Sleep disturbances as early markers of neurodegenerative disease - Poul Jennum

Sleep disturbances are increasingly recognized as early markers of neurodegenerative diseases. Alterations in sleep architecture, circadian rhythms, and sleep–wake regulation may appear years before the onset of classical neurological symptoms. Disorders such as insomnia, excessive daytime sleepiness, and especially rapid eye movement (REM) sleep behavior disorder (RBD) are strongly associated with conditions like Parkinson’s disease, dementia with Lewy bodies, and Alzheimer’s disease. In particular, idiopathic RBD has been identified as a prodromal indicator of synucleinopathies, with many affected individuals later developing neurodegenerative disorders. Understanding these early sleep abnormalities may improve early diagnosis, enable risk stratification, and support the development of preventive or disease-modifying interventions.