The Sutdy On The Changes Of Cerebral Blood Flow And Gray Matter Volume In Patients With Obstructive Sleep Apnea Syndrome

Objective:Obstructive sleep apnea syndrome(OSAS)is a sleep apnea disease caused by frequent hypopnea or apnea caused by partial or complete upper airway obstruction during sleep.Previous studies have shown that OSAS patients have cognitive dysfunction,meanwhile hypoxic exposure and hemodynamic changes may lead to structural and functional defects in multiple brain regions of OSAS patients.However,changes in brain tissue morphology of OSAS have been widely reported,but the pathophysiological mechanism of changes in cerebral blood flow is still unclear.In this study,the commonly used clinical cognitive scale,pseudo-continuous arterial spin labeling(pCASL)and voxel-based morphometry(VBM)were used to study the changes of sleep,cognitive function and cerebral blood flow in patients with OSAS,so as to provide a basis for the potential cognitive function mechanism,pathophysiological mechanism and objective diagnostic criteria of OSAS patients.Methods:This study included 20 patients with OS AS and 36 healthy controls(HC).This study was divided into three parts:(1)A series of clinical and neuropsychological tests were conducted,including body mass index(BMI),apnea hypopnea index(AHI),epworth sleepiness scale(ESS),mini mental state examination scale(MMSE)and montreal cognitive assessment scale(MoCA).BMI,AHI,MMSE,MoCA and ESS ofOSAS group and HC group were compared by independent sample t-test.The duration of illness,BMI,AHI,MMSE,MoCA and ESS of OSAS patients were analyzed by Spelman correlation analysis,and Bonferroni correction was used for multiple comparison correction.(2)and(3)pCASL imaging and fast field echo(Fast field echo,FFE)pulse sequence was used for scanning.The data were preprocessed and the cerebral blood flow(CBF)and gray matter volume(GMV)values of OSAS group and HC group were calculated and compared by independent sample t-test.The values of CBF and GMV of the different brain regions between the two groups and the clinical variables of the patient group were analyzed by Spelman correlation analysis,and the Bonferroni correction was used for multiple comparison correction.Results:The results of the three parts of the study are as follows:(1)the BMI score,AHI score and ESS score of OSAS patients are higher than those of HC group.The scores of MMSE and MoCA in OSAS group were lower than those in HC group.Theduration of OSAS was negatively correlated with MMSE score and MoCA score,the AHI score of OSAS patients was positively correlated with ESS score,and the MMSE score of OSAS patients was positively correlated with MoCA score,but there was no significant correlation.(2)compared with HC group,CBF values in right medial prefrontal lobe,left precentral gyrus and right insular lobe increased in OSAS group,while CBF values decreased in right temporal pole and right cerebellar Crus2 area.The increase of CBF in the left precentral gyrus was positively correlated with BMI score,but there was no significant correlation.(3)compared with HC group,the GMV value of right dorsal lateral prefrontal cortex(DLPFC),right occipital pole and cerebellar vermis decreased in OSAS group.The decrease of GMV value in right DLPFC brain region was positively correlated with MMSE score and MoCA score,while the decrease of GMV value in right occipital pole brain region was positively correlated with MMSE score.Conclusion:Our results show that:(1)BMI abnormalities are closely related to OSAS patients;cognitive abnormalities exist in OSAS patients,and cognitive function may decrease with the increase of OSAS severity.(2)abnormal blood flow in the right medial prefrontal lobe,left precentral gyrus,right temporal pole and right cerebellum in patients with OSAS may lead to abnormal cognitive function in patients with OSAS,and abnormal blood perfusion in the right insular lobe in patients with OSAS may be a potential neuroimaging biomarker of OSAS.(3)the GMV value of right DLPFC and right occipital polar brain region decreased and positively correlated with MMSE score and MoCA score,suggesting that DLPFC and occipital polar brain region of OSAS patients were closely related to cognitive function,while cerebellar GMV decreased in OSAS patients,indicating that the decrease of cerebellar GMV may lead to abnormal behavior in OSAS patients.It is suggested that there are widespread structural and blood metabolic abnormalities in patients with OSAS,especially in the frontal lobe and cerebellum,which are closely related to abnormal behavior,psychological and cognitive function.