Sleep-disordered breathing in amyloid-positive elderly is associated with brain volume

Data that sleep-disordered breathing (SDB) was associated with medial temporal lobe volume in amyloid-positive older adults without cognitive impairment agewell A randomized trial showed.

In cognitively intact adults with amyloid plaques, greater severity of sleep apnea is associated with gray matter atrophy in areas affected early pathologically in Alzheimer’s disease, France. Dr. Geraldine Rausch of the University of Normandy in New York and co-authors reported.

Sleep apnea severity based on the Apnea-Hypopnea Index (AHI) was associated with decreased volume of the medial temporal lobe subregion in amyloid-positive, but not amyloid-negative, individuals. , the researchers wrote in their paper. neurology. Specifically, AHI and amyloid status significantly influence the amount of:

• entorhinal cortex (P.<0.001)
• Whole hippocampus (P.<0.001)
• hippocampus (P.=0.002)
• Horn of Ammon 1 (P.=0.002)
• Dentate gyrus (P.=0.003)

Similarly, greater oxygen saturation indices were associated with entorhinal cortex and hippocampal volumes only in amyloid-positive patients.

“Alzheimer’s disease is known to affect the entorhinal cortex before the ammonium horn 1 and subiculum subfields due to widespread tau pathology in the early stages of the disease,” the research group wrote. “Interestingly, the medial temporal lobe subregion is also known to be sensitive to hypoxia, a major consequence of SDB. , indicating that it may be the most vulnerable region to Ammonia, but other sub-regions, such as the ammonia angle 3, are spared.”

“Our results suggest that some people may be more susceptible to the adverse effects of sleep apnea,” Laux said in a press release.

“People in the very early stages of ongoing Alzheimer’s disease show a unique vulnerability to sleep apnea,” she added. “Further research should explore whether treating sleep-disordered breathing may improve cognitive function and prevent or delay neurodegeneration.”

These findings may provide insight into the effects of SDB on the healthy human brain.

“The fact that we found no association between SDB and medial temporal lobe integrity in amyloid-negative participants suggests that a younger population (i.e., young middle-aged “This is in contrast to several previous reports showing SDB-related hippocampal changes in ‘individuals and children with obstructive sleep apnea’,” the researchers wrote.

“We can speculate that SDB may exacerbate Alzheimer’s disease in all participants, but amyloid-negative individuals may not have SDB. [there was not] They may still have enough time to show neurodegeneration, or they may be more resistant to the adverse effects of SDB than amyloid-positive people,” the researchers added.

“Importantly, in our cohort, only a fraction of participants with moderate to severe SDB showed symptoms of excessive daytime sleepiness (11 of 91 participants).” pointed out Rauchs and co-authors. “Furthermore, they may be highly educated overall and have no cognitive impairment, thus exhibiting high cognitive reserve. may be at risk of

No significant associations were found between baseline SDB parameters and end-of-study memory scores. Lower baseline volumetric measurements in the whole hippocampus were observed across the study cohort (P.=0.005) and CA1 (P.=0.003) were associated with worse episodic memory performance at follow-up.

Further adjustment for patient gender showed that, in females only, higher AHI scores were associated with decreased gray matter in the hippocampus, entorhinal cortex, parahippocampal cortex, Ammon angle 1, and dentate gyrus. rice field.

In this study, Rauchs et al. used data from the Age-Well trial of the Medit-Aging European project from 2016 to 2020.

A total of 122 participants participated in the study. Of these, 63.1% were female, mean age was 69.4 years, and 21.3% were amyloid positive. Amyloid-positive patients tend to be significantly older and are more likely to be amyloid-positive. APOE4 Carriers outperform amyloid-negative counterparts.

Sleep was assessed with home polysomnography. Participants underwent cognitive testing, MRI, and PET at baseline. Cognition was assessed again after an average of 20.66 months.

The researchers concluded, “Further studies are needed to assess the impact of tau pathology and to evaluate the potential beneficial effects of SDB treatment.”