Sleep difficulties in children with Tourette syndrome and chronic tic disorders: a systematic review of characteristics and associated factors

Sleep difficulties are common in children and young people with Tourette syndrome and chronic tic disorders (TS/CTD). However, it is unclear whether sleep problems can be considered typical of the TS/CTD phenotype or whether they reflect concomitant factors such as individual patient characteristics (e.g. medication use), underlying neurodevelopmental disorders and/or co-occurring psychiatric symptoms. To help address this question, this review systematically explored types and frequency of sleep problems in children and young people with TS/CTD, while also examining the heterogeneity and methodological quality of studies. Psycinfo, Ovid Medline, Embase, and Web of Science databases were searched using a range of terms relating to tics, sleep and co-occurring psychopathology. Studies were considered that included a sample of children with TS/CTD (n > 5) for whom sleep difficulties were measured. Eighteen studies met criteria for inclusion in the review. Findings supported the high prevalence of sleep difficulties in children with TS/CTD, though estimates of sleep difficulties ranged from 9.7% to 80.4%. Twelve studies reported on other factors affecting sleep in this patient group including tic severity, comorbid psychopathological or neurodevelopmental disorders and medication use. Studies varied in terms of methodology, sample characteristics and research quality, but most concluded that children with TS/CTD experienced high levels of sleep difficulties with children with co-occurring anxiety most at risk. The current review highlights the need for further empirical investigation of sleep in children with TS/CTS, with a view to informing understanding and clinical management.

Sleep Disorders in Huntington's Disease

Huntington's chorea (Huntington's disease, HD) is a genetic disorder caused by autosomal dominant mutation, leading to progressive neurodegenerative changes in the central nervous system. Involuntary movements such as chorea occur typically in HD patients, accompanied by progressive cognitive and psychiatric disturbances. Other common symptoms of HD are circadian and sleep abnormalities, which are observed from the earliest stages of the disease or even before the occurrence of clinical symptoms. The most common sleep problems reported by HD patients include insomnia, difficulties in falling asleep, frequent nocturnal awakenings, and excessive daytime sleepiness. Also, specific changes in sleep architecture have been identified in HD. In this paper, we review studies on sleep and circadian rhythm disorders in HD. We outline findings concerning sleep patterns and disturbances of circadian rhythms in HD patients, as well as the role of psychiatric disorders and motor disorders in HD patients' sleep problems. We also discuss problems related to the different methods of diagnosing sleep disorders in HD. Furthermore, the adverse effects of medication used for the treatment of core HD symptoms as one of the sources of sleep disturbances in HD are emphasized. In conclusion, the diversity and complexity of the determinants of sleep and circadian rhythm disorders in HD are highlighted. Finally, the relevance of effective treatment to improve patients' functioning and quality of life as well as the potential relief of their cognitive and emotional symptoms is addressed.

[Sleep in neurodegenerative disorders]

Neurodegenerative disorders are a group of heterogeneous, progressive disorders of varying etiology that affect one or more systems. They occur predominantly at older age, during which the structure and amount of sleep undergo changes. Neurodegenerative processes cause structural changes of the sleep/wake generators in the brainstem which result in disorders such as daytime sleepiness, insomnia, sleep-related movement and breathing disturbances, and disorders of the circadian rhythms. Some sleep disorders manifest years before the onset of neurodegenerative disorders and may serve as predictors. Polysomnography shows sleep fragmentation, tonic or phasic movements of the extremities, alteration of respiratory muscles, reduced slow wave sleep, REM sleep absence or without muscle atonia, increased arousal or wake activity, epileptiform EEG activity, and changes in sleep-related breathing. Very frequently, REM sleep behaviour disorder is associated with neurodegenerative disorders. In this overview we present symptoms, pathophysiology, and polysomnographic findings of sleep disorders in prevalent neurodegenerative disorders.