Sundowning (dementia)

In medicine, sundowning is a syndrome involving the occurrence or increase of one or more abnormal behaviors in a circadian rhythm. Sundowning typically occurs during the late afternoon, evening, and night, hence the name. It occurs in persons with certain forms of dementia and psychosis, such as seen in Alzheimer's disease. Although not widely surveyed, sundowning is estimated to occur in 45% of persons diagnosed with Alzheimer's disease. A person who is experiencing sundowning may become abnormally demanding, suspicious, upset or disoriented, and see or hear things that are not there. Sundowning often co-occurs with wandering, and the combination of these two syndromes is an important contributing factor to an emergency situation: elopement at night. The cause is unknown.

Cause

Although the cause of sundowning is unknown, proposed causes include sensory deprivation from lower light conditions in the evening, and fatigue.Fact|date=August 2008 Alzheimer's disease alters the normal daily cycle of changes in body temperature, and sundowning appears to be related to delay of those changes that normally occur in the evening.cite journal
author=Volicer L, Harper DG, Manning BC, Goldstein R, Satlin A
title=Sundowning and circadian rhythms in Alzheimer's disease
journal=Am J Psychiatry
volume=158
issue=5
pages=704–11
year=2001
month=May
pmid=11329390
doi=
url=http://ajp.psychiatryonline.org/cgi/content/full/158/5/704] [cite journal
author=Satlin A, Volicer L, Stopa EG, Harper D
title=Circadian locomotor activity and core-body temperature rhythms in Alzheimer's disease
journal=Neurobiol. Aging
volume=16
issue=5
pages=765–71
year=1995
pmid=8532109
doi=]

Prognosis

In persons with early Alzheimer's disease, the presence of sundowning has been associated with faster decline in cognitive functions. [cite journal
author = Scarmeas N, Brandt J, Blacker D, "et al"
title = Disruptive behavior as a predictor in Alzheimer disease
journal = Arch. Neurol.
volume = 64
issue = 12
pages = 1755–61
year = 2007
month = December
pmid = 18071039
doi = 10.1001/archneur.64.12.1755
url =
issn = ]

Treatment

Behavioural disturbance is often treated with antipsychotic medication such as haloperidol, risperidone, or olanzapine. However, these have significant side effects.Fact|date=August 2008

In light of the temporal pattern of sundowning, some researchers hypothesize that modifying the person's environment to reinforce a normal circadian rhythm, and using supportive medication, may help to limit sundowning. [PMID 17323834] Medications that may be supportive include parasympathomimetic drugs and melatonin. A growing body of evidence, albeit mostly clinical and anecdotal, indicates that melatonin both reduces sundowning and slows the decline of cognitive function.cite journal
author = Cardinali DP, Brusco LI, Liberczuk C, Furio AM
title = The use of melatonin in Alzheimer's disease
journal = Neuro Endocrinol. Lett.
volume = 23 Suppl 1
issue =
pages = 20–3
year = 2002
month = April
pmid = 12019347
doi =
url =
issn = ] [cite journal
author = Srinivasan V, Pandi-Perumal SR, Cardinali DP, Poeggeler B, Hardeland R
title = Melatonin in Alzheimer's disease and other neurodegenerative disorders
journal = Behav Brain Funct
volume = 2
issue =
pages = 15
year = 2006
pmid = 16674804
pmc = 1483829
doi = 10.1186/1744-9081-2-15
url =
issn = ] [cite journal
author = Cardinali DP, Furio AM, Reyes MP
title = Clinical perspectives for the use of melatonin as a chronobiotic and cytoprotective agent
journal = Ann. N. Y. Acad. Sci.
volume = 1057
issue =
pages = 327–36
year = 2005
month = December
pmid = 16399904
doi = 10.1196/annals.1356.025
url =
issn = ]

References