Non-rapid Eye Movement Sleep Stages Research Articles

Objective sleep characteristics and risk factors for sleep apnea in heart failure patients with different left ventricular ejection fraction

To investigate the objective sleep characteristics and the independent risk factors for sleep apnea in heart failure (HF) patients with different left ventricular ejection fractions (LVEF). A total of 107 patients with chronic HF hospitalized in the Department of Cardiology of our hospital from April, 2019 to October, 2020 were included in this study. According to the LVEF measured by echocardiography, the patients were divided into reduced ejection fraction (HFrEF) group (n=35), mid-range ejection fraction (HFmrEF) group (n=21), and preserved ejection fraction (HFpEF) group (n=51). The baseline demographic and clinical characteristics of the patients were recorded. To assess the objective sleep characteristics, whole night polysomnography was scheduled for all the patients. Spearman correlation and multinomial logistic regression analyses were used to explore the factors affecting objective sleep characteristics. The patients in HFpEF group had significantly lower proportion of non-rapid eye movement sleep stage 1, apnea hypopnea index (AHI), and central sleep apnea (CSA) than those in HFrEF group (all P < 0.05). The baseline demographic data or sleep structures in HFmrEF group did not differ significantly from those in the other two groups. Spearman correlation analysis revealed significant correlations of the male sex, diuretics use, NT-proBNP, LVEF, and total cholesterol levels with the severity of AHI (all P < 0.05). After adjusting for potential confounders, multiple logistics regression analysis showed that age, drinking, and LVEF levels were independently associated with the severity of AHI (all P < 0.05). Abnormal objective sleep architectures occur in all HF patients, manifested mainly by sleep apnea. The incidences of sleep apnea and CSA are lower in patients with HFpEF than in those with HFrEF. Age, drinking, and LVEF levels are independent risk factors for the occurrence and severity of sleep apnea.

The effects of auricular acupressure on the sleep of the elderly using polysomnography, actigraphy and blood test: Randomized, single-blind, sham control

AimThis study was conducted to examine the effects of auricular acupressure on sleep in elderly people with sleep disorders. MethodsThis was a randomized, double-blind, sham-controlled study. The participants aged over 65 years old were randomly assigned to the experimental group (n = 21) and the sham control group (n = 21). The participants in the experimental group and the sham control group received auricular acupressure on sleep-disorder-related points or to sleep-disorder-unrelated points, respectively. The intervention was implemented for a total of eight weeks. To validate the effects of the treatment, polysomnography with the Alice portable sleep diagnostic system; actigraphy with Fitbit Alta; and melatonin, serotonin, and cortisol blood tests were conducted. ResultsNon-Rapid Eye Movement sleep stage 3 duration change (Z = −2.187, p = .029) and Non-Rapid Eye Movement sleep stage 3 ratio change (Z = −2.423, p = .014), measured by polysomnography, of the experimental group showed a significant increase over time compared to the sham control group. ConclusionsAuricular acupressure applied for eight weeks was found to be effective in increasing Non-Rapid Eye Movement sleep stage 3 duration and Non-Rapid Eye Movement sleep stage 3 ratio among sleep stages of the elderly. Consequently, it showed that auricular acupressure can be used as a proven nursing intervention method for sleep disorder in elders to increase deep sleep duration and ratio.

Measuring the effects of sleep on epileptogenicity with multifrequency entropy

ObjectiveWe demonstrate that multifrequency entropy gives insight into the relationship between epileptogenicity and sleep, and forms the basis for an improved measure of medical assessment of sleep impairment in epilepsy patients. MethodsMultifrequency entropy was computed from electroencephalography measurements taken from 31 children with Benign Epilepsy with Centrotemporal Spikes and 31 non-epileptic controls while awake and during sleep. Values were compared in the epileptic zone and away from the epileptic zone in various sleep stages. ResultsWe find that (I) in lower frequencies, multifrequency entropy decreases during non-rapid eye movement sleep stages when compared with wakefulness in a general population of pediatric patients, (II) patients with Benign Epilepsy with Centrotemporal Spikes had lower multifrequency entropy across stages of sleep and wakefulness, and (III) the epileptic regions of the brain exhibit lower multifrequency entropy patterns than the rest of the brain in epilepsy patients. ConclusionsOur results show that multifrequency entropy decreases during sleep, particularly sleep stage 2, confirming, in a pediatric population, an association between sleep, lower multifrequency entropy, and increased likelihood of seizure. SignificanceWe observed a correlation between lowered multifrequency entropy and increased epileptogenicity that lays preliminary groundwork for the detection of a digital biomarker for epileptogenicity.

EEG Patterns Prior to Motor Activations of Parasomnias: A Systematic Review.

IntroductionNon-rapid eye movement (NREM) parasomnias are defined as abnormal nocturnal behaviors that typically arise from the NREM sleep stage 3 during the first sleep cycle. The polysomnographic studies showed an increase in sleep fragmentation and an atypical slow wave activity (SWA) in participants with NREM parasomnias compared to healthy controls. To date, the pathophysiology of NREM parasomnias is still poorly understood. The recent investigation of the EEG patterns immediately before parasomnia events could shed light on the motor activations’ processes. This systematic review aims to summarize empirical evidence about these studies and provide an overview of the methodological issues.MethodsA systematic literature search was carried out in PubMed, Web of Science, and Scopus, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). The documents obtained were evaluated using the Newcastle–Ottawa Scale (NOS).ResultsNine studies were included in the qualitative synthesis. The major evidence revealed an increased slow frequency EEG activity immediately before the motor activations in frontal and central areas and increased beta activity in the anterior cingulate cortices.DiscussionThe investigation of EEG patterns before parasomniac episodes could provide new insight into the study of NREM parasomnia pathophysiology. The high- and low-frequency EEG increase before the episodes could represent a predictive electrophysiological pattern of the motor activations’ onset. Overall, identifying specific sleep markers before parasomnias might also help differentiate between NREM parasomnias and other motor sleep disorders. Different methodological protocols should be integrated for overcoming the lack of consistent empirical findings. Thus, future studies should focus on the topographical examination of canonical EEG frequency bands to better understand spatial and time dynamics before the episodes and identify the networks underlying the onset of activations.

Determination of the sleep-wake pattern and feasibility of NREM/REM discrimination using the non-invasive piezoelectric system in rats.

The piezoelectric cage-floor sensors have been used to successfully dissect sleep patterns in mice based on signal features related to respiration and body movements. We studied performance of the piezoelectric system to quantify the sleep-wake pattern in the rat over 7days of recording compared with a visual electroencephalogram/electromyogram scoring, and under two light/dark (LD12:12 and LD16:8) photoperiods leading to change in the 24-hr sleep characteristics (N=7 per group). The total sleep time (%/24hr) over the 7days recording and hourly sleep time over the last 24-hr recording were not statistically different between methods under the two photoperiods. Both methods detected higher total sleep time with the LD16:8 photoperiod compared with LD12:12 (p<.05), and correlated significantly (p<.001) at light and dark periods during each photoperiod. The accuracies for discrimination of sleep-wake patterns between methods were 81.9% and 84.9% for LD12:12 and LD16:8, respectively. In addition, spectral analysis of the respiratory signal given by piezo during all 10-s periods of the corresponding non-rapid eye movement and rapid eye movement sleep periods recorded by electroencephalogram/electromyogram resulted in selection of 36 features that could be inserted in an automated non-rapid eye movement sleep and rapid eye movement sleep classification, with 90% accuracy with the electroencephalogram/electromyogram visual scoring. The piezo system proved to be a reliable non-invasive alternative to electroencephalogram recording to study total sleep time in rat, with feasibility to discriminate between non-rapid eye movement and rapid eye movement sleep stages. This will be interesting in pharmacological or bio-behavioural studies evaluating sleep patterns or the restorative functions of sleep in the body and the brain.

Mandibular advancement device as treatment trial for catathrenia (nocturnal groaning).

Catathrenia is a rare disease, classified as isolated symptoms and normal variants under sleep-related breathing disorders in the International Classification of Sleep Disorders, third edition. Because of its rarity, the research on its pathogenesis and treatment is insufficient. This study aimed to evaluate whether the mandibular advancement device (MAD) could be considered an alternative treatment trial and if so, to explore factors predicting its effectiveness. Thirty patients (12 men and 18 women, aged 16-67 years) with catathrenia participated in the study. They underwent standard clinical evaluation, questionnaires, physical examinations, craniofacial evaluations, video polysomnography, and imaging of the upper airway before and after the insertion of the MAD. The groaning index (groaning episodes per hour of sleep) and apnea-hypopnea index were evaluated, and anatomic factors predicting effectiveness were explored. The sleep efficiency of most patients was higher than 80%, and groaning was present throughout all stages of sleep. With the insertion of the MAD, the groaning index decreased significantly from 5.8 (2.7-14.3) to 2.8 (1.3-12.2) events/h (P = .014). Age had a negative effect on efficacy. Mandibular repositioning of the MAD, especially the amount of vertical opening and changes of the cross-sectional area of the hypopharynx, was positively related with efficacy. The MAD could be considered a possible treatment trial for those seeking treatment for groaning. Registry: Chinese Clinical Trial Register; Name: The etiology of catathrenia based on oral and maxillofacial system; URL: http://www.chictr.org.cn/showproj.aspx?proj=22286; Identifier: ChiCTR-COC-17013239. Yu M, Hao Z, Xu L, Wen Y, Han F, Gao X. Mandibular advancement device as treatment trial for catathrenia (nocturnal groaning). J Clin Sleep Med. 2021;17(9):1767-1776.

Human blood adenosine biomarkers and non-rapid eye movement sleep stage 3 (NREM3) cortical functional connectivity associations during a 30-day head-down-tilt bed rest analogue: Potential effectiveness of a reactive sledge jump as a countermeasure.

We investigated the alterations of sleep regulation and promotion biomarkers as adenosine through its enzymes total adenosine deaminase (tADA)/adenosine deaminase (ADA2) in a microgravity analogue environment of head-down-tilt bed rest and their association with brain connectivity networks during non-rapid eye movement sleep stage 3 (NREM3), as well as the effectiveness of the reactive sledge (RSL) jump countermeasure to promote sleep. A total of 23 healthy male volunteers were maintained in 6° head-down-tilt position for 30days and assigned either to a control or to a RSL group. Blood collection and polysomnographic recordings were performed on data acquisition day 1, 14, 30 and -14, 21, respectively. Immunochemical techniques and network-based statistics were employed for adenosine enzymes and cortical connectivity estimation. Our findings indicate that human blood adenosine biomarkers as well as NREM3 cortical functional connectivity are impaired in simulated microgravity. RSL physical activity intervened in sleep quality via tADA/ADA2 fluctuations lack, minor cortical connectivity increases, and limited degree of node and resting-state networks. Statistically significant decreases in adenosine biomarkers and NREM3 functional connectivity involving regions (left superior temporal gyrus, right postcentral gyrus, precuneus, left middle frontal gyrus, left postcentral gyrus, left angular gyrus and precuneus) of the auditory, sensorimotor default-mode and executive networks highlight the sleep disturbances due to simulated microgravity and the sleep-promoting role of RSL countermeasure. The head-down-tilt environment led to sleep deterioration projected through NREM3 cortical brain connectivity or/and adenosine biomarkers shift. This decline was more pronounced in the absence of the RSL countermeasure, thereby highlighting its likely exploitation during space missions.

Correlations of diurnal brain functional variations with serum biomarkers and objective sleep quality in patients with chronic insomnia disorder

Objectives: To investigate the correlations of diurnal brain functional variations with serum biomarkers and objective sleep quality in patients with chronic insomnia disorder (CID). Methods: A total of 60 CID patients and 30 healthy sleep volunteers who visited Department of Sleep Disorders of Chaohu Hospital affiliated to Anhui Medical University from March 2018 to June 2019 were collected. Diurnal brain function state was evaluated by Quantitative Measurement System of Brain Functional Status, and serum concentrations of corticotropin-releasing hormone (CRH) and glial fibrous acidic protein (GFAP) were detected using enzyme-linked immunosorbent assay (ELISA). The sleep quality in the CID group was evaluated using ploysomnography (PSG) at the same time. The brain function status indicators with significant changes in CID group were acquired, and the consistency of these indicators with serum biological markers and objective sleep quality was analyzed. Results: There were 23 males and 37 females in chronic in somnia patients; 15 males and 15 females in the healthy control group. Compared with the healthy controls, four brain function indicators of CID patients increased (brain inertia (196.0(163.0, 258.0)vs 168.5(148.8,182.5)), brain chaos (5.0(1.0, 10.0)vs 0(0,2.0)), internal concentration (31.0(13.0, 45.0)vs 2.0(0,27.5)) and endogenous anxiety (12.0(4.0, 18.0)vs 0(0,6.5)), but one indicator decreased (brain inhibitory value (47.0(32.0, 58.0)vs 59.0(46.3,66.3))) (all P<0.05).The brain chaos value positively correlated with the serum GFAP level (r=0.374,P=0.006), and the brain inertia value positively correlated with the serum CRH level (r=0.299,P=0.031). The value of brain inhibition positively correlated with the sleep latency (r=0.284,P=0.042). However, the values of internal concentration negatively correlated with the sleep efficiency (r=-0.276,P=0.048) and the time in non-rapid eye movement sleep stage 1 (r=-0.341, P=0.024). Conclusion: The brain waves of CID patients show significant changes in their brain function indicators, which are related to serum biological markers and objective sleep quality.

NREM sleep stages specifically alter dynamical integration of large-scale brain networks.

SummaryFunctional dissociations in the brain observed during non-rapid eye movement (NREM) sleep have been associated with reduced information integration and impaired consciousness that accompany increasing sleep depth. Here, we explored the dynamical properties of large-scale functional brain networks derived from transient brain activity using functional magnetic resonance imaging. Spatial brain maps generally display significant modifications in terms of their tendency to occur across wakefulness and NREM sleep. Unexpectedly, almost all networks predominated in activity during NREM stage 2 before an abrupt loss of activity is observed in NREM stage 3. Yet, functional connectivity and mutual dependencies between these networks progressively broke down with increasing sleep depth. Thus, the efficiency of information transfer during NREM stage 2 is low despite the high attempt to communicate. Critically, our approach provides relevant data for evaluating functional brain network integrity and our findings robustly support a significant advance in our neural models of human sleep and consciousness.

Altered thalamic connectivity in insomnia disorder during wakefulness and sleep.

Insomnia disorder is the most common sleep disorder and has drawn increasing attention. Many studies have shown that hyperarousal plays a key role in the pathophysiology of insomnia disorder. However, the specific brain mechanisms underlying insomnia disorder remain unclear. To elucidate the neuropathophysiology of insomnia disorder, we investigated the brain functional networks of patients with insomnia disorder and healthy controls across the sleep–wake cycle. EEG‐fMRI data from 33 patients with insomnia disorder and 31 well‐matched healthy controls during wakefulness and nonrapid eye movement sleep, including N1, N2 and N3 stages, were analyzed. A medial and anterior thalamic region was selected as the seed considering its role in sleep–wake regulation. The functional connectivity between the thalamic seed and voxels across the brain was calculated. ANOVA with factors “group” and “stage” was performed on thalamus‐based functional connectivity. Correlations between the misperception index and altered functional connectivity were explored. A group‐by‐stage interaction was observed at widespread cortical regions. Regarding the main effect of group, patients with insomnia disorder demonstrated decreased thalamic connectivity with the left amygdala, parahippocampal gyrus, putamen, pallidum and hippocampus across wakefulness and all three nonrapid eye movement sleep stages. The thalamic connectivity in the subcortical cluster and the right temporal cluster in N1 was significantly correlated with the misperception index. This study demonstrated the brain functional basis in insomnia disorder and illustrated its relationship with sleep misperception, shedding new light on the brain mechanisms of insomnia disorder and indicating potential therapeutic targets for its treatment.

Changes in Heart Rate Variability and Baroreflex Sensitivity During Daytime Naps.

Background and ObjectivesChanges in autonomic cardiac activity during night sleep are well documented. However, there is limited information regarding changes in the autonomic cardiac profile during daytime naps. Heart rate variability (HRV) and baroreflex sensitivity (BRS) are reliable measures of autonomic cardiac activity. The purpose of this study was to determine the changes in HRV and BRS during daytime naps in healthy men.MethodsThis was a cross-sectional study of 25 healthy men. Polysomnographic recording with electrocardiogram monitoring was conducted for all volunteers during a 50–80 min nap between 3.30 pm and 5.30 pm. Five-minute segments during pre-nap wakefulness, non-rapid eye movement (NREM) sleep stages (N1, N2, and N3), rapid eye movement (REM) sleep stage, and post-nap wakefulness were used to measure changes in the variation in HRV parameters, including inter-beat interval (RR-interval), total spectral power (TP), high-frequency power (HF), low-frequency power (LF), and low frequency/high-frequency ratio (LF/HF). BRS was also measured for 10 min during pre- and post-nap wakefulness using finger arterial pressure measurement (Finometer Pro ®).ResultsHRV increased significantly during NREM sleep compared with that during pre-nap wakefulness (p < 0.05), as reflected by RR-interval prolongation, higher HF, and increased HFnu (normalized units). Furthermore, there was a parallel reduction in TP, LF, and LF/HF ratio during NREM sleep, indicating parasympathetic predominance over cardiac autonomic activity. HF and HFnu were significantly reduced during REM sleep compared with that during NREM sleep (p < 0.05). BRS did not show significant differences between pre- and post-nap wakefulness.ConclusionWe observed a progressive increase in parasympathetic activity during daytime sleep as NREM sleep deepened compared with that during wakefulness and REM sleep. Daytime nap may have a favorable cardiovascular impact.

Correlation between suicidal ideation and polysomnography parameters in late-life depression patients

To investigate the relationship between sleep parameters and suicidal ideation in patients with late-life depression (LLD). Seventy-seven LLD patients over 60 years old from Sir Run Run Shaw Hospital of Zhejiang University during July 2017 and July 2018 were included in the study. All patients were assessed with Hamilton Depression Rating Scale (HAMD) and polysomnography (PSG) overnight. The suicidal score of item 3 in HAMD (HAM-D3)was used to define whether there was a suicidal ideation. Participants were subsequently grouped according to endorsement of presence (HAM-D3 score ≥1, n=46) versus absence (HAM-D3 score=0, n=31) of suicidal ideation symptoms. The sleep efficiency, total sleep time, wakefulness after sleep onset, rapid eye movement percent/latency, and non-rapid eye movement sleep stages 1-3 (N1-N3) were assessed. ANOVA analyses were conducted to explore the correlation of sleep parameters with suicidal ideation between the groups with and without suicidal ideation. In model 1, the HAM-D3 constituted the independent variable in separate ANOVA tests; in model 2 the impact of depressive symptoms were assessed as a covariate with sleep parameters. There was less stage N3 [(55±41)min, t=-4.731, P<0.05] and the reduced percentage of N3 [(15±11)%, t=-4.194, P<0.05] in LLD patients with suicidal ideation, compared with the LLD patients without suicidal ideation [(104±49) min, (26±11)%]. Correlation analyses revealed that there was a significant correlation between the suicidal ideation and the percentage of stage N3 and sleep time of stage N3 (both P<0.05). Suicidal ideation is associated with less N3 sleep in LLD patients.

Circadian and state-dependent core body temperature in people with spinal cord injury

Prospective cohort study. To analyze the circadian rhythm and state-dependent modulation of core body temperature (Tcore) in individuals with spinal cord injury (SCI) under controlled environmental conditions. Institute of the Neurological Sciences of Bologna, Italy. We assessed 48-h rectal Tcore and sleep-wake cycle by means of video-polygraphic recording in five cervical SCI (cSCI), seven thoracic SCI (tSCI), and seven healthy controls under controlled environmental conditions. cSCI showed higher night-time Tcore values with reduced nocturnal decrease, higher MESOR and earlier acrophase compared with tSCI and controls (p < 0.05 in all comparisons). The mean Tcore values during wake and non-rapid eye movement (NREM) and rapid eye movement (REM) sleep stages were higher in cSCI compared with tSCI and controls (p < 0.05). Tcore variability throughout the 24 h differed significantly between cSCI, tSCI, and controls. cSCI had higher Tcore values without physiological night-time fall compared with controls and tSCI, and a disrupted Tcore circadian rhythm. Furthermore, SCI individuals did not display the physiological state-dependent Tcore modulation. The disconnection of the sympathetic nervous system from its central control caused by the SCI could affect thermoregulation including Tcore modulation during sleep. It is also possible that the reduced representation of deep sleep in people with SCI impairs such ability. Further studies are necessary to evaluate whether improvement of sleep could ameliorate thermoregulation and vice versa.

Sleep and Nocturia in Under Age 50 Male Patients with Obstructive Sleep Apnea Syndrome

Objectives To investigate the prevalence of nocturia in young patients with obstructive sleep apnea syndrome (OSAS) and to find out the risk factors of nocturia in the patients. Methods We enrolled 415 untreated male OSAS patients (apnea-hypopnea index, AHI ≥5/h on polysomnography) who were under 50 years old (mean age 37.5±8.0 years). Participants completed Korean version of Beck depression inventory II (K-BDI-II), Pittsburgh sleep quality index-Korean (PSQI-K), insomnia severity index (ISI), and Epworth sleepiness scale (ESS). Participants were classified into nocturia and non-nocturia group according to the following question “Do you find yourself waking up to urinate more than twice each night?” All information was compared between two groups. Results 22.7% (94/415) of patients reported to have nocturia. Patients with nocturia had higher score of K-BDI-II, PSQI-K, ISI, and ESS although their age and the proportion of consumption of alcohol or caffeine and metabolic diseases were not different from patients without nocturia. AHI was not significantly higher in nocturia group (38.0±29.2/h) than non-nocturia group (32.8±25.7/h, p=0.118), however, parameters indicating sleep quality were worse in nocturia group, i.e. lesser non-rapid eye movement sleep stage 3 (N3) sleep % and higher arousal index, total apnea index, and 90% oxygen desaturation index (ODI). 90% ODI and N3 sleep % were revealed to be independent factors associated with nocturia. Conclusions Considerable numbers of male OSAS patients who are under 50 years suffer from nocturia and they have worse sleep quality compared to non-nocturia patients. Higher oxygen desaturation and lesser N3 sleep % are highly predictive factors for nocturia rather than AHI in these patients. Keywords: Nocturia; Sleep apnea, obstructive; Sleep; Hypoxia

Dream Recall upon Awakening from Non-Rapid Eye Movement Sleep in Older Adults: Electrophysiological Pattern and Qualitative Features

Several findings support the activation hypothesis, positing that cortical arousal promotes dream recall (DR). However, most studies have been carried out on young participants, while the electrophysiological (EEG) correlates of DR in older people are still mostly unknown. We aimed to test the activation hypothesis on 20 elders, focusing on the Non-Rapid Eye Movement (NREM) sleep stage. All the subjects underwent polysomnography, and a dream report was collected upon their awakening from NREM sleep. Nine subjects were recallers (RECs) and 11 were non-RECs (NRECs). The delta and beta EEG activity of the last 5 min and the total NREM sleep was calculated by Fast Fourier Transform. Statistical comparisons (RECs vs. NRECs) revealed no differences in the last 5 min of sleep. Significant differences were found in the total NREM sleep: the RECs showed lower delta power over the parietal areas than the NRECs. Consistently, statistical comparisons on the activation index (delta/beta power) revealed that RECs showed a higher level of arousal in the fronto-temporal and parieto-occipital regions than NRECs. Both visual vividness and dream length are positively related to the level of activation. Overall, our results are consistent with the view that dreaming and the storage of oneiric contents depend on the level of arousal during sleep, highlighting a crucial role of the temporo-parietal-occipital zone.

Melatonin effects on EEG activity during non-rapid eye movement sleep in mild-to-moderate Alzheimer´s disease: a pilot study

Introduction There is evidence to suggest that melatonin diminishes non-rapid eye movement sleep (NREMS) latency in patients with Alzheimer´s disease (AD). However, melatonin’s effects on cortical activity during NREMS in AD have not been studied. The objective of this research was to analyze the effects of melatonin on cortical activity during the stages of NREMS in 8 mild-to-moderate AD patients that received 5-mg of fast-release melatonin. Methods During a single-blind, placebo-controlled crossover study, polysomnographic recordings were obtained from C3-A1, C4-A2, F7-T3, F8-T4, F3-F4 and O1-O2. Also, the relative power (RP) and EEG coherences of the delta, theta, alpha1, alpha2, beta1, beta2 and gamma bands were calculated during NREMS-1, NREMS-2 and NREMS-3. These sleep latencies and all EEG data were then compared between the placebo and melatonin conditions. Results During NREMS-2, a significant RP increase was observed in the theta band of the left-central hemisphere. During NREMS-3, significant RP decreases in the beta bands were recorded in the right-central hemisphere, compared to the placebo group. After melatonin administration, significant decreases of EEG coherences in the beta2, beta1 and gamma bands were observed in the right hemisphere during NREMS-3. Discussion We conclude that short NREMS onset related to melatonin intake in AD patients is associated with a significant RP increase in the theta band and a decrease in RP and EEG coherences in the beta and gamma bands during NREMS-3. These results suggest that the GABAergic pathways are preserved in mild-to-moderate AD.

Sleep structure in sleep bruxism: A polysomnographic study including bruxism activity phenotypes across sleep stages.

The aim of the study was to assess sleep structure, phenotypes related to bruxism activity and basic respiratory parameters among a large group of participants with sleep bruxism and without obstructive sleep apnea. Adult participants with clinical suspicion of sleep bruxism and with no other significant medical history were recruited. Video-polysomnography was performed to detect masseter muscles activity. Polysomnographic scoring was performed according to the American Academy of Sleep Medicine Criteria. Finally, 146 participants were included. The participants were divided into three subgroups: severe, mild and no sleep bruxism. There were no differences in total sleep time, sleep latency, sleep efficiency, wake duration after sleep onset, rapid eye movement, and measured respiratory parameters. The severity of sleep bruxism contributed to the increased intensity of all sleep bruxism phenotypes in almost all sleep stages, apart from tonic and mixed activity in non-rapid eye movement stage 3 sleep (slow-wave sleep). Those with bruxism spent more time in rapid eye movement sleep compared to controls; there were no differences in non-rapid eye movement sleep stages. The results confirmed that sleep bruxism does not significantly affect sleep duration, efficiency and continuity (in terms of sleep-wake cycles). Sleep bruxism contributes to a higher percentage of rapid eye movement sleep in the total sleep time. Those with bruxism present more frequent episodes during all stages of sleep; however, in the case of slow-wave sleep, tonic and mixed activity observed in participants with sleep bruxism are comparable to those of healthy people.

Can be compared obstructive respiratory events during drug induced sleep endoscopy (DISE) and nocturnal polysomnography.

Obstructive sleep apnea (OSA) is a collapse of pharynx muscles during sleep that can cause obstruction in the upper airway. It is better to determine the site and pattern of obstruction in the upper airway with drug-induced sleep endoscopy (DISE) before surgery. OSA usually occurs in a non-rapid eye movement (NREM) sleep and sometimes it gets longer and more intense in REM; hence, the study is meant to explore whether the sleep stage and results in DISE may have any similarity with usual nocturnal polysomnography or not. In this study, 38 patients with OSA diagnosed on the basis of polysomnography, underwent DISE. Moreover, EEG (12 channels), pulse oximetry and effort channel (respiratory inductance plethysmography) were recorded during DISE to determine the sleep stage and mean respiratory event duration (MRED). Thirty-eight patients were enrolled in this study. Eighty-four percent (84%) of obstructive respiratory events were observed in NREM sleep in Lab-PSG and 71% in DISE. 28.9% of patients' events occurred in the wake state in DISE. The mean respiratory event duration (MRED) values in DISE and nighttime sleep were 24.5 ± 7.5s and 25.4 ± 7.7s, respectively without significant difference (P value = 0.744), while the minimum values for SPO2 were 74.0 ± 17.3 and 73.6 ± 20.3, respectively (P = 0.885). Considering the fact that the majority of respiratory events occurred in NREM sleep stage in both PSG and DISE, DISE results can be trusted. Due to absence of REM stage in DISE, the level of the obstruction may mislead the surgeon.

Daytime sleep state misperception in a tertiary sleep centre population

Study objectivesSleep state misperception is common in various sleep disorders, especially in chronic insomnia with a prevalence ranging between 9–50%. Most prior studies used nocturnal polysomnography (PSG) for the identification of sleep state misperception during nighttime. Our objective was to assess sleep state misperception during daytime in people with sleep disorders with excessive daytime sleepiness (EDS). MethodsIn this prospective observational study, we assessed the occurrence of, and factors influencing sleep state misperception in consecutive patients undergoing a routine multiple sleep latency test (MSLT) in a tertiary sleep-wake centre included between 2014 and 2017. Mixed models were applied to assess the influence of patients’ clinical data on sleep state perception. ResultsPeople with narcolepsy type 1 (NT1, n = 33) and type 2 (NT2, n = 14), idiopathic hypersomnia (IH, n = 56), obstructive sleep apnea (OSA, n = 31) and insufficient sleep syndrome (ISS, n = 31) were included. The prevalence of both classical and reverse sleep state misperception did not differ between the sleep disorders (mean 25%, range 8–37%) after correction for sleep stage, sleep onset latency and age. Longer sleep onset latency and reaching only non-rapid eye movement (REM) sleep stage 1 were significant predictors for classical sleep state misperception. ConclusionsSleep state misperception is common in people with NT1 and NT2, IH, OSA, and ISS. Classical sleep state misperception is more frequent in patients with longer sleep onset latencies who only reach non-REM sleep stage 1 during a nap.

P.407 External validity of the tail suspension test supported by meta-analysis of studies using imipramine

Habitually snoring children are at risk of manifesting disease-related problems even if their sleep studies are overall within normal limits.To compare sleep spindle activity in children with primary snoring and healthy controls.Sleep spindle activity including analysis of fast and slow spindles (ie, >13 Hz and <13 Hz, respectively) was evaluated in polysomnographic (PSG) recordings of 20 randomly selected children with primary snoring (PS; normal PSG recordings except for objective presence of snoring; 12 boys, mean age 6.5 ± 2.1 years), and 20 age- and gender-matched PSG-confirmed non-snoring controls.PS children showed significantly lower spindle indices in all non-rapid eye movement (NREM) sleep stages (p < 0.05). In contrast, fast spindles were found in 40% (n = 8) children with PS and in 25% (n = 5) controls. Sleep spindle activity was particularly higher in NREM sleep stage 2 in controls compared PS (76% versus 43% of all marked sleep spindles events in NREM sleep stage 2, p < 0.001).Children with PS exhibit significantly reduced spindle activity when compared to matched controls. Reduced sleep spindle activity may be an indicator of sleep disruption and, therefore, could be involved in the development of disease-related consequences in snoring children.