Autonomic Dysfunction in Hypersomnia

Purpose of Review This article provides a comprehensive overview of the literature on autonomic dysfunctions in central disorders of hypersomnolence: narcolepsy type 1 and type 2, idiopathic hypersomnia, and the Kleine-Levin syndrome. Clinical implications are discussed. Recent Findings The interactions between the autonomic nervous system and central disorders of hypersomnolence are complex. Patients affected with these rare sleep diseases often report autonomic symptoms. Recent studies systematically assessed these symptoms in large cohorts of well-characterized patients, and some studies objectified autonomic disturbances during wakefulness and sleep, mostly with indirect measures. Summary Autonomic impairment is frequent in central disorders of hypersomnolence, and the pathophysiological mechanisms underlying this dysfunction are not yet fully elucidated. In narcolepsy type 1, the deficiency in orexin/hypocretin neurons could play a role, and that has been confirmed in animal models of the disease. Management of central disorders of hypersomnolence is nowadays only symptomatic, with wake-promoting agents, often psychostimulants. Further research is needed to understand the consequences of these medications on the autonomic nervous system and their possible relation to long-term cardiovascular risk.