Research Of Resting State FMRI In The Obstructive Sleep Apnea-hypopnea Syndrome

Background: Obstructive sleep apnea-hypopnea syndrome(OSAHS)is a common disease with chronic mult-system damage.The central nervous system(CNS)damage of OSAHS is mainly manifested as cognitive impairment and abnormal of neuropsychology,which seriously affects the quality of life and safety of patients.It has been reported that compared with normal people,the brain function of OSAHS patients has significantly changed,but whether the brain function changes in OSAHS patients are related to CNS damage and the mechanism of action remains to be determined.Studies have shown that early intervention of CNS damage in OSAHS patients can reduce the probability of developing dementia and depression.However,at present,cognitive impairment and neuropsychiatric disorders in OSAHS patients are mainly evaluated by relevant scales and questionnaires,lacking objective indicators.Therefore,it is of great significance to find an objective and effective method for early diagnosis of CNS damage in OSAHS patients and explore its potential neuropathological mechanism to guide clinical treatment.In recent years,resting state functional magnetic resonance imaging(rs-fMRI)and its advanced data processing methods have opened up a new path for the study of neuroimaging of OSAHS.Objective: This study adopts the rest-state functional magnetic resonance imaging(rs-fMRI)technique to analyze the brain function status of patients with OSAHS from three aspects of regional homogeneity function(ReHo),fractional amplitude of low-frequency fluctuation(fALFF)and degree centrality(DC)respectively.To understand the brain regions with abnormal neural activity in OSAHS patients under resting state and explore the possible mechanisms,and to provide valuable clues for exploring the early diagnosis,timely intervention and precise treatment of CNS damage of OSAHS.Methods: A total of 30 male patients with OSAHS who were initially diagnosed and untreated by polysomnography(PSG)in the Department of Respiratory Medicine of the Affiliated People’s Hospital of Hubei University of Medicine were collected,and 30 volunteers with normal sleep,similar age and education level monitored by PSG during the same period were selected as the Group Normal(GN)group.All subjects were assessed with Epworth sleepiness scale(ESS)score and Montreal cognitive assessment scale(MoCA)score,rs-fMRI examination was performed to obtain blood oxygen level dependent(BOLD)signals.Reho,fALFF and DC analysis were used to compare the OSAHS group with the GN group to find out the brain regions with significant differences.Then take the different brain regions as the region of interest(ROI),calculated the average ReHo value,fALFF value and DC value,Then,they are correlated with ESS score,MOCA score and sleep index monitored by PSG to explore the possible neuropathological mechanism of brain function impairment of OSAHS,and to provide evidence-based medicine evidence for early diagnosis,timely intervention and precise treatment of OSAHS.Results: 1.Compared with the GN group,there were several brain areas significant differences in ReHo value,fALFF value and DC value in the OSAHS group(P<0.001):(1)The brain regions with increased ReHo value included left pons,left anterior cerebellar lobe and right anterior cerebellar lobe,while there was no significant decrease of ReHo value in the whole brain.(2)fALFF value increased in the left posterior lobe of the cerebellum,left superior temporal gyrus,left fusiform gyrus,fALFF value decreased in the left paracentral lobule.(3)The brain regions with increased DC value included left pons,right limbic lobes,left superior temporal gyrus,right inferior frontal gyrus,left superior frontal gyrus and right superior frontal gyrus.The DC value decreased in the right posterior lobe of cerebellum and the left cuneus.2.Correlation analysis showed that :(1)The ESS score of OSAHS patients was significantly positively correlated with AHI(r= 0.757,P <0.001)and AI(r=0.696,P<0.001).(2)MOCA score was significantly positively correlated with Mini SaO2(r =0.509,P = 0.004),and negatively correlated with AI(r =-0.669,P <0.001)and AHI(r=-0.725,P <0.001).(3)The mean fALFF value of the left paracentral lobule in OSAHS patients was significantly negatively correlated with AI(r =-0.808,P=0.000).The mean DC value of the right posterior lobe was positively correlated with the MOCA score(r=0.656,P=0.000).There was a significant positive correlation between the mean DC of the left Cuneus and Mini SaO2(r=0.519,P=0.003).Conclusion:1.Daytime sleepiness and cognitive dysfunction in OSAHS patients are related to hypoxia and repeated awakenings during sleep.2.In OSAHS patients,the local activity consistency,activity amplitude and degree centrality of brain neurons in multiple brain regions all changed,which may be the neuropathological basis of CNS damage:(1)The brain regions with changes in fALFF value in OSAHS patients were mostly concentrated in the left cerebral hemisphere,Functional rearrangement of left and right cerebral hemispheres in OSAHS patients may be the basis of its CNS damage.(2)The decrease of fALFF value in Left paracentric lobule may be related to repeated microarousal during sleep.(3)The decrease of DC value in the left cuneus was closely related to hypoxia.(4)The decrease of DC value in the right posterior lobe of the cerebellum was related to the cognitive impairment of patients.3.Resting state fMRI has the potential to be a non-invasive method for early identification of brain functional abnormalities in OSAHS patients and exploration of the mechanism of CNS damage.