Development of the Angelman syndrome video assessment: quantifying meaningful change.

BACKGROUND: The Angelman Syndrome Video Assessment (ASVA) is a clinician-reported outcome measure that was developed to assess the functional ability of individuals with Angelman Syndrome (AS) in a familiar environment. Through standardized tasks and associated scorecards, clinicians assess four meaningful domains of functioning: communication, activities of daily living (ADLs, which include fine motor skills), gross motor, and external direction (i.e., the ability to follow directions) via scorecards with pre-established criteria. The aim of this project was to develop and refine the scorecards using a rigorous process in partnership with caregivers, clinicians, and researchers in the AS community. METHODS: The Scorecard development process included four phases: (1) video source material study, (2) identification of initial scoring criteria, (3) scorecard drafts, and (4) two (Caregiver and Clinician panel and PT panel) two-round modified Delphi processes to reach consensus. All phases were conducted remotely except for Round 2 of the Caregiver and Clinician Delphi Panel, which was conducted in person. Votes were held for each scoring criterion and consensus was defined as ≥ 70% agreement. RESULTS: In the communication, ADLs, and external direction domains, scorecard criteria reached 80 to 100% agreement among caregivers (n = 8) and clinicians (n = 2), resulting in a total of 218 scoring criteria and levels across 10 tasks. In the gross motor domain, scorecard criteria reached 100% agreement among physical therapists (n = 8) with a total of 347 scoring criteria and levels across 8 tasks. CONCLUSIONS: The ASVA was developed with insights from the AS community, including caregivers of individuals with AS, clinicians, and researchers. The ASVA is a novel, disease-specific, clinician-reported outcome measure that uses standardized video capture and scorecards that were developed through a rigorous process, resulting in well-developed criteria to quantify meaningful changes of function in individuals with AS in communication, ADLs, gross motor function, and external direction.