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Sleep apnea severity in the REM phase is associated with verbal memory impairment
Last reviewed: 02.07.2025
A team of researchers led by the University of California, Irvine, has found a link between the frequency of rapid eye movement (REM) sleep apnea events and the degree of verbal memory impairment in older adults at risk for Alzheimer's disease. Verbal memory refers to the cognitive ability to store and recall information presented in the form of spoken words or written text, and is particularly vulnerable to Alzheimer's disease.
A study recently published in the journal Alzheimer's Research & Therapy found a specific correlation between the severity of sleep apnea — when breathing is interrupted during sleep — and cognitive decline. Higher scores during REM sleep compared to non-REM sleep were associated with worse memory.
"Our findings highlight specific memory-related features of sleep apnea, which is important because clinically, events that occur during REM sleep are often ignored or minimized," said study co-author Bryce Mander, an assistant professor of psychiatry and human behavior at UC Irvine.
"Most hours of sleep are spent in the non-REM phase, so overall average apnea severity scores may appear much lower than what is typically seen during REM sleep. This means that someone at risk may be misdiagnosed and underestimated because current assessment standards do not focus on apnea severity by sleep stage."
“What’s more,” said study co-author Ruth Benka, professor and chair of the department of psychiatry and behavioral medicine at Wake Forest University School of Medicine, “we found that women tend to have a higher proportion of REM sleep apnea compared to men, which could potentially contribute to their greater risk of developing Alzheimer’s disease.”
Scatter plots showing the relationship between (A) apnea-hypopnea index (AHI), (B) respiratory disturbance index (RDI), and (C) oxygen desaturation index (ODI) during REM sleep and overall RAVLT learning scores, controlling for age, sex, time between assessments, years of education, body mass index (BMI), and APOE4 status. Source: Alzheimer's Research & Therapy (2024). DOI: 10.1186/s13195-024-01446-3
The study involved 81 middle-aged and older adults from the Alzheimer’s Research Center in Wisconsin with elevated risk factors, 62% of whom were women. Participants underwent polysomnography — a comprehensive test that records brain waves, eye movements, muscle activity, blood oxygen levels, heart rate, and breathing during sleep — and verbal memory assessments. The results showed that REM apnea events are a critical factor in verbal memory decline, especially among people with a genetic predisposition to Alzheimer’s and those with a family history of the disease.
“Our findings highlight the complex relationships between sleep apnea, memory function, and Alzheimer’s disease risk,” Mander said. “Identifying and addressing REM-specific events is important for developing proactive, personalized assessment and treatment approaches that are tailored to individual sleep patterns.”