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Sleep disorders in people with dementia

Review of Karageorgiou E, Walsh C, Yaffe K et al (2017) Sleep disorders and dementia: from basic mechanisms to clinical decisions. Psychiatric Annals. 47, 5, 227-228.

Review of Karageorgiou E, Walsh C, Yaffe K et al (2017) Sleep disorders and dementia: from basic mechanisms to clinical decisions. Psychiatric Annals. 47, 5, 227-228.

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Sleep disorders often precede cognitive impairment by many years. This is partly because some degenerative diseases originate in the hypothalamus and brain stem, which means fragmented sleep, daytime napping and sleep-phase disorders are early signs of these diseases. However, recent research indicates that amyloid proteins are removed from the brain during deep sleep so poor sleep can increase the amyloid plaques seen in Alzheimer’s disease. It is also known that sleep-disordered breathing can lead to periods of hypoxia, increasing vascular dementia.

As dementia progresses, production of the sleep-promoting hormone, melatonin, fluctuates across the day, leading to alternating sleep and wakefulness. Secretion of melatonin while a patient is still awake is a possible explanation for ‘sundowning’ with increased confusion because cognitive states associated with sleep intrude into wakefulness. The opposite also occurs with behaviours such as talking when asleep. Studies of brainwaves of patients with Alzheimer’s disease show a ‘twilight zone’ in which they are never deeply asleep and never fully alert.

Sleep should be promoted through the maintenance of a regular schedule; avoiding stimulants, such as coffee, after 2pm; and avoiding heavy meals and alcohol close to bedtime. Exercise and sunlight during the day are helpful, as are warm showers 1-2 hours before bed and sleeping in a slightly cool room. In terms of medication, trazodone increases sleep duration without cognitive deficits the next day. Benzodiazepines should be avoided because they increase daytime confusion. Cholinesterase inhibitors, frequently prescribed in dementia, should be given in the morning because they reduce deep sleep and promote vivid dreams.


Reviewed by Ruth Sander, independent consultant in care of the older person

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