PTOTSLPCohortJournal of intellectual disability research : JIDR2025

Criterion Validity, Scalability and Stability of Scoring on the Bayley-III in Children With Angelman Syndrome.

Maartje Ten Hooven-Radstaake, Sabine Herrman-Mous, Anjali Sadhwani and 10 others

PMID 41083159

WHAT IT FOUND

The Bayley-III works well for tracking groups of children with Angelman syndrome but is unstable for individual patients.

Scores often fluctuate due to attention and motor issues, meaning a single test result may not reflect true ability or change.

Key findings

01Motor difficulties did not significantly distort cognitive scale scores, but speech difficulties invalidated the expressive language scale.

02Individual scoring is unstable, with many children showing items they passed earlier failing later, particularly on the cognitive scale.

03The test does not accept augmentative and alternative communication (AAC) as a response mode, limiting its ability to capture true expressive ability.

STILL TO COME

How it was doneWhat they foundWhat it means for PTsWhat it means for OTsWhat it means for SLPs

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What it does not show

The study used the Bayley-III out of its normed age range (0-42 months) for many children, which may affect validity. Assessors differed between visits, and factors like illness, medication changes, or non-convulsive seizures were not controlled for. Use of AAC and type of schooling were not controlled, which may have influenced developmental trajectories. Children with the deletion subtype were younger than those with non-deletion subtypes, potentially confounding comparisons.

Declared interests

The authors declared no conflicts of interest. The study was part of the Natural History Study (NCT00296764), funded by the Angelman Syndrome Foundation and other sources.

The easy way to misread this

Do not interpret a change in a single Bayley-III score for one child as true developmental progress or regression. The study found that individual scores are unstable, with many children failing items they previously passed due to attention or fatigue, not loss of skill.

Summarised by AI from the full paper, without a clinician reviewing it. Check it against the source before it changes what you do. Read it on PubMed →