The causes of sundowning in dementia patients aren't well understood, according to the Alzheimer's Association. However, disturbances to a person's circadian rhythm, the inability to separate waking reality from dreams during sleep and fear and confusion sparked by lengthening evening shadows and strange sounds contribute to the phenomenon.
Physical discomfort from pain, significant constipation and infection can also increase the risk of sundowning, notes WebMD. Poor nourishment and interactions between multiple medications may also drive the development of this behavior, as can a noisy or otherwise disruptive sleeping environment.
Keeping to a predictable routine, maintaining a familiar environment and reducing the sources of upsetting stimulation may help reduce troubling behavior, according to Mayo Clinic. Limiting caffeine, sugar and daytime napping while encouraging daytime activity may also help to promote a more normal sleep-wake cycle.
Sundowning is collection of behaviors exhibited by up to 20 percent of all people with dementia during the late afternoon and early evening hours of the day, explains WebMD. During this time, some people with dementia exhibit increasing confusion, agitation and restlessness. They may become more combative, may try to wander and not sleep well. This behavior often peaks during the middle stages of dementia and lessens as the disease progresses.