Association of hypoxic burden with brain atrophy in Alzheimer's disease.

<h4>Background</h4>Obstructive Sleep Apnea (OSA) is a common comorbidity in Alzheimer's Disease (AD) and may exacerbate neurodegeneration. This study investigates the association between a novel metric of OSA severity-hypoxic burden (HB)-and measures of AD-related neurodegeneration.<h4>Methods</h4>In this retrospective exploratory study, patients with AD at stage 3 and stage 4 (NIA-AA 2018 criteria), enrolled at a Center for Neurodegenerative Diseases, underwent a complete sleep assessment including polysomnography and 3 T brain Magnetic Resonance Imaging. Correlation analyses were conducted between HB and brain volumes.<h4>Results</h4>Twenty-two patients (36.4% males, mean age 69.8 ± 7.5) were enrolled. OSA was diagnosed in 40.9% of patients. HB inversely correlated with left hippocampus (ρ = -0.553, p = 0.02) and left amygdala (ρ = -0.496, p = 0.04) volumes. AD patients with OSA showed significantly reduced left hippocampal volume than those without OSA (p = 0.038).<h4>Conclusions</h4>This study highlights that greater OSA severity, measured by HB, correlates with left hippocampus and amygdala atrophy, suggesting a possible association between chronic hypoxia and neurodegeneration in AD.