BACKGROUND
This study aimed to compare sleep architecture using the apnea-hypopnea index (AHI) and wake after sleep onset (WASO) in 150 participants aged 65 to 80 years with and without mild cognitive impairment (MCI), using polysomnography, actigraphy, and home sleep monitoring, and assessed cognitive performance using the Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA).
MATERIAL AND METHODS
A total of 150 participants were enrolled, including 75 patients with MCI and 75 cognitively healthy controls. Sleep architecture was evaluated using polysomnography, actigraphy, and home sleep monitoring systems. Cognitive function was assessed using MMSE and MoCA. Differences in sleep parameters, including AHI and WASO, were compared between groups. Pearson correlation and multiple linear regression analyses were performed to evaluate associations between sleep parameters and cognitive scores.
RESULTS
Compared with controls, the MCI group showed significantly reduced slow-wave sleep duration (22.6±14.6 vs 45.3±16.7 min; P<0.01), increased WASO (42.5±7.1% vs 29.1±5.9%; P<0.01), and higher AHI (18.7±6.2 vs 5.3±2.0; P<0.01). Slow-wave sleep duration was positively correlated with MMSE (r=0.72; P<0.01) and MoCA (r=0.68; P<0.01), whereas WASO was negatively correlated with MMSE (r=-0.65; P<0.01) and MoCA (r=-0.63; P<0.01). Multiple linear regression analysis demonstrated that slow-wave sleep duration remained independently associated with cognitive performance (β=0.41; P<0.001).
CONCLUSIONS
Alterations in sleep architecture, particularly reduced slow-wave sleep and increased nocturnal wakefulness, are significantly associated with poorer cognitive performance in older adults with MCI. Multi-channel sleep monitoring may facilitate early identification of sleep-related cognitive impairment and support clinical evaluation.

Keywords: Brain; Cognitive Dysfunction; Mild Cognitive Impairment; Multichannel Analysis; Sleep Apnea, Obstructive; Sleep Monitoring