Baby Observational Selective Control AppRaisal (BabyOSCAR): Construct validity and test performance

Area of Science:

• Pediatric Physical Therapy
• Developmental Pediatrics
• Rehabilitation Science

Background:

• Assessing independent joint motion in infants with cerebral palsy (CP) is crucial for early intervention.
• The Baby Observational Selective Control AppRaisal (BabyOSCAR) is a novel assessment tool designed for this purpose.
• Evaluating the psychometric properties of new clinical assessments is essential for their reliable application.

Purpose of the Study:

• To investigate the construct validity of the BabyOSCAR assessment.
• To determine the reliability and item properties of BabyOSCAR using Rasch analysis.
• To confirm BabyOSCAR's suitability for assessing infants with and without CP.

Main Methods:

• BabyOSCAR was administered to 75 infants (45 with CP, 30 without).
• Rasch analysis and classical test theory were employed to evaluate item fit, unidimensionality, reliability, and differential item functioning.
• Cronbach's alpha was calculated to assess internal consistency.

Main Results:

• The BabyOSCAR assessment demonstrated good fit to the Rasch model, indicating sound psychometric properties.
• Unidimensionality analysis suggested two distinct dimensions: arm and leg movements.
• Reliability indices for item calibration (0.84-0.86) and infant measures (0.82-0.91) were strong, with Cronbach's alpha ranging from 0.90 to 0.95.

Conclusions:

• The BabyOSCAR assessment exhibits excellent construct validity and reliability for evaluating independent joint motion in infants.
• The tool effectively differentiates between three infant ability levels and provides an interval-level measurement scale.
• Separate arm and leg subscales are supported, offering a comprehensive assessment of motor skills.