EEG Characteristics And Clinical Significance Of Arousal Instability In Young And Middle-aged Patients With Obstructive Sleep Apnea-hypopnea Syndrome

Purpose:To compare the characteristics of arousal of sleep EEG and alternating circulation patterns of sleep in young and middle-aged adults with different severities of obstructive sleep apnea-hypopnea syndrome(OSAHS),and to investigate the relationship between sleep microstructural fragmentation and cognitive impairment,as well as daytime sleepiness,in these patients.Methods:A total of 134 young and middle-aged snoring patients(mean age 37.54±7.66 years)with suspected OSAHS who were admitted to the sleep center of the Second Affiliated Hospital of Suzhou University from July 2017 to June 2019 were screened,general data of all patients were collected.They were all monitored with overnight polysomnography(PSG),analyzed nighttime sleep EEG signals and interpreted sleep microstructures,including assessment of arousal parameters:overall arousal index(OAI),respiratory-related arousal index(RRAI),and spontaneous arousal index(SAI),cyclical alternating patterns(CAP)parameters:CAP rate,CAP time,CAP index,duration time of phase A and phase B,and indices of each subtype,And the macrostructural parameters of sleep:the proportion of NREM1(N1),NREM2(N2),NREM3(N3)and REM(R)sleep.Based on the apnea-hypopnea index(AHI),patients were divided into four groups:primary snoring(AHI<5 times/hour,n=25),mild OSAHS(5 times/hour<AHI ≤ 15 times/hour,n=28),moderate OSAHS(15 times/hour≤AHI≤30 times/hour,n=26),and severe OSAHS(AHI>30 times/hour,n=55).Cognitive function and daytime sleepiness were assessed using Montreal Cognitive Assessment(MoCA)and Epworth Sleepiness Scale(ESS).General information,PSG parameters,arousal parameters and CAP parameters of the patients were compared among the groups,the correlation between the MoCA score and the ESS score and the PSG parameters and the arousal and CAP were analyzed.Results:1.Comparison of general data and clinical symptoms among the four groups of patients:There were no significant differences in age,gender,complain daytime sleepiness,poor memory and years of education between the four groups of patients,However,there was a difference between the two groups in the primary snoring group and the severe OSAHS group(P<0.05),and the BMI in the severe OSAHS group was(27.5812.67),which was statistically different from the other three groups(all<0.01);As OSAHS severity increased,systolic blood pressure and diastolic blood pressure increased gradually(both P<0.05),and there was statistical difference between systolic and diastolic blood pressure in the severe group and the primary snoring group.(both P<0.05);As the severity of OSAHS increased,MoCA scores decreased gradually(P<0.01),ESS scores increased gradually(P<0.01),the MoCA score in the primary snoring group was(27.10±1.37),and there was statistical difference between the mild OSAHS group(26.08± 1.19),the moderate OSAHS group(25.13± 1.77),and the severe group(25.03±1.95)(all P<0.01).2.Comparison oF traditional PSG parameters(respiration parameters and sleep macrostructure)in four groups of patients:the N1%,N2%,N3%and R period latency differences among the four groups were statistically significant(all P<0.05),only the severe OSAHS group and the other three groups had statistically significant difference in N1%,N2%,and N3%(all P<0.05).The ODI,TS90%,and LSa02 were significantly higher in the severe OSAHS group compared with the other three groups(all P<0.01).3.Comparison of arousal and CAP of four groups of patients:OAI,RRAI,CAP time,CAP rate(N1 CAP rate and N2 CAP rate),A phase index(A1 phase index and A3 phase index),There were significant statistical differences between the number of CAP cycles,the average duration of phase A(average duration of phase A2 and the mean duration of phase A3)and the average duration of phase B(both P<0.05 or P<0.01);At the same time,OAI,RRAI,CAP time,CAP rate,phase A index,number of CAP cycles,and the average duration of phase A differed significantly in the moderate and severe OSAHS groups compared with the mild OSAHS and primary snoring groups(all P<0.05).4.Correlation analysis results:Linear correlation analysis showed that the MoCA score was negatively correlated with N1%,OAI,RRAI,CAP time,CAP rate,A phase index,A3 phase index and the average duration of phase A,and positive with R%.The ESS score was positively correlated with OAI,RRAI,CAP time,CAP rate,A phase index,A2 phase index,A3 phase index,CAP cycle number and A and B phase average duration,and negatively correlated with N3%;stepwise regression analysis showed:MoCA=25.412-0.028 A3 phase index+0.063 R period percentage(r2=0.380,F=10.986,P=0.000),ESS=8.968+0.104 A3 phase index-0.222 A2 phase index(r2=0.413,F=13.372,P=0.000),MoCA is negatively correlated with A3 phase index,positively correlated with R%,ESS is positively correlated with the A3 phase index,and negatively correlated with A2 phase index.It is suggested that the A3 index is related to MoCA and ESS.Conclusions:1.With the increase of the severity of OSAHS,the MoCA scores of young and middle-aged patients gradually decreased,and the ESS scores gradually increased,suggesting that the cognitive function of patients gradually decreased,and the degree of daytime sleepiness gradually increased.2.There is a disorder of sleep structure in young and middle-aged patients with OSAHS.The macrostructure of sleep EEG only shows an increase in the proportion of shallow sleep and a decrease in the proportion of deep sleep in the severe group.The sleep microstructure is more sensitive,and it is shown in the mild OSAHS group.Differences,especially in the medium and severe groups.3.Linear regression and stepwise regression analysis showed that the A3 index of CAP parameters was negatively correlated with cognitive function and positively correlated with daytime sleepiness,suggesting that the A3 index of CAP parameters is one of the sensitive indicators for assessing OSAHS sleep structural disorder.