How Should We Measure Repetitive Behaviors in Infants and Toddlers with Autism Spectrum Disorder?

Background:

There has been increased interest in restrictive and repetitive behaviors (RRBs) in individuals with autism spectrum disorder (ASD), since this symptom domain has been neglected compared to social-communication. This interest has recently applied to very young children with ASD, since the age of reliable diagnosis has been extended downward to 24 months and younger. It will be important to understand if infants and toddlers show the same forms of RRBs as older children, whether there are developmentally younger versions, or if there is discontinuity from RRBs shown in infancy to older children. These issues also have clinical implications, since reduced recognition of RRBs in infants and toddlers could potentially lead to fewer early diagnoses using the reconstructed DSM-5 criteria. Recently RRBS have been investigated in young children using the Repetitive Behavior Scale-Revised and the Repetitive Behavior Questionnaire. However, it is important to consider the implications of extending RRB descriptions and frameworks that were initially created for older individuals to infants and toddlers. Others have reported on early RRBs using the ADOS2 and ADOS-T, as well as other structured play tasks (Harrop et al., 2015); however, the RRB categories and exemplars have been predetermined, are potentially narrow, and do not allow for what children may show in other settings and at home. This study addressed these concerns by starting with a large set of behaviors observed and reported across settings for infants and toddlers diagnosed with ASD, matching them to categories that previous and current research has suggested, and creating a format to record those both observed by clinicians and reported by parents.

Objectives: To  1)  Review currently available instruments and methods of measuring RRBs in young children with ASD. 2) Describe development of an instrument for measuring RRBs in infants and toddlers.

Methods:  1) Eight screening and assessment instruments for RRBs in very young children with ASD were reviewed for frameworks and consistencies in defining RRBs. 2) An exhaustive list of RRBs was developed by the first author to create the Infant-Toddler RRB Inventory (IRBBI). Item categories, based on previous research using factor analysis and other construct validity strategies include: Repetitive Behavior (Motor and Visual Stereotypies, Repetitive Play), Insistence on Sameness, Restricted Interests/Areas of Unusual Ability, and Sensory Behaviors. The exemplars were drawn from both existing instruments and extensive clinical experience with infants through preschoolers with ASD. The checklist was refined through review by highly experienced evaluators (n=5), piloting during diagnostic evaluations with 48 young children, and coding the checklist using 75 previous evaluation reports.

Results:  The review of instruments showed more disagreement than agreement on what both the major categories of RRBs should be and what exemplars should operationalize them. The IRRBI was developed, piloted, and refined until it accommodated symptoms reported in clinical charts and during evaluations by experienced clinicians; the resulting categories, subcategories, and exemplars are presented.

Conclusions:  There is currently little agreement on how and what to measure as RRBs in infants and toddlers. A new instrument developed from a combination of research frameworks and clinical experience/observation is described.