Review
Measurement of restricted and repetitive behaviour in children with autism spectrum disorder: Selecting a questionnaire or interview

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Abstract

Assessment of children's restricted and repetitive behaviours offers potential opportunities to improve early diagnosis of autism spectrum disorder (ASD) and timely access to interventions and support. To facilitate this requires understanding of the phenomenology of repetitive behaviours in ASD, including differentiating behaviours seen in ASD from other populations such as young typically developing and developmentally delayed children. A key factor in achieving understanding is valid and reliable measurement.

This review considers the issues in conceptualisation of repetitive behaviours which should guide the choice of measurement tool, including definition of subtypes of repetitive behaviours, associations with age and ability, and categorisation of frequency and severity. The resulting conclusions about the requirements for measurement are applied within a systematic review of quantitative interview and questionnaire measures of repetitive behaviour used with children with ASD. The conclusions of the review lead to recommendations for existing and future research on restricted and repetitive behaviours in ASD.

Highlights

► There are multiple tools for measuring restricted and repetitive behaviour in children with ASD. ► Interview and questionnaire tools vary in definitions, content and response metric. ► The paper presents a framework for examination of the measurement properties of tools. ► The three most commonly used interview/questionnaire tools are reviewed. ► Selection of the most appropriate tool depends on the hypothesis of the study, population, remit of the tool, and interpretation of responses.

Introduction

Restricted and repetitive behaviours (RRB) such as special interests, compulsions, resistance to change, and odd movements are a significant problem for children with a range of developmental disorders, including autism spectrum disorder (ASD). Living with RRB can be challenging for individuals with ASD and their families (Gabriels, Cuccaro, Hill, Ivers, & Goldson, 2005). Excessive RRB can interfere with the acquisition of skills (Dunlap, Dyer, & Koegel, 1983), decrease the likelihood of positive interaction and be stigmatising (Durand and Carr, 1987, Lee et al., 2007, Loftin et al., 2008). RRB also present a significant challenge for researchers and clinicians tasked with the development of effective therapeutic packages to address the negative impact of these behaviours (Patterson, Smith, & Jelen, 2010) Surprisingly then, despite the centrality of RRB to ASD, relatively little is currently known about the aetiology of RRB or their function. This paucity of knowledge is problematic for a number of reasons; for example, it makes identification and differential diagnosis difficult, as well as preventing the development of effective therapeutic advances. One of the keys to unlocking this area of work lies in effective, valid and reliable measurement of RRB. There are a wide variety of measurement tools for RRB reported in the literature although to date no review of these tools has been undertaken.

The growth in research interest in RRB is promising; the body of publications using interview and questionnaire measures can provide the basis for an appraisal of the conceptualisation of and measurement requirements for RRB in ASD. As such this paper has two broad aims:

  • (a)

    First to consider the issues and challenges faced by the researcher or clinician when considering the knowledge base for RRB in ASD to guide practice or plan future research.

  • (b)

    Second we aim to provide an overview of measures cited in the literature which report RRB in ASD. We will focus on the measures about which there is sufficient published information in order to present a detailed critical evaluation of their strengths and weaknesses. The aim of this section is not to provide the reader with a ‘gold standard’ candidate measure of RRB. Indeed the issues highlighted in the early part of the paper will provide evidence that a ‘one measure fits all’ approach could not be good practice. Rather we will provide the reader with a critical framework for considering the advantages and disadvantages of different tools that may serve to guide decision making.

We are assessing only one broad type of measurement in this review. Questionnaire and interview methods are the most commonly used methods, possibly because they allow capture of information about a range of situations which observational measures cannot access (Turner, 1999). We acknowledge that significant advances have been made in the development of alternative methods, such as observation of very young children (Baranek, 1999, Watt et al., 2008) and direct assessments (Lord et al., 1999, Kim and Lord, 2010); however it is beyond the scope of this paper to encompass all paradigms. Similarly whilst our focus is on ASD we will acknowledge that RRB are a feature of a range of other conditions such as Obsessive Compulsive Disorder (OCD), learning disability and developmental delay (DD). We hope that the issues raised and principles highlighted will have utility and are transferable across different methodological approaches and alternative clinical groups.

Despite the pervasiveness of RRB there is a startling lack of consensus regarding a definition of the term (Leekam, Prior, & Uljarevic, 2011), which in turn creates challenges for the researcher/clinician in designing valid and reliable assessments of RRB. RRB encompass a very wide range of behaviours from self-injurious behaviour, through stereotyped motor mannerisms, echolalic speech, insistence on sameness and compulsions to sensory interests and abnormalities and circumscribed interests (Bodfish et al., 2000, Lewis and Bodfish, 1998, Turner, 1999). The breadth and variety in behaviours under the banner of RRB raises the question: is it meaningful to strive towards an overarching definition of RRB at the conceptual level, or rather are RRB best conceptualised as a multidimensional construct encompassing a number of correlated but distinct categories? This uni- versus multi-dimensionality debate has critical implications for theory, assessment and treatment for RRB.

RRB are seen in ASD, typical development (TD) (Leekam et al., 2007, Thelen, 1979) and other atypical populations including DD (Bodfish et al., 2000, Hattori et al., 2006), OCD (Zandt, Prior, & Kyrios, 2007) and language impairments (LI) (Honey, McConachie, Randle, Shearer, & Le Couteur, 2008). Varying use of terminology and definitions makes comparisons across populations extremely difficult. Given the wide range of RRB, subcategories have been proposed to provide a degree of specificity. ICD-10 criteria (WHO, 2007) for ASD identify four subcategories of RRB based upon their external manifestation:

  • (a)

    Encompassing preoccupations or circumscribed patterns of interest.

  • (b)

    Apparently compulsive adherence to specific non-functional routines or rituals.

  • (c)

    Stereotyped and repetitive motor mannerisms.

  • (d)

    Preoccupations with part-objects or non-functional elements of materials.

An alternative categorisation model based on typical development subdivides RRB according to the requisite level of cognitive skills (Turner, 1999). ‘Lower level’ behaviours encompass motor repetitions and stereotyped behaviours including tics, repetitive manipulations of objects and stereotyped movements. ‘Higher level’ behaviours include attachment to objects, maintenance of sameness and circumscribed interests.

These models are based on clinical observations of RRB. A number of factor analytic studies have further examined subcategories of RRB. Using the Autism Diagnostic Interview-Revised (ADI-R) (Le Couteur et al., 2003, Lord et al., 1994) a range of two and three factor solutions have been identified (see Appendix A). The proposed two factor solutions using ADI-R data (Bishop et al., 2006, Cuccaro et al., 2003, Mooney et al., 2009, Richler et al., 2007, Shao et al., 2003, Szatmari et al., 2006) provide some support for Turner's (1999) categorisation of ‘higher’ and ‘lower’ level behaviours. However, these models are limited by the omission of ‘unusual attachment to objects’ and ‘abnormal idiosyncratic responses’, despite the presence of these behaviours in ICD-10 diagnostic criteria and other descriptions of RRB in typical and atypical populations (e.g. Honey et al., 2007, Turner, 1999). Similarly, ‘unusual preoccupations’ does not feature in all models despite being identified as one of the most prevalent RRB in young children with ASD (Young, Brewer, & Pattison, 2003). Any model excluding these behaviours therefore lacks completeness.

Factor analysis of other RRB measures has also been conducted. Leekam et al. (2007) used the Repetitive Behaviour Questionnaire-2 (RBQ-2), to study RRB in TD 2-year olds and proposed a two and a four factor solution in line with both ICD-10 and Turner's RRB categories. Their four factor solution accounted for 51.4% of the overall variance and the two factor solution accounted for 39%. Lam and Aman (2007) used the Repetitive Behaviour Scale-Revised (RBS-R) (Bodfish et al., 2000) and identified 5 factors, the additional factor encompassing self-injurious behaviour. Furthermore, there is evidence to support combining sensory and motor behaviours to create a three factor solution whilst maintaining a valid and reliable model (Cuccaro et al., 2003, Honey et al., 2008, Lam et al., 2008, Leekam et al., 2007, Shao et al., 2003, Szatmari et al., 2006).

In summary, the debate regarding the conceptualisation of RRB continues. Indeed it could be argued that consensus cannot be achieved in the absence of good measurement. There is some agreement for the RRB categories proposed by ICD-10 across factor analytic studies of RRB in TD children and children with ASD of varying ages and abilities. A ‘Circumscribed Interests’ factor is likely to be necessary to account for ‘unusual preoccupations’ and ‘attachment to objects’. It is clear that valid measurement of RRB should be underpinned by a robust factorial model to allow for appropriately focused examination.

A growing awareness of ASD by parents and professionals, alongside the monitoring of children considered ‘at risk’, has created an increase in infant and toddler referrals for possible ASD diagnosis (Chawarska, Klin, Paul, & Volkmar, 2007). Evidence suggests parents can identify features of ASD in some infants as young as 12–18 months old (Gray and Tonge, 2005, Reznick et al., 2007, Robins et al., 2001) and diagnosis in preschoolers has been shown to be reliable (Charman and Baird, 2002, Chawarska et al., 2007, Cox et al., 1999, Lord, 1995, Moore and Goodson, 2003, Stone et al., 1994). RRB are present in typical development until around 5 years (Arnott et al., 2009, Evans et al., 1997, Gesell, 1928, Gesell et al., 1974, Leekam et al., 2007, Thelen, 1979). This highlights that any attempts to aid early diagnosis of ASD require methods for accurate identification and analysis of the differences between RRB in ASD and other populations.

Research indicates that at 16–18 months of age children with ASD show significantly higher and more intense levels of RRB than do TD children (Kim and Lord, 2010, Watt et al., 2008, Werner and Dawson, 2005) and DD children (Bodfish et al., 2000, Hattori et al., 2006, Kim and Lord, 2010, Werner and Dawson, 2005). The RRB which children engage in may also be a differentiating factor, with young children with ASD displaying a wider range of RRB than TD and DD peers (Goldman et al., 2009, Kim and Lord, 2010, Morgan et al., 2008, Watt, 2006, Watt et al., 2008) and more commonly specific types of RRB, including playing with parts of objects (Baranek, 1999, Morgan et al., 2008, Watson et al., 2007, Watt, 2006, Watt et al., 2008), simple routines (Watson et al., 2007), body mannerisms (Goldman et al., 2009, Morgan et al., 2008) and examining objects from ‘odd angles’ (Goldman et al., 2009). However, other studies have found no differences between RRB seen in ASD and other populations. For example, Cox et al. (1999) found that no specific types of RRB distinguished young children with ASD from those with LI or TD. Similarly, Hattori et al. (2006) found no significant differences in the total RRB scores of children with pervasive developmental disorder (PDD) and attention deficit hyperactivity disorder (ADHD). However, both of these studies used small samples and may lack power to identify between-group differences.

RRB are also common in OCD (Jacob et al., 2009, Ruta et al., 2010, Zandt et al., 2007). There are similarities (as well as differences) in the presentation of RRB in OCD and ASD and careful assessment may be needed to allow differential diagnosis (King & Scahill, 1999). This may be further complicated because for individuals with ASD a secondary diagnosis of OCD may be appropriate (Reaven and Hepburn, 2003, Towbin, 2003) and mixed ASD/OCD presentations pose significant challenges for assessment and treatment services (Bejerot, 2007).

RRB change with age and cognitive development, and sensitive measurement needs to be able to detect these changes. Studies of predominant types of RRB at different ages in children with ASD have identified that stereotyped movements, sensory RRB and restricted interests are less frequent in older than younger children (Lam and Aman, 2007, Militerni et al., 2002), whilst complex routines, ritualistic and sameness behaviours are more common in older children (Bishop et al., 2006, Lam and Aman, 2007, Militerni et al., 2002). Longitudinal studies reflect a similar pattern, with reduction of sensory-motor behaviours and some increase in rituals and routines (Johnson, McConachie, Watson, Freeston, & Le Couteur, 2006) though Richler, Huerta, Bishop, and Lord (2010) found consistency over time in the severity of sensory-motor behaviours. It is suggested that it is the continuation of age-inappropriate RRB which causes distress for parents (Burton et al., 2008).

The report of age-related changes in RRB should be considered carefully given overlap with the higher cognitive requisites for some RRB (e.g. rituals and routines, specific interests) and age-related expectations (e.g. flexibility in play themes with friends). Developmental level has been identified as a mediator for the frequency of RRB, with fewer RRB seen in children of higher ability (Burton et al., 2008, Chawarska et al., 2007). Cognitive ability has also been found to mediate the types of RRB seen in ASD. Children with higher levels of ability are less likely to show RRB with lower cognitive demands (e.g. sensory-motor behaviours) compared to RRB requiring higher cognitive skills (e.g. insistence on sameness and rituals) (Bishop et al., 2006, Cuccaro et al., 2003, Goldman et al., 2009, Militerni et al., 2002, Mooney et al., 2009, Richler et al., 2010, Schultz and Berkson, 1995, Szatmari et al., 2006).

Thus, RRBs vary in type and degree between individuals with ASD at different ages and ability levels. Is it therefore realistic for one measure to be applicable to the entire ASD population? Ideally, measures should include developmentally appropriate RRB and be sensitive both to change over time and to subtle differences between populations in which RRB are also present at a young age, i.e. TD and DD. Of course, developing a greater understanding of the developmental trajectory of RRB in ASD is predicated on reliable and valid measurement.

Just as consensus has not been achieved with regard to the conceptualisation of RRB, there is lack of agreement on the ways in which RRB should be measured. What are the most important aspects of RRB to measure and record? What would individuals with ASD and their parents/carers regard as the most salient aspects of RRB and does this match with the characteristics identified by researchers and clinicians attempting to develop theory and intervention? Is it that the total amount of different types of RRB is most relevant or is it the frequency with which repetitiveness is engaged in that matters? Or indeed is it the intensity with which the behaviour is experienced, the degree of interference with everyday living or the distress that results from attempts to intervene or prevent the behaviour that is the most meaningful? The likelihood is that all of these features matter and interact in complex and multidimensional ways. To gain a true sense of the meaning of living with RRB for people with an ASD and their families, researchers and clinicians need to be aware of the influence of scaling metrics they use on their understanding of RRB and consider and acknowledge the gaps consequent upon the tools selected.

Thus the way in which RRB are quantified is a critical factor in reliable and valid measurement. Response options across available questionnaires range from identifying whether a behaviour is present/not present, its frequency, intensity or its impact upon others. These scaling methods are not mutually exclusive and measures may include several metrics. It would be conceptually difficult to achieve consistency of scaling for behaviours such as hand flapping (usually measured by frequency) and collecting Pokemon cards (where intensity of resistance to being diverted might be the most informative). However, South, Ozonoff, and McMahon (2007) comment that it is difficult to compare even the same behaviours meaningfully across measures as different scaling has been used. In principle it is important to have information about the characteristics of behaviour in order to distinguish between diagnostic groupings, and potentially to differentiate aetiologies. For example, Woodcock, Oliver, and Humphreys (2009) have shown that resistance to change is expressed differently by individuals with Prader-Willi syndrome (more likely to show anger) and individuals with Fragile X syndrome (more likely to show anxiety). Similarly, there is differentiation between ASD (where RRB are correlated with anxiety) and Williams syndrome (where they are not).

There is still much work to be done to achieve a good conceptualisation and definition of RRB. The identification of the developmental trajectory of RRB within ASD is critical to enable the provision of appropriate lifespan support for people living with autism. Good measurement can increase our understanding of the differences in RRB in ASD and other populations to help improve diagnostic procedures, leading to provision of timely interventions and support. Furthermore, a greater understanding of RRB profiles in ASD may offer opportunities to increase homogeneity in research studies by creating subgroups of participants according to RRB profiles, most particularly in genetic studies (Hus et al., 2007, Shao et al., 2003).

The proliferation of measurement techniques for RRB in the ASD literature potentially adds to confusion, and an understanding of measurement issues is required so that systematic and informed choices are made. Given the complexity of RRB it would be naïve to assume that one ‘gold standard’ measure could be developed. Rather researchers and clinicians should consider the features of the measures available against a range of criteria and in the light of the specific question they are posing. The following section provides a summary and brief description of the interview or questionnaire measures of RRB reported to date in the empirical literature on children with ASD. Most measures have been used relatively infrequently making it difficult at this time to undertake a fair review of their strengths and weaknesses. Therefore, we focus on the three most frequently cited measures because there is sufficient empirical evidence upon which judgments can be made. This process illustrates some of the quality criteria that could be utilised in making a choice of RRB measure. As the field develops and more evidence emerges, a more inclusive review of the remaining measures will be possible.

Section snippets

Search strategy

A systematic search was conducted in December 2010 with subsequent updating in October 2011 to identify papers in which the primary research aim was to examine RRB in children with ASD using quantitative interview and/or questionnaire measures. Four search engines (Web of Knowledge, OVID, PsychNet, CSA) were used to search nine databases. In addition, six databases (Lefebvre, Manheimer, & Glanville, 2008) covering documents, reports and dissertations were searched (Conference Proceedings,

Quality comparisons

The quality of the selected measures was examined using twelve evaluation criteria reflecting qualities identified as essential for a measure of RRB as well as more general evaluations of psychometric properties. Criteria were derived from the literature reviewed in earlier in this paper and more generic literature relating to measurement development. Scoring procedures were developed to assess the strength of specific aspects of each measure. Each criterion was scored from 0 to 2 with higher

Discussion

We began this review by reporting that RRB in ASD are increasingly on the research agenda. Our review highlights that, as we have seen an increase in the body of published literature in this area, we have also seen growth in the production of measurement tools to assess RRB. This potentially creates a confusing landscape for researchers and clinicians striving to select the best tools for their purpose, and to identify the key criteria upon which to make these selections. To date there has been

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