Key points are not available for this paper at this time.
Abstract Introduction Aging is often accompanied by sleep disturbances and cognitive impairment. However, the relationship between specific sleep parameters and cognitive decline remains unclear. This study investigates the longitudinal association of objective measures of sleep disruption including sleep architecture and hypoxia in relation to levels of cognitive function, as ascertained by the Montreal Cognitive Assessment (MoCA) scores. We hypothesize that certain sleep characteristics, including degree of hypoxia, significantly influence cognitive aging trajectories. Methods This study involved an analysis of patients with mild cognitive impairment (MCI) in Alzheimer's Disease (AD) between 2011 and 2023. The main predictor variables were various sleep study parameters, including the Apnea-Hypopnea Index (AHI), mean SpO2 levels, arousal index, and sleep stage percentages. Covariates in the analysis were sex and age. To assess cognitive function, we used the MoCA which is a comprehensive tool scoring (range 0-30; assesses visuospatial, executive function, memory, attention, etc.), where higher scores indicate better cognitive function. Our statistical approach involved multivariable linear mixed models, adjusted for the covariates, to evaluate the MoCA scores over time (-1 to +3 years from sleep study) with sleep parameters. Results The study included 275 patients with MCI-AD, across 816 observations with an average age of 69.6 ± 8.7 years. Among them, 65.1% were male, 85.1% white with median 16 (IQR:12-17) years of education. Over 21 months mean follow-up among those with repeat MoCA testing, scores declined by -0.06 points/month (95% CI -0.08, -0.04; p 0.001). A significant finding was the association of higher mean oxygen saturation with a more rapid cognitive decline, at -0.10 points per month for each 1% increase in oxygen levels (95% CI -0.19, -0.01; p=0.033). Other sleep measures including sleep architecture showed no significant associations with MoCA score changes. Conclusion This study sheds light on the intricate relationship between sleep quality, oxygen saturation, and cognitive aging. Our findings reveal a novel association between higher sleep-related oxygen saturation levels and accelerated cognitive decline in MCI-AD patients is biologically plausible given reports of altered EEG activity with task-evoked potentials in response to hyperoxia. Future investigation should clarify effects of hyperoxia on neural activity and oxidative stress in neurodegeneration. Support (if any)
Khazaie et al. (Sat,) studied this question.