Development and Validation of a Brief Fall Questionnaire ( FALL ‐ HD ) for Patients with Huntington's Disease

BACKGROUND: Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder caused by a mutation in the huntingtin gene on chromosome 4, leading to progressive cognitive decline, motor impairment, and functional disability. Falls represent the leading cause of nursing home placement in HD. Despite the significant clinical implications, validated instruments for fall assessment, including fall frequency, are lacking in HD. OBJECTIVES: To construct and evaluate the psychometric properties of a questionnaire for assessing fall status, including fall frequency, in ambulatory patients with HD. METHODS: We developed a concise 3-item questionnaire based on a comprehensive literature review and initial pilot study. We evaluated the responses of 107 HD gene-positive participants in the main study. Reliability (test-retest, internal consistency) and validity (criterion, convergent, divergent) were assessed. RESULTS: The FALL-HD Questionnaire demonstrated reliability with a test-retest correlation coefficient of r = 0.85 and an internal consistency (Cronbach's alpha) of 0.71. Convergent validity was established using Spearman correlations with the UHDRS Total Motor Score (r = 0.75, p < 0.001), Total Maximal Chorea Score (r = 0.65, p < 0.001), and Total Functional Capacity (r = 0.53, p < 0.001), in addition to Total Body Sway (TBS, r = 0.62, p < 0.001), a measure of postural stability from the BTrackS™ Balance System. Using ROC curves, the FALL-HD outperformed (AUC = 0.90) existing measures of balance such as the Total Body Sway (AUC = 0.85), Chair Sit-to-Stand Test (AUC = 0.65) and Timed Up and Go (AUC = 0.58). CONCLUSIONS: The FALL-HD is a brief, valid and reliable, screening instrument of fall status, including fall frequency, in ambulatory patients with HD.