F073 Clinimetric Analysis of the Problem Behaviors Assessment Short Form

<h3>Background</h3> The Problem Behaviors Assessment – Short Form (PBA-s) is a widely used measure of behavioral symptoms in HD research given its comprehensiveness and development for use with people with Huntington’s disease (pwHD). <h3>Aims</h3> We examined the factor structure, reliability, and distributional properties of the PBA-s in a large sample of pwHD within the context of the Huntington’s Disease Integrated Staging System (HD-ISS) framework. <h3>Methods</h3> Baseline PBA-s item total scores (frequency × severity) were analyzed from 14,111 participants in Enroll-HD. Participants were categorized as Stage 0/1 (n = 3,249; 23%), Stage 2 (n = 1,709; 12%), or Stage 3 (n = 9,153; 65%), following HD-ISS criteria. <h3>Results</h3> Rates of missing responses were low overall. Item total score distributions were significantly positively skewed in Stages 0/1 and 2. Skewness was also observed in Stage 3, but to a lesser extent. Internal consistency (α) of the PBA-s was moderate across groups (.73-.76), despite five items with weak corrected item-to-total correlations. Exploratory factor analysis (EFA) results differed by HD-ISS stage; in Stages 0/1 and 2, a three-factor model representing internalizing problems, externalizing problems, and cognitive control problems was identified and in Stage 3, a five-factor solution consisting of internalizing problems, suicidality, externalizing problems, cognitive dysfunction, and cognitive control problems was indicated. <h3>Conclusions</h3> Reliability of the PBA-s was adequate, however, we observed high rates of non-endorsement (i.e., item total scores = 0) and a variable factor structure with disease progression, suggesting the PBA-s may have limited utility for assessing behavioral symptoms across all disease stages.