The contribution of gender differences in motor, behavioral and cognitive features to functional capacity, independence and quality of life in patients with Huntington's disease

Introduction: Huntington's disease (HD) is a neurodegenerative autosomal dominant disorder affecting patients’ motor, behavioral and cognitive domains leading to total dependency for activities of daily life. This study compares whether gender differences in motor, cognitive and behavioral symptoms affect function and how functional impairment affects quality of life (QoL). Methods: We recruited 2191 subjects from the REGISTRY data base that provides personal data, HD age of onset, visit date, CAG mutation size, UHDRS and TFC scores from at least one visit. For 1166 participants SF-36 was also available. We calculated Spearman coefficients for correlations between particular symptomatic domains and functional scales, Fisher z-transform was used to test whether differences in correlations between genders were statistically significant. Simultaneous linear regression with least-square fit method was used to determine for how much variability in functional scales the particular symptomatic domains are responsible. ANOVA was used to look for QoL differences between TFC-stage based groups. Baseline statistics showed no significant differences between genders. Results: Motor, cognitive and behavioral domains contributed significantly to function and independence. The motor domain contributed most followed by the cognitive and to a lesser degree by the behavioral domain. Motor symptoms correlated more with functional ability and influenced function variability more in women than in men. The decline in functional abilities correlated significantly with QoL decline. Conclusion: Motor symptoms have highest impact on function in HD, moreover these symptoms affect female function and independence more than males. Results indicate that symptomatic treatment targeting motor symptoms is needed to improve HD function and QoL.