Altered Regional Functional Connectivity And Topological Attribute Of Brain Default Network In Patients With Obstructive Sleep Apnea

Part 1 Altered regional brain activity of functional connectivity in patients with obstructive sleep apnea based on independent component analysisObjective:Depending on independent component analysis(ICA)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.All subjects underwent polysomnography,collected general data and scale measurement and obtained sleep apnea hypopnea index,oxygen desaturation index,simple mental scale,and epworth sleepiness scale,etc.Results:Body Mass Index(BMI),AHI,oxygen desaturation index(ODI)and Epworth Sleepiness Scale(ESS)in the OSA group were significantly higher than those in the control group,while mini-mental state examination(MMSE)was lower than these in the control group(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).Conclusion: 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.Part 2 The alteration of topological properties of brain functional networks in patients with obstructive sleep apneaObjective:To explore the changes of topological properties of brain functional networks in subjects with obstructive sleep apnea(OSA).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.They were scanned with BOLD-f MRI,and the whole brain was divided into 90 districts by automated anatomical labeling(AAL)by GRETNA.The correlation matrix Z(N*N,N=90)generated by Fisher Z transformation.The whole brain functional network was constructed,with the sparsity 0.1~0.2(step length 0.01),to compare the attribute changes of the two groups.Related parameters: clustering coefficient Cp,gamma,lambda,sigma,global efficiency Eglo,local efficiency Eloc and node parameter.All subjects underwent polysomnography,collected general data and scale measurement and obtained sleep apnea hypopnea index,oxygen desaturation index,simple mental scale,and epworth sleepiness scale,etc.Results:Body Mass Index(BMI),AHI,oxygen desaturation index(ODI)and Epworth Sleepiness Scale(ESS)in the OSA group were significantly higher than those in the control group,while mini-mental state examination(MMSE)was lower than these in the control group(all P<0.001).The OSA group and the normal control group had the ‘small world' attribute,and there was no significant statistical difference between the "small world" attribute and the global attribute.The left posterior cingulate gyrus,middle temporal gyrus,and the right frontal lobe,wedge lobe local node attribute had significant statistical difference compared with the normal control group(P < 0.05).Conclusion: The whole brain function in patients with OSA network ‘small world' properties and global properties underwent no obvious change,OSA disease has not obvious effects on the brain function network global information integration,but there existed abnormity in part of the brain regions node properties and local information transfer.