REVIEW   

Minerva Psichiatrica 2017 March;58(1):26-39

DOI: 10.23736/S0391-1772.17.01923-9

Copyright © 2017 EDIZIONI MINERVA MEDICA

language: English

Sleep disturbances as prodromes, risk factors and treatment targets in dementia

Kazuo MISHIMA ✉

Department of Psychophysiology, National Institute of Mental Health, National Center of Neurology and Psychiatry, Tokyo, Japan

With population aging, the number of patients with dementia is increasing. Elderly people with dementia have an extremely high incidence of sleep disturbances accompanied by behavioral and psychological symptoms. Their sleep disturbances are largely refractory to treatment and impose a substantial care burden. Therefore, appropriate management of these disturbances is urgently necessary and clinically important. In individuals with dementia, irreversible organic brain damage is observed in brain areas where the nuclei and projections involved in the regulation of sleep and circadian rhythms are concentrated (e.g., brain stem, hypothalamus, and thalamus), causing serious nocturnal insomnia, hypersomnia, and irregular sleep-wake patterns. Whereas thalamic lesions result in a reduction in or the disappearance of sleep spindles, lesions in the pons are associated with the frequent appearance of rapid eye movement (REM) sleep disorders or delirium. In individuals with a broad lesion in the cerebral cortex, it is difficult to distinguish between sleep and wake stages because of the loss of vertex sharp waves and spindles as well as an overall increase in low amplitude slow waves. These individuals also have various factors that adversely affect sleep quality, such as pain and itchiness due to physical complications, comorbid mental disorders such as mood disorder, as well as side effects of medications, reduced physical activity, increased afternoon nap time, social isolation, and anxiety. The differential diagnosis of sleep disorders is also difficult in patients with dementia because of the involvement of various sleep disorders such as delirium, insomnia disorder, sleep-related breathing and movement disorders, parasomnias, and circadian rhythm sleep-wake disorders. Because dementia is associated with poor action of hypnotic/sedative psychotropic drugs and a high incidence of drug side effects, it is necessary to effectively incorporate sleep hygiene and non-pharmacological therapy (e.g. chronotherapy) while taking into account the risk-benefit ratio.

KEY WORDS: Dementia - Sleep disorders - Circadian rhythm - Alzheimer disease - Lewy body disease - Chronotherapy