Circadian Rhythm, Cognition, and Mood Disorders in Huntington's Disease.

BACKGROUND: Sleep disturbances are an early and prominent feature of Huntington's disease (HD). OBJECTIVE: The current study investigated the relation between sleep quality impairment and cognitive and psychiatric symptoms in patients with HD. METHODS: Sleep quality, daytime sleepiness, and neurocognitive symptoms were assessed in 38 mutation carriers (23 premanifest and 15 early stage) and 38 age-and sex-matched controls using standardized questionnaires (the Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale, the cognitive section of the Unified Huntington's Disease Rating Scale, the Hospital Anxiety and Depression Scale, and the Irritability Scale). RESULTS: Compared to controls, HD patients had worse sleep quality (p = 0.016), which was associated with more severe cognitive impairment and higher anxiety, depression and irritability scores. These findings suggest that HD patients may have a delayed sleep phase, as indicated by the increased sleep onset latency (p = 0.019) and later wake-up time (0.013), which was associated with worse cognitive performance and greater depressive and anxiety symptoms. CONCLUSIONS: Our data provide further evidence for an association between sleep quality in HD and cognitive performance and psychiatric symptoms.