Evaluation of Internal Construct Validity and Unidimensionality of the Brachial Assessment Tool, A Patient-Reported Outcome Measure for Brachial Plexus Injury

Abstract

Objective To evaluate the internal construct validity and dimensionality of a new patient-reported outcome measure for people with traumatic brachial plexus injury (BPI) based on the International Classification of Functioning, Disability and Health definition of activity. Design Cross-sectional study. Setting Outpatient clinics. Participants Adults (age range, 18–82y) with a traumatic BPI (N=106). Interventions There were 106 people with BPI who completed a 51-item 5-response questionnaire. Responses were analyzed in 4 phases (missing responses, item correlations, exploratory factor analysis, and Rasch analysis) to evaluate the properties of fit to the Rasch model, threshold response, local..