Abstract: Objective To investigate the characteristics of sleep disorders in the elderly patients with different degrees of dementia. Methods A total of 752 elderly patients were enrolled from the Department of Geriatrics in the First Affiliated Hospital of Chongqing Medical University from 2016 to 2019. The patients were divided into normal cognition group (n=411) and dementia group (n=341) according to the score of Mini-Mental State Examination (MMSE).The dementia group was further divided into three groups as mild group (n=133, 21-26 scores), moderate group (n=167,10-20 scores) and severe group (n=41, 0-9 scores). The scores of Pittsburgh Sleep Qualit Index (PSQI) scales of the four groups were analyzed and compared. Results The total score of PSQI and the scores of sleep onset, sleep efficiency and day function disorder were significantly higher in dementia group than those in normal cognition group (P<0.05). The total score of PSQI was generally increased with the increase of the degree of dementia (P<0.05). The score of day function disorder in the the mild group was less than that in the other two groups (P<0.05), while the scores of sleep onset, sleep efficiency and day function disorder in severe group were higher than those in mild group and moderate group (P<0.05). Conclusions The patients with dementia present with sleep disorders which is associated with the degree of dementia. Day function is affected at the early stage of dementia, followed by sleep onset and sleep efficiency.

Key words: dementia, sleep disorders, cognitive impairment, degree of dementia, clinical characteristics, aged