Correlation between Sleep Time, Sleep Quality, and Emotional and Cognitive Function in the Elderly

Abstract

Background. To explore the relationship between sleep time, sleep quality, and emotional and cognitive function in the elderly. Methods. A total of 150 elderly patients over 65 years old who were admitted to our hospital from February 2019 to April 2021 were divided into a normal cognitive function group (Mini-Mental State Examination (MMSE) score: illiteracy, >17; primary school, >20; and middle school and above, >24; $N=86$ ) and cognitive impairment group (MMSE score: illiteracy, ≤17; primary school, ≤20; and middle school or above, ≤24; $N=64$ ). The sleep quality was evaluated by the Pittsburgh Sleep Quality Index (PSQI), and anxiety and depression were evaluated by Hamilton anxiety scale (HAMA) and Hamilton depression scale (HAMD), respectively. The cognitive function between the two groups was compared via the Montreal Cognitive Assessment (MoCA) score, visual spatial execution, and attention. Pearson correlation analysis was used to analyze the correlation between sleep quality, sleep time, and emotional and cognitive function. Results. In the comparison of sleep quality between the two groups, the total score of PSQI, sleep quality, falling asleep time, sleep time, and sleep efficiency of patients with cognitive impairment were higher than those of patients with normal cognitive function ( $P<0.05$ ). There was no significant difference in the scores of hypnotic use and daytime dysfunction between the two groups, but the scores of nocturnal sleep disorders and ESS in the cognitive impairment group were significantly higher than those in the normal group ( $P>0.05$ ). Compared between the two groups, the MoCA score, visual spatial execution, and attention in the cognitive impairment group were significantly lower than those in the normal group, and the difference was statistically significant ( $P<0.05$ ). The delayed recall in the cognitive impairment group was significantly higher than that in the control group ( $P<0.05$ ). There was no significant difference in orientation, naming, language, and abstract ability between the two groups ( $P>0.05$ ). The scores of HAMA and HAMD in the cognitive impairment group were significantly higher than those in the normal group. Pearson correlation analysis was used to analyze the correlation between sleep therapy, sleep time, and the score of cognitive scale. The results showed that PSQI was negatively correlated with MoCA and MMSE, and ESS was negatively correlated with MoCA and MMSE. Pearson correlation analysis results indicated that PSQI was positively correlated with HAMA and HAMD, while ESS was negatively correlated with HAMA and HAMD. Conclusion. The sleep quality and sleep time of elderly patients are positively correlated with their cognitive function. The worse the sleep quality is, the worse their cognitive function is and the more serious their anxiety and depression are. In the course of clinical therapeutics, more attention should be paid to the sleep quality of elderly.