Obstructive Sleep Apnea Events During REM Sleep Impacts Verbal Memory in Those at Risk for AD

The severity of obstructive sleep apnea (OSA) events during rapid eye movement (REM) sleep is associated with worse verbal memory impairment in older adults at risk for Alzheimer disease (AD), according to a study published in the journal Alzheimer’s Research & Therapy.

“Our findings identified the specific features of sleep apnea that are associated with memory, which is important because, clinically, events occurring during REM sleep are often overlooked or minimized,” said co-corresponding author Bryce Mander, PhD, associate professor of psychiatry and human behavior at the University of California, Irvine. “Most hours of sleep are non-REM, so the overall averages of apnea severity can look much lower than what is typically observed during REM sleep. This means that someone at risk can be misdiagnosed and undertreated because current evaluation standards are not focused on sleep-stage-specific apnea severity.”

The study included 81 middle- and older-age adults from the Wisconsin Alzheimer Disease Research Center. Among them, 32% were APOE carriers and 70% had a parental history of AD. Participants underwent polysomnography, including OSA assessment in total, non-REM, and REM sleep. REM to non-REM ratios of OSA features were also calculated.

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According to the study, apnea–hypopnea index, respiratory disturbance index, and oxyhemoglobin desaturation index during REM sleep were negatively linked with total learning and long-delay recall performance on the Rey Auditory Verbal Learning Test. Additionally, the study found that more apnea–hypopnea index, respiratory disturbance index, and oxyhemoglobin desaturation index events in REM sleep, compared with non-REM sleep, were associated with worse total learning and recall.

The findings were particularly applicable to adults older than 60 years and those with a genetic risk for and a parental history of AD. 

“Our findings highlight the intricate relationship among sleep apnea, memory function, and Alzheimer risk,” said Dr Mander. “Identifying and addressing REM-specific events are crucial for developing proactive, personalized approaches to assessment and treatment that are tailored to individual sleep patterns.”

References

Lui KK, Dave A, Sprecher KE, et al. Older adults at greater risk for Alzheimer's disease show stronger associations between sleep apnea severity in REM sleep and verbal memory. Alzheimers Res Ther. 2024;16(1):102. doi:10.1186/s13195-024-01446-3

UC Irvine-led study links sleep apnea severity during REM stage to verbal memory decline. News release. University of California – Irvine; May 14, 2024. Accessed May 17, 2024.