| In people with sleep disorders,a phenomenon which subjective estimations of sleep quality are inconsistent with objective observations often occurs.The mismatch between subjective and objective sleep is called sleep misperception.Previous studies have paid more attention to the negative bias of subjective and objective sleep perception,that is,compared with the objective records of polysomnography(PSG)or actigraphy,people subjectively overestimate their sleep onset latency(SOL),wakefulness after sleep onset(WASO),underestimate their total sleep time(TST)and sleep efficiency(SE).In many studies,sleep misperception is specifically referred to as a subjective underestimation of sleep quality relative to objective estimation.Sleep misperception are known to exist in healthy populations,insomnia populations and patients with comorbid psychiatric/medical disorders.Studies have shown that those who underestimate their sleep quality may be more prone to sleep disorders,and some researchers believe that the distorted perception of sleep is one of the core maintenance processes of chronic insomnia.The hyperarousal model suggests that this subjective negative perception of sleep quality can be explained by excessive arousal,specifically by cognitive,somatic,and cortical activation before and during sleep.Stress is one of the important causes of high arousal during sleep.If individuals who are susceptible to stress after suffering from stress can be identified in advance,more targeted prevention can be done.Thereby the development of chronic sleep disorders could be blocked.Stress susceptibility of the sleep system could be explained as the tendency to get sleep disturbance in response to stressful challenges.It is usually measured through the Ford Insomnia Response to Stress Test(FIRST)developed by Drake and his colleagues.Stress susceptibility of the sleep system is considered to be a heritable trait.Individuals with high stress susceptibility are more likely to get sleep disturbances at the night after stress stimulation,and show higher levels of presleep/mid-sleep arousal.Long-term follow-up studies also show that individuals with high stress susceptibility were more likely to get insomnia in subsequent years than individuals with low stress susceptibility.Therefore,identification of psychological influencers and biomarkers of high stress susceptibility has great potential for the prevention and intervention of chronic sleep disorders.However,subjective underestimation of sleep,an important predictor of hyperarousal and sleep disturbance,is unknown in individuals with different levels of stress susceptibility.Therefore,we attempted to investigate the sleep perception of individuals with high and low stress susceptibility respectively,and their sleep perception under two different conditions include their daily life and stress exposure through two studies.In Study 1,in order to avoid the additional impact of sleep disorders and mood disorders,266 subjects with good sleep quality were selected to explore the differences of daily emotional experience scale,sleep experience scale,subjective and objective sleep quality between individuals with high and low stress susceptibility.Sleep diary is used to record subjective sleep,and actigraphy is used to record objective sleep.The difference between subjective sleep and objective sleep is measured by subjective and objective sleep duration misperception,that is,subjective sleep duration minus objective sleep duration.The results show that in the emotional experience scales,the high stress susceptibility group showed higher levels in the Depression Self-rating Scale,Trait Anxiety Questionnaire,and Rumination Questionnaire compared with the low stress susceptibility group;in the sleep experience scales,the high stress susceptibility group showed higher scores in the Insomnia Severity Index,the Epworth Sleepiness Scale,and the response factor dimension in the Hyperarousal Scale.While there are no differences in the daily subjective sleep duration,subjective sleep quality,objective sleep duration,objective sleep efficiency,and subjective-objective sleep duration misperception between two groups.Further we try to explore the potential influencing factors of sleep misperception and found that only in the low stress susceptibility group was it found to be correlated with the emotional experience scale,while in the high stress susceptibility group no correlations were found.For these results,we speculated that the daily average sleep data hides the information of shortterm sleep abnormalities,and other influencing factors such as brain mechanisms may regulate the subjective and objective sleep of the high and low stress susceptibility groups.Therefore,further stress exposure is needed to explore the subjective and objective sleep patterns of individuals with different stress susceptibility after stress exposure.Study 2 selected 44 subjects with good sleep quality,and mainly explored the stress level of individuals with high and low stress susceptibility under neutral cognitive stress,as well as their subjective and objective sleep quality of 90 minutes after stress.Based on the purpose of the research,we used the object location memory task in the scanner to induce the stress of the subjects.The self-report data of the stress was collected respectively in the baseline period which denotes stage 1,after the memory task which denotes stage 2,and after sleep which denotes stage 3.Sleep diary was used to collect subjective sleep information,and 64-channel electroencephalogram-functional magnetic resonance imaging(EEG-f MRI)is used to simultaneously collect objective sleep data.The misperception between subjective and objective sleep quality were measured as subjective parameter values minus objective parameter values.The misperception indexes include SOL misperception,WASO frequency misperception,WASO duration misperception,TST and SE misperception.The results showed that the main effect of time was significant through repeated-measures ANOVA for the threestage stress ratings.In terms of subjective sleep perception,the high stress susceptibility group experienced higher somatic arousal before going to bed than the low stress susceptibility group,but the two groups did not differ in other subjective sleep parameters and feelings after waking up.In objective sleep,the two groups did not differ significantly in macroscopic sleep progression,but in more microscopic sleep,the low stress susceptibility group experienced more N3 sleep,and the high stress susceptibility group experienced more N2 sleep.As for subjective-objective sleep misperception,no abnormalities were found in the high and low stress susceptibility groups,which was not consistent with our expectations.The fractional amplitude of low frequency(0.01–0.08 Hz)in f MRI(zf ALFF)during sleep can be used as a measure of spontaneous arousal levels.Therefore,we intercepted 5-minute functional magnetic resonance imaging of each stage of sleep,and used the zf ALFF value to measure the level of cortical hyperarousal during sleep in the high and low stress susceptibility groups.The results showed that the high stress susceptibility group significantly activated the dorsolateral superior frontal gyrus,medial superior frontal gyrus and medial-orbital superior frontal gyrus during sleep,and the brain activation levels were correlated with subjective and objective sleep misperception,indicating that in the dynamic function plasticity process of sleep,the high stress susceptibility group may undergo an abnormal reorganization process in the frontoparietal and default mode networks.To sum up,our research can draw the following main conclusions.Firstly,stress susceptibility will affect the daily experience of individuals,including emotional experience and sleep experience,and the high stress susceptibility group reflects a worse state,but the underestimation of objective sleep relative to subjective sleep was not found in the common subjective and objective sleep of several days.Based on the unknown of daily stress in Study1,we found that under stress exposure of neutral cognitive tasks in Study 2,the objective sleep quality of high stress susceptibility group was impaired in the subsequent sleep,and the brain activation levels in each stage of sleep were higher.We also found the correlation between brain activation and sleep misperception.The above results expand our understanding of stress susceptibility.Individuals with high stress susceptibility have abnormal cognition-emotional,somatic and brain arousal in daily mood and sleep experience,especially under stressful stimuli.This may lead to a single night’s sleep reduction and it could also be the maintenance factor for the development of insomnia.Therefore,it is necessary for us to identify in advance sensitive individuals before the onset of insomnia,that is,the high-stress susceptibility group of the sleep system,and carry out targeted interventions such as the application of cognitive-behavioral therapy in correcting negative cognition-emotional arousal in high-stress susceptible groups to prevent the of generation and development of insomnia,reduce somatic arousal through rational athletics.Our study of brain activation of stress susceptibility also provides a target reference for brain stimulation treatment of insomnia disorder. |
PDF Full Text Request