Caregiver Meaningful Score Differences and Meaningful Score Regions for the Observer-Reported Communication Ability...

Area of Science:

• Neurology
• Developmental Pediatrics
• Clinical Psychology

Background:

• Angelman syndrome (AS) presents significant communication challenges.
• The Observer-Reported Communication Ability (ORCA) Measure is used to assess communication in AS.
• Establishing meaningful score differences and regions is crucial for interpreting ORCA Measure results.

Purpose of the Study:

• To develop a novel anchor-based method for estimating meaningful score differences (MSDs) and meaningful score regions (MSRs) for the ORCA Measure in individuals with AS.
• To provide preliminary MSD and MSR estimates for the ORCA Measure.

Main Methods:

• Utilized longitudinal data from the AS Natural History Study, including the ORCA Measure, Vineland Adaptive Behavior Scales-3, and Bayley Scales of Infant and Toddler Development-4.
• Employed a Delphi-based study for caregivers to provide MSDs and MSRs for Vineland-3 and Bayley-4.
• Applied mixed models with random intercepts to estimate ORCA MSDs and MSRs using correlations with Vineland-3/Bayley-4 derived thresholds.

Main Results:

• Data from 192 caregivers completing the ORCA Measure were analyzed.
• ORCA T-score MSRs were estimated for expressive, receptive, and pragmatic communication domains.
• Estimated ORCA MSDs ranged from 0.38-4.55 (based on Vineland-3) and 1.79-4.62 (based on Bayley-4).

Conclusions:

• A novel anchor-based methodology for deriving MSD and MSR thresholds for clinical outcome assessments was presented.
• The derived MSD and MSR estimates for the ORCA Measure are preliminary.
• The proposed methods offer a strategy for establishing meaningful change thresholds in rare disease populations.