Higher sleep apnea severity related to lower medial temporal lobe subregion volumes in amyloid-positive, but not amyloid-negative, individuals.
Sleep-disordered breathing (SDB) is associated with medial temporal lobe atrophy in cognitively unimpaired amyloid-positive older adults, according to a study published online May 31 in Neurology.
Claire André, Ph.D., from Normandie University in France, and colleagues examined the impact of amyloid positivity on the associations between SDB severity, medial temporal lobe subregions, and episodic memory performance in cognitively unimpaired older adults using data from the Age-Well randomized controlled trial. Participants aged older than 65 years and free of neurological, psychiatric, or chronic medical disease were recruited. They completed a neuropsychological evaluation, in-home polysomnography, a Florbetapir positron emission tomography, and magnetic resonance imaging. A total of 122 older adults were included in baseline analyses, and 111 were included at follow-up (mean, 20.66 months).
The researchers found interactions for the apnea-hypopnea index with entorhinal, whole hippocampal, subiculum, Cornu Ammonis (CA)1, and dentate gyrus volumes, with higher sleep apnea severity related to lower medial temporal lobe subregion volumes in amyloid-positive, but not amyloid-negative, individuals. Lower whole hippocampal and CA1 volumes at baseline were associated with worse episodic memory performance at follow-up in the whole cohort.
“We found that people with amyloid plaques who had more severe sleep apneas also were more likely to have lower volumes in the medial temporal lobe area of the brain, including the hippocampus, which plays a role in memory and Alzheimer’s disease,” a coauthor said in a statement.