[Narcolepsy]

[Sleep and neurological diseases]

Knowledge of the physiology of sleep-wake regulation can contribute to an understanding of the pathophysiology and symptoms of neurological diseases and is helpful for initiating specific therapies for sleep-wake cycle stabilization. Based on historically important observations on the close relationship between sleep and neurological diseases, new insights and developments in selected neurological entities are presented in this review article.

[Sleep disorders in neurological diseases]

Sleep disorders can be diagnosed in approximately 15 % of the population and have been shown to increase with age. The relationship between sleep disorders and neurological disorders, however, is still insufficiently considered in the clinical practice. Sleep disorders can be an early symptom of the disease, such as the presence of rapid eye movement (REM) sleep behavior disorder (RBD) as an early indicator of neurodegeneration. Sleep disorders have also been shown to be a main symptom of various neurological syndromes, such as in restless legs syndrome (RLS), periodic limb movement disorder (PLMD) and narcolepsy. The international classification of sleep disorders 2nd edition (ICSD 2) describes the main diagnoses, insomnia, circadian rhythm sleep disorders, sleep-related breathing disorders and hypersomnia but all of these can also appear as symptoms in various neurological diseases. Parasomnias are largely considered a differential diagnosis to nocturnal epilepsy. In this review, the main sleep disorders are described with a particular focus on how they relate to neurological diseases; in particular, how they influence disease-related symptoms and how they affect the course of the disease.