A Study Of Cognitive Dysfunction In Obstructive Sleep Apnea Hypopnea Syndrome Patients Based On VBM Combined With ALFF

Objective: This study used voxel based morphometry(VBM)and amplitude of low frequency fluctuation(ALFF)to assess the structural and functional changes in the gray matter areas of the brain in patients with obstructive sleep apnea hypopnea syndrome(OSAHS)and its correlation with cognitive dysfunction,to explore the possible mechanisms of cognitive dysfunction in OSAHS patients,with the aim of providing a theoretical basis for early clinical intervention in OSAHS.Methods: Thirty-one patients with OSAHS who were hospitalized at the Second Hospital of Dalian Medical University from September 2020 to December 2022 were included,including 9 cases with mild(5<AHI≤15 times/h)and 22 cases with moderate or severe(AHI>15 times/h),and 30 cases of normal controls were included in the same period.PSG sleep monitoring,MRI image acquisition and assessment of MMSE,Mo CA and ESS scales were performed in both groups.Cognitive scale scores were compared between the two groups and analyzed for bias correlation with PSG parameters.Brain areas with changes in brain gray matter volume and function in OSAHS patients were searched for using MRI VBM and ALFF,and were analyzed with bias correlation with cognitive function scores,respectively.Results: 1.(1)There were no statistically significant differences in age,gender,education,history of hypertension,and history of diabetes between the OSAHS and normal groups(P > 0.05),and statistically significant differences in BMI(P < 0.05).There was no statistically significant difference in the basic information between the mild and moderately severe groups(P>0.05).(2)AHI and ODI in the OSAHS group were higher than those in the control group,and LSa O2 was lower than that in the control group,and the differences were statistically significant(P<0.05);the differences in MSaO2,light sleep time,deep sleep time,and sleep efficiency were not statistically significant(P>0.05).The differences were statistically significant(P<0.05),and the differences in MSa O2,light sleep time and sleep efficiency were not statistically significant(P>0.05).(3)The total MMSE score and its subscales,and the total Mo CA score and its subscales in the OSAHS group were lower than those in the control group,and the differences were statistically significant(P<0.05).There was no statistically significant difference between the two groups for both mild and moderately severe patient scores(P>0.05).(4)BMI as a control variable,correlation analysis between cognitive function scores and PSG parameters in OSAHS patients: the total MMSE score and its subscales of attention and calculation,orientation and apnea hypopnea index(AHI)in OSAHS patients were negatively correlated(r=-0.525,-0.447,-0.398.P<0.05)and Oxygen reduction index(ODI)(r=-0.487,-0.367,-0.452;P<0.05);the total MMSE score and its subscales of attention and computational power were positively correlated with deep sleep time(r=0.435,0.500;P<0.05).Mo CA total score and its subscores of visuospatial and executive ability and delayed memory were negatively correlated with AHI(r=-0.510,-0.451,-0.496;all P<0.05)and with ODI(r=-0.510,-0.477,-0.470;all P<0.05);Mo CA single item naming was positively correlated with MSa O2(r= 0.379,P<0.05),visuospatial executive ability was positively correlated with LSa O2(r=0.397,P<0.05);total Mo CA score and its subscales visuospatial and executive ability,delayed memory were positively correlated with deep sleep duration(r=0.506,0.486,0.364;all P<0.05),attention and computational power were positively correlated with sleep efficiency(r =0.384,P<0.05).2.(1)The OSAHS group had less gray matter volume(GMV)in the bilateral insula,temporal pole,hippocampus,thalamus,amygdala and left superior temporal gyrus,left inferior frontal gyrus,left postcentral gyrus,left central sulcus,and left cuneus than the control group,and the difference was statistically significant(GRF corrected,P<0.05).There was no statistically significant difference in whole-brain GMV between the mild and moderate-severe groups of OSAHS patients.(2)BMI was used as a control variable,and the differences between cognitive function scores and GMV in OSAHS patients were statistically significant brain area correlation analysis: Mo CA scores in OSAHS patients were positively correlated with left central sulcus GMV(r=0.467,P<0.05),and abstraction ability was positively correlated with left postcentral gyrus GMV(r=0.409,P<0.05).3.(1)The ALFF values of bilateral precentral gyrus,left cuneus,left paracentral lobule,left postcentral gyrus,right superior occipital gyrus,and right superior parietal gyrus in the OSAHS group were smaller than those in the control group,and the differences were statistically significant(FDR-corrected,P<0.05);the ALFF values of right middle temporal gyrus and right parahippocampal gyrus were larger than those in the control group,and the differences were statistically significant(FDR-corrected,P<0.05).There was no statistically significant difference in whole-brain ALFF values between the mild and moderate-severe groups of OSAHS patients.(2)BMI was used as a control variable,and the differences between cognitive function scores and ALFF values in OSAHS patients were statistically significant brain area correlation analysis: MMSE orientation was positively correlated with ALFF values in the right superior occipital gyrus(r=0.400,P<0.05),attention was negatively correlated with ALFF values in the right middle temporal gyrus(r=-0.423,P<0.05)in OSAHS patients;Mo CA orientation was positively correlated with the left lingual gyrus ALFF value(r=0.370,P<0.05).Conclusion:1.Cognitive decline was present in OSAHS patients and was associated with reduced nocturnal hypoxia and deep sleep and decreased sleep efficiency.2.Smaller gray matter volumes and reduced amplitude of spontaneous neuronal activity in several brain regions in OSAHS patients may be one of the mechanisms of their cognitive dysfunction.