Behavior and Sensory Interests Questionnaire: Validation in a sample of children with autism spectrum disorder and other developmental disability.

Repetitive behaviors, restricted interests and other unusual sensory behaviors often significantly impact the lives of many individuals with developmental disabilities, including Autism Spectrum Disorder (ASD). Identifying specific patterns of atypical behaviors across different disorders allows for improved specificity of diagnoses, monitoring response to treatment and elucidating the genetic and neurobiological underpinnings of these disorders. The Behavior and Sensory Interests Questionnaire (BSIQ) is a newly designed, continuous dimensional instrument that comprehensively assesses the type, frequency, intensity, age of onset, and duration of these behaviors. The BSIQ takes 15-40 min to administer to a caregiver in an interview format. Using a large sample of children with either ASD, intellectual disabilities or who were typically developing, the construct validity of the BSIQ was confirmed using a series of multi-group confirmatory factor analysis models. Configural and metric invariance were satisfied, but not scalar invariance, as expected. The BSIQ showed acceptable internal consistency, excellent inter-rater reliability and excellent test-retest reliability.