Phasic Rapid Eye Movement Research Articles

Enhanced Delta-gamma Phase Amplitude Coupling during Phasic REM Sleep in isolated REM Sleep Behavior Disorder.

This study aims to analyze phase-amplitude coupling (PAC) patterns during rapid eye movement (REM) sleep in patients with isolated REM sleep behavior disorder (iRBD), compared with demography-matched healthy control (HC) participants. At baseline, electroencephalogram data from 13 iRBD patients and 10 HCs during REM sleep were analyzed. During follow-up, 4 patients (converters) later converted to alpha-synucleinopathies. Phasic and tonic REM states were determined by eye movement in 3-second epochs. PAC was compared between the groups, and correlations with clinical indicators were investigated. Additionally, the contribution of each electrode to PAC components was assessed. Patients with iRBD exhibited increased delta (1-3 Hz)-gamma (30-50 Hz) PAC only during the phasic REM state, but not during the tonic state, compared to the HCs (p < 0.05). Elevated PAC in patients negatively correlated with the REM atonia index (p = 0.011) and olfactory function (p = 0.038). Increase PACs were predominent in the fronto-temporo-occipital regions (corrected p < 0.05). Furthermore, patients showed reduced gamma-amplitude contributions of the parietal region (corrected p < 0.05). This reduction exhibited a progressively decreasing trend from HC to non-converters, and further to converters (p for trend = 0.044). Our findings suggest PAC patterns during REM sleep could provide pathophysiological insights for iRBD. The widespread increase of PAC and reduced gamma-amplitude contribution in the parietal region suggest PAC during phasic REM sleep as potential biomarkers for disease progression in iRBD.

Closed-loop auditory stimulation targeting alpha and theta oscillations during REM sleep induces phase-dependent power and frequency changes.

Alpha and theta oscillations characterize the waking human electroencephalogram (EEG) and can be modulated by closed-loop auditory stimulation (CLAS). These oscillations also occur during rapid eye movement (REM) sleep, but their function here remains elusive. CLAS represents a promising tool to pinpoint how these brain oscillations contribute to brain function in humans. Here we investigate whether CLAS can modulate alpha and theta oscillations during REM sleep in a phase-dependent manner. We recorded high-density EEG during an extended overnight sleep period in 18 healthy young adults. Auditory stimulation was delivered during both phasic and tonic REM sleep in alternating 6s ON and 6s OFF windows. During the ON windows, stimuli were phase-locked to four orthogonal phases of ongoing alpha or theta oscillations detected in a frontal electrode. The phases of ongoing alpha and theta oscillations were targeted with high accuracy during REM sleep. Alpha and theta CLAS induced phase-dependent changes in power and frequency at the target location. Frequency-specific effects were observed for alpha trough (speeding up) and rising (slowing down) and theta trough (speeding up) conditions. CLAS-induced phase-dependent changes were observed during both REM sleep substages, even though auditory evoked potentials were very much reduced in phasic compared to tonic REM sleep. This study provides evidence that faster REM sleep rhythms can be modulated by CLAS in a phase-dependent manner. This offers a new approach to investigate how modulation of REM sleep oscillations affects the contribution of this vigilance state to brain function.

Rapid eye movement sleep and epilepsy: exploring interactions and therapeutic prospects.

While research interest in the relationship between sleep and epilepsy is growing, it primarily centres on the effects of non-rapid eye movement (NREM) sleep in favouring seizures. Nonetheless, a noteworthy aspect is the observation that, in the lives of patients with epilepsy, REM sleep represents the moment with the least epileptic activity and the lowest probability of having a seizure. Studies demonstrate a suppressive effect of phasic REM sleep on interictal epileptiform discharges, potentially offering insights into epilepsy localisation and management. Furthermore, epilepsy impacts REM sleep, with successful treatment correlating with improved REM sleep quality. Novel therapeutic strategies aim to harness REM's anti-epileptic effects, including pharmacological approaches targeting orexinergic systems and neuromodulation techniques promoting cortical desynchronisation. These findings underscore the intricate relationship between REM sleep and epilepsy, highlighting avenues for further research and therapeutic innovation in epilepsy management.

Unraveling the complexity of rapid eye movement microstates: insights from nonlinear EEG analysis.

Although rapid eye movement (REM) sleep is conventionally treated as a unified state, it comprises two distinct microstates: phasic and tonic REM. Recent research emphasizes the importance of understanding the interplay between these microstates, hypothesizing their role in transient shifts between sensory detachment and external awareness. Previous studies primarily employed linear metrics to probe cognitive states, such as oscillatory power, while in this study, we adopt Lempel-Ziv Complexity (LZC), to examine the nonlinear features of electroencephalographic (EEG) data from the REM microstates and to gain complementary insights into neural dynamics during REM sleep. Our findings demonstrate a noteworthy reduction in LZC during phasic REM compared to tonic REM states, signifying diminished EEG complexity in the former. Additionally, we noted a negative correlation between decreased LZC and delta band power, along with a positive correlation with alpha band power. This study highlights the potential of nonlinear EEG metrics, particularly LZC, in elucidating the distinct features of REM microstates. Overall, this research contributes to advancing our understanding of the complex dynamics within REM sleep and opens new avenues for exploring its implications in both clinical and nonclinical contexts.

0080 Selective Brain and Eye Responses to Auditory Stimuli During Phasic and Tonic REM Sleep

0080 Selective Brain and Eye Responses to Auditory Stimuli During Phasic and Tonic REM Sleep

Relationships between rumination and different types of rapid eye movement sleep in patients with chronic insomnia disorder

Background and objectiveRumination, a common factor of chronic insomnia disorder (CID) caused by cognitive-emotional arousal, is associated with an increased amount of rapid eye movement (REM) sleep. However, the specific subtypes, such as phasic REM and tonic REM, that contribute to the increased REM sleep have not been reported. This study aimed to determine the association between rumination and different REM sleep subtypes in patients with CID. MethodsThis study enrolled 35 patients with CID and 27 age- and sex-matched healthy controls. The Immersion-Rumination Questionnaire evaluated participants' rumination, and the Insomnia Severity Index was used to assess insomnia severity. Finally, polysomnography was used to monitor objective sleep quality and quantification of different types of REM. ResultsThe CID patients had higher rumination scores than the healthy controls. They had a shorter REM sleep duration, less phasic REM, a lower percentage of phasic REM time, and a higher percentage of tonic REM time. Spectral analysis revealed that the patients affected by insomnia had higher β power during REM sleep, higher β and σ power during phasic REM sleep, and higher β, and γ power during tonic REM sleep. Partial correlation analysis showed that rumination in the CID patients correlated negatively with the duration of phasic REM sleep. Additionally, rumination correlated negatively with δ power in REM sleep and positively with β power in REM sleep, tonic REM sleep, phasic REM sleep, N3and N2 sleep in the patients with CID. ConclusionThe CID patients had stronger rumination, reduced total and phasic REM sleep, and the stronger rumination was, the shorter phasic REM was and the higher fast (β) wave power in REM sleep.

Fundamentals of sleep regulation: Model and benchmark values for fractal and oscillatory neurodynamics

Homeostatic, circadian and ultradian mechanisms play crucial roles in the regulation of sleep. Evidence suggests that ratios of low-to-high frequency power in the electroencephalogram (EEG) spectrum indicate the instantaneous level of sleep pressure, influenced by factors such as individual sleep-wake history, current sleep stage, age-related differences and brain topography characteristics. These effects are well captured and reflected in the spectral exponent, a composite measure of the constant low-to-high frequency ratio in the periodogram, which is scale-free and exhibits lower interindividual variability compared to slow wave activity, potentially serving as a suitable standardization and reference measure. Here we propose an index of sleep homeostasis based on the spectral exponent, reflecting the level of membrane hyperpolarization and/or network bistability in the central nervous system in humans. In addition, we advance the idea that the U-shaped overnight deceleration of oscillatory slow and fast sleep spindle frequencies marks the biological night, providing somnologists with an EEG-index of circadian sleep regulation. Evidence supporting this assertion comes from studies based on sleep replacement, forced desynchrony protocols and high-resolution analyses of sleep spindles. Finally, ultradian sleep regulatory mechanisms are indicated by the recurrent, abrupt shifts in dominant oscillatory frequencies, with spindle ranges signifying non-rapid eye movement and non-spindle oscillations – rapid eye movement phases of the sleep cycles. Reconsidering the indicators of fundamental sleep regulatory processes in the framework of the new Fractal and Oscillatory Adjustment Model (FOAM) offers an appealing opportunity to bridge the gap between the two-process model of sleep regulation and clinical somnology.

Differential brain and eye responses to external auditory information in phasic and tonic REM sleep

Differential brain and eye responses to external auditory information in phasic and tonic REM sleep

Sleep Pattern Interference in the Cognitive Performance of Lusitano Horses.

Like most mammalian, polyphasic sleep, equine sleep can be divided into two phases: the REM (rapid eye movement) phase and the NREM (non-rapid eye movement) phase. For this study, a randomized crossover experiment was conducted using ten purebred Lusitano horses, all dressage athletes aged from three to seven years old. The horses were filmed before the intervention to characterize their sleep patterns. REM sleep deprivation was achieved by not letting the horses attain sternal or lateral recumbency for three consecutive days, totaling 72 h. A spatial memory task and a visual attention test were performed. A recording time of 48 h appeared to be long enough to characterize the sleep patterns of the stalled horses. The total recumbency time of the studied population was lower than that previously reported in horses. Although the recumbency times before and after the intervention were similar, there was a tendency shown by the delta (p = 0.0839) towards an increased time needed to resolve spatial memory tasks in the sleep-deprived group. Future studies may deepen the understanding of horse sleep requirements and patterns, and the effects of environmental changes on horse sleep.

Snoring and lack of REM sleep is associated with same-day atrial arrhythmias in a cohort of patients with atrial fibrillation: initial results of TriggersAF

Abstract Introduction Sleep-disordered breathing (SDB) is a known risk factor for the development of atrial fibrillation (AF). Few studies analyse the temporal relation between snoring, sleep phases and atrial arrhythmia episodes. Purpose The TriggersAF trial (NCT05526170) investigates the temporal relation between atrial arrhythmias and potential triggers. In this preliminary analysis, the authors hypothesised that snoring and disturbance of sleep phases may be associated with same-day atrial arrhythmias. Methods In a single-centre prospective cohort study patients with previously diagnosed AF were recruited for home monitoring of 7 days. A single-lead continuous electrocardiogram (ECG) of the reference Holter monitor (Bittium, Kuopio, Finland) documented the cardiac rhythm. The recordings were manually annotated as: 1) AF, 2) atrial tachycardia or flutter (AT), 3) frequent premature atrial contractions (PAC), defined as bigeminy, trigeminy, quadrigeminy or couplets, and 4) no arrhythmia. Sleep disorders were evaluated using a validated sleep tracking mat (Withings Sleep Analyzer, Issy-les-Moulineaux, France) and described by the number of snoring episodes, durations of snoring, light, deep, and rapid-eye-movement (REM) phases. Heart echocardiography with strain imaging of left atrium (LA) was performed to further characterize the subjects. Results The study consisted of 49 patients, aged 55.8±11.7 years, 67.3% male. All patients were with previously diagnosed non-permanent AF and sinus rhythm at the moment of inclusion. The monitoring duration yielded a total of 300 days. The occurrence of AF, AT and PAC was detected in 32/300, 108/300 and 85/300 of days, respectively. As revealed by the sleep analysis a greater number of snoring episodes was associated with the same-day episodes of AF when compared to patients with no AF (5.0 (2-10.2) vs. 2.0 (0-7), P=0.029, respectively). A longer snoring duration was associated with the same-day episodes of AF (36 (6-80) min vs. 12 (0-52) min, P=0.057). A shorter duration of the REM phase was associated with AT (63 (28-93) min vs. 79 (42-105) min, P=0.032) and PAC (60 (32-91) min vs. 79 (37-102) min, P= 0.058). No significant relations were observed between the durations of light or deep phases and any type of arrhythmias. A smaller mean conduit strain of LA was highly associated with AF (-7,5 (-12,5, -7,5)) compared to patients with no AF (-11,0 (-14,8, -8,5), P= 0.002). In the Fast-and-Frugal Decision Tree for the prediction of same-day AF, a model combining the mean conduit strain of less than -9, a body mass index of more than 27.8, and a snoring duration of more than 29 minutes yielded a sensitivity of 97%, a specificity of 59% and a balanced accuracy of 78%. Conclusions The higher frequency and duration of snoring, as well as reduced REM phase of sleep are linked to same-day atrial arrhythmias. Long-term SDB monitoring and LA strain imaging predict the episodes of AF with high accuracy.Number of snoring episodes vs. AFAF by LA strain, BMI and snoring

The Psychoneurobiology of Insomnia: Hyperarousal and REM Sleep Instability

Chronic insomnia (insomnia disorder—ID) afflicts up to 10% of the adult population, increases with age and affects more women than men. ID is associated with significant daytime impairments and an increased risk for developing major somatic and mental disorders, especially depression and anxiety disorders. Almost all insomnia models assume persistent hyperarousal on cognitive, emotional, cortical and physiological levels as a central pathophysiological component. The marked discrepancy between only minor objective alterations in polysomnographic parameters of sleep continuity and the profound subjective impairment in patients with insomnia is still puzzling. We and others have proposed that alterations in the microstructure of sleep, especially in REM sleep (REM sleep instability), may explain this discrepancy and be at the core of the experience of fragmented and poor sleep in ID. The REM sleep instability concept is based on evidence showing REM time to be related to subjective wake time in insomnia as well as increased micro- and macro-arousals during REM sleep in insomnia patients compared to good-sleeper controls. Our own work showed that ID patients awoken from REM sleep more frequently reported the perception of having been awake than good sleepers as well as having had more negative ideations. The continuous measurement of event-related potentials throughout the whole night demonstrated reduced P2 amplitudes specifically during phasic REM sleep in insomnia, which points to a mismatch negativity in ID reflecting automatic change detection in the auditory system and a concomitant orienting response. REM sleep represents the most highly aroused brain state during sleep and thus might be particularly prone to fragmentation in individuals with persistent hyperarousal, resulting in a more conscious-like wake experience reflecting pre-sleep concerns of patients with ID, i.e., worries about poor sleep and its consequences, thus leading to the subjective over-estimation of nocturnal waking time and the experience of disrupted and non-restorative sleep. Chronic REM sleep instability might also lead to a dysfunction in a ventral emotional neural network, including limbic and paralimbic areas activated during REM sleep. Along with a postulated weakened functioning in a dorsal executive neural network, including frontal and prefrontal areas, this might contribute to emotional and cognitive alterations and an elevated risk of developing depression and anxiety.

Rapid eye movements associated with REM sleep is involved in consolidation of visuospatial learning in rats

Rapid eye movement (REM) sleep plays a significant role in visuospatial learning and memory consolidation; however, its mechanism of action is unknown. Rapid eye movements (REMs), a characteristic active feature of REM sleep, is a potential correlate of neural processing for visual memory consolidation. The superior colliculus (SC) plays a central role in oculomotor control and spatial localization of objects in the visual field. We proposed that local reversible inactivation of the SC during post-learning sessions might interfere with REMs and negatively impact REM sleep associated consolidation of the visuospatial learnt task. Under gaseous anesthesia, bilateral cannulae aiming SC and electrodes for recording electrophysiological signals to classify sleep-waking were implanted. Following standard protocol, all rats were subjected to Morris water maze (MWM) training for 5 consecutive days followed by probe trial. After MWM training, on all except the probe test days, the rat SC were bilaterally infused with either vehicle (control, Group 1), Lidocaine hydrochloride a local anesthetic (Lox 2%, Group 2), or muscimol (Mus, GABA agonist, Group 3) and sleep-wakefulness recorded after day 1, 4, and post-probe learning sessions. Post-learning, compared to vehicle, Mus treated group significantly decreased REMs, phasic REM sleep, percent time spent in REM sleep and REM sleep frequency/hr. Also, during probe test, the escape latency was significantly increased, and the percentage time spent in the platform quadrant were significantly decreased in both, Mus and Lox 2% treated rats, while the number of platform location crossings was decreased in Mus treated group. The results showed that Lox 2% and Mus into SC reduced consolidation of visuospatial learning. The findings support our contention that SC mediated activation of REMs exerts a positive influence in processing and consolidation of visual learning during REM sleep. The findings explain the role of REMs during REM sleep in visual memory consolidation.

Parkinson's Disease: A Narrative Review on Potential Molecular Mechanisms of Sleep Disturbances, REM Behavior Disorder, and Melatonin.

Parkinson's disease (PD) is one of the most common neurodegenerative diseases. There is a wide range of sleep disturbances in patients with PD, such as insomnia and rapid eye movement (REM) sleep behavior disorder (or REM behavior disorder (RBD)). RBD is a sleep disorder in which a patient acts out his/her dreams and includes abnormal behaviors during the REM phase of sleep. On the other hand, melatonin is the principal hormone that is secreted by the pineal gland and significantly modulates the circadian clock and mood state. Furthermore, melatonin has a wide range of regulatory effects and is a safe treatment for sleep disturbances such as RBD in PD. However, the molecular mechanisms of melatonin involved in the treatment or control of RBD are unknown. In this study, we reviewed the pathophysiology of PD and sleep disturbances, including RBD. We also discussed the potential molecular mechanisms of melatonin involved in its therapeutic effect. It was concluded that disruption of crucial neurotransmitter systems that mediate sleep, including norepinephrine, serotonin, dopamine, and GABA, and important neurotransmitter systems that mediate the REM phase, including acetylcholine, serotonin, and norepinephrine, are significantly involved in the induction of sleep disturbances, including RBD in PD. It was also concluded that accumulation of α-synuclein in sleep-related brain regions can disrupt sleep processes and the circadian rhythm. We suggested that new treatment strategies for sleep disturbances in PD may focus on the modulation of α-synuclein aggregation or expression.

Eye movements during phasic vs. tonic REM sleep are biomarkers of dissociable EEG processes for the consolidation of novel problem-solving skills.

The hallmark eye movement (EM) bursts that occur during Rapid Eye Movement (REM) sleep are markers of consolidation for procedural memory involving novel cognitive strategies and problem-solving skills. Examination of the brain activity associated with EMs during REM sleep might elucidate the processes involved in memory consolidation, and may uncover the functional significance of REM sleep and EMs themselves. Participants performed a REM-dependent, novel procedural problem-solving task (i.e., the Tower of Hanoi; ToH) before and after intervals of either overnight sleep (n=20) or a daytime 8-hour wake period (n=20). In addition, event-related spectral perturbation (ERSP) of the electroencephalogram (EEG) time-locked to EMs occurring either in bursts (i.e., phasic REM), or in isolation (i.e., tonic REM), were compared to sleep on a non-learning control night. ToH improvement was greater following sleep compared to wakefulness. During sleep, frontal-central theta (~2-8 Hz) and central-parietal-occipital sensorimotor rhythm (SMR) activity (~8-16 Hz) time-locked to EMs, were greater on the ToH night vs. control night, and during phasic REM sleep, were both positively correlated with overnight memory improvements. Furthermore, SMR power during tonic REM increased significantly from the control night to ToH night, but was relatively stable from night-to-night during phasic REM. These results suggest that EMs are markers of learning-related increases in theta and SMR during phasic and tonic REM sleep. Phasic and tonic REM sleep may be functionally distinct in terms of their contribution to procedural memory consolidation.

Reduction in the propensity of rapid eye movement sleep and phasic-to-tonic ratio in patients with refractory epilepsy.

Patients with epilepsy exhibit disturbed sleep architecture and shorter rapid eye movement (REM) sleep compared with healthy controls. REM sleep consists of two microstates, phasic and tonic REM. Studies suggest that epileptic activity is suppressed in phasic but not in tonic REM. However, changes in the REM microstructure in patients with epilepsy are still unknown. Therefore, this study evaluated the differences in REM microstructure between patients with refractory and medically controlled epilepsy. This retrospective case-control study included patients with refractory and medically controlled epilepsy. Sleep parameters of the patients were recorded by standard polysomnography. In addition, the microstructures of sleep and REM sleep were compared between the two epilepsy groups. Forty-two patients with refractory epilepsy and 106 with medically controlled epilepsy were evaluated. The refractory group showed significantly decreased REM sleep (p = 0.0062), particularly in the first and second sleep cycles (p = 0.0028 and 0.00482, respectively), as well as longer REM latency (p = 0.0056). Eighteen and 28 subjects in the refractory and medically controlled epilepsy groups, respectively, with comparable REM sleep percentages, underwent REM microstructure examination. Phasic REM sleep was significantly lower in the refractory group (4.5% ± 2.1% vs. 8.0% ± 4.1%; p = 0.002). In addition, the phasic-to-tonic ratio was significantly decreased (4.8 ± 2.3 vs. 8.9 ± 4.9; p = 0.002) and negatively associated with refractory epilepsy (coefficient = -0.308, p = 0.0079). Patients with refractory epilepsy exhibited REM sleep disturbance at both macro and microstructure levels.

Seasonal variations of nonmotor symptoms in patients with Parkinson's disease in Southeast China.

Studies suggest seasonal fluctuations of symptoms in Parkinson's disease (PD) patients in Western countries. However, the association between seasonal change and variation in nonmotor symptoms (NMS) in Chinese PD patients is unclear. Here, we studied whether there is a change rule with annual cycle with severity of NMS for patients with PD in Southeast China. We studied 1005 PD patients between April 2008 and October 2020. Patients were classified into four seasons according to the 24 Chinese solar terms, based on assessment date. We compared comprehensive NMS scales and polysomnography parameters among groups and conducted further analysis of disease severity. Among the 1005 patients studied, the mean age was 64.2 ± 9.7 years and 569 (56.6%) of them were men. Relative to the summer group, patients assessed during winter had higher Scales for Outcomes in Parkinson's disease-Autonomic Dysfunction (SCOPA-AUT) scores ( P = 0.045). The sleep efficiency factor scores of Pittsburgh Sleep Quality Index in patients were higher during spring than summer ( P = 0.009). Among patients who completed polysomnography during the same period ( n = 135), compared with summer follow-ups, we observed a higher percentage of NREMS1 in winter and spring follow-ups ( P = 0.042, P = 0.011), a higher NREMS1 time in spring follow-ups ( P = 0.0024), a lower NREMS2 time in winter follow-ups ( P = 0.007), and a higher percentage of phasic RSWA in autumn and winter follow-ups ( P = 0.026 and P = 0.020, respectively). In a subset of patients with PD and REM sleep behavior disorder (RBD; n = 182), those visited during winter had higher scores for RBD questionnaire- Hong Kong and its factor 1 (dream-related sub-score) than those visited during summer ( P = 0.034, P = 0.020). We observed similar findings for SCOPA-AUT and sleep efficiency factor scores in early stage patients in subgroup analysis. PD patients assessed for follow-up during summer showed less severe symptoms of autonomic dysfunction and RBD symptoms than those assessed in winter, and less sleep disturbance than those in spring and winter, suggesting that seasonal change and NMS fluctuation are related, especially in patients with early stage PD.

Respiration and rapid eye movement (REM) sleep substructure: short versus long episodes.

Rapid eye movement (REM) sleep in rodents is defined by the presence of theta rhythm in the absence of movement. The amplitude and frequency of theta oscillations have been used to distinguish between tonic and phasic REM sleep. However, tonic REM sleep has not been further subdivided, although characteristics of network oscillations such as cross-frequency coupling between theta and gamma vary within this sub-state. Recently, it has been shown that theta-gamma coupling depends on an optimal breathing rate of ~5 Hz. The frequency of breathing varies strongly throughout REM sleep, and the duration of single REM sleep episodes ranges from several seconds to minutes, whereby short episodes predominate. Here we studied the relation between breathing frequency, accelerometer activity, and the length of REM sleep periods. We found that small movements detected with three-dimensional accelerometry positively correlate with breathing rate. Interestingly, breathing is slow in short REM sleep episodes, while faster respiration regimes exclusively occur after a certain delay in longer REM sleep episodes. Thus, merging REM sleep episodes of different lengths will result in a predominance of slow respiration due to the higher occurrence of short REM sleep periods. Moreover, our results reveal that not only do phasic REM sleep epochs predominantly occur during long REM sleep episodes, but that the long episodes also have faster theta and higher gamma activity. These observations suggest that REM sleep can be further divided from a physiological point of view depending on its duration. Higher levels of arousal during REM sleep, indicated by higher breathing rates, can only be captured in long REM sleep episodes.

Polysomnography findings in preschool children with obstructive sleep apnea are affected by growth and developmental level.

We investigated the effect of growth and development level on polysomnography results in preschool children with obstructive sleep apnea (OSA). Preschool children (ages 3-6) with symptoms of snoring and were diagnosed with OSA by polysomnography in the sleep center were selected as the research object. They were split into three groups based on their growth rates: restricted, normal, and excessive. Sleep structure, respiratory events, and oxygenation index were compared between the three groups. A total of 183 (111 boys and 72 girls) preschool children were enrolled. There were 26 cases in the growth restricted group, 112 cases in the normal growth group, and 45 cases in the overgrowth group. The weight and Body Mass Index (BMI) of children in the growth restricted and overgrowth groups were significantly different from those in the normal group. In terms of sleep structure, the sleep efficiency of the growth restricted group was poorer than that of the normal group. For sleep breathing events, the growth restricted group showed a greater apnea-hypopnea index (AHI), obstructive apnea hypopnea index (OAHI), hypoventilation index, and more hypoventilation than the normal group. In terms of oxygenation, the difference in degree of hypoxia between the three groups was statistically significant, and the overgrowth group had lower minimum oxygen saturation during the rapid eye movement phase than the normal group, as well as a quicker mean heart rate. OSA is more likely in preschool-aged children with stunted or overgrown growth than in children with OSA alone, and the more severe the disorder, especially when accompanied with stunted growth.

The Effect of Bi-Level Positive Airway Pressure on Sleep Structure in Patients with Overlap Syndrome

Objective: The present study aimed to observe the effect of bi-level positive airway pressure on sleep structure in patients with overlap syndrome (OS). Method: Forty patients with OS were randomly divided into control and experimental groups, respectively, with 20 cases in each group. Patients in both the control and experimental groups were given anti-infection, dilating bronchi, expectoration, and oxygen inhalation treatment according to the conditions. Bi-level positive airway pressure was conducted in patients in the experimental group for approximately 10 hr a day over a one-week therapeutic course. Polysomnography, Sleep questionnaire survey was performed before treatment and after one week of treatment in both the control and experimental groups to measure sleep structure to investigate the drowsiness and quality of life of the patients. Results: (1) Prior to treatment, differences in the total sleep time, sleep latency, rapid eye movement (REM) latency, sleep efficiency, phase I, II, and III sleep, REM phase sleep and sleep questionnaire survey was not statistically significant between the two groups (P &gt; 0.05). (2) One week after treatment, compared with the control group, the REM latency in the experimental group was shortened, the percentage of REM sleep and Rem sleep in total sleep time was prolonged, the second stage sleep time and the percentage of second stage sleep in total sleep time were shortened, and the scores of Epworth drowsiness, fatigue, dizziness, lack of energy and anxiety decreased in the sleep questionnaire. There was no significant difference in other indexes (P &gt; 0.05). After treatment in the experimental group, REM latency was shortened, REM sleep time and the percentage of Rem sleep in total sleep time were prolonged, second-stage sleep time and second-stage sleep in total sleep time were shortened. Sleep questionnaire survey showed that Epworth drowsiness score, fatigue, dizziness, mental in concentration and anxiety symptoms decreased. There was no significant difference in other indexes (P &gt; 0.05). The sleep questionnaire in the control group after treatment showed that the score of fatigue symptoms decreased, and the difference was statistically significant (P &lt; 0.05). There was no significant difference in other indexes (P &gt; 0.05). Conclusion: Bi-level positive airway pressure can potentially shorten REM latency, prolong REM sleep, and shorten phase II sleep, alleviate the symptoms of drowsiness, fatigue, dizziness, distraction and anxiety, and improve the quality of life in patients with OS.

Generalized EEG Slowing Across Phasic REM Sleep, Not Subjective RBD Severity, Predicts Neurodegeneration in Idiopathic RBD.

PurposeIdiopathic rapid eye movement sleep behavior disorder (iRBD) is the prodromal marker of α-synuclein degeneration with markedly high predictive value. We aim to evaluate the value of electroencephalography (EEG) data during rapid eye movement (REM) sleep and subjective RBD severity in predicting the conversion to neurodegenerative diseases in iRBD patients.MethodsAt the baseline, iRBD patients underwent clinical assessment and video-polysomnography (PSG). Relative spectral power for nine frequency bands during phasic and tonic REM sleep in three regions of interest, slow-to-fast ratios, clinical and PSG variables were estimated and compared between iRBD patients who converted to neurodegenerative diseases (iRBD-C) and iRBD patients who remained disease-free (iRBD-NC). Receiver operating characteristic (ROC) curves evaluated the predictive performance of slow-to-fast ratios, and subjective RBD severity as assessed with RBD Questionnaire-Hong Kong.ResultsTwenty-two (33.8%) patients eventually developed neurodegenerative diseases. The iRBD-C group showed shorter total sleep time (p < 0.001), lower stage 2 sleep percentage (p = 0.044), more periodic leg-movement-related arousal index (p = 0.004), increased tonic chin electromyelographic activity (p = 0.040) and higher REM density in the third REM episode (p = 0.034) than the iRBD-NC group. EEG spectral power analyses revealed that iRBD phenoconverters showed significantly higher delta and lower alpha power, especially in central and occipital regions during the phasic REM state compared to the iRBD-NC group. Significantly higher slow-to-fast ratios were observed in a more generalized way during the phasic state in the iRBD-C group compared to the iRBD-NC group. ROC analyses of the slowing ratio in occipital areas during phasic REM sleep yielded an area under the curve of 0.749 (p = 0.001), while no significant predictive value of subjective RBD severity was observed.ConclusionOur study shows that EEG slowing, especially in a more generalized manner during the phasic period, may be a promising marker in predicting phenoconversion in iRBD, rather than subjective RBD severity.