Development and Psychometric Evaluation of Gastrointestinal Symptom Measures in Autistic Children and Adults

PROJECT SUMMARY/ABSTRACT Gastrointestinal (GI) symptoms appear to be common and disabling in children and adults on the autism spectrum. Co-occurring GI symptoms are associated with physical, mental, and behavioral health issues, and lower quality of life. Yet, autistic children and adults face important barriers in terms of having their GI

symptoms recognized and therefore treated. The accurate and reliable measurement of GI symptoms is essential for the timely screening and diagnosis of GI conditions in both research and clinical contexts and for assessment of the safety and effectiveness of clinical interventions. Our prior work has demonstrated the

limitations of existing GI measures and/or the lack of information on psychometric performance of these measures in the autistic population. Limitations of prior measures include omission of items regarding mealtime behaviors/dietary patterns or non-verbal behavioral symptoms that may be indicators of GI distress, especially

in individuals who are minimally-speaking or have a cognitive disability. To address many of the problems with existing GI symptom measures in the autism literature, the PI of this application developed the Autism Gastrointestinal and Related Behaviors Inventory (GIRBI). The current version of the GIRBI is a 36-item multi-

dimensional symptom parent-report measure, designed to comprehensively characterize GI signs and symptoms in autistic children 6-17-years, in the context of research studies. However, only a parent-version of the pediatric measure currently exists. While some autistic individuals may have difficulties communicating

their internal GI experience to a caregiver, others can reliably report on their own symptoms. Additionally, a version of the GIRBI for adults does not presently exist. Therefore, the proposed research will focus on the development, refinement, and psychometric evaluation of four Autism GIRBI questionnaires (i.e., self-report

and parent-report versions of both the pediatric and the adult measures). To accomplish this, our research team will work with community participants to generate and evaluate initial scale items for self-report and parent-report versions of the pediatric and adult Autism GIRBI (Aim 1); and test and confirm structure,

reliability, measurement invariance, and construct and convergent validity in the whole analytic sample and within strata of age, intellectual disability, and language level (Aim 2). We will leverage existing resources (SPARK for Autism Research Match) to conduct a large-scale, online, nationwide study of GI symptoms in

7,000 autistic individuals 3-years of age and older (4,000 children, 3,000 adults). This proposed project is consistent with the R21 mechanism, by further developing, refining, and evaluating a set of novel measures that could have a major impact on GI research and ultimately support the health and well-being of autistic

children and adults.