Apnea During REM May Affect Brain Regions Related to Memory Consolidation

TUESDAY, May 13, 2025 (HealthDay News) — Greater obstructive sleep apnea (OSA)-related hypoxemia is associated with frontoparietal cerebrovascular pathology, which is linked to reduced medial temporal lobe (MTL) integrity and impaired sleep-dependent memory consolidation, according to a study published online May 7 in Neurology.

Destiny E. Berisha, from the University of California Irvine, and colleagues recruited cognitively unimpaired older adults for an observational, in-lab overnight polysomnography (PSG) study in which emotional mnemonic discrimination ability was examined before and after sleep. PSG-derived OSA variables included the apnea-hypopnea index, total arousal index, and minimum oxygen saturation. At an earlier time point, magnetic resonance imaging was used to assess global and lobar white matter hyperintensity (WMH) volumes and MTL structure (hippocampal volume; entorhinal cortex [ERC] thickness).

The study included 37 older adults. The researchers found that measures of hypoxemia significantly predicted global WMH volume, which was driven by hypoxemia severity during REM sleep; this also predicted frontal and parietal WMH burden. The relationship between REM sleep hypoxemia and ERC thickness was mediated indirectly by greater frontal WMH burden. In turn, reduced ERC thickness was associated with worse overnight mnemonic discrimination ability.

“Taken together, our findings may partially explain how obstructive sleep apnea contributes to cognitive decline associated with aging and Alzheimer”s disease through the degeneration of brain regions that support memory consolidation during sleep,” coauthor Bryce A. Mander, Ph.D., also from the University of California Irvine, said in a statement.

Several authors disclosed ties to the biopharmaceutical industry.

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