sundowning

1. (medicine, psychology, psychiatry) A state of agitation, confusion, or delirium, especially in patients suffering from Alzheimer's disease, which begins daily at nightfall and which is alleviated by daylight.Examples: "Impaired judgment and sundowning (increased confusion when orienting cues diminish at night) often makes it necessary to restrict and protect the delirious patient."; "Polysomnography and othersleep measures show sleep fragmentation with shortening of N3 sleep togetherwith excessive daytime sleepiness (EDS) and sundowning as the main findings in AD patients."Synonyms: nocturnal delirium, sundowner syndromeuncountable