Rapid Eye Movement Sleep Stage Research Articles

The dynamics of cyclic‐periodic phenomena during non‐rapid and rapid eye movement sleep

SummarySleep is a complex physiological state characterized by distinct stages, each exhibiting unique electroencephalographic patterns and physiological phenomena. Sleep research has unveiled the presence of intricate cyclic‐periodic phenomena during both non‐rapid eye movement and rapid eye movement sleep stages. These phenomena encompass a spectrum of rhythmic oscillations and periodic events, including cyclic alternating pattern, periodic leg movements during sleep, respiratory‐related events such as apneas, and heart rate variability. This narrative review synthesizes empirical findings and theoretical frameworks to elucidate the dynamics, interplay and implications of cyclic‐periodic phenomena within the context of sleep physiology. Furthermore, it invokes the clinical relevance of these phenomena in the diagnosis and management of sleep disorders.

Associations between bedroom environment and sleep quality when sleeping less or more than 6h: A cross sectional study during summer

A cross-sectional study was conducted in 50 bedrooms in Shanghai, each for one week during summer, to investigate the effects of the bedroom environment on sleep quality. Sleep quality was recorded with a wrist-worn sleep tracker and assessed with a questionnaire. The measurements from 168 person-nights were analysed after excluding unreliable data. The overnight means of bedroom temperature, relative humidity, CO2 and PM2.5 concentrations, which were continuously measured were between 21 to 30 °C, 43 to 86 %, 375 to 2756 ppm, and <1 to 43 μg/m3, respectively. Sleep duration in 36.3 % of the nights was less than 6 h, which is too short according to the recommendation of the American Sleep Foundation. The nights were then classified into two categories, with sleep duration above or below 6 h. The results show that the sleep quality in the short-sleep category was more sensitive to the bedroom environment. In the longer-sleep duration category, light sleep decreased with higher humidity and increased with higher PM2.5 concentration. In the short-sleep duration category, all the main sleep quality parameters including sleep efficiency and the duration and percentage of deep and rapid eye movement sleep stage decreased, and time spent awake increased with increased bedroom temperature, humidity, CO2 and PM2.5 concentration. The occupants who used air conditioning had a lower indoor temperature and humidity at night; opening windows decreased the indoor CO2 concentration but increased the PM2.5 concentration. These results suggest the need for alternative solutions to natural ventilation during summer in dwellings in Shanghai.

The Impact of Inadequate Sleep on Overtraining Syndrome in 18-22-Year-Old Male and Female College Athletes: A Literature Review.

Both male and female athletes experience acute fatigue and decreased performance from intense training sessions and training cycles with inadequate recovery. The concept of training with insufficient recovery time is known as overtraining syndrome (OTS). Primary stressors leading to OTS include excessive training, environmental factors, and inadequate levels of sleep. Sleep is a critical component of rest, recovery, memory, and cognitive function in collegiate athletes, known as male and female athletes between 18 and 22 years old. Collegiate athletes are more prone to inadequate levels of sleep, which can lead to elevated levels of fatigue, a lack of energy, motivation, alertness, and a weakened immune system. Additionally, inadequate levels of sleep lead to decreased glycogen stores in the body, affecting the functioning of physiological pathways. The processes of removing toxins and the release of growth hormones (GHs) are also impacted. GH is secreted as the rapid eye movement (REM) phase alternates with the non-REM phase and continues to rise until it peaks in the REM sleep stage, which is important for physical recovery, memory formation, and emotional regulation. This literature review aims to summarize current research on overtraining and the physiological changes that are present in both males and females from inadequate levels of sleep, emphasizing its importance in body homeostasis.

REM Sleep Stage Identification with Raw Single-Channel EEG.

This paper focused on creating an interpretable model for automatic rapid eye movement (REM) and non-REM sleep stage scoring for a single-channel electroencephalogram (EEG). Many methods attempt to extract meaningful information to provide to a learning algorithm. This method attempts to let the model extract the meaningful interpretable information by providing a smaller number of time-invariant signal filters for five frequency ranges using five CNN algorithms. A bi-directional GRU algorithm was applied to the output to incorporate time transition information. Training and tests were run on the well-known sleep-EDF-expanded database. The best results produced 97% accuracy, 93% precision, and 89% recall.

Deep-learning detection of mild cognitive impairment from sleep electroencephalography for patients with Parkinson's disease.

Parkinson's disease which is the second most prevalent neurodegenerative disorder in the United States is a serious and complex disease that may progress to mild cognitive impairment and dementia. The early detection of the mild cognitive impairment and the identification of its biomarkers is crucial to support neurologists in monitoring the progression of the disease and allow an early initiation of effective therapeutic treatments that will improve the quality of life for the patients. In this paper, we propose the first deep-learning based approaches to detect mild cognitive impairment in the sleep Electroencephalography for patients with Parkinson's disease and further identify the discriminative features of the disease. The proposed frameworks start by segmenting the sleep Electroencephalography time series into three sleep stages (i.e., two non-rapid eye movement sleep-stages and one rapid eye movement sleep stage), further transforming the segmented signals in the time-frequency domain using the continuous wavelet transform and the variational mode decomposition and finally applying novel convolutional neural networks on the time-frequency representations. The gradient-weighted class activation mapping was also used to visualize the features based on which the proposed deep-learning approaches reached an accurate prediction of mild cognitive impairment in Parkinson's disease. The proposed variational mode decomposition-based model offered a superior accuracy, sensitivity, specificity, area under curve, and quadratic weighted Kappa score, all above 99% as compared with the continuous wavelet transform-based model (that achieved a performance that is almost above 92%) in differentiating mild cognitive impairment from normal cognition in sleep Electroencephalography for patients with Parkinson's disease. In addition, the features attributed to the mild cognitive impairment in Parkinson's disease were demonstrated by changes in the middle and high frequency variational mode decomposition components across the three sleep-stages. The use of the proposed model on the time-frequency representation of the sleep Electroencephalography signals will provide a promising and precise computer-aided diagnostic tool for detecting mild cognitive impairment and hence, monitoring the progression of Parkinson's disease.

0845 Individuals with Persistent Low Back Pain Have Less Time in Deep Sleep Stage than Asymptomatic Controls

Abstract Introduction Sleep consists of stages of light sleep, deep sleep, and rapid eye movement (REM), which have different characteristics. These stages are thought to be associated with different physiological and psychological processes. Pain is an unpleasant sensory and emotional experience generated by neural activity that potentially impacts several networks in the brain. There is limited information regarding the potential association between objectively determined sleep characteristics and persistent low back pain (pLBP). The purpose of this study was to examine whether sleep characteristics differ between individuals with pLBP and asymptomatic controls. Methods Individuals in a current episode of back pain with symptoms impacting function and persisting greater than 3 months (pLBP group, n=20) and asymptomatic individuals (control group, n=16) participated in the study. They wore a home sleep test device (Zmachine® Insight+, General Sleep Corporation) for three nights. Results The pLBP and control groups had similar age (24.8 ± 5.8 and 25.4 ± 4.3 years, respectively; mean ± SD), height, weight, and waist and hip circumferences. The two groups also had similar total sleep time (6.0 ± 1.2 and 6.6 ± 1.0 hours, for pLBP and control groups, respectively), sleep efficiency (82.8 ± 8.8% and 84.9 ± 5.7%), and wake time after sleep onset (35.8 ±27.4 and 31.5 ±18.1 minutes). The duration in REM (1.5 ± 0.5 and 1.5 ± 0.6 hours) and light sleep (3.1 ± 0.7 and 3.4 ± 0.9 hours) stages were also similar. However, the pLBP group had less deep sleep time (1.4 ± 0.4 hours) than the control group (1.7 ± 0.3 hours) (p = 0.029). Conclusion Individuals with pLBP had less deep sleep time than asymptomatic controls, although other objectively determined sleep characteristics appear to be similar. These results suggest an association between the deep sleep stage and persistent low back pain that requires further investigation. Support (if any) National Institutes of Health R01HD095959 and University of South Carolina ASPIRE 80004373.

Effects of dexmedetomidine on postoperative sleep quality: a systematic review and meta-analysis of randomized controlled trials

Study objectivesTo assess the effect of dexmedetomidine (DEX) on postoperative sleep quality using polysomnography (PSG) to identify possible interventions for postoperative sleep disturbances.MethodsAn electronic search of PubMed/MEDLINE, EMBASE, Cochrane Library and Web of Science was conducted from database inception to November 20, 2022. Randomized controlled trials (RCTs) on the effect of DEX administration on postoperative sleep quality using PSG or its derivatives were included. No language restrictions were applied. The sleep efficiency index (SEI), arousal index (AI), percentages of stage N1, N2 and N3 of non-rapid eye movement (NREM) sleep, and rapid eye movement (REM) sleep were measured in our meta-analysis.ResultsFive studies, involving 381 participants were included. Administration of DEX significantly improved SEI, lowered AI, decreased the duration of stage N1 sleep and increased the duration of stage N2 sleep compared to placebo groups. There were no significant differences in the duration of stage N3 sleep and REM sleep. DEX administration lowered the postoperative Visual Analogue Scale (VAS) score and improved the Ramsay sedation score with no adverse effect on postoperative delirium (POD). However, high heterogeneity was observed in most of the primary and secondary outcomes.ConclusionsOur study provides support for the perioperative administration of DEX to improve postoperative sleep quality. The optimal dosage and overall effect of DEX on postoperative sleep quality require further investigation using large-scale randomized controlled trials.

Analysis of the effect of brexpiprazole on sleep architecture in patients with schizophrenia: A preliminary study.

Brexpiprazole is an atypical antipsychotic drug widely used in Japan for the treatment of schizophrenia. Previous studies have investigated the therapeutic effects of some antipsychotics on sleep variables; however, to our knowledge, the effects of brexpiprazole on sleep architecture have not been examined in patients with schizophrenia. Therefore, we aimed to exploratorily investigate the effect of brexpiprazole on sleep variables measured by polysomnography in patients with schizophrenia. This study included 10 patients with schizophrenia who were originally treated with haloperidol alone. Sleep variables of the participants were measured using polysomnography. After excluding those who did not meet the study criteria, seven patients (five men and two women; mean age [SD], 59.0 [10.0] years) were eligible for further analysis. Polysomnography was repeated at 4 weeks after the participants were prescribed brexpiprazole in addition to haloperidol. We compared the sleep architecture of the participants, measured using polysomnography, before and after taking brexpiprazole. Add-on brexpiprazole significantly prolonged rapid eye movement latency, increased the duration and percentage of stage N2 and stage N3 sleep (min, %), and decreased the duration and percentage of stage rapid eye movement sleep (min, %) at a significance level of nominal p < 0.05. Although not significant after correcting for multiple comparisons, the present results showed that add-on brexpiprazole could alter the sleep architecture of patients with schizophrenia. Future studies are warranted to replicate these findings and to further investigate the beneficial influence of brexpiprazole on sleep.

Association Between Sleep Microstructure and Incident Hypertension in a Population-Based Sample: The HypnoLaus Study.

Background Poor sleep quality is associated with increased incident hypertension. However, few studies have investigated the impact of objective sleep structure parameters on hypertension. This study investigated the association between sleep macrostructural and microstructural parameters and incident hypertension in a middle- to older-aged sample. Methods and Results Participants from the HypnoLaus population-based cohort without hypertension at baseline were included. Participants had at-home polysomnography at baseline, allowing assessment of sleep macrostructure (nonrapid eye movement sleep stages 1, 2, and 3; rapid eye movement sleep stages; and total sleep time) and microstructure including power spectral density of electroencephalogram in nonrapid eye movement sleep and spindles characteristics (density, duration, frequency, amplitude) in nonrapid eye movement sleep stage 2. Associations between sleep macrostructure and microstructure parameters at baseline and incident clinical hypertension over a mean follow-up of 5.2years were assessed with multiple-adjusted logistic regression. A total of 1172 participants (42% men; age 55±10years) were included. Of these, 198 (17%) developed hypertension. After adjustment for confounders, no sleep macrostructure features were associated with incident hypertension. However, low absolute delta and sigma power were significantly associated with incident hypertension where participants in the lowest quartile of delta and sigma had a 1.69-fold (95% CI, 1.00-2.89) and 1.72-fold (95% CI, 1.05-2.82) increased risk of incident hypertension, respectively, versus those in the highest quartile. Lower spindle density (odds ratio, 0.87; 95% CI, 0.76-0.99) and amplitude (odds ratio, 0.98; 95% CI, 0.95-1.00) were also associated with higher incident hypertension. Conclusions Sleep microstructure is associated with incident hypertension. Slow-wave activity and sleep spindles, 2 hallmarks of objective sleep continuity and quality, were inversely and consistently associated with incident hypertension. This supports the protective role of sleep continuity in the development of hypertension.

High Rapid Eye Movement Sleep Apnea Hypopnea Index is Associated with Hypertension in Patients with Obstructive Sleep Apnea

PurposeObstructive sleep apnea (OSA) plays an important role in the pathogenesis of hypertension. The aim of this cross-sectional study was to explore the clinical and polysomnographic characteristics of OSA patients with hypertension and to explore the gender differences in the relationship between rapid eye movement (REM) OSA and hypertension.Patients and MethodsA total of 808 patients with OSA at a tertiary hospital were enrolled in this study, and OSA patients were divided into groups presenting with or without hypertension. The clinical and polysomnographic characteristics were compared between the groups. Multivariate binary logistic analysis was performed to assess the association between REM OSA and hypertension.ResultsAfter adjustment for potential confounders, the risk of hypertension in patients with OSA increased with severity categories of apnea hypopnea index during rapid eye movement sleep stage (REM AHI) (OR = 1.61 for REM AHI ≥58.87 events/h relative to REM AHI <30.50 events/h, 95% CI 1.07–2.42, P = 0.022). Consistent with this, when taken as a continuous variable, this association still remains significant (OR = 1.007, 95% CI 1.001–1.014, P < 0.05). This effect was more pronounced in women patients, the OR for REM AHI ≥57.24 events/h relative to REM AHI <30.36 events/h was 2.79 (95% CI, 1.16–6.73; P = 0.022); however, there was no significant difference in male patients.ConclusionREM AHI was significantly and positively associated with hypertension in patients with OSA, and the effect was more pronounced in female patients.

An Automated Wavelet-Based Sleep Scoring Model Using EEG, EMG, and EOG Signals with More Than 8000 Subjects.

Human life necessitates high-quality sleep. However, humans suffer from a lower quality of life because of sleep disorders. The identification of sleep stages is necessary to predict the quality of sleep. Manual sleep-stage scoring is frequently conducted through sleep experts’ visually evaluations of a patient’s neurophysiological data, gathered in sleep laboratories. Manually scoring sleep is a tough, time-intensive, tiresome, and highly subjective activity. Hence, the need of creating automatic sleep-stage classification has risen due to the limitations imposed by manual sleep-stage scoring methods. In this study, a novel machine learning model is developed using dual-channel unipolar electroencephalogram (EEG), chin electromyogram (EMG), and dual-channel electrooculgram (EOG) signals. Using an optimum orthogonal filter bank, sub-bands are obtained by decomposing 30 s epochs of signals. Tsallis entropies are then calculated from the coefficients of these sub-bands. Then, these features are fed an ensemble bagged tree (EBT) classifier for automated sleep classification. We developed our automated sleep classification model using the Sleep Heart Health Study (SHHS) database, which contains two parts, SHHS-1 and SHHS-2, containing more than 8455 subjects with more than 75,000 h of recordings. The proposed model separated three classes if sleep: rapid eye movement (REM), non-REM, and wake, with a classification accuracy of 90.70% and 91.80% using the SHHS-1 and SHHS-2 datasets, respectively. For the five-class problem, the model produces a classification accuracy of 84.3% and 86.3%, corresponding to the SHHS-1 and SHHS-2 databases, respectively, to classify wake, N1, N2, N3, and REM sleep stages. The model acquired Cohen’s kappa () coefficients as 0.838 with SHHS-1 and 0.86 with SHHS-2 for the three-class classification problem. Similarly, the model achieved Cohen’s of 0.7746 for SHHS-1 and 0.8007 for SHHS-2 in five-class classification tasks. The model proposed in this study has achieved better performance than the best existing methods. Moreover, the model that has been proposed has been developed to classify sleep stages for both good sleepers as well as patients suffering from sleep disorders. Thus, the proposed wavelet Tsallis entropy-based model is robust and accurate and may help clinicians to comprehend and interpret sleep stages efficiently.

Enhanced dehydroepiandrosterone levels are positively correlated with N3 sleep stage in long-term mindfulness meditation practitioners.

ObjectivesMeditation practices positively influence the neural, hormonal and autonomic systems. We have demonstrated that long-term practice of mindfulness meditation increases N3 and rapid eye movement (REM) sleep stages and bring efficient autonomic modulation during sleep. In the present study, the probable humoral correlation that could bring about these changes is evaluated.Material and MethodsLong-term Vipassana meditators (n=41) and controls (n=24) (males, 30-60 years of age) underwent a two-day consecutive whole night polysomnography recording. During the second day, with exposure to 100Lux brightness, blood was sampled from the antecubital vein between 8-9 PM and in subsequent early morning. Sleep stage was scored as per American Society of Sleep Medicine (ASSM) guidelines for the second-day recording. Sleep-related hormones were estimated - melatonin by radioimmunoassay; dehydroepiandrosterone (DHEA), cortisol, growth hormone (GH) and prolactin with enzyme-linked immunosorbent assay (ELISA); DHEA/cortisol ratio was calculated. Percentage of sleep stages and hormonal levels were compared between both groups using independent ‘t’ test and Pearson’s correlation was estimated between sleep stages and hormonal levels.ResultsMeditators showed increased N3, REM sleep stages. Though evening cortisol was comparable between the two groups; early morning cortisol, diurnal DHEA and melatonin were significantly higher in meditators. Diurnal DHEA correlated significantly with the N3 sleep stage in meditators.DiscussionHigher diurnal DHEA despite variations in corresponding cortisol in meditators demonstrates that long-term Vipassana meditation practice modulates the hypothalamicpituitary-adrenal (HPA) axis and thereby influences sleep. Thus, the study provides evidence to explore the mechanism most likely involved with mindfulness meditation intervention in insomnia.

Evaluation of the Heart Rhythm Coherence Ratio During Sleep: A Pilot Study With Polysomnography.

The psychophysiological coherence model proposes that a heart rhythm pattern, known as heart rhythm coherence (HRC), is associated with dominant parasympathetic activity and the entrainment of respiratory function, blood pressure, and heart rhythms. Although the HRC pattern has primarily been assessed during wakefulness, changes in cardiac and autonomic activity that occur during sleep stages can also be associated with the HRC pattern. The objective of this study was to examine whether any differences in the HRC pattern could be detected among various sleep stages. Eighteen healthy young individuals participated in this study. Two consecutive polysomnographic (PSG) recordings were obtained from each participant, several segments of cardiac activity were obtained from the second PSG. The HRC pattern was quantitatively evaluated by calculating the HRC ratio (HRCR). The highest peaks in the coherence band (Coher-Peak), 0.1-Hz index, respiratory sinus arrhythmia (RSA), and heart rate (HR) were evaluated. A Friedman test showed significant differences among sleep stages in the Coher-Peak, 0.1-Hz index, RSA, and HR; the Coher-Peak and RSA values were lower in rapid eye movement (REM) sleep, while the 0.1-Hz and HR values were higher in REM sleep. Post hoc analyses identified significant differences between the N2 and REM sleep stages. Among the various sleep stages, HR and RSA measurements behaved independently of the HRC pattern, and the HRC pattern did not appear to be associated with the 0.1Hz frequency. Further studies are required to identify the characteristics of the HRC pattern during sleep.

REM Sleep Parasomnias and REM Behavior Disorder: Clinical Features, Diagnosis, and Management

Parasomnias are unexpected and undesirable motor activities during sleep. Parasomnias may occur during non-rapid eye movement (NREM) sleep or rapid eye movement (REM) sleep. Nightmare disorder, recurrent isolated sleep paralysis, sleep-related hallucinations, REM behavior disorder (RBD), and status dissociatus (agrypnia excitata) are some of the REM parasomnias. Parasomnia overlap syndrome is a term used for parasomnias that occur in both REM and NREM sleep stages, such as catathrenia. RBD is a parasomnia that occurs during REM sleep stage and is characterized by acting out dreams (oneirism), leading to unwanted motor actions such as kicking, punching, or slapping, or sudden abrupt movements that can cause unexplained injuries to self or bedpartner. Memory of the associated dream is usually preserved. Diagnosis is obtained via video polysomnography with findings of REM activity without atonia and video recording of the oneirism. Treatment starts with developing a safety plan, improving sleep hygiene, and identifying any medications or other triggers such as snoring or leg movements. Melatonin, benzodiazepines, and a few other medications are used for treatment of RBD and other REM parasomnias. [ Psychiatr Ann . 2021;51(12):560–565.]

Short-Term Effects of Pressure Controlled Versus Volume Controlled Noninvasive Ventilation in Subjects With Amyotrophic Lateral Sclerosis.

Comparison of the effects of pressure controlled and volume controlled noninvasive ventilations (NIV) has usually been limited to the degree of improvement in blood gases. We compared sleep quality, abnormal respiratory events, and patient-ventilator asynchronies during administration of pressure controlled continuous mandatory ventilation (PC-CMV) and volume controlled continuous mandatory ventilation (VC-CMV) in subjects with amyotrophic lateral sclerosis naive to NIV after titration aimed at maximally improving nocturnal arterial blood gases. A crossover evaluation of PC-CMV and VC-CMV was performed in 27 subjects with amyotrophic lateral sclerosis. After baseline polysomnography, ventilators were set in random order so as to warrant similar and satisfactory oxygen saturation and transcutaneous [Formula: see text] in both NIV modalities during day and night. Soon after titration, polysomnography was repeated during administration of each type of NIV. With respect to the baseline night, non-rapid eye movement 3, and rapid eye movement sleep stages increased, and the arousal index decreased during PC-CMV (P = .005, P = .02, and P = .01, PC-CMV vs VC-CMV, respectively) but not during VC-CMV. The arousal index during NIV was correlated to the peak pressure delivered by the ventilators (ρ = 0.47, P < .001). Few abnormal respiratory events were observed in both NIV modes. Patient-ventilator asynchronies were more frequent during VC-CMV (median [IQR] 20.8 [0.0 - 22.0] vs 31.8 [30.1 - 34.0] no./h, PC-CMV vs VC-CMV; P = .002). Twenty-one subjects declared that they preferred PC-CMV therapy. In the short term, PC-CMV may be a preferred NIV modality to VC-CMV for patients with amyotrophic lateral sclerosis, even when both NIV modes are similarly effective in the correction of hypoventilation. Evaluation of the effectiveness of NIV should not be limited to the assessment of blood gas correction.

Role of sleep on respiratory failure after extubation in the ICU

BackgroundSleep had never been assessed immediately after extubation in patients still in the ICU. However, sleep deprivation may alter respiratory function and may promote respiratory failure. We hypothesized that sleep alterations after extubation could be associated with an increased risk of post-extubation respiratory failure and reintubation. We conducted a prospective observational cohort study performed at the medical ICU of the university hospital of Poitiers in France. Patients at high-risk of extubation failure (> 65 years, with any underlying cardiac or lung disease, or intubated > 7 days) were included. Patients intubated less than 24 h, with central nervous or psychiatric disorders, continuous sedation, neuroleptic medication, or uncooperative were excluded. Sleep was assessed by complete polysomnography just following extubation including the night. The main objective was to compare sleep between patients who developed post-extubation respiratory failure or required reintubation and the others.ResultsOver a 3-year period, 52 patients had complete polysomnography among whom 12 (23%) developed post-extubation respiratory failure and 8 (15%) required reintubation. Among them, 10 (19%) had atypical sleep, 15 (29%) had no deep sleep, and 33 (63%) had no rapid eye movement (REM) sleep. Total sleep time was 3.2 h in median [interquartile range, 2.0–4.4] in patients who developed post-extubation respiratory failure vs. 2.0 [1.1–3.8] in those who were successfully extubated (p = 0.34). Total sleep time, and durations of deep and REM sleep stages did not differ between patients who required reintubation and the others. Reintubation rates were 21% (7/33) in patients with no REM sleep and 5% (1/19) in patients with REM sleep (difference, − 16% [95% CI − 33% to 6%]; p = 0.23).ConclusionsSleep assessment by polysomnography after extubation showed a dramatically low total, deep and REM sleep time. Sleep did not differ between patients who were successfully extubated and those who developed post-extubation respiratory failure or required reintubation.

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.

800 Similarities of Sleep Macrostructure in Cognitively Normal Elderly and Patients with Traumatic Brain Injury

Abstract Introduction The stability of sleep architecture and breathing across nights can depend on factors relating to the integrity of the nervous system. Traumatic brain injury (TBI) represents a sudden-onset dysfunction of the nervous system while normal aging is associated with more gradual changes to the nervous system. While normal aging and history of TBI are both associated with sleep complaints, less is known about the stability of sleep physiology variables in these populations. Therefore, the aims of our study are to determine which sleep variables have greater night-to-night stability in separate populations of individuals with TBI and in cognitively normal older individuals. Methods All volunteers completed 2 consecutive in-laboratory nocturnal polysomnograms (NPSG). The TBI sample (N=35) comprised 71% women and 26% men (average age of 47.3 years). The cognitively normal older sample (N=78) included 74% women and 25% men (average age of 66.4 years). Descriptive statistics and intra-class correlations (ICCs) were calculated for sleep macrostructure variables (total sleep time (TST), sleep efficiency (SE), arousal index (ArI), rapid eye movement (REM), non-REM 1 &amp; 2 (N1, N2), slow-wave sleep (SWS)), and sleep apnea including stage-specific apneas (i.e., AHI4%, AHI3A). Results Among volunteers with TBI, ICCs for sleep architecture variables were: TST (0.68), SE (0.65), ArI (0.92), %SWS (0.77), %REM (0.50), %N1 (0.83), %N2 (0.62). ICC’s for sleep apnea variables were: AHI4% (0.86), AHI3A (0.86), REM AHI4% (0.63), REM AHI3A (0.65). Among cognitively normal older volunteers, ICCs for sleep architecture variables were: TST (0.26), SE (0.29), ArI (0.80), %SWS (0.68), %REM (0.39), %N1 (0.66), %N2 (0.49). ICC’s for sleep apnea variables were: AHI4% (0.91), AHI3A (0.92), REM AHI4% (0.85), REM AHI3A (0.83). All ICCs were statistically significant in both groups, except for %N1 among cognitively normal older volunteers. Conclusion In both populations, ICC’s for arousal index were greater than for TST or SE. Likewise, ICC’s were higher in %SWS and %N1 than for %N2 or %REM. Breathing variables were more stable than architecture variables. REM-specific breathing variables showed comparatively less consistency, possibly the product of lower ICC’s for %REM sleep versus other sleep stages. Support (if any) 5T32HL129953-04, R01AG056682, R01AG066870, R21AG059179, 1RF1NS115268-01, K24HL109156, P30AG059303, P30AG066512, AASM 231-BS-20, R25HL105444

A Systematic Review, Meta-Analysis and Meta-Regression on the Effects of Carbohydrates on Sleep.

This study aimed to assess the effects of quantity, quality and periodization of carbohydrates consumption on sleep. PubMed, SCOPUS and Cochrane Library were searched through October 2020. Data were pooled using random-effects meta-analysis. Eleven articles were included in the meta-analysis which consisted of 27 separate nutrition trials, resulting in 16 comparison data sets (sleep quantity n = 11; sleep quality n = 5). Compared to high carbohydrate (HCI), low carbohydrate intake (LCI) moderately increased duration and proportion of N3 sleep stage (ES = 0.37; 95% CI = 0.18, 0.56; p < 0.001 and ES = 0.51; 95% CI = 0.33, 0.69; p < 0.001, respectively). HCI prolonged rapid eye movement (REM) stage duration (ES = −0.38; 95% CI = 0.05, −8.05; p < 0.001) and proportion (ES = −0.46; 95% CI = −0.83, −0.01; p < 0.001), compared to LCI. The quality of carbohydrate intake did not affect sleep stages. Meta-regression showed that the effectiveness of carbohydrate quantity and quality in sleep onset latency was significantly explained by alterations of carbohydrate intake as a percentage of daily energy intake (R2 = 25.87, p = 0.018) and alterations in the glycemic load (R2 = 50.8, p = 0.048), respectively. Alterations in glycemic load partially explained the variance of the effectiveness of carbohydrate quality in sleep efficiency (R2 = 89.2, p < 0.001) and wake after sleep onset (R2 = 64.9, p = 0.018). Carbohydrate quantity was shown to affect sleep architecture, and especially N3 and REM sleep stages. Alterations in both quantity and quality of carbohydrate intake showed a significant effect on sleep initiation. Variations in carbohydrate quality significantly affected measures of sleep continuation. Further studies are needed to assess the effect of long-term carbohydrate interventions on sleep.

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.