Using the Bayley-4 and Vineland-3 in Angelman syndrome: barriers, solutions, and challenging items.

Objective: The Bayley Scales of Infant and Toddler Development- 4th Edition (Bayley-4) and Vineland Adaptive Behavior Scales - 3rd Edition (Vineland-3) are outcome measures often considered as primary endpoints in clinical trials for Angelman syndrome (AS). We explored barriers encountered when administering these instruments to individuals with AS and associated guidance for their use in trials and research studies.

Methods: We interviewed nine clinicians who have administered the Bayley-4 and/or the Vineland-3 to individuals with AS and analyzed their transcripts using a quasi-deductive analysis approach.

Results: Barriers to administering the Bayley-4 included participant's lack of interest, overexcitement, emotional impact on caregiver, the mental workload of administering the Bayley-4, and environmental factors (e.g., administration setting). Barriers to administering the Vineland-3 included determining the most appropriate start point, emotional impact on caregiver, distractions, conflicting answers from two caregivers, and the mental workload of administering the Vineland-3. Participants provided potential solutions to each barrier. Lastly, we identified overarching item-level concerns for both the Bayley-4 (i.e., administration challenges, items not aligned with abilities) and the Vineland-3 (i.e., misalignment of assessment criteria and condition characteristics, limitations in observation and contextual understanding, requires specialized training).

Conclusion: Clinical trials often rely on the Bayley-4 and Vineland-3 assessments as outcome measures, yet our identified barriers threaten their validity. The associated solutions provide a path forward for improving administration of the Bayley-4 and Vineland-3 in clinical practice, research, and future trials focused on individuals with AS and other intellectual and developmental disabilities.