Behavioural intervention practices for stereotypic and repetitivebehaviour in individuals with autism spectrum disorder: a systematicreview

STEPHANIE Y PATTERSON | VERONICA SMITH | MICHAELA JELEN

Department of Educational Psychology, Faculty of Education, University of Alberta, Edmonton, Alberta, Canada.

Correspondence to Stephanie Y Patterson at 6–123f Education North, University of Alberta, Edmonton, Alberta T6G 2G5, Canada. E-mail: syp1@ualberta.ca

PUBLICATION DATA

Accepted for publication 19th November 2009.

LIST OF ABBREVIATIONSASD Autism spectrum disorderNCR Non-contingent reinforcementPND Per cent of non-overlapping dataSRB Stereotypic and repetitive behaviour

AIM The purpose of this systematic review was to examine the quality of conduct of experimental

studies contributing to our empirical understanding of function-based behavioural interventions

for stereotypic and repetitive behaviours (SRBs) in individuals with autism spectrum disorders

(ASDs).

METHOD Systematic review methodology was used to identify relevant articles, to rate the level

of evidence and quality of conduct of the studies, and to extract data systematically.

RESULTS Ten single case studies examining 17 participants (14 males, 3 females; age 2y

11mo–26y) diagnosed with various ASDs were included. Overall, studies reported decreases in

SRBs using behavioural interventions and some collateral increase in desirable behaviours.

INTERPRETATION Only a small number of intervention studies for SRBs explicitly state the func-

tion of the behaviour; therefore, relatively little is known about the efficacy of SRB interventions in

relation to the range of possible behavioural functions. Evidence supporting SRB interventions is

preliminary in nature, and caution should be used in choosing and implementing SRB intervention

practices for individuals with ASDs.

Autism spectrum disorders (ASDs) are a class of neurodevelop-mental disorders of unknown aetiology. One of three core fea-tures required for a diagnosis of ASD is the demonstration ofrestricted, repetitive, and stereotyped patterns of behaviours,interests, and activities (including repetitive motor movements,inflexible need for routine, restricted and repetitive interests, orintense, constant interest in particular parts of an object).1

Turner2 divided stereotypic and repetitive behaviours (SRBs)into two categories, low-level and high-level behaviours. Low-level behaviours consist of repetitive movement, manipulationof objects, and repetitive self-injurious behaviour, whereashigh-level behaviours include object attachment, insistence onroutine, repetitive language, and restricted interests.2 SRBshave been documented to encompass a large portion of thebehavioural repertoire of individuals with autism.3 Further,SRBs have been shown to interfere with learning4 and canbecome so intrusive that they affect the individual’s abilityto attend and interact, such that they require intervention.5

Individuals with other neurological, cognitive, health, anddevelopmental delays also demonstrate SRBs.6 However, inASDs, SRBs span a wider topography, with both increasedseverity and frequency.4 Happe et al.7 have suggested thateach of the three core symptoms of ASDs may require individ-ual analysis and separate intervention practices. With thisrecommendation in mind, this paper examined the inter-

ventions directed at the core behaviour of restricted, repetitive,and stereotyped patterns of behaviour, interests, and activities.

SRBs are reported to emerge at around 3 to 4 years of age,occurring less frequently in very young children with ASDs.8

Approximately 90% of adolescents and adults with ASDsreport engaging in repetitive behaviours.9 Although SRBs maybe prominent behaviours over the course of an individual’slifetime, the form and nature of the behaviours may changeover time. Militerni et al.10 reported that young children withASDs display simple motor and sensory SRBs, whereas olderchildren were found to demonstrate more complex motor andverbal behaviours. Mixed findings have been reported regard-ing the association between chronological age and develop-mental level with the form of the SRB. Szatmari et al.11 andMiliterni et al.10 reported that lower-functioning childrentended to have higher levels of motor and sensory SRBs,whereas Lord and Pickles12 found that neither language norcognitive age was correlated with SRBs in their sample. Fur-ther, SRBs with objects have been linked to a child’s greatercapacity for symbolic representation as well as social compe-tence in the second year of life.8 The potential link betweenSRBs and developmental capacity provides insights into thetrajectory of SRBs over an individual’s lifespan. However, thedevelopmental mechanisms and pathophysiology behind SRBsin individuals with ASDs are largely unknown6 (for a theoretical

318 DOI: 10.1111/j.1469-8749.2009.03597.x ª The Authors. Journal compilation ª Mac Keith Press 2010

DEVELOPMENTAL MEDICINE & CHILD NEUROLOGY SYSTEMATIC REVIEW

review of SRB pathophysiology see Lewis and Kim13). Yet,despite the lack of firm understanding of the underlyingmechanisms and pathophysiology of SRBs, interventionefforts exist to address the negative consequences of SRBs.

Closely linked with our understanding of the form of SRBsare the underlying functions of the behaviours. In line withthe need for treatment protocols to create effective individual-ized intervention programmes as determined by the NationalResearch Council,14 is the notion that it is important to designinterventions for SRBs that target the functional response ofthe behaviour rather than the topographical nature of thebehaviour alone.4 Several functions have been proposed forSRBs that occur among typically developing children in thefirst 4 years of life. For example, SRBs can serve to enhancelearning through repetition as well as by increasing the pre-dictability of a routine, thus decreasing anxiety.4 Although thefunction of lifelong SRBs may not be as clear for children withASDs,6 SRBs are believed to be maintained by a variety ofreinforcement contingencies.4 Traditionally, the mechanismsand motivations underlying SRBs were considered to be sen-sory, relying upon automatic reinforcement contingencies (seeHutt and Hutt15 and Zentall and Zentall16), but, morerecently, other forms of reinforcement, such as social positive,non-social positive, and negative reinforcement, have alsogained some support in the literature.4 Owing to the variabil-ity of not only the possible functions of SRBs, but also theinterventions themselves, it is important to understand whichfunctions apply to the target behaviour of interest for a par-ticular individual when considering intervention strategies.Without an analysis of the function of the behaviour, it isdifficult to individualize treatment to manipulate the environ-ment effectively not only to extinguish the undesirablebehaviour, but also to teach effective appropriate replacementbehaviours.17 Also, the frequency at which a behaviouroccurs, when and where it occurs, why it occurs, and withwhat outcomes, are all necessary pieces of the interventionpuzzle.18

Intervention practices for SRBs vary in design, intensity,and theory, spanning multiple broad categories of treatment,including behavioural, developmental, and pharmaceuticalinterventions. Challenges in identifying and utilizing standard-ized terminology with regard to SRBs19, as well as the hetero-geneity of the SRBs themselves and the characteristics ofindividuals with ASDs, have contributed to difficulties indetermining intervention efficacy.20 The implementation of acomprehensive treatment programme often requires highlevels of training for personnel, as well as weighty financialand human resources.21 Thus, a better understanding of thegamut of intervention practices for SRBs, the characteristics ofthe individuals (including age, ASD severity, intellectual abil-ity, etc.) for which any given intervention has demonstratedempirical efficacy, as well as the form and function of SRBsthat have been targeted may aid in reducing ineffective use ofresources, errors, and any potential harm. Evaluation ofstudies by using a systematic review methodology, an unbiasedand transparent quantitative and qualitative procedure usingreplicable procedures, can help to determine intervention

efficacy and, thus, best practices for intervention providers.22

Further, statistical methods, such as the calculation of effectsize, are often used to examine intervention efficacy.23 It is alsoimportant to determine the quality of conduct of a study whencritically examining the effects of an intervention.24 Qualityassessment via evaluative scales can be used for this purpose ina systematic review.24 Therefore, the purpose of this review isto provide a systematic assessment of behavioural interven-tions directed at reducing SRBs with identified functions inindividuals with autism. Pharmacological interventions, whichtypically attempt to address the underlying neurobiologicalmechanisms of SRBs, rather than the behavioural functions,were, therefore, not the focus of this review (see Soorya et al.25

for a recent review of psychopharmacological interventions).For the purpose of our review, we specifically endeavoured to(1) identify the intervention practices used to reduce SRBs inindividuals with ASDs for whom the function of the behaviourhas been determined and to describe the participants, out-comes, and intervention methods and (2) evaluate the method-ological quality of the empirical evidence using quality ofconduct evaluation scales set out by the American Academyfor Cerebral Palsy and Developmental Medicine(AACPDM),24 supplemented by further criteria reported bySmith et al.26

METHODSearch strategyFirst, a systematic search was conducted in 20 electronicdatabases (e.g. MEDLINE, PsycINFO, ERIC); a completelist is presented in see Appendix SI, (supporting informationpublished online) covering educational, psychological, andbiomedical areas of study in June 2008 (see Appendix SII,supporting information published online, for a detaileddescription of the MEDLINE search and a complete list ofelectronic databases). Second, the reference lists of relevantarticles were examined to identify other pertinent studies.Grey literature was not searched; however, unpublisheddissertations, theses, and reports retrieved during the searchwere included. A complete list of the search strings can beobtained from the first author.

Study selection: criteria for inclusionTwo independent reviewers utilized multiple criteria inscreening relevant articles for inclusion in the review. In thecase of articles in which multiple experiments were reported,experiments were separated (e.g. Fisher et al.27) and evaluatedindividually for inclusion. A study must have met the followingcriteria to be included in the review. (1) The study must haveutilized an experimental design including randomizedcontrolled trials, quasi-group designs (i.e. non-randomizedcomparison group design), or single-participant research

What this paper adds• A unique examination of behavioural intervention studies that target SRBs in

individuals with autism.• Focus on explicitly stated function, thereby providing insights into a distinctive

cross-section of intervention.

Systematic Review 319

designs (e.g. multiple baseline design, reversal, alternatingtreatment design). Studies that utilized a pre-experimentaldesign, such as AB, pre–post test, and case study designs, wereexcluded (e.g. Arntzen et al.28). (2) Studies utilizing a groupdesign must have examined in the statistical analysis at least90% of participants enrolled. (3) The study must haveincluded participants of any age diagnosed with autistic disor-der, pervasive developmental disorder, or Asperger syndrome.Individuals with a comorbid diagnosis were also included;however, individuals with Rett syndrome or childhood disinte-grative disorder were not included because of the significantlydifferent clinical trajectory of these diagnoses. (4) Single casestudies must have reported graphical data that could be usedto calculate the per cent of non-overlapping data (PND) for atleast one of the participants. (5) Group studies must havereported data that allow for the calculation of effect sizes. (6)Studies must include an intervention to ameliorate an SRB. (7)Studies must have explicitly stated or hypothesized the func-tion of the SRB using a method such as a functional analysis.Studies that included a functional analysis but reported incon-clusive findings (e.g. Orr et al.29) or failed to explicitly describea hypothesized function of the SRB (e.g. Fertel-Daly et al.30;Smith et al.31) were excluded. (8) The study must have beenreported in the English language and published between theyears 1994 and June 2008. The year 1994 was selected as acut-off in accordance with the last revision of the DSM-IVand implementation of the International Classification ofDisease (10th edition). Reasons for exclusion were docu-mented. A complete list of excluded articles is available fromthe first author.

Quality assessmentAll 10 included studies utilized single-case research designs. Arating scale developed by the AACPDM24 was used to evaluatethe methodological quality of these studies. The scale consistsof 14 questions that address selection and description ofparticipants, description of intervention, and accuracy ofmeasurement. A score of 11 to 14 represents a study of strongquality, a score of 7 to 10 represents a study of moderatequality, and a score of 6 or below represents a study of lowquality. Second, the Smith et al.26 quality criteria for single-case research were utilized to provide additional ratings ofquality, including measurement of intervention fidelity andgeneralization of effects.

Using these scales, the methodological quality of the studieswas assessed and a final numerical score was determined thatwas then equated to a ranking of relative quality. Two inde-pendent reviewers applied the published quality assessmentcriteria. Interrater reliability was 94.81% on the AACPDMscale and 97.40% on the Smith et al.26 scale. Interrater reli-ability was determined by dividing the number of agreementsby the total number of criteria in the scale and then multiply-ing this by 100 to obtain a percentage. The total number ofcriteria in the AACPDM scale was 14, and the total was 7 forthe Smith scale.26 Disagreements among reviewers wereresolved through dialogue and, if necessary, adjudication by athird reviewer.32

Data extraction, analysis, and presentation of resultsThe data from the included studies were synthesized qualita-tively. Reported data included participant characteristics anddemographic information, design, intervention components,per cent of non-overlapping data (PND), and conclusions.Only data on dependent variables examining SRBs wereextracted. Secondary target behaviours (e.g. on task behaviour)are noted in Table I; however, conclusions drawn in the analy-sis are not related to the possible effects of the interventionwith dependent variables other than SRBs. Owing to the widevariation in intervention practices included in this review, nodirect statistical comparisons could be made.

RESULTSThe systematic search of electronic databases resulted in theidentification of 1808 citations (Fig. S1, supporting informa-tion published online). After removal of duplicates, reviews,and irrelevant articles, 141 studies were retrieved for furtherreview. Ten studies met inclusion criteria, all using single-participant designs. The median year of publication of theincluded studies was 2003, ranging from 2000 to 2007. The10 articles included one dissertation33 alongside nine peer-reviewed journal articles. All 10 studies were conducted in theUSA. A list of excluded references and reasons for exclusioncan be obtained from the first author.

Participant characteristicsSeventeen participants were included in the 10 studies, amedian sample size of 1. Fifteen participants were diagnosedwith autism, one with pervasive developmental disorder, andone with high-functioning autism. Five participants were alsoreported to have comorbid diagnoses of mental retarda-tion.*34–37 In addition, one participant was reported to havecomorbid gastrointestinal difficulties,38 and another was alsodiagnosed with cerebral palsy.35 The participants were primar-ily male (n=13) and of school age. However, one toddler, twoadolescents, and four adults were also included. Only twostudies reported the severity of the participants’ autism symp-toms, one reporting mild symptoms5 and one reporting severesymptoms.33 Only one study5 described participant ethnicity,family socio-economic status, and participant intellectual testscores.

Target behaviourThe authors utilized a variety of experimental functionalassessments and informal functional analysis techniques tohypothesize that the function of 15 participants’ SRBs wassensory stimulation. The function of the remaining two partic-ipants’ SRBs was proposed to be social attention, while oneparticipant’s SRBs served both an attention and an escapefunction.

Four types of SRB were reported: stereotyped movements,stereotyped manipulation of objects, repetitive use of language,and circumscribed interests.33 Three studies described stereo-typed movements for at least one participant. These SRBs are

*UK usage: learning disability.

320 Developmental Medicine & Child Neurology 2010, 52: 318–327

Tabl

eI:

Sum

mar

yof

stud

ych

arac

teris

tics

and

thei

rqua

lity

Stu

dy

Part

icip

an

ts(n

)D

esi

gn

Inte

rven

tio

nFu

nct

ion

:ty

pe

of

SR

B(D

V)

Ou

tco

me

(PN

Dm

ean

⁄ran

ge

a⁄e

ffica

cy)

Seco

nd

ary

ou

tco

mes

Meth

od

olo

gic

al

qu

ality

Ah

earn

et

al.

42

(US

A)

Ch

ild

ren

:m

ale

(2),

fem

ale

(2);

mean

ag

e7y

3m

o:P

DD

(1),

au

tism

(3)

Revers

al;

level4

Resp

on

sein

terr

up

tio

nan

dre

dir

ect

ion

Sen

sory

;re

peti

tive

lan

gu

ag

e:

vo

caliza

tio

n

89.4

7%

⁄57.8

9–1

00%

⁄eff

ect

ive

Ap

pro

pri

ate

vo

caliza

tio

ns

AA

CP

DM

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od

era

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);S

mit

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)

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net

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34

(US

A)

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male

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mean

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art

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(1)

Systematic Review 321

rhythmic movements repeated in an invariant manner that iscontextually inappropriate39 and included hand flapping,5 facerubbing ⁄ touching,34 and leg or hand movement.40 Repetitiveobject manipulation (inappropriate and unusual manipulationof objects),39 including object mouthing, was described byanother three studies.35,38,41 Repetitive use of language, or a‘linguistic device or phrase either copied or self generated thatis inappropriate and repeatedly used’33 was reported as thetarget behaviour in two studies.41,42 Finally, circumscribedinterests were reported as the target behaviour by one study.35

The circumscribed interests were described as perseverativespeech that focused on three topics.

InterventionAll interventions evaluated in the included studies werebehavioural in nature. For a detailed description of the variousforms of intervention see Appendix SIII (supporting informa-tion published online). Non-contingent reinforcement (NCR)was the most frequently examined intervention (n=4).33–35,38

NCR was examined in isolation and in combination withother interventions, including response interruption,33

matched stimulation,36 and response blocking.38 Responseblocking was examined in one other article in which schedulethinning of the blocking procedure was evaluated.41 Responseinterruption was also examined by one other study.42 Finally,the efficacy of differential reinforcement on the reduction ofSRBs37 and the efficacy of functional communication train-ing40 were examined in one article each.

Research designThe intervention practices were evaluated using a variety ofsingle-participant research designs. A reversal design was usedin six studies,33,36–38,41,42 whereas alternating treatmentdesign5,34 and multiple baseline design35,40 were utilized intwo studies each.

MeasuresSRBs were quantified in two ways in the included studies. Thefrequency of the behaviours was expressed either as a percent-age of time engaged in the SRB per interval or session or byfrequency counts of the number of observed behaviours orattempts to engage in the target behaviour.

Quality of conductTable II provides the quality of conduct items for theAACPDM scale,24 and the Smith scale,26 as well as an overallsummary of study characteristics. Total scores for includedstudies for both scales can be found in Table I. The 10included studies achieved scores ranging from 5 to 10 pointsout of a possible 14 points on the AACPDM quality of con-duct rating scale. Nine studies scored between 7 and 10 pointsequating to a ranking of ‘moderate’. The authors of the scalewere contacted regarding how scale rankings, weak, moderate,and strong, were defined. Although the intent of theAACPDM scale is to quantify quality of conduct of a study,the difference between the rankings is somewhat arbitrary;clearly, however, a larger score is indicative of higher quality.

Tabl

eI:

(Con

tinue

d)

Stu

dy

Part

icip

an

ts(n

)D

esi

gn

Inte

rven

tio

nFu

nct

ion

:ty

pe

of

SR

B(D

V)

Ou

tco

me

(PN

Dm

ean

⁄ran

ge

a⁄e

ffica

cy)

Seco

nd

ary

ou

tco

mes

Meth

od

olo

gic

al

qu

ality

Ro

an

eet

al.

35

(US

A)

Ch

ild

ren

;m

ale

(1);

ag

e8y;au

tism

,co

mo

rbid

cere

bra

lp

als

yan

dm

od

era

tem

en

tal

reta

rdati

on

MB

Dacr

oss

sett

ing

;le

vel2

No

n-

con

tin

gen

tacc

ess

Sen

sory

ob

ject

man

ipu

lati

on

:o

bje

ctm

ou

thin

g

Cla

ssro

om

:100%

⁄very

eff

ect

ive;

pla

yro

om

:100%

⁄very

eff

ect

ive;

ou

tdo

or:

100%

;very

eff

ect

ive

No

ne

AA

CP

DM

:m

od

era

te(8

);S

mit

h(1

)

Tarb

ox

et

al.

41

(US

A)

Ch

ild

ren

;m

ale

(1);

ag

e4y,au

tism

;R

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al;

level4

Sch

ed

ule

thin

nin

go

fre

spo

nse

blo

ckin

g

Sen

sory

ob

ject

man

ipu

lati

on

:o

bje

ctm

ou

thin

g

Co

nd

itio

nB

:20%

⁄ineff

ect

ive

treatm

en

t;co

nd

itio

nC

:40%

⁄ineff

ect

ive

treatm

en

t;co

nd

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322 Developmental Medicine & Child Neurology 2010, 52: 318–327

The eight studies in the ‘moderate’ range that scored between7 and 9 points most frequently lacked blind assessment, testsof statistical analysis, replication of intervention effects acrossat least three participants, and a minimum of five data pointsper phase. A score of 11 to 14 points is considered a study of‘strong’ methodological quality.24 One study33 scored 10points, nearly reaching this cut-off. The study lacked blindoutcome assessors and documentation of a minimum of fivedata points per phase of the study (e.g. baseline, intervention).Only one study37 obtained a rating of ‘weak’ methodologi-cal quality, with a score of 5 out of 14 on the AACPDMscale24 and 1 out of 7 on the Smith scale.26 It is notablethat this study lacked operational definitions of the inde-pendent variable and a stable baseline that differentiated itfrom the studies in the ‘moderate’ range. Using the Smithscale26 of quality indicators, the articles scored from 1 to4 out of 7. The study33 with the highest AACPDM rat-ings also received the highest ratings on the Smith scale26

(3 ⁄ 7 points). Overall, with regard to the Smith scale,26

studies most frequently lacked specific inclusion–exclusioncriteria for participant enrolment, measures of treatmentfidelity, and measurement of generalization. For a detailedlisting of the criteria and overall percentage scores by cri-terion for included studies see Table II.

OutcomesPND was calculated for each SRB-related dependent variable(e.g. frequency of SRB, percentage of interval engaged inSRB) or intervention condition (e.g. the Cicero33 dissertationincludes multiple interventions). Procedures outlined byScruggs et al.43 were utilized for computation of PND. PNDvalues were then aggregated across participants in each study.Owing to the heterogeneity of the forms of intervention andtheir implementation, it was not possible to aggregate PNDscores across studies.

One study35 was found to have aggregated PND scoresabove 90%, ranking as ‘very effective’.44 PND values (meanand range) can be found in Table I. A further three stud-ies33,36,38 obtained PND scores in the ‘very effective’ range forat least one dependent variable or intervention condition.‘Effective’ PND scores (70–90%)44 were found for at least onecondition in six studies.33,36,37,40–42 No study obtained a PNDscore in the 50 to 70% range to obtain a rating of questionableefficacy.44 Finally, four studies33,38,40,41 were rated as having atleast one dependent variable PND score below 50%, indicat-ing an ineffective treatment.44 It should be noted that threestudies5,34–38,40 graphically reported floor effects in baselinedata in at least one condition. This effect led to a PND scoreof 0%. However, an effectiveness rating was not assigned, asthe floor effect may lead to misleading conclusions about theefficacy of the intervention.43

DISCUSSIONOverall, the studies included in this systematic review reportedpositive effects for at least one component of the intervention.The 10 included studies examined a number of unique SRBs,including repetitive motor movements, repetitive language,

circumscribed interests, and repetitive object manipulation.Although the span of SRBs increases the complexity of the var-iation amongst the studies, it demonstrates an acknowledge-ment of the range of behaviours that families and professionalsare observing among individuals with ASDs. Participantdemographic information was infrequently provided (e.g. aut-ism symptom severity, socio-economic status, IQ scores, adap-tive behaviour, or developmental ages). Thus, it is difficult tomake clear conclusions regarding the characteristics of theindividuals who benefit from the interventions and how theseindividuals differ. However, all studies reported high averagebaseline frequencies of SRB, indicating that about 60% of thedocumented baseline interval data consisted of time spentengaging in SRBs. For those studies reporting the number ofSRBs per minute interval, up to six behaviours a minute duringbaseline were documented. This indicates that SRBs wereabsorbing a substantial amount of the child’s daily time andenergy in classroom, community, and home settings.

Interesting findings were documented with regard to NCRimplementation. NCR was evaluated alone36 and in combina-tion with response interruption,33 response blocking,38

prompting procedures,34 and matched stimulation.33,46

Although Roane et al.35 reported positive findings of non-con-tingent access to food to reduce repetitive object mouthing(supported by 100% PND scores in all conditions), the long-term clinical utility, social validity, and ethical use of sugaryfood, such as marshmallows and hard candy, to reduce thebehaviour is questionable. It is also questionable whether ornot the repetitive behaviour had in fact been reduced orwhether the mouthing behaviour had only been redirectedfrom objects to food. Cicero33 examined NCR in combinationwith response interruption. NCR alone was found to beineffective in significantly reducing SRBs. Further, the combi-nation of NCR with response interruption was found to be nomore effective than response interruption alone. This indicatesthe possibility that response interruption, rather than NCR,was primarily responsible for the decrease in SRBs when thetwo were combined. Similarly, findings from Carr et al.38 indi-cate that NCR failed to reduce SRBs until combined withresponse blocking, whereas initial response blocking was moresuccessful. These findings are supported by our PND analysis,which indicated that NCR was an ‘ineffective intervention’ inboth of the above-mentioned studies. Although Britton et al.34

do present positive effects for NCR, this effect was found onlywhen combined with a prompting procedure to encourage thechild to access the non-contingent reinforcer. The authorsnote that this ‘relatively minor manipulation of NCR negatedits effectiveness’.34 However, Rapp36 provides evidence to thecontrary, reporting NCR incorporating matched stimulation(audio stimulation from toys) to be effective in reducingrepetitive language. These mixed results across nine partici-pants on the autism spectrum indicate that further researchinto the efficacy of NCR with SRBs that are maintained bysensory consequences is required before conclusions can bemade.

Functional communication training,40 differential re-inforcement,37 and an antecedent-based visual cue card inter-

Systematic Review 323

vention5 were evaluated in one study each. It is notable thatfloor effects in the baseline data of the visual cue card inter-vention5 negated our ability to determine the effectiveness ofthe intervention based on PND calculations.44 Further, thestudy examining functional communication training40 alsoreported floor effects in one of three intervention conditions;thus, we were again unable to determine efficacy from PNDscores. This is unfortunate because baseline data indicate thatSRBs ranged from 0% to nearly 100% per interval; however,during functional communication training intervention, theparticipant engaged in SRBs for only approximately 0 to10% of the intervals. Therefore, the data indicate that a sub-stantial treatment effect occurred; however, this is not repre-

sented in the PND data. This study is of interest because it isthe only included study that examined an SRB that had beendetermined through functional analysis to be reinforced bymultiple factors, including social attention and negative rein-forcement.

The effect of differential reinforcement of alternative behav-iour in combination with extinction procedures on sociallymaintained SRBs was examined in one of the included stud-ies.37 The authors report that differential reinforcement ofalternative behaviour and extinction successfully reducedperseverative speech in an adult male diagnosed with autismand mild mental retardation. This conclusion is supported byour PND analysis, which indicates that the intervention was‘effective’ (85.71% PND). However, this study was scored asbeing ‘weak’ in methodological quality, achieving a score of 5out of a possible 14 on the AACPDM scale24 and a score of 1out of 7 on the Smith scale.26 Owing to independent variablesand intervention conditions with poor operational definitions,the ability of independent researchers to replicate the effectsof this intervention was questionable. Further, the lack of sta-bility in baseline data and the lack of replication of the inter-vention effects reduce the external validity.

Response interruption intervention was examined by twoof the included studies,33,42 both of which were determinedto be of moderate methodological quality (AACPDM).23

One study33 achieved an AACPDM score only 1 point shortof a rating of ‘strong’ methodological quality, the highestscore of any included study. Further, our PND scores for thisresponse interruption indicated a ‘very effective’ interven-tion33,42 across the two studies. However, there are severallimitations to this finding. The implementation of responseinterruption intervention requires the ongoing daily involve-ment of trained staff members to physically administer theinterruption procedure to an individual. It should be notedthat this form of one-on-one intensive intervention cannecessitate high levels of human and financial resources andmay not be feasible to implement or to provide over the longterm. Further, Reichow et al.23 advise that promising evi-dence-based practices are to be used with caution and shouldbe monitored closely until further supportive evidence isgathered. In using the example of response interruption, onlyone of the two studies examined generalization or follow-uplevels of SRB frequency.42 The generalization probes forthree of the four participants provided in textual data indicatea drop in SRB level from 22 to 64% between pre- and post-treatment probes across participants. These data indicatepotential positive effects extending 1 month beyond the lim-ited time frame of intervention conditions. However, it isimportant to note that all three studies examined individualswith SRBs for whom the function of the behaviour was deter-mined to be sensory stimulation. Thus, it is possible that effi-cacy of the intervention may vary with topographicallysimilar SRBs that serve a different function (e.g. sociallymaintained or negatively reinforcing). In addition this studyrepresents a small sample of four children who were poorlydescribed, which prohibits determination of individuals forwhom this intervention is best suited.

Table II: Methodological characteristics of single case studies

Number ofstudies (%), n=10

AACPDM (2008) quality components(1) The participant(s) are well described

to allow comparison with other studiesor with the reader’s own patient population

10 (100)

(2) Independent variables wereoperationally defined to allow replication

9 (90)

(3) Intervention conditions operationallydefined to allow replication

9 (90)

(4) Dependent variables operationallydefined as dependent measures

10 (100)

(5) Interrater ⁄ intrarater reliability ofdependent measures assessedbefore and during each phaseof the study

10 (100)

(6) Outcomes assessor blind 0 (0)(7) Stability of data demonstrated

in baseline5 (50)

(8) Type of single-participant researchdesign was clearly and correctly stated

9 (90)

(9) Adequate number of data pointsin each phase (minimum 5)

1 (10)

(10) Intervention replicated acrossthree or more individuals

2 (20)

(11) Authors conducted and reportedvisual analysis

1 (10)

(12) Graphs used for visual analysisfollow standard conventions

9 (90)

(13) Authors report tests of statistical analysis 1 (10)(14) All criteria met for statistical analysis 1 (10)

Smith et al. (2007) quality components

(1) Use of single-case experimental design 10 (100)(2) Specific inclusion and exclusion

criteria for enrolment in study alongwith drop-outs and intervention failures

0 (0)

(3) Well-defined samples of participantsin the study (i.e. standardized diagnostictests, standardized intelligence tests,adaptive behaviour)

2 (20)

(4) Replication of intervention acrossthree or more participants

2 (20)

(5) Assessment of generalization ofintervention effects to at least one othersetting or maintenance of effects over time

0 (0)

(6) Measurement of outcome conductedblind to the purpose of the study

0 (0)

(7) Fidelity of intervention implementationmonitored through direct observation

3 (30)

AACPDM, American Academy for Cerebral Palsy and DevelopmentalMedicine.

324 Developmental Medicine & Child Neurology 2010, 52: 318–327

In several of the studies, a component of the interventionwas to teach parents, caregivers, or teachers to implement theintervention. Ahearn et al.42 and Conroy and et al.5 taught theparticipants’ classroom teacher and the teaching assistant toimplement the intervention in novel academic settings. Socialvalidity based on the teacher’s report was positive. Similarly,social validity in the Carr et al.38 study, in which intervention-ists expanded the implementation of NCR to different settingsand to new therapists, was also high. The study by Tarboxet al.41 was the only one to include parent training as a compo-nent of the intervention. The training included descriptionsand models of the intervention procedure. Parents were alsoprovided with verbal feedback regarding their implementationof the intervention throughout the process. Involving keymembers of the child’s environment, such as parents andteachers, is a notable feature of these reports and has beenfound in other research45 to help maintain the positive resultsof children’s treatment. As such, this component of these stud-ies should be highlighted.

Recommended clinical practiceThe empirical evidence for a benefit of interventions forSRBs in individuals with ASDs is preliminary in nature; how-ever, positive findings are reported for a wide number ofinterventions as well as in participants of various ages, devel-opmental levels, ASD symptom severity, and ethnicity. Multi-ple factors must be taken into account when evaluating theevidence to support the implementation of a particular inter-vention to reduce SRBs in an individual with ASDs. Althoughmany of the interventions reported in the literature probablydo not cause harm, some may be ineffective. A handful ofstudies examined various combinations or versions of similarintervention practices,34,37,41 whereas only a few directlycompared the efficacy of different intervention prac-tices.33,36,38 Owing to the limited evidence comparing inter-vention methods, no one intervention should be used at theexclusion of another.46 This synthesis of the literature pro-vides limited information about where time, energy, andfinancial resources should be invested to deliver the mostpositive outcomes. Decisions regarding the implementationof these practices should be made with caution, taking intoaccount the values and needs of the family, the unique char-acteristics of the child, and the clinical expertise of profes-sionals in the field.47 For any intervention to be effective, it isimportant that professionals be sensitive to the needs of theindividual child and family in question.48 Examining thefunction of the SRB is part of the individualization of inter-vention services. The function of SRBs for individuals in theincluded studies was frequently determined to be a need forunique sensory input (n=15). Thus, the clinical expertise ofoccupational therapists who work with individuals with ASDsmay prove to be a valuable resource in the decision-makingprocess. Further, the interventions included in this reviewwere behavioural in nature. Consultation with a Board Certi-fied Behaviour Analyst (BCBA) may aid in developing andimplementing an appropriate intervention.

Study strengths and limitationsA strength of this systematic review is the focus on interven-tion studies that explicitly state the function of the targetedSRBs. The literature on SRB intervention is quite wide-spread; however, it is apparent that relatively few interventionstudies examine behavioural function, a necessary piece ofinformation for effective intervention by clinicians. A furtherstrength of the paper is the execution of a comprehensivesearch of indexed literature and theses ⁄ dissertations, whichwas conducted to retrieve studies that examined the efficacyof interventions for SRBs in individuals with ASDs. Thissearch was probably successful in retrieving the majority ofrelevant articles. However, we acknowledge that we did notsearch sources of grey literature and we excluded studies writ-ten in languages other than English, which may have resultedin the omission of relevant contributions. Further, becausethis review focused on studies that explicitly identified thefunction of the SRB, studies that implied but did not explic-itly state a function (e.g. sensory interventions such asweighted vests), or studies that described intervention meth-ods grounded in alternative explanatory models (e.g. pharma-ceuticals such as selective serotonin reuptake inhibitors), wereexcluded.

A limitation of the present findings is that all of the inter-vention studies included in this review were single-participantresearch designs. Although single-case research is a rigorous,scientific methodology used to define basic principles ofbehaviour and establish evidence-based practices,49 it is oftenseen as a starting point for formulating and understandinghow to apply new interventions systematically.26 Strengths ofsingle-participant research are that it (1) yields evidence thata technique has a clear, replicable effect on a specific behav-iour in one or several individuals; (2) allows for individualiza-tion of intervention across participants; (3) measures progressover multiple time points, enabling careful analysis of inter-vention; and (4) requires fewer resources than clinical trials.26

Single-subject methods are particularly well suited to studyindividuals with ASDs, whose characteristics and life circum-stances are exceedingly heterogeneous in nature. This hetero-geneity creates substantial problems when scientists attemptto use group-based methodology to address questions aboutthe effectiveness of treatments. In fact, group-based studiesdesigned to determine the effectiveness of intervention forindividuals with ASDs are in the minority; there exists amuch more substantial body of research using primarily sin-gle-case design methods,50 especially in the area of defininginterventions. This limitation, therefore, speaks more to thestate of the science in SRB research.

Future directionsLooking forward, we have several recommendations for theevaluation of interventions for SRBs in individuals with ASDs,based upon review of the literature. No intervention studyobtained a ranking of ‘strong’ in methodological quality.However, one study obtained a score of 10 out of 14, onepoint below a rating of ‘strong’. This study differed from stud-

Systematic Review 325

ies scoring lower rankings by demonstrating stable baselinedata, reporting appropriate visual analysis, and demonstratingreplication of the intervention effects across three or moreindividuals. However, critical methodological componentsincluding use of blind raters, reporting of an adequate numberof data points per design phase, and appropriate statisticalanalysis were lacking.

Several commonly implemented interventions for individu-als with ASDs were not included in this review. No study exam-ining the effects of diet modification, the use of sensory ‘diets’,or alternative medicines was found in the systematic search ofthe literature, with the exception of one study examining theuse of Chinese medicine with children with ASDs.51 However,this study utilized a research design of low quality and, thus,was not included in the review. Although these controversialinterventions52 have yet to develop a base of empirical evidenceto support their use to reduce SRBs in individuals with ASDs,they are being implemented in homes around the world.

In the pursuit of evidence-based intervention practices forSRBs, a progression to more rigorous experimental designs(group comparison designs) would create a clearer picture ofthe effectiveness of these various intervention practices. How-ever, owing to practical (funding, time constraints, etc.) andethical limitations, group designs can be difficult to imple-ment. To meet the standards for ‘promising’ and ‘establishedevidence-based practices’,23 further replications of interven-tion effects in single-case research could also provide greater

evidential support. The implementation of randomizationprocedure in both multiple baseline and alternating treatmentdesigns would also increase the methodological rigor ofsingle-case designs.

CONCLUSIONSThe 17 participants involved in these studies demonstratedhigh baseline levels of SRBs. These high frequencies, along-side the teacher and parent reports, indicated that thesebehaviours were interfering with the individuals’ ability toengage appropriately in their environment. Overall, positiveeffects were reported for behavioural interventions to reduceSRBs maintained by a variety of identified functions displayedby individuals with ASDs; however, there are several limita-tions to these findings. This evidence is preliminary in naturebecause of the small number of participants in the 10 studiesand the heterogeneity of both the population and the inter-ventions themselves. Caution should be used in choosing andimplementing interventions to ameliorate SRBs in order toreduce the use of ineffective treatment, thus wasting valuableresources. Further research is required to examine the arrayof behavioural, sensory, pharmaceutical, and developmental,interventions for SRBs based upon the function of the behav-iour.

ONLINE MATERIALAdditional material may be found in the online version of this article.

REFERENCES

Asterisks (*) indicate a study included in the review (10 studies).

1. American Psychiatric Association. Diagnostic and statistical

manual of mental disorders. 4th edn. Washington, DC:

American Psychiatric Association, 1994.

2. Turner MA. Annotation: repetitive behaviour in autism: a

review of psychological research. J Child Psychol Psychiatry

1999; 40: 839–49.

3. Rapp JT, Vollmer TR. Stereotypy I: a review of behavioral

assessment and treatment. Res Dev Disabl 2005; 26: 527–

47.

4. Cunningham AB, Schriebman L. Stereotypy in autism: the

importance of function. Res Autism Spectr Disord 2008; 2:

469–79.

5. *Conroy MA, Asmus JM, Sellers JA, Ladwig CN. The

use of an antecedent-based intervention to decrease stereo-

typic behavior in a general education classroom: a case

study. Focus Autism Other Dev Disabl 2005; 20: 223–

30.

6. Lewis MH, Bodfish JW. Repetitive behavior disorders in

autism. Ment Retard Dev Disabil 1998; 4: 80–9.

7. Happe F, Ronald R, Plomin R. Time to give up on a

single explanation for autism. Nat Neurosci 2006; 9: 1218–

20.

8. Watt N, Wetherby AM, Barber A, Morgan L. Repetitive

and stereotyped behaviors in children with autism spectrum

disorders in the second year of life. J Autism Dev Disord

2008; 38: 1518–33.

9. Hollander E, Phillips A, Chaplin W, et al. A placebo con-

trolled crossover trial of liquid fluoxetine on repetitive

behaviors in childhood and adolescent autism. Neuropsycho-

pharmacology 2005; 30: 582–9.

10. Militerni R, Bravaccio C, Falco C, Fico C, Palermo MT.

Repetitive behaviors in autistic disorder. Eur Child Adolesc

Psychiatry 2002; 11: 210–8.

11. Szatmari P, Georgiades S, Bryson S, et al. Investigating the

structure of the restricted, repetitive behaviours and inter-

ests domain of autism. J Child Psychol Psychiatry 2006; 47:

582–90.

12. Lord C, Pickles A. Language level and non-verbal social-

communicative behaviors in autistic and language-delayed

children. J Am Acad Child Adolesc Psychiatry 1996; 35:

1542–50.

13. Lewis M, Kim SJ. The pathophysiology of restricted

repetitive behavior. J Neurodevelop Disord 2009; 1: 114–

32.

14. National Research Council. Educating Children with Aut-

ism. Lord C, McGee JP, editors. Washington, DC:

National Academy Press, 2001.

15. Hutt C, Hutt SJ. Effects of environmental complexity on

stereo-typed behaviors of children. Anim Behav 1965; 13:

1–4.

16. Zentall SS, Zentall TR. Optimal stimulation: a model of

disordered activity and performance in normal and deviant

children. Psychol Bull 1983; 94: 446–71.

17. Wacker DP, Peck S, Derby KM, Berg W, Harding J.

Developing long-tern reciprocal interactions between par-

ents and their young children with problematic behaviour.

In: Koegel LK, Koegel RL, Dunlap G, editors. Positive

Behavioral Support: Including People with Difficult Behav-

ior in the Community. Baltimore: Paul H. Brookes Publish-

ing, 2006, 51–80.

18. Murdoch H. Stereotyped behaviours: how should we think

about them? Br J Special Educ 2003; 24: 71–5.

19. Bodfish JW, Symons FJ, Parker DE, Lewis MH. Varieties

of repetitive behavior in autism: comparisons to mental

retardation. J Autism Dev Disord 2000; 30: 237–43.

20. Goin-Kochel RP, Mackintosh VH, Myers BJ. Parental

reports on the efficacy of treatments and therapies for their

children with autism spectrum disorders. Res Autism Spectr

Disord 2009; 3: 528–37.

21. Lord C, Wagner A, Rogers S, et al. Challenges in evaluat-

ing psychosocial interventions for autistic spectrum disor-

ders. J Autism Dev Disord 2005; 35: 695–708.

22. Lavis J, Davis H, Oxman A, Denis JL, Golden-Biddle K,

Ferlie E. Towards systematic reviews that inform health

care management and policy-making. J Health Serv Res Pol-

icy 2005; 10: 35–48.

23. Reichow B, Volkmar FR, Cicchetti DV. Development of

the evaluative method for evaluating and determining evi-

dence-based practices in autism. J Autism Dev Disord 2008;

38: 1311–9.

24. Logan LR, Hickman RR, Haris SR, Heriza CB. Single-sub-

ject research design: recommendations for levels of evidence

and quality rating. Dev Med Child Neurol 2008; 50: 99–103.

25. Soorya L, Kiarashi J, Hollander E. Psychopharmacologic

interventions for repetitive behavior in autism spectrum dis-

orders. Child Adolesc Psychiatric Clin N Am 2008; 17: 753–71.

326 Developmental Medicine & Child Neurology 2010, 52: 318–327

26. Smith T, Scahill L, Dawson G, et al. Designing research

studies on psychosocial interventions in autism. J Autism

Dev Disord 2007; 37: 354–66.

27. Fisher WW, Lindauer SE, Alterson CJ, Thompson RH.

Assessment and treatment of destructive behavior main-

tained by stereotypic object manipulation. J Appl Behav

Anal 1998; 31: 513–27.

28. Arntzen E, Tonnessen IR, Brouwer G. Reducing aberrant

verbal behavior by building a repertoire of rational verbal

behavior. Behav Intervent 2006; 21: 177–93.

29. Orr TJ, Myles BM, Carlson JK. The impact of rhythmic

entertainment on a person with autism. Focus Autism Dev

Disabil 1998; 13: 163–6.

30. Fertel-Daly D, Bedell G, Hinojosa J. Effects of a weighted

vest on attention to task and self-stimulatory behaviors in

preschoolers with pervasive developmental disorders. Am J

Occup Ther 2001; 55: 629–40.

31. Smith SA, Press B, Koenig KP, Kinnealey M. Effects of

sensory integration intervention on self-stimulating and

self-injurious behaviors. Am J Occup Ther 2005; 59: 418–

25.

32. The Cochrane Collaboration. Cochrane handbook for sys-

tematic reviews of interventions (Version 5.0.1). Higgins

JPT, Green S, editors. Available from: http://www.cochra-

ne-handbook.org/ (accessed 19 June 2009).

33. *Cicero FR. The effects of noncontingent reinforcement

and response interruption on stereotypic behavior main-

tained by automatic reinforcement [dissertation]. New

York: City University of New York, 2007.

34. *Britton LN, Carr JE, Landaburu HJ, Romick KS. The

efficacy of noncontingent reinforcement as treatment for

automatically reinforced stereotypy. Behav Interv 2002; 17:

93–103.

35. *Roane HS, Kelly ML, Fisher WW. The effects of non-

contingent access to food on the rate of object mouthing

across three settings. J Appl Behav Anal 2003; 36: 579–

82.

36. *Rapp JT. Further evaluation of methods to identify mat-

ched stimulation. J Appl Behav Anal 2007; 40: 73–88.

37. *Rehfeldt RA, Chambers MR. Functional analysis and treat-

ment of verbal perseverations displayed by an adult with

autism. J Appl Behav Anal 2003; 36: 259–61.

38. *Carr JE, Dozier CL, Patel MR, Adams AN, Martin N.

Treatment of automatically reinforced object mouthing

with noncontingent reinforcement and response blocking:

experimental analysis and social validation. Res Dev Disabil

2002; 23: 37–44.

39. Turner MA. Towards an executive dysfunction account of

repetitive behaviour in autism. In: Russell J, editor. Autism

as an Executive Function. Oxford: Oxford University Press,

1997, 57–100.

40. Kennedy CH, Meyer KA, Knowles T, Shukla S. Analyzing

the multiple functions of stereotypical behavior for students

with autism: implications for assessment and treatment.

J Appl Behav Anal 2000; 33: 559–71.

41. *Tarbox J, Wallace MD, Tarbox RSF. Successful general-

ized parent training and failed schedule thinning of

response blocking for automatically maintained object

mouthing. Behav Interv 2002; 17: 169–78.

42. Ahearn WH, Clark KM, MacDonald RPF. Assessing and

treating vocal stereotypy in children with autism. J Appl

Behav Anal 2007; 40: 263–75.

43. Scruggs TE, Mastropieri MA, Casto G. The quantitative

synthesis of single-subject research: methodology and

validation. Remedial and Special Education 1987; 8: 24–33.

44. Scruggs TE, Mastropieri MA. Summarizing single-subject

research: issues and applications. Behav Modif 1998; 22:

221–42.

45. Maston ML, Mahan S, Matson JL. Parent training: a review

of methods for children with autism spectrum disorders. Res

Autism Spectr Disord 2009; 3: 868–75.

46. Simpson RL, Smith Myles B, Griswold DE, Adams LG, De

Boer-Ott SR, Kline SA. Autism Spectrum Disorders: Inter-

ventions and Treatments for Children and Youth. Austin:

Corwin Press, 2004.

47. American Speech Language Hearing Association. Introduc-

tion to evidence-based practice. Available from: http://

www.asha.org (accessed 15 September 2006).

48. Freeman BJ. Guidelines for evaluating intervention pro-

grams for children with autism. J Autism Dev Disord 1997;

27: 641–51.

49. Horner R, Carr E, Halle J, McGee G, Odom S, Wolery M.

The use of single subject research to identify evidence-based

practice in special education. Exceptional Children 2005; 71:

165–79.

50. Odom SL, Brown WH, Frey T, Karasu N, Smith-Carter

LL, Strain P. Evidence-based practices for young children

with autism: contributions for single-subject design

research. Focus Autism Dev Disabil 2003; 18: 166–75.

51. Silva LM, Cignolini A. A medical qigong methodology for

early intervention in autism spectrum disorder: a case series.

Am J Chin Med 2005; 33: 315–27.

52. Smith T, Wick J. Controversial treatments. In: Cha-

warska K, Klin A, Volkmar FR, editors. Autism Spec-

trum Disorders in Infants and Toddlers: Diagnosis,

Assessment, and Treatment. New York: Guilford Press,

2008, 243–73.

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