Sleep in Alzheimer's disease and the sundown syndrome

Neurology. 1992 Jul;42(7 Suppl 6):83-93; discussion 93-4.


Approximately 10% of the elderly population have a dementing illness that manifests itself clinically by significant cognitive deficits. Half of these individuals have Alzheimer's disease (AD), a progressive degeneration of cortical and subcortical neurons. Disturbances of sleep and the sleep-wake rhythm are a common clinical observation in AD, as is "sundowning," the onset or exacerbation of delirium during the evening or night. Here we describe the neurologic basis for the disturbed sleep of patients with AD, the phenomenology of that disturbance, and its implications. Further, we describe the prevalence, possible causes, and treatment of sundowning.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.
  • Review

MeSH terms

  • Aged
  • Aged, 80 and over
  • Alzheimer Disease / physiopathology*
  • Alzheimer Disease / psychology
  • Delirium / physiopathology*
  • Delirium / psychology
  • Female
  • Humans
  • Male
  • Psychiatric Status Rating Scales
  • Sleep / physiology*
  • Syndrome
  • Wakefulness / physiology