Review Of Literature
The purpose of this review is to examine the available literature on the effectiveness of using therapeutic vests, weighted vests, and pressure vests on children with Autism spectrum disorders (ASD), Attention deficit disorder (ADHD), Pervasive Development Disorder (PDD), other developmental disabilities and sensory processing abnormalities. The use of therapeutic vests is a commonly accepted practice throughout the special educational and occupational fields.
Scopes and types of design
The scope of this review began with an article by Ayers in (1972), but the main review covered the period beginning from 1999 to date. The types of designs vary from one article to another. Two of the articles were literature reviews: one by Morrison (2007) and another by Stephenson &Carter (2008). Morrison (2007) included five articles in the review. Stephenson (2008) examined seven studies.
The studies that were reviewed used experimental design conducted using only a small number of participants. Two different research studies by Reichow, Barton, Sewell, Good, and Wolery, (2010); and Cox, Gast, Luscre, and Ayes, (2009) studied three participants in an alternating treatment design with the following conditions: no vest (A), vests-no weighted (B), and weighted vests (BC) Cox (2009). Riechow, Barton, Good, and Wolery, (2009) studied one participant and used an experimental design A-B-A withdrawal design (A), weighted vests (B), vests with no weight, and (C) no vests. Hodgetts (2010) studied ten participants and used a single-case, A-B-C-B-C study design with A= baseline behavioral ratings without a vest or heart monitor; B=a vest without weights and a heart monitor; C=weighted vest and a heart monitor Hodgetts (2010). VandenBerg (2001) studied four participants and in his study; two males and two females were receiving school-based occupational therapy. Each of the children had been diagnosed with ADHD. The participants were aged between 5 to 6 years. Fertel-Daly, Bedell, and Hinojosa (2001) studied five participants in a research design using an A-B-A single-subject reversal design:
- baseline,
- weighted vest was worn
- no weighted vests were worn (Fertel et al.2001).
Defination Of Disabilities
Autism is characterized by social interaction impairment witnessed in poor eye gaze and gestures and limited personal relationships. The victim is not at ease communicating verbally and non-verbally in correlation with the age already attained. They delay acquiring a language and at times show a lack of ability to speak and the inability to engage in make-believe play. Their interests and activities are restricted and are not at par with their level of development. Their movements are stereotyped and quite often they flap their hands (Frith, 2003).
Pervasive development disorder is an attention deficit hyperactive syndrome. Children with this disability have problems with focussing their attention appropriately. The victims have a very high degree of physical activity. The victims have a set of characteristics peculiar to them and hence they are different from their peers (Quinn and Malone, 2000).
Attention deficit disorder is a mental disorder that involves high-level portions of the brain. The disease even persists into adulthood and all through the lifespan of a human being. The occurrence of this disability is attributed to a condition known as hypofrontality, a condition characterized by a lack of activity in the front region of the brain (Fisher and Beckley, 1999).
Children with sensory processing abnormalities over-respond when exposed to offending external stimuli. This makes them shut down, withdraw or become aggressive due to fear or anxiety occasioned by misinterpretation of the signal to mean danger. Children with such an abnormality do not attain developmentally appropriate skills and have bad temparament (Nelson, 2000).
The use of weighted vests on children suffering from autism has been researched on by very many scholars. Reichow and colleagues (2010) underscored the need for noting that no protocol has been approved yet for the effective use of weighted vests. Therefore resorting to the use of weighted vests without proper knowledge on it may result into improper usage and therefore a failure to realize the desired relief for patients with autism. Studies that have been advanced on the use of weighted nets are flawed both in their methodology and the fact that their results are difficult to interpret and confirm (Reichow et al., 2010).
Studies initiated by Reichow et al (2010) incorporated three participants. One participant level of engagement was not interfered with even after using weighted vests. The participant therefore completed his task. When the participant had put the weighted vest on, his challenging behaviors kept on changing. However, the stereotypic behaviors displayed kept declining. When the participant put on the weighted vests, the other two participants exhibited noticeable changes in their level of engagement, challenging behavior and more importantly, the stereotypic behaviors. The study also had its inherent limitations and its results were less than perfect.
A study that was carried out by Cox and colleagues (2009) dealt with the use of weighted vests and how they can improve the behavior exhibited by children with special needs when travelling in a car. This study did not find behaviour shown by these children with the special needs improve because of putting on weighted vests. The study however showed that there was a likelihood of improvement if the children were able to use their preferred materials. Despite the fact that the Cox study also had limitations, it is worth noting that the results attained were uniform for all the participants who took part in the study. Other studies have shown that the effects of weighted vests on children with autism changed from participant to participant.
Stephenson and Carter (2008) critically looked at the seven studies that had earlier on been done on the use of weighted vests on children with special needs and concluded that there is no evidence that validates the use of weighted vests on children with special needs. Morrison, in 2007 also concurred with this view.
Olson and Moulton (2004) conducted a survey on occupational therapists using weighted vests on children with special needs ranging from autism, ADHD, and sensory integration disorder. The study concluded that weighted vests help children with special needs by contributing to a decrease in challenging behaviors and record increase in positive behaviors. 70 per cent of those who took part in this study were convinced that the changes they witnessed in their clients were occasioned by the use of weighted vests. Other participats felt that the weighted vests indeed helped children with special needs. However, this is only possible if they were part of the children sensory program. A few participants did not believe there was a correlation between the use of weighted vests and a child’s’ behavior.
On whether the use of weighted vests on children with special needs should be wolesomely adopted or dismissed, Olson and Moulton (2004 p.60) reckons that it is not prudent for someone to make a decision in two or three treatment sessions. They recommend trying some alternative means to use of weighted vests like the use of weighted blanket or blankets.
Fartel-Daly and colleagues (2001) intended to assess effects of weighted vests and pressure vests on increasing attention and decreasing self stimulatory behavior in child suffering from autism. Weighted or pressure vests as has always been reccommended by occupational therapists have limited research that support their usage. Fartel-Daly and colleagues formulated a hypothesis that stipulated that the use of pressure or weighted vests increases attention to tasks and decreases self stimulatory bahaviors in children with such defects. The study made use of alternating treatment design. The participant was a four year old boy who attended school in a self contained classroom. Neither the pressure vest nor the weighted vest increased the child’s’ attention. However, the child’s stimulatory behaviors did not decrease. This study recommended that further studies should focus on the usefulness of using weighted vests on children showing self stimulatory behaviors. Fartel-Daly et al further note that educators ought to be aware that there is no substantive research that has been done on the area of usage of pressure and weighted vests and should therefore consider developing some foresight before allowing these devices to be used in classroom. The methods that were used include subject and setting. The participant in the study was a four year old boy who had been diagnosed with Autism Spectrum Disorder. The boy also had strbismus in both his eyes. He had self stimulatory related behaviors and occasionally mouthed his hands, jumped up and down, tapped both himself and other objects. He attended a private school with a self contained class.
The materials used were the pressure vests and the weighted vest. The weighted vest used was the Bear Hug Vest with bear hug weighted wrap manufactured by Southpaw Enterprises. The bear hug weighted wrap distributes half pound weight across the chest regions. The vest was worn for 30 minute increments after every two hours for the whole school day. The participant was closely monitored.
The pressure vest was purposely used to apply pressure on Kyles torso and on the same areas that weighted vest applied pressure on. It was worn for 30 minutes increments every two hours throughout the school day. Careful observations were made on the participant for the whole time he was having the pressure vest on.
Two variables: attention to task and self stimulatory behaviors were identified. Attention was engaged on the participant’s ability to answer the questions he was asked, taking part in academic activities and thevparticiopants ability to set his eyes on the leader of activity for a particular time interval.
Self stimulatory behaviors involved the tendency by the participant to break the plane of his mouth by the fingers for a record two seconds. Tapping or hittingn objects, repeted jumping up and down more than once.
Alternative treatment vest intervention entailed alternating the use of weighted vests, pressure vests and no vest during the morning cycle time of activity. Teachers were informed on when to put weighted or pressure vests on the participant and when not to put them on. The participant was given the vests 15 minutes before the cycle commenced and they were then removed 15 miutes later after completion of data collection. Obervational sessions were videotaped and stop watch used to take time intervals. Attention to task and self stimulatory behaviors were recorded after every 10 minutes and non occurrence done for the whole interval.
Reichow et al (2009) study examines the effects of wearing pressure vests for young boys with delays in their development. An A-B-A withdrawal design was used to look into the relation that is there between wearing of pressure vests and the behavior of child during the pre school art exhibitions. Despite the fact that data showed variability, there was no notable difference in child engagement when the child puts on the vest and when the vest was never completely worn. The problem behavior however persisted when the vest was worn.
Ayers (1972) maintained that sensoy integration treatment had gained popularuty over the past two decades especially that which involve treating of children with autism and development disorders (Schaaf and Miller 2005; Smith et al., 2005). Children with abnormalities relating to sensory processing are thought to benefit from the integration of their sensory processing abnormalities. Sensory integration helps in processing and sensory information regulation. This results in increased attention, adaptive behaviors and reduction in stereotypic behaviors. Therapy include provision of deep pressure in form of massage (Escalona et al., 2001), weighted vests( Cox et al., 2009; Fartel- Daly et al., 2001; Kane et al., 2005), pressured vests or weighted blankets (Olson and Moulton, 2004). Emperical support for sensory integration is normally very scarce owing to poor fidelity and weak experimental designs. Despite the popularity of therapeutic vests, only one emprical study examining the effects of pressure vests has so far been documented. This study explores the relationship between pressure vests and self stimulatory behaviors in an eight year old girl diagnosed with autism. The study did not establish experimental controls despite its efforts in trying to show decreased self stimulatory behaviors. This made it very difficult to arrive at confident conclusions. The study intended to expand research on pressure vests.
It is very crucial that ASDs should be identified early enough. Children and members of their family should be referred to appropriate services as soon as these diseases are detected. Because of absence of aetiology based intervention for autism, there is still specific treatment for it. Informed choice should be made on the fate of children affected by this disease. There has been widespread misunderstanding over the treatment methods to be involved. New approaches that have been promoted have no enperical support. Francis (2005) said that cure for autism has currently not been developed. The word teaching used to reflect interventions geared towards helping peiple with ASDs to effectivel adjust in the environment. Evidenced basedtreatments for children with autism is still politically and scientifically manipulated. Evidence based treatment that is still being emphasized still attracts a lot of debate as to what type of research method produces credible evidence. Owing to the fact that the study uses different methods, there is difficulty in comparing results and issues bordering on where the resources should be directed and the evidenced that are supposed to be produced before treatment or practice is supported and endorsed. The publications on interventions like early intensive behavioral intervention and sensory integration therapies are receiving most attention.
Rogers and Vismara (2008) while assessing the native reviews of evidence based comprehensive treatments for young children with autism posited that randomized controlled trials show positive effects in long term and short term. The evidence proposes that early intervention programs are remunerative for children with autism, improving their developmental functioning. They decrease maladaptive behaviors and severity of symptoms. The study never shows improvements in developmental functioning on whether it can lead to significant improvement in vocational and social functioning in adulthood.
Rogers and Vismara (2008) allude to the fact that following the few randomized controlled treatment trials carried out, few models must have been tested. Large differences in interventions that have been published show that the prospect of arriving at interventions is still early in autism.
Howlin, Magiati and Charman (2009) reviewed eleven studies that met inclusion criteria. At group level, EIBI gave improved outcomes in comparison to other groups, but at individual level, variability was evident with some inference that the initial IQ was related to progress. They reported that immediate impact of EIBI reduced over time. They concluded that the review they conducted povided an evidence for effectiveness of EIBI on children with autism.
Reichow and Wolery (2009) reviewed EIBI research and arrived at similar conclusions that Howlin et al had also made. There findings suggested effectiveness of EIBI treatment on children sufferring from autism. They further alluded to the fact that EIBI cannot be wholesomely effective for all children suffering from autism. They suggest that chilren that do not respond to EIBI treatment should be identified early enough so that other forms of treatments can be reccommended to them (Reichow and Wolery, 2009 p.39).
Meta-analysis was also conducted- this is the integration of research body on a clinical practice. This involved looking into changes in intelligence scores and noon controlled studies. Their study has limitations bordering on the small sample size of the meta analysis that was conducted. Another nootable limitation was the interpretation of the mean magnitude that was solely based on mean effect size without paying attention to a comparison or a control group (Reichow and Wolery, 2009 p.38).
Spreckley and Boyd (2009) on their meta- analysis sum up their study by noting the inadequacy of evidence that ABI is favored than the other standard care mechanisms for children living with autism. They recommend appropriate clinical trials that are bound to have broader outcomes. This study only incorporated 4 studies in the analysis.
Eledevik et al., (2009 p.441) recently attempted to replicate and major on Reichow and Wolerys meta- analysis. They instead focused on ways with which to improve the methodologies that were used by these two researchers.Their mata- analysis supported the use of EIBI for treating children suffering from autism. This study had a serious limitation and the researchers warn that conclusions from their study should be done with caution and that all conclusions should be treated as tentative (Eledevik et al., 2009 p.448).
The mata-analys studies infer that large, randomized trials that compare EIBI to other interventions are still relevant and are therefore needed. Howlin et al., (2009) decision not to include meta- analysis in their review of EIBI was justified. Researchers should employ use the use of wide range of outcome measures in establishing and evaluating goals of interventions. They note that variables like parental coping ability, family relationships have not been systemically integrated and have a potential of posing methodological challenges to future researchers (Howlin et al., 2009 p.35).
Green et al., (2006) posited that sensory integration is a therapy that is popular and widely used to treat children with autism. Sensory integration therapy (SIT) depends on theory that states that functional performance deficits are related to problems that arise due to difficulty in processing sensory information. Treatment should be directed at changing underlying neurological processing (Ottenbacher, 1982; Schaaf and Miller, 2005). Treatment sessions involved provision of controlled sensory stimuli like brushing or rubbing the body. Sensory diets have now been introduced. They provide children with activities and environmental adjustments to suit the needs of the children. There is no sufficient evidence to allow for reccommendation of sensory integration therapy as a primary intervention method for treatment of autism in children. A number of children with autism have notable sensory amd motor impairments. Aspects of sensory integration therapy can be used to develop specific treatment plans. Recent sensory integration treatment involves wearing of weighted vests. The associates inattentiveness and steriotypic behaviors to undersensitivity or oversensitivity to sensory input. Weighted vest provide sensory input that control inattentiveness and steriotypic behaviors (Olson and Moulton, 2004). It is widely believed that weighted vests exert pressure which calm and organize effects of nervous system.
Cox et al., (2009) studied effects of weighted vests on in-sit participants. These vests had no effect on the participants. The study noted that non contingent reinforcement had optimal effect on participants in seat behavior.
Francis (2005) infered that there was inadequate scientific evidence and that sensory integrated treatment can be used together with proven therapies. Careful evaluation was done to ensure that SIT does not interfere with proven therapies. Major challenges to the researhers were the ability to assess what treatment works for which children, identification of individual characteristics predicting responsiveness to specific programmes and approaches (Howlin et al, 2009), and initial testing and replication of existing models.
Cox et al (2009) do a study whose main aim was to evalute the impacts of weighted vests on the amount of time 3 elementary age school children with autism, intellectual disabilities, and sensory processing abnormalities in in-seat behavior participants. Alternating treatment design helped in examination of duration of appropriate in-seat behavior under the following conditions: baseline or no vests designated (A), vests with no weights designated (B), and weighted vests designated (BC). Owing to the fact that weighted vests never had effect on appropriate in seat behavior for any participant, a subsequent test was conducted. Non contingent reiforcement was assessed within the context of a withdrawal design. Non contingent reinforcement had notable effect on participants in- seat behavior.
In Hodgetts (2010) review of research done on weighted vests and sensory modulation dysfunction, she revisited Olson and Moulton (2004) that surveyed 340 occupartional therapists by mail. The study wanted to establish the participants experience with the weighted vests and whatever they felt about the effectiveness of the vests in specific behaviors. Participants noted that vests were commonly used on children attending elementary schools or those who were in pre-school. Autism spectrum disorder was very common. A total of 82 per cent of respondents confessed to have used weighted vests with such children. Commonly tergeted behavior was staying on task, staying in seat and increasing attention span. There was remarkable variation in practice trends with 62 percent of respondents frequently using two pounds of weight, 73 percent using vests for less than one hour in a session, and 34 per cent of participants recommending that children should wear the vests twice.
The study by Olson and Moulton acted as source of information on general practice patterns on use of weighted vests in paediatric occupational therapy practice. Therapists were however unable to comment on individual practice patterns. With the telephone interview that Olson and Moulton (2004) conducted on further 51 participants, they ellicited qualitative information on individual practice patterns and opinions on weighted vests based on each childs characteristics. In this sample, 68 per cent of participants worked in school settings, where as 92 per cent used weighted vests with children having autism. Attention increase, staying on task and following instructions, decreased rockings, tantrums and wandering were the reported targeted outcome from the children having autism. Vest use protocol varied, with amount of weight starting low and increasing until positive effects are achieved. Many respondents said that there were notable changes upon putting on of weighted vests.
The Edmonton and area Occupational therapy pediatric interest group (2005) did a survey that involved more than 50 participants regarding use of weighted vests in practice. despite the fact that wide range of responses were provided, there consensus supported Olson and Moulton study in the sense that weighted vests were most frequently used with children having autism spectrum disorders; therapists began with 2 pounds of weight and progressed to up to 5 per cent body weight; a wearing schedule of not more than 20 minutes was adhered to.
These surveys showed that, even though weighted vests are commonly used, there is notable lack of consistency regarding amount of weight and the wearing schedule. However, there was unanimity that weighted vests are a very common recommendation for children suffering from autism and therefore weighted vests are deemed beneficial to such children.
Studies on participants’ descriptions included 21 participants identified with ASD. Studies by Cox, Gast, Luscre, and Ayres, (2009); Kane, Luiselli, Dearbon and Young, (2004-2005); and Myles et al., (2004) provide information on how diagnosis was made. None of the participants had their diagnosis confirmed with the ADOS or ADI-R. Participants’ age ranged from 2 to 11 years. Sixteen of the 21 participants were aged below 7 years. Studies on four chilren with ADHD conditions included information aboutdiagnosis. The participants were aged between 3 to 6 years.
Reported effects for children with autism or ASD included increased on task behavior in 6 out of the 14 participants who were examined for this behavior, decreased stimulatory bahavior in 6 out of 13 participants who formed part of the study and no effect for increased sitting, joint attention, decreasing competing or problem behaviors. All the four participants with ADHD exhibited increased on –task behavior.
All the researches were single case design, with overall positive trend in design strength used over time. Initially studies were reported to have used relatively weak AB (VandenBerg, 2001), ABA (Fertel-Daly, Bedell and Hinojosa, 2001) and ABC (Kane et al, 2004-2005) designs. Recent studies have used stronger, single case designs including ABAB (Myles et al., 2004), multiple baselines (Stein, 2007), and alternating treatments (Barton, Reichow and Woley, 2007; Carter, 2005; Cox et al., 2009; Deris, Hagelman, Schilling and DiCarlo, 2006) designs.
Blinding of treatment condition increases onfidence oone can have on the result of a treatment study as it removes an observer’s expectancy bias. Weighted vests are prone to the effects of blinding, however, only one study employed blinding of rateers to treatment condition. Details were however not provided on how the blinding occurred (Barton et al., 2007). Barton and the colleagues presented their study as double blind placebo trials to enable them analyze effects of treatment guarding against participants and observer biases. Owing to the fact that participants who were wearing weighted vests could not be blinded to treatment condition, it is assumed that it was reported as double-blind because the participants were non blind.
Intervention studies have a very important component called treatment fidelity which actually refer to degree to which treatments were implemented as required during the process of study. When the protocol of weighted vest for example is not adhered to, the study is bound to have poor internal validity hence an imposssibilityn in knowing whether the effect was actually due to weighted vests. This aspect was encountered in Cox et al., (2009) study.
Hodgetts (2009) say there was no standard protocol for vest use in research a view that was consistent with Olson and Moultons (2004) study. Fertel-Daly et al., (2001) used only one pound of weight regardless of the weight of the participants. They bserved that use of weighted vests was effective in minimising number of responses to distractions and increasing attention to task for the five participants in the study.
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