Sleep disorders in Wilson's disease

Background: Wilson’s disease (WD) is an autosomal recessive inherited disease with copper accumulation; neurodegeneration is associated with dopaminergic deficit. The aim of the study is to verify sleep co‐morbidity by questionnaire and objective sleep examinations (polysomnography, multiple sleep latency test). Methods: Fifty‐five patients with WD (22 hepatic, 28 neurological, five asymptomatic form) and 55 age‐ and sex‐matched control subjects completed a questionnaire concerning their sleep habits, sleep co‐morbidity, Epworth sleepiness scale (ESS), and answered screening questions for rapid eye movement (REM) behaviour disorder (RBD‐SQ). Twenty‐four patients with WD and control subjects underwent polysomnographic examination. Results: Unlike the controls, patients with WD were more prone to daytime napping accompanied by tiredness and excessive daytime sleepiness, cataplexy‐like episodes and poor nocturnal sleep. Their mean ESS as well as RBD‐SQ was higher than that of the controls. Total sleep time was lower, accompanied by decreased sleep efficiency and increased wakefulness. Patients with WD had lower latency of stage 1 and stage 2 of non‐rapid eye movement (NREM) sleep and less amount of NREM sleep stage 2. One‐third of the patients with WD were found to have short or borderline multiple sleep latency test (MSLT) values independent of nocturnal pathology (sleep apnoea, periodic leg movements and/or restless leg syndrome). Conclusions: Patients with WD often suffer from sleep disturbances (regardless of the clinical form). The spectrum of sleep/wake symptoms raises the suspicion that altered REM sleep function may also be involved.