Modifying the Bayley Test to Benefit Clinical Trials in Angelman Syndrome

Quick Overview

Anjali Sadhwani and Anne Wheeler presented their work on modifying the Bayley test for children with Angelman Syndrome at the 2017 FAST Science Summit. They discussed the limitations of current tests and the need for a sensitive measure of cognitive development in clinical trials. They outlined three initiatives they are working on: analyzing item responses to identify patterns, standardizing accommodations for children with Angelman Syndrome, and piloting the Bayley Special Needs Edition. They emphasized the importance of developing a valid and reliable measure that can accurately assess the progress and potential of children with Angelman Syndrome.


Anjali Sadhwani and Dr. Anne Wheeler are passionate about helping children with Angelman Syndrome. They have been working on modifying different scales for clinical trials and testing purposes to showcase the potential and brilliance of these children. In this talk, they will discuss their work with the ABOM (Biomarker and Outcome Measure Consortium) and their efforts to improve the Bayley test for assessing children with Angelman Syndrome.

Why Measure Development and Cognition?

The first part of their talk focused on the importance of measuring development and cognition in children with Angelman Syndrome. They explained that assessments help with clinical diagnoses, understanding a child’s zone of development for effective interventions, qualifying children for specific services, and identifying progress in specific skills. They emphasized that tests are not the sole indicator of a child’s abilities and should be interpreted in context.

Problems with IQ Tests

The authors acknowledged the challenges of using IQ tests for children with Angelman Syndrome. These tests require certain basic skills, such as following instructions, matching items, and providing verbal responses, which can be difficult for these children. They also mentioned that most IQ tests do not provide standardized scores for older children with Angelman Syndrome.

The Bayley Scale of Early Development

The authors explained that they have chosen the Bayley Scale of Early Development as their primary measure because it is widely used, well-validated, sensitive to change, and FDA-approved. They highlighted that the Bayley does not heavily rely on verbal skills or motor planning, making it more suitable for children with Angelman Syndrome. However, they also acknowledged that the Bayley has limitations, such as containing developmentally inappropriate items for older children and not reflecting day-to-day functioning.

Initiatives to Improve the Bayley Test

The authors outlined three initiatives they are working on to improve the Bayley test for children with Angelman Syndrome:

  1. Item Level Analysis: They are pooling data from three sites to identify patterns of responding in individuals with Angelman Syndrome and to understand the stability and consistency of scores over time.
  2. Standardizing Accommodations: They are developing guidelines for standardized accommodations to address motor and verbal challenges faced by children with Angelman Syndrome during the test administration. The goal is to create a manual of standardization and disseminate it to all research studies and clinics working with individuals with Angelman Syndrome.
  3. Piloting the Bayley Special Needs Edition: They are piloting the Bayley Special Needs Edition, which includes adaptations such as using different materials, enlarging sizes, and changing colors to better suit the needs of children with Angelman Syndrome. This version has shown good validity in previous research.


The authors concluded by acknowledging that there is no perfect tool for assessing the development of children with Angelman Syndrome. However, they are hopeful that with their accommodations, adaptations, and analysis, they can develop a valid, reliable, and effective measure for clinical trials. They expressed gratitude to the ABOM, FAST, and Angelman for providing funding for their work.

Talk details

  • Title: Modifying the Bayley test to benefit clinical trials in Angelman syndrome
  • Author(s): Anjali Sadhwani, Anne Wheeler
  • Author(s)’ affiliation: Boston’s Children Hospital; University of North Carolina at Chapel Hill
  • Publication date: 2017-12-22
  • Collection: 2017 FAST Science Summit