Canadian Journal of Occupational Therapy-2007-Hodgetts-393-400 (1).pdf

VOLUME 74 NUMBER 5 CANADIAN JOURNAL OF OCCUPATIONAL THERAPY DECEMBER 2007 393

Key words Occupational therapy practice Autism Sensory stimulation

Sandra Hodgetts William Hodgetts

There are other trends that influence occupational therapyservices for children with autism. For example, children withautism are increasingly being integrated into inclusive settings,occupational therapy practice is shifting towards a consultativemodel, and there is an increased demand for cost-effectiveinterventions (Baranek, 2002; Simpson, 2005). Consequently,occupational therapists are increasingly challenged to provideeffective intervention recommendations that 1) enable a childto function within inclusive settings, 2) are cost-effective, and 3)can be implemented by a variety of caregivers.

Occupational therapists intervene most frequently in thearea of sensory dysfunction with children with autism (Case-

In the past decade, the treatment of autism has garneredincreasing attention across North America, escalating thedemand for empirically supported treatments and inter-

ventions (Rogers, 1998). Autism is now the most commonneurodevelopmental diagnosis affecting children with asmany as 1 in 166 children receiving a diagnosis along thespectrum (Fombonne, 2003). Accordingly, the number ofchildren with autism on occupational therapists' caseloadsincreased during the last decade (Case-Smith & Miller, 1999).Given the current prevalence of autism, it is fair to expectthat there will be continued demand for occupational ther-apy services.

RsumDescription. Il existe beaucoup de donnes permettant d'affirmer que les enfants atteints d'autisme ont des dficits sensorielspouvant avoir des effets sur leur capacit de participer des activits fonctionnelles. Les ergothrapeutes recommandentfrquemment des interventions bases sur la stimulation somatosensorielle afin d'attnuer les dficits sensoriels et d'amliorer lescapacits fonctionnelles de l'enfant. But. Cet article examine la raison d'tre et les donnes probantes qui soutiennent lesinterventions bases sur la stimulation somatosensorielle auprs des enfants atteints d'autisme. Mthodologie. Une revuecomplte de la littrature portant spcifiquement sur la stimulation somatosensorielle a t effectue. Cette recension a permis dereprer six tudes publies portant sur les interventions qui peuvent s'insrer dans la routine quotidienne de l'enfant. Discussion.Bien que la recherche associe la stimulation somatosensorielle soit devenue plus rigoureuse, les donnes empiriques demeurentlimites; ainsi, il est important, lorsque ces interventions sont mises en uvre, de les valuer systmatiquement. Consquencespour la pratique. Afin d'aider les ergothrapeutes recommander des interventions en toute confiance, les auteurs proposent desstratgies visant (1) utiliser des pratiques exemplaires pour intervenir dans un domaine o les donnes probantes sont limiteset (2) produire davantage de donnes probantes l'aide de la recherche clinique.

Abstract Background. There is considerable evidence that children with autism experience sensory dysfunction, which can affect theirability to participate in functional activities. Occupational therapists frequently recommend somatosensory stimulationinterventions to mitigate sensory dysfunction and improve a child's ability to function. Purpose. This paper examines therationale and evidence supporting somatosensory stimulation interventions for children with autism. Method. A comprehensivereview of the literature specific to somatosensory stimulation was conducted, resulting in six published studies that addressedinterventions feasible within a child's daily routine. Discussion. Although research related to somatosensory stimulationinterventions is becoming more rigorous, empirical support remains limited; therefore, when these interventions are implemented,they should be systematically evaluated. Practice Implications. To help occupational therapists recommend interventions withconfidence, strategies are provided to (1) utilise best practices to intervene in an area in which evidence is limited, and (2) helpexpand the evidence base through clinical research.

Somatosensory stimulation interventions for children with autism:Literature review and clinical considerationsdoi:10.2182/cjot.07.013 This paper was published in the CJOT Early Electronic Edition, Fall 2007.

Mots cls Pratique de l'ergothrapie Autisme Stimulation sensorielle

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Smith & Miller, 1999; Watling, Deitz, Kanny & McLaughlin,1999). Sensory dysfunction is based on the assumption thataberrant behaviours reflect the central nervous system's(CNS) inability to integrate incoming sensory informationand modulate arousal (Baranek, 2002). In terms of arousal, achild may be described as overaroused (the child respondsmore to stimulation from his or her environment than otherchildren), or underaroused (the child responds less to stimu-lation from his or her environment than other children)(Rogers & Ozonoff, 2005). A child may also fluctuate betweenthese two states of arousal (Schneck, 2001).

Occupational therapists often recommend sensory stim-ulation as a way to address sensory dysfunction within inclu-sive settings. Sensory stimulation involves applying one typeof sensation, such as deep pressure, directly to a person withthe purpose of eliciting a behavioural response (Bundy &Murray, 2002). Somatosensory stimulation is a specific sub-type of sensory stimulation that focuses on tactile, vibratory,or proprioceptive input. Examples of somatosensory stimu-lation interventions include massage, joint compressions,brushing or rubbing parts of the body, pressure garments,and weighted items such as vests or blankets.

Some of the more commonly expected clinical outcomesof sensory stimulation interventions, including somatosen-sory stimulation, are improved arousal modulation,decreased sensory defensiveness, increased socialisation,decreased self-stimulatory behaviours, and decreased anxiety(Case-Smith & Miller, 1999; Schneck, 2001). Somatosensorystimulation interventions are frequently recommended inhome and school settings by occupational therapists(Watling et al., 1999), perhaps because of the ease with whichthey can be easily integrated into an inclusive setting withoutdisrupting other children.

Sensory stimulation intervention is frequently confusedwith sensory integration treatment both within and outsideof the occupational therapy profession (Anzalone & Murray,2002). Sensory integration treatment is based on meaningful,self-directed, adaptive interactions (Bundy & Murray, 2002),while sensory stimulation intervention may involve the childas a passive recipient of stimulation, and intervention doesnot have to be provided in the context of meaningful occu-pation. Therefore, although sensory stimulation strategiesmay be incorporated into sensory integration treatment,these terms are not synonymous. However, the use of sensorystimulation interventions may be based on sensory integra-tion theory. Advocates of sensory integration theory suggestthat sensory stimulation broadly improves the CNS's abilityto organise and process sensory information to allow for better adaptive responses. Case-Smith and Bryan (1999) postulate that the provision of controlled sensory stimulationenables a child to "modulate incoming sensory informationand achieve homeostasis, so he or she is able to focus on relevant stimuli, assimilate incoming sensory information,

and respond in developmentally appropriate ways" (p. 490).Proponents of massage therapy suggest that somatosensorystimulation affects positive outcomes, such as increasedattention to task, due to enhanced parasympathetic activity(Escalona, Field, Singer-Strunck, Cullen & Hartshorn, 2001;Field et al., 1997), which represents a response at the level ofthe autonomic nervous system. In actuality, the underlyingneurological basis for sensory dysfunction and anticipatedoutcomes of sensory stimulation are not yet understood(Baranek, 2002).

Regardless of our understanding of underlying mecha-nisms, interventions that include sensory stimulation are themost common occupational therapy recommendation forchildren with autism (Case-Smith & Miller, 1999; Watling etal., 1999). However, occupational therapists report that theydo not have a clear rationale for sensory-based interventions,and that guidelines for implementing these interventions arelacking (Olson & Moulton, 2004). The purpose of this paperis to provide occupational therapists and others with a betterunderstanding of somatosensory stimulation interventionsfor children with autism by evaluating and summarising thecurrent state of research in this area. This review focusedspecifically on somatosensory stimulation interventions fea-sible within inclusive settings.

MethodsSearches were conducted using MEDLINE, CINAHL,PsychINFO, and OTDBase. Intervention studies specific tochildren with autism spectrum disorder and published inEnglish language peer-reviewed journals between 1985 and2005 were examined. Subject headings and keywordsincluded general terms related to occupational therapy inter-vention (occupational therapy, intervention, effectiveness,evidence-based practice); diagnostic terms (autism, autismspectrum disorder, pervasive developmental disorder); andterms broadly related to somatosensory stimulation inter-ventions (sensory integration, sensory modulation, sensoryprocessing, sensory stimulation, habituation, arousal, atten-tion, touch, pressure). Unpublished Master's theses and con-ference proceedings were not included in this review, as theyare not accessible to the general public. Studies that addressedsomatosensory stimulation not feasible within the context ofdaily activity and not typically available to therapists orclients (e.g., Grandin's hug machine) were also excluded. Atotal of six published studies meeting the inclusion criteriawere found that addressed the effectiveness of somatosensorystimulation interventions feasible within an inclusive setting.Table 1 provides a comparative summary of the studies. Thisreview was not systematic in nature. Articles were reviewedand synthesized based on the manuscript critique processoutlined in Seals and Tanaka (2000). Our aim was to providepracticing clinicians with an understandable qualitativeassessment of the current literature in this area.

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Results

Case studiesCase studies are commonly used to introduce new interven-tions or techniques by exploring individual responses.Indeed, the first three published studies that reported theeffects of somatosensory stimulation interventions for chil-dren with autism were case studies. Larrington (1987)reported numerous positive responses to a variety of sensoryinputs including some somatosensory stimulation (e.g.,weighted vests, vibration) for a 15-year-old boy with autismand severe mental retardation, who had a long-standing history of destructive behaviours. McClure and Holtz-Yotz(1991) described decreases in self-stimulatory and self-inju-rious behaviours, and increases in social interaction andattention span as a result of pressure and tactile input provided through bilateral, foam arm splints for a 13-year oldboy with autism and severe mental retardation. Zissermann

(1992) reported that the use of pressure garments resulted indecreased negative behaviours for an 8-year-old girl withautism, severe developmental delay, and possible seizure dis-order.

Although many positive outcomes were reported, theresults provided by these studies must be interpreted withcaution given design limitations. Case studies do not enablethe researcher to control for potential confounders such asinvestigator bias, maturation, changing medications, and co-occurring treatments. This lack of control significantly limitsconfidence in the findings.

Two studies (Larrington, 1987; McClure & Holtz-Yotz,1991) used numerous interventions simultaneously, andLarrington included numerous outcomes, making specificconclusions difficult. Furthermore, results may not be gener-alisable to younger children with autism, since two of thethree case studies focused on adolescents and all three of theparticipants were dually diagnosed. Moreover, one has to ask

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TABLE 1 Summary of somatosensory stimulation intervention studies for children with autism

Citation Age Design N Intervention Outcomes Measured Reported findings

Escalona et al. x = 5.2 yrs RCT with 20 Touch (massage) On-task behaviour, Massage group demonstrated(2001) alternative therapy vs. reading stereotypical more on-task behaviour, less

treatment attention control behaviour, social stereotypic behaviour,group relatedness, sleep increased social relatedness,

diaries fewer sleep problems

Field et al. x = 4.5 yrs RCT with 22 Touch (massage) Off-task behaviour, Off-task behaviour and touch (1997) alternative therapy vs. touch touch aversion, aversion decreased in both

treatment control group (hold withdrawal groups; orienting to irrelevantin lap and play sounds and stereotypic game) behaviours decreased in both

groups, but significantly more in touch therapy group

Fertel-Daly et al. 2-4 yrs ABA single- 5 Weighted vest Attention to task, Decreased in number of (2001) subject number of distractions, increase in

design distractions, self- attention to task, decrease in stimulatory behaviours self-stimulatory behaviours

Larrington (1987) 15 yrs Case report 1 Multi-sensory input Variety of outcomes: Positive outcomes for many including weighted alertness, attention, outcomes including decreased vest, vibration and play skills, self-abuse, destructive behaviour andoral stimulation destructive behaviour self-injury, increased

social interaction and play skills

McClure 13 yrs Case report 1 Elbow splints; Self-injurious Decrease self-injurious & Holtz-Yotz followed by elastic behaviour behaviour and self-(1991) arms wrappings stimulations; increased social

interaction with elastic bandages

Zisserman (1992) 8 yrs Case report 1 Pressure gloves Self-stimulatory Decrease in self-stimulatory and vest (hand-hitting) behaviour with vest

behaviours

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if the participants in these case studies would be consideredautistic by today's diagnostic standards, since much haschanged with respect to the diagnosis of autism since thesestudies were published (e.g., Autism Diagnostic ObservationScale, Lord et al., 2000; Autism Diagnostic Interview, Lord,Rutter, & Le Couteur, 1994).

Although the strength of the research is significantly lim-ited, these case studies do provide an interesting introductioninto the rationale for clinical interventions. For example,McClure and Holtz-Yotz (1991) originally recommendedsplints to physically inhibit self-injurious behaviours. Theydiscovered that when the splints were no longer available, theparticipant would attempt to wrap his arms with towels orbedding. Concurrently, self-stimulatory, self-injurious, andaggressive behaviours toward others increased. Thus, theauthors hypothesised that the deep pressure and tactile inputprovided by the splints and arm wrappings calmed the childby acting as a substitute for the self-injurious and self-stimu-latory behaviours. Zissermann (1992) reported on a child forwhom firm hugs and back rubs decreased behavioural prob-lems (e.g., hitting a table) and increased calmness. Shehypothesised that wearing tight-fitting gloves or a vest wouldhave the same results, while allowing the child to participatein functional activities. Larrington's rationale differed signif-icantly, however, as she approached assessment and interven-tion from a traditional sensory integration philosophy.

Single-subject researchFertel-Daly, Bedell, and Hinojosa (2001) explored the effectsof using a weighted vest to address classroom behaviours forfour preschool-aged children with pervasive developmentaldisorder (not specified) and one child with autism.Measurements were taken of the number of distractions, thelength of focused attention to task, and the duration and typeof self-stimulatory behaviours during a table-top, fine motoractivity. One-pound weighted vests were determined effectivein decreasing the number of distractions, increasing atten-tion to task, and decreasing the duration of self-stimulatorybehaviours in four out of five participants.

The authors chose an ABA single-subject design for theirstudy, which enables systematic evaluation of behaviourswhile allowing for individual variations. The ABA design isconsidered more rigorous than case studies (or AB designs)because it adds increased control through replication of thebaseline phase. However, an ABAB design would have furtherstrengthened the results by providing increased controlthrough replication of both the baseline and intervention.The authors reported that this design was not possible due totime constraints.

The visual results were presented clearly, however, nostatistical interpretation was used to support the visual inter-pretation of the graphs (e.g., two standard deviationapproach; Barlow & Hersen, 1988). Of most concern, how-

ever, is that only one rater was used during the interventionand return-to-baseline phases. Therefore, rater bias andobserver drift may have influenced the results. Given that therater was the first author and, therefore, not blinded to inter-vention condition or to the expected outcomes of the study,this concern is noteworthy. The authors did take care that thetime of day for data collection remained consistent for eachchild, thus controlling for systematic behaviour fluctuationsduring the day. Generalisability was also greatly enhanced, asthe study was conducted in the participants' naturalpreschool environment. This study does provide importantpreliminary support for an intervention strategy reported tobe used by 82% of occupational therapists who work withchildren with autism (Olson & Moulton, 2004).

Group comparison designsField and colleagues (1997) investigated the effects of mas-sage therapy for preschool children with autism. Twenty-twochildren were randomly assigned to receive either two 15-minute massage sessions per week for four weeks (experi-mental condition) or two 15-minute play sessions per weekfor four weeks (control condition). During the play sessions,the child sat on the research assistant's lap and played a game. Classroom observations of touch aversion, off-task behaviour, orienting to irrelevant sounds, and stereotypicalbehaviours were conducted on the first and last days of thestudy. Touch aversion and off-task behaviours decreased inboth groups. Orienting to irrelevant sounds and stereotypicalbehaviours decreased in both groups, but significantly morein the massage therapy group. The authors point out that thedecreases in both groups are not surprising given that bothinterventions provided additional one-on-one time andphysical contact with an adult.

Escalona and colleagues (2001) hypothesised that positiveresults reported in the treatment group in the previous study(Field et al., 1997) would be improved upon with more fre-quent massages by a familiar person. Therefore, in their ownstudy, twenty children with autism were randomly assigned toeither receive a 15-minute massage (experimental condition)or be read a Dr. Seuss story for 15-minutes (control condition).Both conditions were implemented at bedtime by the child'sparent for one month. Groups were stratified to ensure groupequivalence based on IQ, speech and language assessmentscores, and adaptive functioning. The effects of massage ther-apy on behavioural outcomes including hyperactivity, on-taskbehaviour, stereotypical behaviours, and sleep problems wereinvestigated. The effects of the intervention were assessedthrough sleep diaries (kept by the parents) and observations(made by teachers and research assistants) at school.Improvements were noted for all targeted behaviours for thetreatment group. However, it must be noted that the data fromthe sleep diaries may have been biased since parents were notblinded to the intervention condition.


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For both of these studies, confidence in the results wasincreased by random assignment to groups, teachers andresearch assistants blinded to group assignment, and equiva-lent baselines between groups. This stratification (combinedwith the small age range) helped to control for the heterogene-ity inherent in the diagnosis of autism. However, the ratio ofmales to females in the study by Field and colleagues (1997)was 12:10 and the study by Escalona and colleagues (2001) was12:8, which is not representative of the widely accepted ratio ofapproximately 4:1 (Fombonne, 2003). Although these ratios(12:10 and 12:8) may have occurred by chance, one has towonder how representative these two samples were of allyoung children with autism. Also, the natural settings in thesestudies enhance the generalisability of the results. This gener-alisability is especially true in the study by Escalona and colleagues (2001), where the intervention took place in the privacy of the child's home at no cost to the family with posi-tive results noted both at home (sleep diaries) and school.

Although many positive results were reported, theirinterpretation is difficult given that the targeted behaviourswere not operationally defined. In the absence of any clearunderstanding of how the variables were measured, itbecomes difficult to evaluate the mean change scores, whichtended to be small and comparable between groups. In addi-tion, the papers do not distinguish between statistically andclinically significant differences.

Both studies would have been strengthened by providingstandard deviations and confidence intervals as part of theresults. Inclusion of these measures would have allowed otherresearchers to calculate effect sizes and estimate the clinicalsignificance, thereby gaining insight into whether repeatednightly massage with a primary caregiver resulted in a largereffect than massage given twice weekly by a researcher. TheBonferroni correction reported by both Field and colleagues(1997) and Escalona and colleagues (2001) is meant to correct the alpha level to be more conservative that the typi-cally accepted 0.05 level, controlling for type 1 error whenmultiple comparisons are made. However, given that theauthors reported the results at the 0.05 level, it is difficult toknow whether results reported as significant did indeedinclude this correction.

Summary of available researchHalf of the existing research related to autism andsomatosensory stimulation is in the form of descriptive casestudies (Larrington, 1987; McClure & Holtz-Yotz, 1990;Zisserman, 1991). Although these designs have high facevalidity for the practicing clinician, they are known to beweak study designs (Barlow & Hersen, 1988) since they offerlittle to no control of extraneous variables (e.g., co-occurringtreatments, maturation, investigator bias). Therefore, theclinician cannot be confident that the results actually repre-sent the effects of the intervention.

There have been three more rigorous studies investigat-ing the effectiveness of various somatosensory stimulationinterventions for children with autism including one single-subject ABA design (Fertel-Daly et al., 2001) and two ran-domised controlled trials (Escalona et al., 2001; Field et al.,1997). The clinician can be more confident in the results sug-gested by these studies, since they offer more control overextraneous variables. However, generalisability may still belimited due to small sample size and a lack of detail providedabout the participants.

DiscussionVariability of interventions

Of the six studies published that relate to somatosensorystimulation interventions for children with autism, twoinvestigate the effects of massage therapy, one investigates theeffects of weighted vests, one investigates the effects of a pres-sure vest and gloves, one investigates the effects of arm splintsand pressure arm wrappings, and one investigates a variety ofsensory stimulation. Can we really compare between all ofthese interventions? Although these interventions are basedon the same general assumption that providing somatosen-sory stimulation will have a calming or organizing effect onthe nervous system, none of these studies address this under-lying assumption. We need to test the underlying theory-somatosensory stimulation induces physiological effects onthe nervous system-to see if effects are similar with varioustypes of somatosensory stimulation. Similar effects with different types of stimulation can increase one's confidencethat individualised interventions may be effective. In addi-tion, we need to replicate studies that address behaviouraland functional outcomes of commonly used somatosensorystimulation (e.g., weighted vests) to increase our confidencethat specific interventions are effective.

Variability of outcomesWe were surprised by the variability of outcomes expectedfrom the interventions used. Can we reasonably expectsomatosensory stimulation interventions to influence all ofthese outcomes? Are the outcomes used conceptually congru-ent with the interventions? In theory, different behaviours areimproved if somatosensory stimulation affects the nervoussystem; however, we need to better define our outcomes, bothin research and in clinical practice, to determine if our inter-ventions are truly effective. In the literature and in our ownclinical experience, broad goal statements such as "improvedsensory modulation" are not uncommon. However, whatdoes this mean? Will a parent or teacher of a child with autismfeel comfortable spending time, money, and energy on anintervention that will improve sensory modulation? We sug-gest that a parent or a teacher would be more satisfied if out-comes were specific, for example, increased time on task in theclassroom or decreased self-hitting behaviour. Claims of


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intervention effectiveness are strengthened with replication ofresearch with different participants, in different settings, andby different researchers. Therefore, replication of specific out-comes from previous studies, with increased control wherewarranted, may be a promising area for future sensory stimu-lation intervention research.

Variability of autismEmpirical research related to intervention effectiveness is alsodifficult because autism is comprised of an extremely hetero-geneous spectrum of disorders. The course of autism variessignificantly between individuals and within an individual.For example, a child may seek sensory input one day, then besensitive to sensory input the next (Schneck, 2001).Therefore, it is difficult to determine the effectiveness of anintervention because it may appear effective for some indi-viduals and ineffective for others, or it may appear effectivefor one child one day and ineffective for the same child thenext day. This variability was addressed, in part, by Field andcolleagues (1997) and Escalona and colleagues (2001), whocontrolled for intelligence quotient and other factors. Futureresearch also needs to control for variability in autism ingroup designs, or provide detailed documentation of indi-vidual profiles in single-subject research. Although limitingparticipants initially decreases the generalisability of results,rigorous replication with various subgroups will strengthenthe confidence that researchers, funders, families, and clini-cians can have in recommended interventions.

Best practice: the need for rigorous research

Many factors can affect the perceived or real level of func-tioning of a child when evaluating the effectiveness of anintervention. Awareness of potential biases and confoundersbecomes increasingly important when an intervention doesnot have a strong base of empirical support. The difficultylies in deciphering the contributions of the intervention fromother contributing variables. For example, did the childreceive extra attention from a teacher or therapist coincidingwith the implementation of the intervention? Is the therapistbiased towards interpreting behaviours based on assump-tions of sensory processing dysfunction? Did the childmature over time, take new medications, or receive someother intervention at the same time? Appropriate controlsand methods are needed to address alternative explanationsso clinicians, caregivers, and children do not spend emotionalor financial resources, or their already limited time on inef-fective interventions, especially when other interventions doexist that have empirical support (Baranek, 2002).

Referring to the lack of empirical research on these inter-ventions, Goldstein (2000) stated:

Perhaps more than any other area in the behavioural sci-ences, the field of autism research should have taught us

a strong form of a popular maxim: 'If it is too good to betrue, it is too good to be true' (p. 423).Researchers open the door to criticism by using less rig-

orous study designs and analysis. Although it is recognizedthat all research has humble beginnings, such as anecdotalreports or descriptive case studies (Johnson & Danhauer,2002), it is time for occupational therapy interventionresearch to move beyond weak designs. We do not mean thatall research should incorporate randomised controlled trials.That is neither feasible nor warranted at this stage. Single-subject research that enables each child to serve as his or herown control may be the most appropriate design given thatwe often treat each child individually. Single-subject researchis not meant to demonstrate generalisable outcomes, but canprovide preliminary evidence to support a clinical hypothesisand can help guide future research the design that bestmatches the question should be used (Bartlett et al., 2005).

More rigorous study designs will enable clinicians to feelmore confident in their intervention recommendations, andwill make clients, caregivers, and third party payers moreconfident that they have not wasted valuable energy, time,and resources. Most importantly, more rigorous research inthis area will allow us to be more effective in helping the chil-dren who need it most.

It does appear that research related to somatosensorystimulation for children with autism has become more rigor-ous over the past decade. One can feel more confident that theresults of the three most recently published studies representa true effect related to the somatosensory stimulation inter-vention due to increased control over potential confounders.However, it is still of concern that the interventions mostcommonly recommended by occupational therapists for chil-dren with autism are only supported by six studies, three ofwhich are case studies and none of which are replications.

Implications for occupational therapyOccupational therapists must be concerned by the evidenceon which interventions are based. As demonstrated here,much of the literature on somatosensory interventions forchildren with autism has significant limitations. Although itappears that somatosensory stimulation (specifically thatwhich provides deep pressure input) may have positivebehavioural outcomes, there is not enough evidence to spec-ify that these outcomes are based on our theoretical premiseof affecting underlying mechanisms. However, occupationaltherapists can take some comfort that the rigor of research inthis area seems to be improving.

It is important to recognize that a lack of empirical evi-dence supporting the effectiveness of an intervention maynot be synonymous to ineffective interventions; rather, effec-tiveness may not yet have been empirically examined(Baranek, 2002; Miller, 2003). However, ineffective interven-tions become harmful when they replace effective interven-


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tions and when they mislead caregivers into believing thattheir effectiveness is established (Gresham, Beebe-Frankenberger & MacMillan, 1999; Simpson, 2005).

Occupational therapists incorporate clinical observationand experience into intervention recommendations.However, clinicians must also provide an empirical rationalefor their recommendations, especially when financial,human, and emotional resources are expended. "For a proce-dure with no evidence of efficacy to be used on the publicwith claims of success, to charge money for these services,and to train practitioners in this model borders on unethicalbehaviour" (Shaw, 2002, p. 1). The use of empirical data tosupport clinical recommendations promises to enhance thereputation of both the individual clinician and the entireprofession.

Until we have a strong base of empirical support, thereare steps occupational therapists can take that shouldincrease the confidence with which they can intervene. Tenrecommendations for practicing clinicians are provided inAppendix 1. In addition, clinicians can add valuable data tothe research literature by collecting well-controlled, consis-tent data on their clients, including the influence of possibleextraneous variables that may affect a child's performance.

Best-practice guidelines recommend that cliniciansalways take baseline measures before intervention begins(Canadian Association of Occupational Therapists, 1996).Taking repeated baseline-intervention measurements can be relatively simple. As long as it is ethical, removing intervention for a short time to measure if treatment effectssubside or remain also provides support to either continue ordiscontinue an intervention. By taking small measures suchas these, one can only improve his or her credibility and reputation as an ethical, responsible clinician. In addition,communication with others and dissemination of findingscan strengthen occupational therapy intervention research.

ConclusionSensory-based interventions, including somatosensory stimulation, are the most common occupational therapy recommendation for children with autism. The results of thisreview indicate that research investigating the effectiveness ofsomatosensory stimulation interventions for children withautism has become more rigorous over time; however, stud-ies are still few in number and replication is limited.Although these interventions appear promising, it is still dif-ficult for clinicians to recommend interventions with confi-dence. Researchers and clinicians are therefore challenged tosystematically investigate the effects of sensory stimulationinterventions for children with autism. Building our knowl-edge will enable occupational therapists to contribute toautism intervention and enhance the lives of children withautism and their families.

AcknowledgementsThis work is supported by a SickKids Foundation, Childrenand Youth Home Care Network, Doctoral Award (HC 06-311), and the Canadian Institutes of Health Research, AutismResearch Training Program received by the first author. Theauthors would like to thank Dr. Joyce Magill-Evans forreviewing an earlier draft of this paper.

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Appendix 1

The following list provides clinical considerations for inter-vention in an area in which empirical support is limited.Some of these considerations have been adapted fromBaranek (2002) and Gresham et al. (1999).1. Have a healthy skepticism of intervention strategies

based only on subjective data and anecdotal evidence.2. Have a healthy skepticism of any interventions whose

authors or advocates are defensive when their program ishonestly criticized.

3. Obtain baseline data prior to starting any intervention.4. Control for as many variables as possible when trying to

determine if an intervention is effective. For example, donot try to measure the success of a new intervention at atime when the child attends a new school, works with anew teacher, or becomes ill.

5. Provide interventions in shorter, monitored increments(e.g., one to three months), documenting progress in asystematic manner.

6. Be very clear in your rationale for recommending a spe-cific intervention. For example, is a weighted vest recom-mended to address attention to task, or simply becausethey are frequently recommended for children withautism?

7. Recognize that some new interventions may ultimatelybe effective, but have not yet been empirically validated.

8. Remember that sensory stimulation intervention strate-gies are only one of several options.

9. Remember there is no cure for autism. Not every inter-vention will work for every child.

10. Be honest with clients and caregivers. Until evidence isavailable, it is unethical to declare an intervention hasbeen proven to work.

AuthorsSandra Hodgetts, MClSc, OT is a Doctoral Candidate,

Faculty of Rehabilitation Medicine, University of Alberta,2-64 Corbett Hall, Edmonton, Alberta, Canada T6G 2G4.Tel: (780) 492-8568. E-mail: [email protected]

William Hodgetts, MSc is a Doctoral Candidate, Faculty ofRehabilitation Medicine, Assistant Professor, Departmentof Speech Pathology and Audiology, Faculty ofRehabilitation Medicine, University of Alberta, 2-16Corbett Hall, Edmonton, Alberta, Canada, T6G 2G4

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