Altered regional brain activity of functional connectivity in patients with obstructive sleep apnea

Abstract

Objective: To investigate the changes of default mode network in subjects with obstructive sleep apnea (OSA) using functional connectivity (FC). Methods: Clinical data were collected from thirty-three subjects with OSA who went to the Zhongda Hospital, Southeast University, and twenty-nine normal controls were recruited from community from Jan 2016 to Jan 2018. The OSA group was divided into two subgroups according to apnea-hypopnea index (AHI) and the lowest oxygen saturation at night: 15 patients in the mild group and 18 in the moderate to severe group. Both of the two group subjects underwent functional magnetic resonance imaging scans, and their default network was extracted based on independent component analysis to compare the differences in FC. Results: Body Mass Index (BMI), AHI, oxygen desaturation index (ODI), mini-mental state examination (MMSE) and Epworth Sleepiness Scale (ESS) in the OSA group were significantly higher than those in the control group [(27.1±4.3) vs (22.2±2.7) kg/m(2), (29.5±22.1) vs (2.4±1.6) events/h, 19.5 (4.6, 39.1) vs 0.6 (0.2, 1.6) events/h, (27.5±1.5) vs (29.4±0.8) score, (8.6±3.3) vs (3.5±1.6) score] (all P<0.001). The OSA group showed an increase in left limbic lobe, left cingulate, left parietal lobe, left inferior parietal lobule; a decrease in bilateral temporal lobe, bilateral limbic lobe and parahippocampa gyrus, left frontal lobe in FC value, compared with the normal control group (all P<0.001). The moderated-severe group showed a significant increase in the left occipital lobe, bilateral cuneus, right parietal lobe; a decrease in the bilateral parietal lobe, inferior parietal lobule in FC value compared with the mild group (all P<0.01). Conclusions: The FC of default mode network in OSA group is disrupted, with parts of brain regions suffering injury,while parts of brain regions experiencing compensatory reaction. Additionally, the compensatory period translates to the decompensation period with disease progression in OSA group.