Dynamic Regional Homogeneity In Patients With Moderate And Severe Obstructive Sleep Apnea:a FMRI Study

Background and Purpose:Previous studies have found that abnormal local spontaneous brain activity in patients with obstructive sleep apnea(OSA)was associated with cognitive impairment,but the exact neurological mechanism of cognitive impairment is still unclear.Dynamic local functional connections can show the change of local brain activity with time during the resting state functional magnetic resonance imaging(rs-f MRI)acquisition.Based on dynamic regional homogeneity(dReHo),the purpose of this study was to investigate the dynamic characteristics of regional brain connectivity and its relationship with cognitive function in patients with moderate and severe OSA,and to explore whether the dynamic changes can be used to distinguish OSA patients from healthy controls(HCs).Methods:In this study,seventy-nine moderate and severe male OSA patients without any treatment and eighty-four male HCs with similar age and education were recruited from the Respiratory Department or Otorhinolaryngology sleep monitoring room of the first Affiliated Hospital of Nanchang University from July 2017 to January 2022,and their clinical data and rs-f MRI imaging data were collected.DPABI and SPM12 software was used to preprocess rs-f MRI data based on MATLAB R2018 b platform.The dReHo was calculated using a sliding window technique,and a double-sample t test was used to test the difference in the dReHo map between OSA patients and HCs.We explored the relationship between dReHo and clinical and cognitive function in OSA patients using correlation analysis.A support vector machine was used to classify the OSA patients and HCs based on abnormal dReHo.Result:(1)Compared with HCs,OSA patients exhibited higher dReHo values in the right medial frontal gyrus and significantly lower dReHo values in the right putamen,right superior temporal gyrus,right cingulate gyrus,left insula and left precuneus(voxel-level P<0.01,cluster-level P<0.05,two-tailed,Gaussian random field theory corrected).The correlation analysis showed that the dReHo values of right medial frontal gyrus and right putamen were correlated with nadir oxygen saturation in patients with OSA(r=-0.311,P=0.005;r=0.225,P=0.046);the dReHo value of the left anterior cuneiform lobe was positively correlated with orientation(r=0.241,P=0.032);the dReHo value of the left insula was negatively correlated with the oxygen depletion index(r=-0.257,P=0.022)and the total score of the Montreal Cognitive Assessment score(r=-0.242,P=0.032);the dReHo value of the right cingulate gyrus was positively correlated with the sleep period time(r=0.263,P=0.019).(2)The support vector machine classification accuracy based on the dReHo difference of brain regions between the two groups was 81.60%,the precision was81.01%,the sensitivity was 81.01%,the specificity was 82.14%,and the area under the curve was 0.89.Conclusion:The results of this study suggested that:(1)Compared with HCs,patients with OSA have abnormal spontaneous activity of dynamic brain regions,which is related to clinical and neurocognitive assessment,which is helpful to further understand the neuropathological mechanism of patients with OSA;(2)Based on the d Reho value of different brain regions between the two groups,OSA and HCs can be classified by support vector machine,which indicates that dReHo may be a potential objective neuroimaging biomarker to distinguish OSA patients from HCs,and may provide new help for the clinical diagnosis of OSA.