NREM Sleep Stages Research Articles

HUBUNGAN KUALITAS TIDUR DENGAN DERAJAT HIPERTENSI DI POSBINDU DESA PANERUSAN WETAN BANJARNEGARA

Introduction: The incidence of hypertension in Central Java, 8,700,512 persons, or 30.4% of the population, have hypertension by the time they are over 15 years old in 2021. Based on the results of measurements on residents aged 18 years and over according to characteristics in Central Java, the highest was in the female sex (40.17%) compared to the male sex (34.17%). Some of the risk factors that lead to hypertension include genetic factors, gender, age, diet, obesity, and lifestyle such as smoking and consuming alcohol. Sleep quality plays an important role for every individual in maintaining sleep conditions and achieving the right REM and NREM sleep stages. The aim of these findings is to identify the characteristics of respondents, characteristics of the degree of hypertension, sleep quality and analyze the relationship between sleep quality and degree of hypertension.
 Methods: This research applies quantitative through a non-experimental design, data collected using a cross-sectional approach, the total population is 120 respondents with a sample size of 92 respondents.
 Result: The results of this study indicate that 70 respondents (76,1%) experienced poor sleep quality. In mild hypertension, there were 43 respondents (46.7%).

Dissociation of Arousal Index Between REM and NREM Sleep in Elderly Adults with Cognitive Impairment, No Dementia: A Pilot Study.

Sleep disruption in elderly has been associated with an increased risk of cognitive impairment and its transition into Alzheimer's disease (AD). High arousal indices (AIs) during sleep may serve as an early-stage biomarker of cognitive impairment non-dementia (CIND). Using full-night polysomnography (PSG), we investigated whether CIND is related to different AIs between NREM and REM sleep stages. Fourteen older adults voluntarily participated in this population-based study that included Mini-Mental State Examination, Neuropsi battery, Katz Index of Independence in Activities of Daily Living, and single-night PSG. Subjects were divided into two groups (n = 7 each) according to their results in Neuropsi memory and attention subtests: cognitively unimpaired (CU), with normal results; and CIND, with -2.5 standard deviations in memory and/or attention subtests. AIs per hour of sleep during N1, N2, N3, and REM stages were obtained and correlated with Neuropsi total score (NTS). AI(REM) was significantly higher in CU group than in CIND group. For the total sample, a positive correlation between AI(REM) and NTS was found (r = 0.68, p = 0.006), which remained significant when controlling for the effect of age and education. In CIND group, the AI(N2) was significantly higher than the AI(REM). In CIND older adults, this attenuation of normal arousal mechanisms in REM sleep are dissociated from the relative excess of arousals observed in stage N2. We propose as probable etiology an early hypoactivity at the locus coeruleus noradrenergic system, associated to its early pathological damage, present in the AD continuum.

Adaptive Deep Brain Stimulation for sleep stage targeting in Parkinson’s disease

BackgroundSleep dysfunction is disabling in people with Parkinson’s disease and is linked to worse motor and non-motor outcomes. Sleep-specific adaptive Deep Brain Stimulation has the potential to target pathophysiologies of sleep. ObjectiveDevelop an adaptive Deep Brain Stimulation algorithm that modulates stimulation parameters in response to intracranially classified sleep stages. MethodsWe performed at-home, multi-night intracranial electrocorticography and polysomnogram recordings to train personalized linear classifiers for discriminating the N3 NREM sleep stage. Classifiers were embedded into investigational Deep Brain Stimulators for N3 specific adaptive DBS. ResultsWe report high specificity of embedded, autonomous, intracranial electrocorticography N3 sleep stage classification across two participants and provide proof-of-principle of successful sleep stage specific adaptive Deep Brain Stimulation. ConclusionMulti-night cortico-basal recordings and sleep specific adaptive Deep Brain Stimulation provide an experimental framework to investigate sleep pathophysiology and mechanistic interactions with stimulation, towards the development of therapeutic neurostimulation paradigms directly targeting sleep dysfunction.

Sleep, oscillations, and epilepsy.

Sleep and wake are defined through physiological and behavioral criteria and can be typically separated into non-rapid eye movement (NREM) sleep stages N1, N2, and N3, rapid eye movement (REM) sleep, and wake. Sleep and wake states are not homogenous in time. Their properties vary during the night and day cycle. Given that brain activity changes as a function of NREM, REM, and wake during the night and day cycle, are seizures more likely to occur during NREM, REM, or wake at a specific time? More generally, what is the relationship between sleep-wake cycles and epilepsy? We will review specific examples from clinical data and results from experimental models, focusing on the diversity and heterogeneity of these relationships. We will use a top-down approach, starting with the general architecture of sleep, followed by oscillatory activities, and ending with ionic correlates selected for illustrative purposes, with respect to seizures and interictal spikes. The picture that emerges is that of complexity; sleep disruption and pathological epileptic activities emerge from reorganized circuits. That different circuit alterations can occur across patients and models may explain why sleep alterations and the timing of seizures during the sleep-wake cycle are patient-specific.

Sleep patterns correlates with the efficacy of tDCS on post-stroke patients with prolonged disorders of consciousness

BackgroundThe subclassification of prolonged disorders of consciousness (DoC) based on sleep patterns is important for the evaluation and treatment of the disease. This study evaluates the correlation between polysomnographic patterns and the efficacy of transcranial direct current stimulation (tDCS) in patients with prolonged DoC due to stroke.MethodsIn total, 33 patients in the vegetative state (VS) with sleep cycles or without sleep cycles were randomly assigned to either active or sham tDCS groups. Polysomnography was used to monitor sleep changes before and after intervention. Additionally, clinical scale scores and electroencephalogram (EEG) analysis were performed before and after intervention to evaluate the efficacy of tDCS on the patients subclassified according to their sleep patterns.ResultsThe results suggest that tDCS improved the sleep structure, significantly prolonged total sleep time (TST) (95%CI: 14.387–283.527, P = 0.013) and NREM sleep stage 2 (95%CI: 3.157–246.165, P = 0.040) of the VS patients with sleep cycles. It also significantly enhanced brain function of patients with sleep cycles, which were reflected by the increased clinical scores (95%CI: 0.340–3.440, P < 0.001), the EEG powers and functional connectivity in the brain and the 6-month prognosis. Moreover, the changes in NREM sleep stage 2 had a significant positive correlation with each index of the β band.ConclusionThis study reveals the importance of sleep patterns in the prognosis and treatment of prolonged DoC and provides new evidence for the efficacy of tDCS in post-stroke patients with VS patients subclassified by sleep pattern.Trial registration URL: https://www.clinicaltrials.gov. Unique identifier: NCT03809936. Registered 18 January 2019

Instability of non-REM sleep in older women evaluated by sleep-stage transition and envelope analyses.

Traditionally, age-related deterioration of sleep architecture in older individuals has been evaluated by visual scoring of polysomnographic (PSG) recordings with regard to total sleep time and latencies. In the present study, we additionally compared the non-REM sleep (NREM) stage and delta, theta, alpha, and sigma wave stability between young and older subjects to extract features that may explain age-related changes in sleep. Polysomnographic recordings were performed in 11 healthy older (72.6 ± 2.4 years) and 9 healthy young (23.3 ± 1.1 years) females. In addition to total sleep time, the sleep stage, delta power amplitude, and delta, theta, alpha, and sigma wave stability were evaluated by sleep stage transition analysis and a novel computational method based on a coefficient of variation of the envelope (CVE) analysis, respectively. In older subjects, total sleep time and slow-wave sleep (SWS) time were shorter whereas wake after sleep onset was longer. The number of SWS episodes was similar between age groups, however, sleep stage transition analysis revealed that SWS was less stable in older individuals. NREM sleep stages in descending order of delta power were: SWS, N2, and N1, and delta power during NREM sleep in older subjects was lower than in young subjects. The CVE of the delta-band is an index of delta wave stability and showed significant differences between age groups. When separately analyzed for each NREM stage, different CVE clusters in NREM were clearly observed between young and older subjects. A lower delta CVE and amplitude were also observed in older subjects compared with young subjects in N2 and SWS. Additionally, lower CVE values in the theta, alpha and sigma bands were also characteristic of older participants. The present study shows a decrease of SWS stability in older subjects together with a decrease in delta wave amplitude. Interestingly, the decrease in SWS stability coincided with an increase in short-term delta, theta, sigma, and alpha power stability revealed by lower CVE. Loss of electroencephalograms (EEG) variability might be a useful marker of brain age.

Thalamocortical coherence and causality in different sleep stages using deep brain stimulation recordings

Previous research has shown an interplay between the thalamus and cerebral cortex during NREM sleep in humans, however the directionality of the thalamocortical synchronization is as yet unknown. In this study thalamocortical connectivity during different NREM sleep stages using sleep scalp electroencephalograms and local field potentials from the left and right anterior thalamus was measured in three epilepsy patients implanted with deep brain stimulation electrodes. Connectivity was assessed as debiased weighted phase lag index and granger causality between the thalamus and cortex for the NREM sleep stages N1, N2 and N3. Results showed connectivity was most prominently directed from cortex to thalamus. Moreover, connectivity varied in strength between the different sleep stages, but barely in direction or frequency. These results imply relatively stable thalamocortical connectivity during NREM sleep directed from the cortex to the thalamus.

Role of medullary cardiorespiratory neurons on the maintenance of altered sleep function in heart failure

Sleep‐disordered breathing (SDB) and sleep fragmentation (SF) (i.e. repetitive short interruptions of sleep) are frequently reported in heart failure (HF) patients. Interestingly, SDB and SF has been both closely associated with the generation of breathing disorders. Importantly, our previous work showed that partial ablation of pre‐sympathetic catecholaminergic neurons (C1) located at the rostral ventrolateral medulla (RVLM) results in marked improvements in breathing disorders in rats with HF. However, the contribution of RVLM‐C1 neurons on sleep‐related disorders in the setting of cardiac failure has not been previously studied. Therefore, we aimed to determine the contribution of RVLM‐C1 neurons on sleep architecture in HF. Adult male Sprague‐Dawley rats (250 g) underwent volume overload to induce HF. After four weeks, anti‐dopamine β‐hydroxylase‐saporin (DβH–SAP: 2.5ng/150nl; or saline) was used to selectively destroy RVLM‐C1 neurons (‐12.36 mm AP from bregma; ± 2.2 mm ML; 8.5 mm DV). Breathing function was determined by unrestrained whole‐body plethysmograph and sleep function/sleep stages were assessed in electroencephalogram and electromyogram recordings obtained for chronic implanted leads. Compared to Sham rats, HF animals displayed no differences in the total time spent in rapid eye movement (REM) and non‐rapid eye movement (nREM) sleep stages. However, duration of each nREM epoch was significantly (p&lt;0.05) lower in HF rats (3.4 ± 0.3 vs. 2.2 ± 0.2 min, Sham vs. HF, respectively). Accordingly, HF rats showed an increased number of nREM epochs compared to Sham animals (12.0 ± 2 vs. 17 ± 2 events/h, Sham vs. HF, respectively). Interestingly, HF rats displayed loss of ventilatory stability compared to Sham rats only at nREM sleep (Irregularity score, nREM: 12.1 ± 2.0 vs. 15.9 ± 1.8%; REM: 22.9 ± 2.0 vs 24.1 ± 3.2%; Sham vs. HF, respectively). Furthermore, the incidence of sigh‐triggered arousal events during nREM sleep was increased in HF rats. Conversely, sleep probability was decreased by ~35% in HF animals compared to Sham animals. Remarkably, ablation of RVLM‐C1 neurons with DβH–SAP in HF improved nREM breathing regularity and restores normal nREM sleep duration (3.4 ± 0.3 vs. 3.1 ± 0.3 min, Sham vs. HF+DβH–SAP, respectively). In addition, DβH–SAP treatment in HF decreased sigh‐triggered arousals by ~45% being the outcome a reduction in SF in HF rats that underwent C1 ablation. Our data shows that irregular breathing is closely linked to altered sleep in HF rats and support a role for RVLM‐C1 neurons on sleep regulation in the setting of HF.

Sleep patterns differ across Alzheimer's disease phenotypes: Implications for selective vulnerability and customized treatment.

Sleep-wake disturbances are a prominent feature in Alzheimer's Disease (AD), negatively impacting patients and caregivers' quality of life. Growing evidence suggests that sleep-wake dysregulation happens early in AD due to the AD-tau degeneration of the arousal system (i.e., locus coeruleus). However, whether the pattern of sleep-wake dysfunction is different among AD clinical variants and how it is different remains unclear. It is an unmet gap of high importance because these differing patterns may require tailored treatment strategies. Since AD phenotypes with different clinical profiles have distinct regional patterns of cortical tau, we hypothesized that AD variants may also have differential sleep patterns. Therefore, we aim to contrast the behavioral sleep features within AD variants. A cohort of 24 patients, including 8 amnestic AD and 16 non-amnestic AD (7 lvPPA, 9 PCA), with a neuropathological or biomarker based diagnosis of AD, underwent an overnight EEG monitoring. Sleep stages were evaluated by PRANA software and confirmed by REM Logic spectral analyses. We performed nonparametric analyses to study group differences in the amount of each sleep stage as a percent of total sleep time. Additionally, we performed linear regression models adjusting by the age of onset, MMSE, and CDR Total. There were no differences between amnestic AD, lvPPA, and PCA groups in gender, age of onset (59±11, 55±6, 59±8, respectively), global cognition (MMSE 21±7, 23±3, 21±5), or functional performance (CDR Total 0.9±0.5, 0.7±0.3, 1±0.4). Compared to non-amnestic AD, amnestic AD had more REM sleep (p<0.05) and a trend toward lower NREM sleep stages 1 and 3. In the same line, this pattern was still observed when comparing the three clinical variants (amnestic AD, lvPPA, and PCA) (p<0.05). Regression models confirmed that clinical AD variants accounted for differences in REM sleep (p<0.01). We are continuing to evaluate additional AD participants and age-matched healthy controls. Preliminary results suggest that sleep profiles might differ between AD variants. The existence of specific sleep-wake profiles would suggest differential degeneration patterns of the arousal system within AD phenotypes, which would open the door to uncover the selective vulnerability of subcortical structures for the first time.

Aspects of tree shrew consolidated sleep structure resemble human sleep

Understanding human sleep requires appropriate animal models. Sleep has been extensively studied in rodents, although rodent sleep differs substantially from human sleep. Here we investigate sleep in tree shrews, small diurnal mammals phylogenetically close to primates, and compare it to sleep in rats and humans using electrophysiological recordings from frontal cortex of each species. Tree shrews exhibited consolidated sleep, with a sleep bout duration parameter, τ, uncharacteristically high for a small mammal, and differing substantially from the sleep of rodents that is often punctuated by wakefulness. Two NREM sleep stages were observed in tree shrews: NREM, characterized by high delta waves and spindles, and an intermediate stage (IS-NREM) occurring on NREM to REM transitions and consisting of intermediate delta waves with concomitant theta-alpha activity. While IS-NREM activity was reliable in tree shrews, we could also detect it in human EEG data, on a subset of transitions. Finally, coupling events between sleep spindles and slow waves clustered near the beginning of the sleep period in tree shrews, paralleling humans, whereas they were more evenly distributed in rats. Our results suggest considerable homology of sleep structure between humans and tree shrews despite the large difference in body mass between these species.

Increased chin muscle tone during all sleep stages in children taking selective serotonin reuptake inhibitor antidepressants and in children with narcolepsy type 1.

To assess if selective serotonin reuptake inhibitor (SSRI) antidepressants are able to modify the chin electromyogram (EMG) tone during sleep also in children. Twenty-three children and adolescents (12 girls, mean age 14.1 years, SD 2.94) under therapy with antidepressant for their mood disorder were consecutively recruited and had a PSG recording. Twenty-one were taking were taking SSRI and treatment duration was 2-12 months. An age- and sex matched group of 33 control children (17 girls, mean age 14.2 years, SD 2.83) and 24 children with narcolepsy type 1 (12 girls, mean age 13.7 years, SD 2.80) were also included. The Atonia Index was then computed for each NREM sleep stage and for REM sleep, also all EMG activations were counted. Atonia Index in all sleep stages was found to be significantly reduced in children with narcolepsy followed by the group taking SSRI antidepressants and the number of EMG activations was also increased in both groups. Fluoxetine, in particular, was found to be significantly associated with reduced Atonia index during NREM sleep stages N1, N2, and N3, and with an increased number of EMG activations/hour during sleep stage N3. Similarly to adults, SSRI antidepressants are able to modify the chin EMG tone in children during REM sleep, as well as during NREM sleep stages. Different pharmacological properties of the different SSRI might explain the differential effect on chin tone during sleep found in this study.

Acute mild dim light at night slightly modifies sleep but does not affect glucose homeostasis in healthy men

ObjectiveWe evaluated the effect of acute mild light exposure at night on sleep architecture and glucose homeostasis. Patients/methodsTwenty healthy normal-weight men took part in two conditions of a randomized, controlled, balanced cross-over experimental study: i) two-consecutive nights with 8-h of sleep under dLAN (<5 lux) or ii) total darkness (CON). Sleep was evaluated by polysomnography. In the morning following 'night2', glucose homeostasis was assessed by an intravenous glucose tolerance test (ivGTT) with consecutive measures of glucose, insulin, and c-peptide. Plasma cortisol was measured at night before sleep, after morning awakening, and during mid-afternoon hours. ResultsThere was no significant difference in total sleep time, sleep efficiency, and sleep latency between conditions (all p > 0.66). However, NREM sleep stage N3 latency was prolonged after dLAN (p = 0.02) and NREM sleep stage 2 was decreased after two nights with dLAN (p = 0.04). During the first sleep hour, power in slow-oscillations, slow-waves, and delta bands diminished after dLAN (all p < 0.04). Glucose, insulin, and c-peptide were not altered by dLAN (all p > 0.14). Cortisol was reduced in the afternoon after 'night1' and in the morning after 'night2' (both p < 0.03). ConclusionsdLAN slightly disturbed sleep architecture and quality without impairment of glucose homeostasis. Longer exposure to chronic dLAN might be needed to unmask its hypothesized metabolic consequences.

Polysomnographic markers of suicidal ideation in untreated unipolar major depressed individuals

Given the major role played by sleep in the particular relationship between suicidality and major depression, the aim of this study was to empirically identify polysomnographic markers specific to suicidal ideation in major depressed individuals in order to allow better suicide prevention in this high-risk subpopulation. Demographic and polysomnographic data from 190 individuals (34 healthy controls and 156 untreated unipolar major depressed individuals) recruited from the sleep laboratory database were analysed. Suicidal ideation were considered present if the score in item G of the Beck Depression Inventory was ≥1 and/or if they were highlighted during the systematic psychiatric assessment conducted on admission to the sleep laboratory. Independently of depression severity, major depressed individuals with suicidal ideation present a decrease in deep NREM sleep (slow-wave sleep) and an increase in light NREM sleep (stage 1 + stage 2) compared to those without suicidal ideation. There are no significant differences for the other polysomnographic parameters. In our study, we highlighted the existence of potential polysomnographic markers of suicidal ideation in untreated unipolar major depressed individuals, which seems to open up new perspectives for the identification and management of individuals at high-risk of suicide in this particular subpopulation.

285 Pilot field study of Ambulatory Sleep-Staging in Shift-Working Air Traffic Controllers

Abstract Introduction The simplicity of wrist actigraphy for sleep-wake monitoring in the field contributes to its ubiquity in shift-work research. However, devices based solely on recording activity levels are generally not suitable to quantify sleep architecture. This is a limitation as quantifying changes in sleep stages caused by circadian misalignment is important to better assess the consequences of sleep-wake disruption in shift-working populations. This pilot study was conducted to evaluate whether sleep stages vary with respect to different shift types. Methods Six male air traffic controllers aged 48.5±8.4 years (mean±SD) completed the protocol which entailed two ~9-day periods, each with up to 6 workdays. Schedules comprised 1 or 2 early night shifts (19:30–03:30h), followed by an evening shift (15:00–23:00h), day shift (09:00–17:00h), morning shift (06:30–14:30h), and 1 or 2 full night shifts (23:00–7:00h). A portable sleep-staging device (Somno-Art, Paris, France) that monitored activity levels and heart rate was worn on the non-dominant forearm during bedtime and produced estimates of REM and NREM sleep stages with a proprietary algorithm. Total sleep time (TST) and sleep stages were assessed per shift type with mixed-effects models. Results Final analyses were based on 70 sleep periods preceding workdays, standardized to 24 h to account for the different intervals between consecutive shifts. Analyses revealed significant effects of shift type for TST (p=.016), stages N1 (p=.010) and N2 (p=.043), but none for N3 (p=.055) or REM (p=.117) sleep. TST and stage N1 sleep prior to night shifts was shorter than for day, evening, or early night shifts (all p&amp;lt;.05). Participants obtained less stage N2 sleep prior to night shifts than days shifts (p=.049). Conclusion This pilot study suggests variations in TST across shifts were predominantly due to differences in light sleep stages, whereas no significant differences in N3 and REM sleep were observed. Thus, while TST was reduced for night shifts, participants obtained similar durations of the most recuperative stages. These findings highlight the importance of refined monitoring of sleep in field research involving shift-work. Support (if any) Project funded by NAV Canada. Devices lent by the Somno-Art company. A.K. received a postdoctoral fellowship from the Fonds de Recherche en Santé du Québec (FRQS).

Sleep-improving effects of a novel motion mattress

To promote better sleep, we designed a motion mattress producing slow and swaying movements by slow regional changes of height generated by 10 separated air cells underneath. The motion induces a stretching movement and a gentle swaying movement of the user’s body. In this study, we examined its sleep-improving effects. Subjects who were not fully satisfied with their sleep were recruited. The study was performed for three periods, each of which was a week with a distinct condition. The first period was assigned as pre-experimental (PRE) period when the subjects sleep using their own mattress. The other two periods were assigned as motion mattress active (MM1) period and motion mattress control period. All subjects were randomly divided into two groups for a cross-over study. The subjects recorded electroencephalograms at home for themselves during these 3 weeks. Subjects were asked to perform sleep questionnaires. We examined the effects of this motion mattress at home by measuring the subjective and objective sleep parameters of 11 subjects. As for the objective sleep parameters, Sleep efficiency, NREM sleep stage 3, and awakening index significantly improved during MM1 compared with PRE (p < 0.05). As for the subjective sleep quality, subjects gave significantly higher value to the questions about “falling asleep quickly”, “slept soundly”, and “woke up refreshed”. Our newly developed motion mattress improved both objective and subjective sleep parameters.

Comparison of autonomic activity between N2 and N3 stages of NREM sleep: evaluation through heart rate variability metrics

Heart rate variability (HRV) considered as an indicator of the autonomic activity, shows differences between NREM and REM sleep. However, when evaluating during NREM sleep, some authors evaluate without considering the different stages, while others do it. There are discrepancies between values obtained from stages N2 and N3. Our objective was to evaluate whether differences exist between stages N2 and N3 based on several metrics of HRV that reflect the autonomic activity. Additionally, we analyzed the structure of these metrics through principal component analysis (PCA) at each sleep stage. Polysomnograms were recorded in 24 healthy subjects. We found significant differences in the LF and THM metrics with higher values in stage N2. The relative power of HF metric showed a significant difference with higher value in stage N3, however, this metric showed inconsistencies related to other HF representations. Two factors were extracted with PCA and their structure was stable across sleep stages. One factor accounted for 92% of the variance during stage N2 with moderate to high loadings for metrics most strongly associated with the parasympathetic activity. A second factor accounted for 91% of the variance during stage N3 with moderate to high loadings for metrics associated with parasympathetic and blood pressure control. Physiological mechanisms regulated by central commands that may involve neurons in the hypothalamus, pons, and midbrain may explain the differences in LF and THM metrics. The combination of stages N2 and N3 as NREM should be done according to the type of HRV metrics used.

Sleep and Epilepsy: a Focused Review of Pathophysiology, Clinical Syndromes, Co-morbidities, and Therapy.

A healthy brain requires balancing of waking and sleeping states. The normal changes in waking and sleeping states result in neurophysiological conditions that either increase or decrease the tendency of seizures and interictal discharges to occur. This article reviews the manifold and complex relationships between sleep and epilepsy and discusses treatment of the sleep-related epilepsies. Several forms of epilepsy predominantly or exclusively manifest during sleep and seizures tend to arise especially from light NREM sleep. Diagnostic interictal epileptiform discharges on the electroencephalogram are also most likely to be activated during deep NREM sleep stage N3. Epileptiform discharges and antiepileptic medications may in turn detrimentally impact sleep. Co-morbid sleep disorders also have the potential to worsen seizure control. Sleep has an important key association with sudden unexpected death in epilepsy (SUDEP). Further research is necessary to understand the complex relationships between sleep and epileptic disorders and their treatments.

Increased rapid eye movement density in Chinese patients with Parkinson's disease and RBD.

Impaired rapid eye movement sleep is common among patients with Parkinson's disease (PD). However, information on rapid eye movement density (REM) among PD patients is currently lacking. The current study sought to characterize REM density in PD patients and to examine the associations between REM density sleep parameters and clinical manifestations. We retrospectively recruited 172 PD patients. All participants were assessed with a two-night polysomnography, and REM density was calculated. Clinical assessments were completed in PD patients before polysomnography. Rapid eye movement sleep behavior disorder (RBD) was observed in 93 patients (54.1%). The disease duration, UPDRS part III score, Hoehn and Yahr (H-Y) stage, and HAMA, HAMD, PDQ-39 scores, and REM density in the Parkinson's disease patients with rapid eye movement sleep behavior disorder (RBD) were significantly higher than in the patients without RBD (P < 0.05). However, NREM sleep stage 3 time (N3 time) and percentage of N3 time of total sleep time (N3%) were significantly lower in the RBD patients than in the patients without RBD (P < 0.05). The forward binary logistic regression model showed that REM density, UPDRS-III score, and N3 sleep time were associated with RBD in the PD patients. Our results confirm the high prevalence of RBD in patients with PD. Increased REM density was the main risk factor of RBD.

0788 Increased Rapid Eye Movement Density in Chinese Patients with Parkinson’s Disease and RBD

Abstract Introduction Impaired rapid eye movement sleep is common among patients with Parkinson’s disease (PD). However, information on rapid eye movement density (REM density) among PD patients is currently lacking. The current study sought to characterize REM density in PD patients and to examine the associations between REM density sleep parameters and clinical manifestations. Methods We retrospectively recruited 172 PD patients. All participants were assessed with a two-night polysomnography, and REM density was calculated. Clinical assessments were completed in PD patients before polysomnography. Results Rapid eye movement sleep behavior disorder (RBD) were observed in 93 patients (54.1%). The disease duration, UPDRS part III score, Hoehn and Yahr (H-Y) stage, and HAMA, HAMD, and PDQ-39 scores in the Parkinson’s disease patients with rapid eye movement sleep behavior disorder (RBD) were significantly higher than in the patients without RBD (P&amp;lt;0.05). The REM density was also significantly higher in the RBD patients than in the patients without RBD (P&amp;lt;0.05). NREM sleep stage 3 time (N3 time) and percentage of N3 time of total sleep time (N3%) were higher in patients without RBD. The forward binary logistic regression model showed that REM density, UPDRS-III score and N3 sleep time were associated with RBD in the PD patients. Conclusion Our results confirm the high prevalence of RBD in patients with PD. Increased REM density was the main risk factor of RBD. Support Special Funds of the Jiangsu Provincial Key Research and Development Projects (grant No. BE2018610)

0147 Dynamic Alterations in Functional Connectivity Between Sleep- and Wake-Promoting Regions of the Human Brain at the Sleep Onset Period

Abstract Introduction The sleep onset period, involving so-called stage N1 sleep largely, is characterized by a reduction in the amount of alpha activity compared to wakefulness. Various kinds of physiological and psychological changes are also apparent, such as slow eye movements, changes in muscle tonus, and the hypnagogic dream-like mentation. These phenomena are thought to be the reflection of dynamic alterations in the brain during the transition period, however, details of these changes have still been uncovered. Methods We aimed to investigate a dynamic shift in the brain connectivity at sleep onset using the method of EEG-fMRI simultaneous recording. Twenty-three healthy subjects participated. EEG/fMRI were recorded simultaneously during an hour’s nap in a 3T-MRI scanner and real-time monitoring of EEG was performed. To record the transition period between multiple times, an experimenter inside a scanner room touched a subject’s foot for inducing arousal when a shift to NREM sleep stage 1 was observed. EEG data were scored according to the AASM criteria. Based on sleep stages defined by polysomnographic findings, we investigated alterations in functional connectivity of sleep- and wake- promoting regions within the hypothalamus and other areas including the thalamus. Results Posterior alpha power showed significant positive correlation with BOLD signals in the anterior and medial dorsal thalamus. Connectivity between the thalamus and cortical regions reduced sharply in the descent to sleep stage. Meanwhile, BOLD signals of the sleep- and wake- promoting regions within the hypothalamus fluctuated with certain temporal lags from fluctuations of alpha rhythm at sleep onset. Conclusion Present findings provide preliminary evidence of dynamics of wake- and sleep- promoting regions in the human brain in vivo. Our data also support the hypothesis that reduced thalamocortical connectivity which limits the capacity to integrate information is associated with the transition of consciousness at sleep onset. Support None