactions of children with autism spectrum disorders.
Education, 131(2), 393-403.
Leew, S., Stein, N., & Gibbard, B. (2010). Weighted vests' effect on social attention for toddlers with autism spectrum disorders. Canadian
Journal of Occupational Therapy, 77(2), 113-124.
Moss, J, & Howlin, P. (2009). Autism spectrum disorders in genetic syndromes: implications for diagnosis, intervention and understanding the
wider autism spectrum disorder population. Journal of Intellectual Disability Research, 53(10), 852-873.
Reichow, B., Barton, E., Good, L., & Wolery, M. (2009). Brief report: effects of pressure vest usage on engagement and problem behaviors of a
young child with developmental delays. Journal of Autism and Developmental Disorder, 39, 1218-1221.
Sansosti, F. (2010). Teaching social skills to children with autism spectrum disorders using tiers of support: a guide for school-based
professionals. Psychology in the Schools, 47(3), 257-278.
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