Skip to main content
NIHPA Author Manuscripts logoLink to NIHPA Author Manuscripts
. Author manuscript; available in PMC: 2017 Aug 1.
Published in final edited form as: J Autism Dev Disord. 2016 Aug;46(8):2813–2820. doi: 10.1007/s10803-016-2813-6

Reduced Restricted and Repetitive Behaviors after Pivotal Response Treatment

Pamela E Ventola 1, Daniel Yang 1, Sebiha M Abdullahi 1, Courtney A Paisley 1, Megan L Braconnier 1, Denis G Sukhodolsky 1
PMCID: PMC4939123  NIHMSID: NIHMS792734  PMID: 27230762

Abstract

Children with ASD show high frequency of restricted and repetitive behaviors (RRBs); however, higher-order RRBs, such as restricted interests, have remained largely resistant to treatment. This study evaluated change in severity of RRBs following a 16-week open trial of Pivotal Response Treatment (PRT). Participants included 15 children with ASD ages 4 to 7 years. RRBs, as measured by the Repetitive Behavioral Scales- Revised (RBS-R) and Aberrant Behaviors Checklist (ABC), decreased significantly after treatment. These reductions remained significant after controlling for change in social communication skills. PRT shows promise in reducing RRBs; although PRT explicitly addresses pivotal social communication skills, there is a secondary and less direct effect on RRBs.

Keywords: Restricted and repetitive behaviors, Pivotal Response Treatment (PRT), behavior therapy, Repetitive Behavior Scale-Revised (RBS-R)


Restricted repetitive behaviors (RRBs) are core symptoms of Autism Spectrum Disorder (ASD), and these behaviors interfere with the daily functioning of the individual as well as the family (Gabriels, Cuccaro, Hill, Ivers, & Goldson, 2005; Harrop et al., 2014; Lounds, Seltzer, Greenberg, & Shattuck, 2007; Nadig, Lee, Singh, Bosshart, & Ozonoff, 2010; Richler, Bishop, Kleinke, & Lord, 2007; Shattuck et al., 2007). RRBs are a diverse set of behaviors that are often divided into two factors: repetitive sensory motor (RSMs) behaviors and insistence on sameness (IS) behaviors. RSM behaviors include lower-level behaviors, such as repetitive mannerisms and sensory seeking behaviors, while IS behaviors include higher-order behaviors, such as compulsions, rituals, difficulty shifting, and circumscribed interests (Cuccaro et al., 2003; Honey, McConachie, Turner, & Rodgers, 2012; Szatmari et al., 2006). RRBs are not unique to individuals with ASD and are observed across individuals with other developmental disorders and intellectual disabilities; however, children with ASD have higher frequency of RRB compared to children with non-spectrum developmental disorders and intellectual disabilities (Bodfish, Symons, Parker, & Lewis, 2000; Hattori et al., 2006; Kim & Lord, 2012; Richler et al., 2007; Werner & Dawson, 2005).

Severity and type of RRB correlate with age and functioning level in individuals with ASD. For example, stereotyped movements are more common in younger individuals with ASD, and ritualistic behavior, compulsions, and restricted interests often emerge or increase in severity later in development (Bishop, Richler, & Lord, 2006; Esbensen, Seltzer, Lam, & Bodfish, 2009; Lam & Aman, 2007; Militerni, Bravaccio, Falco, Fico, & Palermo, 2002). Similarly, repetitive sensory motor behaviors are negatively correlated with nonverbal IQ (NVIQ), while circumscribed interests are positively correlated with NVIQ (Bishop et al., 2006; Cuccaro et al., 2003; Goldman et al., 2009; Militerni et al., 2002; Mooney, Gray, Tonge, Sweeney, & Taffe, 2009; Richler, Huerta, Bishop, & Lord, 2010; Schultz & Berkson, 1995; Szatmari et al., 2006). Additionally, individuals with lower levels of language skills exhibit higher frequency of RRBs overall (Ray-Subramanian & Ellis Weismer, 2012). RRBs are also associated with higher levels of anxiety in children with ASD (Sukhodolsky et al., 2008).

RRBs have been directly targeted as a primary outcome within pharmacological trials (Carrasco, Volkmar, & Bloch, 2012; Soorya, Kiarashi, & Hollander, 2008; King et al., 2009), but with inconsistent results and notable adverse effects. Focused behaviorally-based intervention strategies based on principles of Applied Behavioral Analysis (ABA) have shown reductions in some lower-order sensory-oriented and repetitive behaviors (Kuhn, Hardesty, & Sweeney, 2009; Rapp & Vollmer, 2005; see Boyd, McDonough, & Bodfish, 2012; Harrop, Gulsrud, Shih, Hovsepyan, & Kasari, 2015 for comprehensive reviews). The majority of these studies, however, have included small sample sizes, limiting the generalizability of the results. All studies also followed principles of ABA with highly intensive, individualized intervention.

Although there have been positive results in reduction of some RRBs, namely lower order repetitive sensory motor behaviors, following targeted behavioral treatment, there is significant need for treatments to also target higher-order behaviors, particularly insistence on sameness behaviors, such as rituals, difficulty with flexibility, preoccupations, and circumscribed interests. Additionally and more specifically, there is great need for behavioral treatments, such as Pivotal Response Treatment (PRT), that are appropriate across the range of social functioning and intellectual levels found in individuals with ASD (Boyd et al., 2012; Harrop et al., 2015).

PRT is a particularly appropriate approach for investigating RRB reduction, since in PRT, it is common practice to functionally incorporate RRBs into the treatment, as for example, using circumscribed interests as natural reinforcement to motivate the child (e.g., Koegel & Koegel, 2012). Most studies using PRT have focused on improvement in social communication or cognitive ability. For example, several recent RCTs of PRT have shown significant improvement in language and social functioning (Hardan et al., 2014; Mohammadzaheri, Koegel, Rezaee, & Rafiee, 2014; Mohammadzaheri, Koegel, Rezaei, & Bakhshi, 2015). To date, though, no studies have investigated the effects of PRT on RRB reduction. Therefore, the purpose of the current study was to explore the differential effects of PRT with a focus on reduction in RRB following a 16-week trial of PRT.

Methods

Participants

Participants included fifteen children (5 female, 10 male), aged 4 to 7 years diagnosed with an autism spectrum disorder (ASD) using “gold-standard” diagnostic procedures. All children entered the study with a prior diagnosis of ASD, and the diagnosis was confirmed by a highly experienced licensed clinical child psychologist. Diagnostic impressions were informed by the Autism Diagnostic Observation Schedule (ADOS; Lord et al., 1999) and the Autism Diagnostic Interview-Revised (ADI-R; Rutter, LeCouteur, & Lord, 2003). Clinicians administering these measures were research reliable. Refer to Table 1 for characterization information.

Table 1.

Participant demographic and clinical characteristics.

Male/Female 10/5
Age in years 6.11 (1.13)
General Conceptual Ability (DAS-II)* 98.60 (20.20), Range 55 to 128
  Verbal* 94.00 (20.80)
  Nonverbal* 105.40 (17.09)
  Spatial* 97.20 (17.75)
ADOS Calibrated Severity Score (CSS) 15.33 (5.72)
CELF Core Language* 88.75 (23.13)
SRS-2 Total Raw Score 84.53 (21.80)
*

Mean 100, s.d. 15

Fourteen of the fifteen children participating in the study were enrolled in public school with both typically developing children and children with special needs. One child attended a special education school. All of the children received speech and language therapy and social skills instruction in school, and six of the fifteen received occupational therapy. None of the children were taking psychotropic medications. The families were asked not to add any behavioral treatments during the course of the study participation. No changes in educational placement or major changes in educational services were reported by the parents while their children were in the study.

Design

The current study is an open study of PRT that is part of a larger project on PRT aimed at investigation of feasibility, effects on social function, and brain mechanisms (Ventola et al., 2014; Ventola et al., 2015). This paper describes the differential effects of PRT with a focus on the change in RRBs before and after PRT. Baseline measures were taken immediately prior to treatment (t1), and post treatment measures were taken at the conclusion of 16 weeks of treatment (t2).

Treatment Approach

PRT is a naturalistic, behaviorally-based treatment approach based on principles of Applied Behavior Analysis (ABA). It involves specific components (child choice, child attending, clear opportunity, contingent reinforcement, natural reinforcement, reinforcement of attempts, and interspersed maintenance/acquisition tasks) designed to increase the child’s social motivation. Additionally, the approach is highly naturalistic, so for the context of the current study, the sessions were play-based and used materials such as craft supplies, balls, blocks, and ‘play-doh.’

For each child, treatment lasted 16 weeks, with a total of seven hours of treatment per week. Sessions were held in the clinic as well as in the child’s home. Five hours per week were direct intervention with the child, and two hours per week consisted of parent guidance. The treatment targeted pivotal areas, including social initiation and responsivity, with the premise that improvements in these areas should lead to more widespread and generalized improvements in multiple areas of development and represent core changes in social motivation.

RRBs were targeted in this trial but within the context of a primary focus on pivotal social communication skill development. For instance, reciprocity was directly targeted as a pivotal area of PRT, but a focus on reciprocity also addressed restricted interests and flexibility. As an example, when taking turns within a conversation, the child needed to flexibly shift between topics. As another example, treatment focused on social initiations as a pivotal area, but within this context, stereotyped speech was addressed. If a child used stereotyped language (e.g., always used the exact same language to request), the child was prompted to use more flexible speech and make the request in different ways with different vocabulary and structure to the language. Therefore, PRT did address RRBs, particularly higher order RRBs, but within the context of social communication skill development.

Additionally, of importance, clinicians were able to utilize topics and activities related to circumscribed interests as a means of motivating the child. For example, clinicians utilized materials, such as games and craft activities, related to a child’s circumscribed interest to increase their motivation and engagement in the interaction. Using this approach allowed clinicians to make the child’s strong interests more functional, as the child was able to practice reciprocal engagement while using content related to their strong interest. As another example, access to materials related to a child’s circumscribed interest was used as natural reinforcement for appropriate social communication; access to a highly desired material related to a circumscribed interest would be withheld until the child appropriately requested the material. A more detailed description of PRT can be found in the original instruction manual (Koegel, Schreibman, Good, Cerniglia, Murphy, & Koegel, L.K., 1989) and in an updated guide (Koegel & Koegel, 2012).

Fidelity of Implementation

The lead clinician was trained in PRT by faculty from the University of California Santa Barbara (UCSB), the research institution where PRT was developed. The lead clinician sent two separate videotaped sessions (of different children) to the trainer to ensure maintenance of treatment fidelity. Both videos met the standard fidelity criteria. To ensure that the bachelors-level clinicians were correctly implementing PRT during their sessions, they met with the lead clinician (licensed clinical psychologist) for two hours per week. During these meetings, clinicians discussed the children’s progress, current presentation, and specific activities for the treatment sessions that would be motivating and foster skill development. Additionally, the lead clinician observed sessions live and via videotape at least once weekly for each participant.

Formal fidelity of implementation was assessed for two randomly coded treatment sessions for each subject. Two randomly selected five-minute segments per session were used for this fidelity assessment. The standard fidelity assessment published by the developers of the approach was used, and per convention, fidelity was defined as demonstrating the treatment components (child choice, child attending, clear opportunity, contingent reinforcement, natural reinforcement, reinforcement of attempts, and interspersal of maintenance/acquisition tasks) in 80% of opportunities (Koegel & Koegel, 2012). The scoring was dichotomous; if the therapist demonstrated the component, a checkmark was used, and if not, a minus was used. All therapists maintained the defined treatment fidelity across the duration of the study.

Subject Characterization Assessment

Differential Ability Scales-II (DAS-II), Early Years Battery (Elliott, 2007)

The DAS-II is a standardized assessment of cognitive abilities that measures verbal, nonverbal and spatial reasoning abilities. The DAS-II was used in the current study for subject characterization at t1.

Autism Diagnostic Interview-Revised (ADI-R; Rutter, 2003)

The ADI-R is a comprehensive diagnostic parent-report interview that focuses on language/communication, reciprocal social interactions and restricted, repetitive and stereotyped behaviors and interests. The ADI-R was administered to the mothers of each subject at t1 for characterization.

Autism Diagnostic Observation Schedule (ADOS; Lord, 1999)

The ADOS is a semi-structured diagnostic assessment that allows clinicians to observe and assess social, communication and repetitive behaviors associated with ASD. The ADOS was performed on each subject at t1 by expert clinicians with no other involvement in the current study. The ADOS was used for subject characterization.

Clinical Evaluation of Language Fundamentals-Preschool-2 (CELF-P-2: Wiig, 2004); Clinical Evaluation of Language Fundamentals-Fourth Edition (CELF-4; Wiig, 2006)

The CELF-P-2 is a standardized language assessment for children 3 to 6 years, and the CELF-4 is a standardized language assessment for children 5 to 21 years. These measures evaluate receptive and expressive syntactic and semantic skills. They are useful for providing specific information regarding amounts and types of information the child understands and is capable of using. The CELF-P-2 or CELF-4 was administered to each subject at t1 for characterization. Test selection was based on the child’s age. Children ages 4–6 completed the CELF-P-2 (n= 13), and children aged 7 completed the CELF-4 (n= 2).

Outcome Measures

Repetitive Behavior Scale-Revised (RBS-R; Bodfish et al., 2000)

The RBS-R is a 43-item parent report questionnaire assessing a range of restricted and repetitive behaviors in ASD. The scale includes six subscales: Stereotyped Behavior, Self-injurious Behavior, Compulsive Behavior, Ritualistic Behavior, Sameness Behavior, and Restricted Behavior. Items are rated from 0–3, and parents are instructed to report on frequency and interference of specific behaviors. The measure yields subscale scores and a total score. Mean scores from prior studies range widely (e.g., M 26.4, SD 17.0, Kanne & Mazurek, 2011; M 8.88, SD 5.22 for high NVIQ sample, Gabriels et al., 2005; 24.02 for low RRB group and 62.24 for high RRB group, Gabriels et al., 2008). It is a commonly used and well-accepted measure to assess RRB (Honey et al., 2012). The mothers of participating children completed the RBS-R at t1 and t2 as an outcome measure.

Aberrant Behavior Checklist- Community Version (ABC; Aman, 1985)

The ABC is a 58-item parent report scale assessing maladaptive behaviors. It includes 5 empirically-derived subscales: Irritability, Lethargy/Social Withdrawal, Stereotypic Behavior, Hyperactivity, and Inappropriate Speech. Items are scored from 0–3, and parents are instructed to consider the frequency of the behavior and the degree to which is interferes with adaptive functioning. The scale yields subscale scores. The mothers of participating children completed the ABC at t1 and t2 as an outcome measure.

Social Responsiveness Scale-Second Edition (SRS-2; Constantino, 2012)

The Social Responsiveness Scale-Second Edition is a 65-item parent report scale designed specifically for use in ASD to quantitatively measure an individual’s ability to engage in reciprocal social behavior in a naturalistic social setting. Each item on the scale inquires about an observed aspect of reciprocal social behavior that is rated on a scale from 0 (never true) to 3 (almost always true). Behaviors are assessed over five domains: Social Awareness, Social Cognition, Social Communication, Social Motivation, and Autistic Mannerisms. The total score generated serves as an index of severity of social deficits. The mothers of participating children completed the SRS-2 at t1 and t2 as an outcome measure.

Results

RRBs were measured using two parent-report measures, RBS-R and the Stereotypy subscale of the ABC. Parents of all 15 children completed the ABC and parents of 13 children completed the RBS-R due to changes in study protocol (RBS-R was added to the protocol following enrollment of the first two children). RRBs were assessed before (t1) and after (t2) a 16-week trial of PRT. Social functioning was assessed using the SRS-2. To control for possible effects of initial severity (e.g., regression toward the mean), change scores were modeled using residualized change scores, that is, the post-treatment severity scores minus the predicted post-treatment severity scores as predicted by the pretreatment severity scores. Reduction of RRB was defined as a statistically significant decrease in reported RRB symptoms as assessed by the RBS-R and ABC Stereotypy Domain. The measures assess RRBs by considering frequency, intensity, and amount of interference in daily functioning, as described in detail in the Methods section.

On average, the participants showed significant reduction in RRB symptom severity from pretreatment (M = 26.67, S.D. = 19.69) to post-treatment (M = 15.58, S.D. = 12.25), t(11) = 3.53, p = .005, Cohen’s d = 0.69. Table 2 shows mean and standard deviation values for the measures of RRB symptoms before and after treatment. There was also significant reduction in the six subdomains on the RBS-R: Stereotyped Behavior (e.g. repetitive movements and sensory seeking behavior) (p < .01), Self-injury (e.g. hitting self) (p < .05), Compulsive Behavior subdomain (e.g., ordering objects, counting in a certain way) (p < .05), Ritualistic Behavior (e.g., insisting on a certain order of events or certain repetitive topics or responses within conversations) (p < .05), Sameness (e.g. difficulty with transitions and changes in routines) (p < .02) and Restricted Behaviors (e.g., preoccupation with one subject matter or object) (p < .02). On the ABC, there was a significant reduction in the Stereotypy subdomain (p < 0.001) (e.g., repetitive movements).

Table 2.

Mean scores for Repetitive Behavioral Scales- Revised (RBS-R) and Aberrant Behaviors Checklist (ABC) before and after treatment.

Pre-
treatment
Post
Treatment

Mean Std.
Deviation
Mean Std.
Deviation
p-value

RBS-R
subdomains
  Stereotyped 4.58 4.03 2.42 2.57 0.009
  Self-Injurious 1.83 2.12 0.83 1.47 0.020
  Compulsive 4.33 3.26 2.33 2.42 0.046
  Ritualistic 4.75 3.89 3.08 2.81 0.041
  Sameness 7.50 6.50 4.67 4.19 0.012
  Restricted 3.67 2.84 2.25 2.18 0.014
RBS-R Total
Score
26.67 19.69 15.58 12.25 0.005

ABC Stereotypy
subdomain
3.57 3.23 1.43 2.71 0.001

We also tested whether reduction in RRB symptoms is associated with improvement in the social domain. Consistent with our previous reports (Ventola et al., 2014), the participants showed significant reduction in autism symptom severity indexed by the SRS-2 Total Raw score from pretreatment (M = 86.75, S.D. = 22.25) to post-treatment (M = 73.50, S.D. = 17.83), t(11) = 3.25, p = .008, Cohen’s d = 0.66. (SRS-2 Total Raw score was utilized in the analyses as it provided a greater range of scores as well as finer gradients than T-Score equivalents.) The residualized change scores of RRB symptom severity, as assessed by the RBS-R, and those of autism symptom severity, as assessed by the SRS-2, were uncorrelated, r = .12, p = .71. We also conducted repeated-measures ANCOVA with the pre- to post-treatment change in the SRS-2 Total Raw score as a covariate to test whether change in RRBs was independent from the change in social communication symptoms. When covarying out the effects of the residualized change of the autistic symptom severity, repeated-measures ANCOVA revealed that the participants still showed significant reduction in RRB symptom severity from pre-treatment to post-treatment, F(1, 11) = 12.06, p = .006, partial η2 = .55.

Discussion

The purpose of the current pilot study was to assess the differential effects of PRT, with a particular focus on reduction of restricted and repetitive behaviors (RRB) following a 16-week trial of Pivotal Response Treatment (PRT). Overall, children exhibited a significant reduction of a variety of RRBs, regardless of severity, and this improvement was independent of change in social communication skills.

RRBs are a diverse group of behaviors, and there was significant reduction in symptoms within all of the RRB domains assessed: stereotyped behavior, self-injury, compulsive behavior, ritualistic behavior, insistence on sameness, and restricted behavior. These results are particularly notable given that improvements were found in both lower order behaviors as well as higher order behaviors. As discussed, most behavioral treatments focus on only lower-order sensory behaviors, and there is great need for treatment approaches to focus on higher order behaviors, such as the ones reported here (e.g., ritualistic behavior, insistence on sameness, compulsive behavior). Additionally, reduction in RRBs was independent of improvement in social communication skills, as assessed by the SRS-2, indicating that PRT has separable effects on the overall autism severity and more domain-specific RRB symptom severity. Reduction of RRB was not solely a function of improved social communication. Also, of importance, the independence of these results indicates that the reduction of RRB was likely not a result of parental expectancy bias across parent report measures.

Interestingly, the PRT trial primarily and explicitly focused on improving social communication skills thought to be pivotal areas of development, including initiation, responsiveness, and reciprocity. RRBs were addressed as well, yet less explicitly and directly. As such, a primary focus on core social communication may also have a secondary effect on RRB reduction. Often children demonstrate RRB when either overwhelmed or under-stimulated, so when children are more socially engaged and more able to participate in reciprocal interactions as a result of PRT, they then also demonstrate fewer RRB, respond more flexibly, shift between topics/activities more readily, and use more flexible, generative speech. For example, when a child is taking turns within a natural play scenario, it is unlikely that he/she can focus exclusively on an area of circumscribed interest, engage in repetitive behaviors, or insist on ritualistic behaviors. Furthermore, as treatment focused on social communication skills, children may have experienced less anxiety and uncertainty, which could also have related to a reduction in RRB.

The PRT trial included a high level of parent training (2 hours weekly) in addition to direct work with the child, so following the trial, parents were able to engage and support their children more effectively, which also may have led to reduction in RRB. For example, parents learned how to structure opportunities for their child to engage in flexible behavior (e.g., providing the child two choices of motivating activities that do not involve a circumscribed interest or ritualized behavior). Parents also learned how to support more flexible speech by prompting their child to use different ways of relaying ideas, as opposed to responding to stereotyped language.

Additionally of importance, circumscribed interests were used within the context of the treatment to motivate the child. Therefore, placing contingencies on RRBs, particularly circumscribed interests, may decrease the frequency of the behaviors, and the use of RRBs as natural reinforcement may make these behaviors more functional. Furthermore, practicing reciprocal interactions while engaging in a topic of strong interest may increase the child’s ability to play and converse around a circumscribed interest more functionally.

Overall, the results thus far are promising, but there are clear limitations. This study is a pilot, so the sample size was small, and there was not a control group. Additionally, inclusion criteria included a diagnosis of ASD and overall cognitive abilities of IQ > 50, but only one child had an IQ < 70 (Full Scale IQ= 55 for the one child). Therefore, the results cannot generalize to all children with ASD. Furthermore and importantly, children were not selected based on severity of RRB, and the scores on the RBS-R and ABC stereotypy scales were lower than in studies that evaluated effects of medication on these domain (King et al., 2009; Scahill et al., 2015), although they were consistent with other studies on the clinical features of high-functioning children with ASD (Gabriels et al., 2008; Gabriels et al., 2005; Kanne & Mazurek, 2011). With these initial positive results, though, we have shown differential effects of PRT on a variety of RRBs, and PRT can be considered a promising treatment modality for reducing RRB. Future directions can include a study that selects children based on severity of RRB to assess symptom reduction in a group of children with high levels of RRB and also assesses RRB severity based on multiple sources, not just parent report. Future studies will allow a broader investigation of reduction in RRB, including assessing clinical meaningfulness, evaluating moderating variables on reduction of these behaviors, controlling for concomitant treatments, and assessing further RRB domains that are more/less responsive to treatment.

Acknowledgments

Funding for this study came from Autism Science Foundation, Simons Foundation, Women’s Health Research at Yale, Deitz Family, Esme Usdan & Family, and Dwek Family.

We wish to thank the families of the children included in this study for their time and participation.

Footnotes

Compliance with Ethical Standards

This work was approved by Yale University Institutional Review Board (IRB). All participants provided informed consent for participation.

The authors declare that they have no conflict of interest.

References

  1. Aman MG, Singh NN, Stewart AW, Field CJ. The Aberrant Behavior Checklist: A behavior rating scale for the assessment of treatment effects. American Journalon Mental Deficiency. 1985;89:485–491. [PubMed] [Google Scholar]
  2. American Psychiatric, A., American Psychiatric, A., & Force, D. S. M. T. Diagnostic and statistical manual of mental disorders : DSM-5. 2013 [Google Scholar]
  3. Bishop SL, Richler J, Lord C. Association between restricted and repetitive behaviors and nonverbal IQ in children with autism spectrum disorders. Child Neuropsychol. 2006;12(4–5):247–267. doi: 10.1080/09297040600630288. [DOI] [PubMed] [Google Scholar]
  4. Bodfish JW, Symons FJ, Parker DE, Lewis MH. Varieties of repetitive behavior in autism: Comparisons to mental retardation. Journal of Autism and Developmental Disorders. 2000;30(3):237–243. doi: 10.1023/a:1005596502855. [DOI] [PubMed] [Google Scholar]
  5. Boyd BA, McDonough SG, Bodfish JW. Evidence-Based Behavioral Interventions for Repetitive Behaviors in Autism. Journal of Autism and Developmental Disorders. 2012;42(6):1236–1248. doi: 10.1007/s10803-011-1284-z. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Carrasco M, Volkmar FR, Bloch MH. Pharmacologic Treatment of Repetitive Behaviors in Autism Spectrum Disorders: Evidence of Publication Bias. Pediatrics. 2012;129(5):E1301–E1310. doi: 10.1542/peds.2011-3285. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Constantino JN, Gruber CP. Social Responsiveness Scale. Second. Los Angeles, CA: Western Psychological Services; 2012. [Google Scholar]
  8. Cuccaro ML, Shao Y, Grubber J, Slifer M, Wolpert CM, Donnelly SL, Pericak-Vance MA. Factor analysis of restricted and repetitive behaviors in autism using the Autism Diagnostic Interview-R. Child Psychiatry Hum Dev. 2003;34(1):3–17. doi: 10.1023/a:1025321707947. [DOI] [PubMed] [Google Scholar]
  9. Elliott CD. Differential Ability Scales: Introductory and Technical Handbook. 2nd. San Antonio, TX: Psycholoogical Corporation/A Harcourt Assessment Company; 2007. [Google Scholar]
  10. Esbensen AJ, Seltzer MM, Lam KS, Bodfish JW. Age-related differences in restricted repetitive behaviors in autism spectrum disorders. Journal of Autism and Developmental Disorders. 2009;39(1):57–66. doi: 10.1007/s10803-008-0599-x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Gabriels RL, Agnew JA, Miller LJ, Gralla J, Pan Z, Goldson E, Hooks E. Is there a relationship between restricted, repetitive, stereotyped behaviors and interests and abnormal sensory response in children with autism spectrum disorders? Research in Autism Spectrum Disorders. 2008;2(4):660–670. [Google Scholar]
  12. Gabriels RL, Cuccaro ML, Hill DE, Ivers BJ, Goldson E. Repetitive behaviors in autism: relationships with associated clinical features. Res Dev Disabil. 2005;26(2):169–181. doi: 10.1016/j.ridd.2004.05.003. [DOI] [PubMed] [Google Scholar]
  13. Goldman SE, Surdyka K, Cuevas R, Adkins K, Wang L, Malow BA. Defining the sleep phenotype in children with autism. Developmental Neuropsychology. 2009;34(5):560–573. doi: 10.1080/87565640903133509. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Hardan AY, Gengoux GW, Berquist KL, Libove RA, Ardel CM, Phillips J, Minjarez MB. A randomized controlled trial of Pivotal Response Treatment Group for parents of children with autism. J Child Psychol Psychiatry. 2014 doi: 10.1111/jcpp.12354. [DOI] [PubMed] [Google Scholar]
  15. Harrop C, Gulsrud A, Shih W, Hovsepyan L, Kasari C. Characterizing caregiver responses to restricted and repetitive behaviors in toddlers with autism spectrum disorder. Autism. 2015 doi: 10.1177/1362361315580443. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Harrop C, McConachie H, Emsley R, Leadbitter K, Green J, Consortium P. Restricted and repetitive behaviors in autism spectrum disorders and typical development: cross-sectional and longitudinal comparisons. Journal of Autism and Developmental Disorders. 2014;44(5):1207–1219. doi: 10.1007/s10803-013-1986-5. [DOI] [PubMed] [Google Scholar]
  17. Hattori J, Ogino T, Abiru K, Nakano K, Oka M, Ohtsuka Y. Are pervasive developmental disorders and attention-deficit/hyperactivity disorder distinct disorders? Brain Dev. 2006;28(6):371–374. doi: 10.1016/j.braindev.2005.11.009. [DOI] [PubMed] [Google Scholar]
  18. Honey E, McConachie H, Turner M, Rodgers J. Validation of the repetitive behaviour questionnaire for use with children with autism spectrum disorder. Research in Autism Spectrum Disorders. 2012;6(1):355–364. [Google Scholar]
  19. Kanne SM, Mazurek MO. Aggression in Children and Adolescents with ASD: Prevalence and Risk Factors. Journal of Autism and Developmental Disorders. 2011;41(7):926–937. doi: 10.1007/s10803-010-1118-4. [DOI] [PubMed] [Google Scholar]
  20. Kim SH, Lord C. New autism diagnostic interview-revised algorithms for toddlers and young preschoolers from 12 to 47 months of age. Journal of Autism and Developmental Disorders. 2012;42(1):82–93. doi: 10.1007/s10803-011-1213-1. [DOI] [PubMed] [Google Scholar]
  21. King BH, Hollander E, Sikich L, McCracken JT, Scahill L, Bregman JD, Network SP. Lack of Efficacy of Citalopram in Children With Autism Spectrum Disorders and High Levels of Repetitive Behavior Citalopram Ineffective in Children With Autism. Archives of General Psychiatry. 2009;66(6):583–590. doi: 10.1001/archgenpsychiatry.2009.30. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Koegel LK, Koegel RL, Carter CM. Pivotal responses and the natural language teaching paradigm. Semin Speech Lang. 1998;19(4):355–371. doi: 10.1055/s-2008-1064054. quiz 372; 424. [DOI] [PubMed] [Google Scholar]
  23. Koegel RL, Koegel LK. The PRT Pocket Guide: Pivotal Response Treatment for Autism Spectrum Disorders. ERIC; 2012. [Google Scholar]
  24. Koegel RL, Schreibman L, Good AB, Cerniglia L, Murphy C, Koegel LK. How to teach pivotal behaviors to autistic children. Santa Barbara: University of California. 1989 [Google Scholar]
  25. Kuhn DE, Hardesty SL, Sweeney NM. Assessment and Treatment of Excessive Straightening and Destructive Behavior in an Adolescent Diagnosed with Autism. Journal of Applied Behavior Analysis. 2009;42(2):355–360. doi: 10.1901/jaba.2009.42-355. [DOI] [PMC free article] [PubMed] [Google Scholar]
  26. Lakens D. Calculating and reporting effect sizes to facilitate cumulative science: a practical primer for t-tests and ANOVAs. Front Psychol. 2013;4:863. doi: 10.3389/fpsyg.2013.00863. [DOI] [PMC free article] [PubMed] [Google Scholar]
  27. Lam KS, Aman MG. The Repetitive Behavior Scale-Revised: independent validation in individuals with autism spectrum disorders. Journal of Autism and Developmental Disorders. 2007;37(5):855–866. doi: 10.1007/s10803-006-0213-z. [DOI] [PubMed] [Google Scholar]
  28. Lord C, Rutter M, DiLavore PC, Risi S. Manual. Los Angeles: WPS; 1999. ADOS. Autism diagnostic observation schedule. [Google Scholar]
  29. Lounds J, Seltzer MM, Greenberg JS, Shattuck PT. Transition and change in adolescents and young adults with autism: Longitudinal effects on maternal well-being. American Journal on Mental Retardation. 2007;112(6):401–417. doi: 10.1352/0895-8017(2007)112[401:TACIAA]2.0.CO;2. doi: Doi 10.1352/0895-8017(2007)112[401:Taciaa]2.0.Co;2. [DOI] [PubMed] [Google Scholar]
  30. Mohammadzaheri F, Koegel LK, Rezaee M, Rafiee SM. A randomized clinical trial comparison between pivotal response treatment (PRT) and structured applied behavior analysis (ABA) intervention for children with autism. Journal of autism and developmental disorders. 2014;44(11):2769–2777. doi: 10.1007/s10803-014-2137-3. [DOI] [PMC free article] [PubMed] [Google Scholar]
  31. Mohammadzaheri F, Koegel LK, Rezaei M, Bakhshi E. A Randomized Clinical Trial Comparison Between Pivotal Response Treatment (PRT) and Adult-Driven Applied Behavior Analysis (ABA) Intervention on Disruptive Behaviors in Public School Children with Autism. Journal of autism and developmental disorders. 2015;45(9):2899–2907. doi: 10.1007/s10803-015-2451-4. [DOI] [PMC free article] [PubMed] [Google Scholar]
  32. Militerni R, Bravaccio C, Falco C, Fico C, Palermo MT. Repetitive behaviors in autistic disorder. Eur Child Adolesc Psychiatry. 2002;11(5):210–218. doi: 10.1007/s00787-002-0279-x. [DOI] [PubMed] [Google Scholar]
  33. Mooney EL, Gray KM, Tonge BJ, Sweeney DJ, Taffe JR. Factor Analytic Study of Repetitive Behaviours in Young Children with Pervasive Developmental Disorders. Journal of Autism and Developmental Disorders. 2009;39(5):765–774. doi: 10.1007/s10803-008-0680-5. [DOI] [PubMed] [Google Scholar]
  34. Morris SB, DeShon RP. Combining effect size estimates in meta-analysis with repeated measures and independent-groups designs. Psychol Methods. 2002;7(1):105–125. doi: 10.1037/1082-989x.7.1.105. [DOI] [PubMed] [Google Scholar]
  35. Nadig A, Lee I, Singh L, Bosshart K, Ozonoff S. How does the topic of conversation affect verbal exchange and eye gaze? A comparison between typical development and high-functioning autism. Neuropsychologia. 2010;48(9):2730–2739. doi: 10.1016/j.neuropsychologia.2010.05.020. [DOI] [PMC free article] [PubMed] [Google Scholar]
  36. Rapp JT, Vollmer TR. Stereotypy I: A review of behavioral assessment and treatment. Res Dev Disabil. 2005;26(6):527–547. doi: 10.1016/j.ridd.2004.11.005. [DOI] [PubMed] [Google Scholar]
  37. Ray-Subramanian CE, Ellis Weismer S. Receptive and expressive language as predictors of restricted and repetitive behaviors in young children with autism spectrum disorders. Journal of Autism and Developmental Disorders. 2012;42(10):2113–2120. doi: 10.1007/s10803-012-1463-6. [DOI] [PMC free article] [PubMed] [Google Scholar]
  38. Richler J, Bishop SL, Kleinke JR, Lord C. Restricted and repetitive behaviors in young children with autism spectrum disorders. Journal of Autism and Developmental Disorders. 2007;37(1):73–85. doi: 10.1007/s10803-006-0332-6. [DOI] [PubMed] [Google Scholar]
  39. Richler J, Huerta M, Bishop SL, Lord C. Developmental trajectories of restricted and repetitive behaviors and interests in children with autism spectrum disorders. Development and Psychopathology. 2010;22(1):55–69. doi: 10.1017/S0954579409990265. [DOI] [PMC free article] [PubMed] [Google Scholar]
  40. Rutter M, Le Couteur A, Lord C. ADI-R Autism Diagnostic Interview Revised Manual. Los Angeles: Western Psychological Services; 2003. [Google Scholar]
  41. Scahill L, Aman MG, Lecavalier L, Halladay AK, Bishop SL, Bodfish JW, Dawson G. Measuring repetitive behaviors as a treatment endpoint in youth with autism spectrum disorder. Autism. 2015;19(1):38–52. doi: 10.1177/1362361313510069. [DOI] [PubMed] [Google Scholar]
  42. Schultz TM, Berkson G. Definition of Abnormal Focused Affections and Exploration of Their Relation to Abnormal Stereotyped Behaviors (Vol 99, Pg 376, 1995) American Journal on Mental Retardation. 1995;99(5):476–476. [PubMed] [Google Scholar]
  43. Shattuck PT, Seltzer MM, Greenberg JS, Orsmond GI, Bolt D, Kring S, Lord C. Change in autism symptoms and maladaptive behaviors in adolescents and adults with an autism spectrum disorder. Journal of Autism and Developmental Disorders. 2007;37(9):1735–1747. doi: 10.1007/s10803-006-0307-7. [DOI] [PMC free article] [PubMed] [Google Scholar]
  44. Soorya L, Kiarashi J, Hollander E. Psychopharmacologic interventions for repetitive behaviors in autism spectrum disorders. Child and Adolescent Psychiatric Clinics of North America. 2008;17(4):753-+. doi: 10.1016/j.chc.2008.06.003. [DOI] [PubMed] [Google Scholar]
  45. Sukhodolsky DG, Scahill L, Gadow KD, Arnold LE, Aman MG, McDougle CJ, Vitiello B. Parent-rated anxiety symptoms in children with pervasive developmental disorders: frequency and association with core autism symptoms and cognitive functioning. J Abnorm Child Psychol. 2008;36(1):117–128. doi: 10.1007/s10802-007-9165-9. [DOI] [PubMed] [Google Scholar]
  46. Szatmari P, Georgiades S, Bryson S, Zwaigenbaum L, Roberts W, Mahoney W, Tuff L. Investigating the structure of the restricted, repetitive behaviours and interests domain of autism. Journal of Child Psychology and Psychiatry. 2006;47(6):582–590. doi: 10.1111/j.1469-7610.2005.01537.x. [DOI] [PubMed] [Google Scholar]
  47. Ventola P, Friedman HE, Anderson LC, Wolf JM, Oosting D, Foss-Feig J, Pelphrey KA. Improvements in Social and Adaptive Functioning Following Short-Duration PRT Program: A Clinical Replication. Journal of Autism and Developmental Disorders. 2014;44(11):2862–2870. doi: 10.1007/s10803-014-2145-3. [DOI] [PubMed] [Google Scholar]
  48. Ventola P, Yang DYJ, Friedman HE, Oosting D, Wolf J, Sukhodolsky DG, Pelphrey KA. Heterogeneity of neural mechanisms of response to pivotal response treatment. Brain Imaging and Behavior. 2015;9(1):74–88. doi: 10.1007/s11682-014-9331-y. [DOI] [PMC free article] [PubMed] [Google Scholar]
  49. Werner E, Dawson G. Validation of the phenomenon of autistic regression using home videotapes. Archives of General Psychiatry. 2005;62(8):889–895. doi: 10.1001/archpsyc.62.8.889. [DOI] [PubMed] [Google Scholar]
  50. Wiig EH, Secord WA, Semel E. Clinical evaluation of language fundamentals—Preschool, second edition (CELF Preschool-2) Toronto, Canada: The Psychological Corporation/A Harcourt Assessment Company; 2004. [Google Scholar]
  51. Wiig EH, Secord WA, Semel E. Clinical evaluation of language fundamentals-preschool. 2nd. Marrickville, Australia: harcourt Assessment; 2006. [Google Scholar]

RESOURCES