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Sundowning: severe dementia and bringing on the night

Larry Brash lbrash at ozemail.com.au
Fri Mar 28 05:06:04 EST 2003

"John H." wrote:
> Recently a friend of mine starting working in a dementia ward for severely
> demented individuals. She was advised by other staff that to be careful
> after sundown because many of the patients become violent and extremely
> difficult to control. I'm mystified by this, just wondering if anyone else
> has noticed this in severe dementia and\or if they have any ideas re the
> same. I did note a few months ago a report stating that bright light therapy
> proved beneficial for some dementia patients but this doesn't account for
> the above observations.

This phenomenon occurs in delirium, e.g. post-op delirium, DTs etc.
There is always a clear worsening in the evening. Delirious people seem
almost lucid in the daytime and off the planet at night. 15-20% of
general hospital patients are delirious at any point in time.

It seem to be due to the reduced sensory (mainly visual) input that
occurs at sunset. The degree of reduction in light between full day
light and a well light room at night is actually massive (at least
hundred fold difference). A dimly light room is the worse. A totally
dark room is actually better.

Of course, the intact brain copes with this easily, but the impaired
brain (i.e. delirium) does not cope and starts to experience sensory
distortions (illusions) and hallucinations (mainly visual). Disturbed
behaviour may then result in response to this.

Dementia patients, who are in care, are usually well advanced and
experience delirium very easily. Urinary tract infection, constipation
being some of the more common mundane triggers for this.

Delirium literally means "out of (de) the furrow (lirium)" [Latin].
Dementia means "out of one's mind" and originally referred more to
psychosis than organic impairment.

I don't know if Light Therapy would work but it is an interesting thought.

Larry Brash

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