Correlation between cognitive impairment and sleep structure in patients with early Alzheimer’s disease

Abstract

Objective: To analyze the characteristics of sleep structure and its correlation with cognitive impairment in early Alzheimer’s disease(AD) patients by assessing cognitive function and polysomnography. Methods: Eighty-eight elderly patients who underwent polysomnography were retrospectively analyzed and enrolled. According to the presence or absence of cognitive impairment, 39 patients were in the control group with a total score of montreal cognitive assessment (MoCA) score more than or equal to 26, 49 patients were in the AD group, with a total MoCA score less than 26 and a clinical dementia rating scale (CDR) score=0.5. Pearson correlation analysis and Spearman rank correlation analysis were used to explore the sleep structure characteristics of the early AD patients and its correlation with cognitive impairment. Results: Compared with the control group, the early AD group had statistically significant differences in MoCA, CDR, Hamilton Depression Scale (HAMD), micro perception index, non-rapid eye movement(NREM)/total sleep time (TST)%, N4 stage (N4)/TST% and REM /TST% (P<0.05). Multiple linear regression results showed that N/TST%, N4/TST% and rapid eye movement (REM)/TST% were the key risk factors of cognitive impairment in early AD patients (P<0.05). Conclusions: Patients with early AD have increased microarousal index and proportion of NREM sleep and N4 sleep, and decreased proportion of REM sleep, which are closely related to cognitive impairment. The proportion of NREM sleep, N4 sleep and REM sleep may be potential early warning indicators of cognitive impairment in early AD.

Keywords

• |alzheimer’s disease|cognitive function|sleep structure|risk factor