Altered neurovascular coupling in obstructive sleep apnea: assessment via cerebral blood flow and amplitude of low-frequency fluctuation spatial coupling

Abstract Objectives To investigate alterations in cerebral blood flow and amplitude of low-frequency fluctuation (CBF-ALFF) spatial coupling in obstructive sleep apnea (OSA). Methods Thirty-two patients with OSA and 32 healthy controls (HCs) matched for sex, age, and education background were recruited for this work. All participants received arterial spin labeling (ASL) and resting-state functional MRI (rs-fMRI) examinations. Cerebral blood flow and amplitude of low-frequency fluctuation maps were derived from ASL and fMRI data, respectively. Between-group comparisons were performed to identify differences in ALFF, CBF, and CBF-ALFF coupling metrics. Subsequently, correlation analyses were conducted in OSA patients to investigate whether CBF/ALFF ratios derived from brain regions exhibiting significant group-level differences were associated with polysomnographic and clinical parameters. Results Patients with OSA exhibited reduced global spatial CBF-ALFF coupling relative to HCs. Regionally, decreased CBF/ALFF ratios were primarily observed in the left parahippocampal gyrus, whereas increased ratios were located mainly in the default mode network (DMN), including the left precuneus, right angular gyrus, and left inferior parietal lobule. Conclusions This study demonstrated disrupted spatial CBF-ALFF coupling in OSA patients. Such coupling alterations reflect broad OSA-associated pathophysiological changes, including but not limited to neurovascular dysfunction, offering new insights into the neuropathological mechanisms of OSA. Advances in knowledge Using combined blood oxygen level-dependent and ASL imaging, this study provides the first characterization of both global and regional CBF-ALFF coupling alterations in OSA, revealing distinct uncoupling signatures in the DMN and medial temporal lobe that deepen our understanding of OSA-related neurovascular pathophysiology.