Reliability and factor structure of the Short Problem Behaviors Assessment for Huntington's disease (PBA-s) in the TRACK-HD and REGISTRY studies.

The authors report the inter-rater reliability and factor structure of the Short Problem Behaviors Assessment (PBA-s), a semistructured interview to measure severity and frequency of behavioral problems in Huntington's disease. Video recordings of 410 PBA-s interviews were rescored by an independent rater, and Cohen's kappa calculated to assess inter-rater reliability. The mean kappa was 0.74 for severity and 0.76 for frequency scores, whereas weighted kappa (allowing scores to differ by 1 point) was 0.94 for severity and 0.92 for frequency scores. The results of factor analysis were consistent with previous studies using other measures. The authors conclude that the PBA-s is a reliable measure.

Illness perceptions, coping styles and psychological distress in adults with Huntington's disease.

Individuals with a diagnosis of Huntington's disease (HD) have been shown to experience various emotional, behavioural and psychosocial consequences. The current study employs Leventhal's self-regulation model to explore the biopsychosocial factors related to psychological distress in people with HD, and further examine the relationship between illness perceptions, coping and psychological distress. Eighty-seven people diagnosed with HD completed the Illness Perceptions Questionnaire-Revised adapted for the population. Participants also completed self-report measures of coping and psychological distress. Data were also collected on clinical and demographic variables previously found to be associated with psychological distress. Hierarchical multiple regression analyses demonstrated that illness perceptions of identity, treatment control and timeline cyclical were predictors of anxiety while illness perceptions of identity and perceiving the cause to be related to chance were found to be significant positive predictors of depression. The coping strategy of seeking instrumental support also contributed to scores of depression, and self-report clinical variables of pain and role functioning related to physical difficulties predicted anxiety and depression, respectively. The findings suggest that illness perceptions play a significant role in psychological distress experienced by people with HD. Consequently, a focus on interventions which might change illness perceptions, and perhaps then reduce psychological distress, would be useful for future research.