Phasic Rapid Eye Movement Sleep 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.

The impact of REM sleep loss on human brain connectivity

Brain function is vulnerable to the consequences of inadequate sleep, an adverse trend that is increasingly prevalent. The REM sleep phase has been implicated in coordinating various brain structures and is hypothesized to have potential links to brain variability. However, traditional imaging research have encountered challenges in attributing specific brain region activity to REM sleep, remained understudied at the whole-brain connectivity level. Through the spilt-night paradigm, distinct patterns of REM sleep phases were observed among the full-night sleep group (n = 36), the early-night deprivation group (n = 41), and the late-night deprivation group (n = 36). We employed connectome-based predictive modeling (CPM) to delineate the effects of REM sleep deprivation on the functional connectivity of the brain (REM connectome) during its resting state. The REM sleep-brain connectome was characterized by stronger connectivity within the default mode network (DMN) and between the DMN and visual networks, while fewer predictive edges were observed. Notably, connections such as those between the cingulo-opercular network (CON) and the auditory network, as well as between the subcortex and visual networks, also made significant contributions. These findings elucidate the neural signatures of REM sleep loss and reveal common connectivity patterns across individuals, validated at the group level.

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.

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.

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

Inflammatory Markers and Sleep Architecture in Sleep Bruxism—A Case-Control Study

Background: Sleep bruxism (SB) is a common sleep-related movement behavior with a multifaceted etiology and a deficiently understood pathophysiology. A recent hypothesis suggests a link between SB and systemic inflammation. The scope of the study was to determine whether bruxers have altered sleep structure and different levels of inflammatory parameters compared to nonbruxers. Methods: A total of 83 adults underwent full-night polysomnography. The polysomnograms were evaluated using the American Academy of Sleep Medicine (AASM) guidelines. Then, the blood samples were obtained from the participants by venipuncture and the analyses were performed. The study group was divided based on bruxism episode index (BEI) into two groups: BEI ≤ 4 and BEI &gt; 4. Results: In comparison with nonbruxers, the oxygen desaturation index (ODI) was significantly higher in severe bruxers (7.5 ± 11.08 vs. 3.33 ± 5.75, p &lt; 0.005), as well as the arousal parameters (7.77 ± 4.68 vs. 4.03 ± 2.97, p &lt; 0.001), and the mean oxygen desaturation (3.49 ± 0.69 vs. 3.01 ± 0.67, p &lt; 0.05). Moreover, the differences in sleep architecture and deprivation of the deep sleep phase were observed, the non-REM sleep stage 3 was significantly shorter in severe bruxers (p &lt; 0.03). Differences were also noted in non-REM sleep stage 1 and REM sleep phase. In the investigated group, there were no statistical differences in inflammatory cytokines levels between bruxers and nonbruxers. Conclusions: Sleep bruxism is associated with sleep structure alterations and may be associated with deep sleep phase deprivation. The inflammatory markers are not linearly correlated with the severity of sleep bruxism expressed as BEI.

The importance of REM sleep fragmentation in the effects of stress on sleep: Perspectives from preclinical studies

Psychological stress poses a risk for sleep disturbances. Importantly, trauma-exposed individuals who develop posttraumatic stress disorder (PTSD) frequently report insomnia and recurrent nightmares. Clinical studies have provided insight into the mechanisms of these sleep disturbances. We review polysomnographic findings in PTSD and identify analogous measures that have been made in animal models of PTSD. There is a rich empirical and theoretical literature on rapid eye movement sleep (REMS) substrates of insomnia and nightmares, with an emphasis on REMS fragmentation. For future investigations of stress-induced sleep changes, we recommend a focus on tonic, phasic and other microarchitectural REMS measures. Power spectral density analysis of the sleep EEG should also be utilized. Animal models with high construct validity can provide insight into gender and time following stressor exposure as moderating variables. Ultimately, preclinical studies with translational potential will lead to improved treatment for stress-related sleep disturbances.

EEG Power Spectral Density in NREM Sleep is Associated with the Degree of Hypoxia in Patients with Obstructive Sleep Apnea.

Obstructive sleep apnea (OSA) is a prevalent sleep-related breathing disorder. Research conducted on patients with OSA using electroencephalography (EEG) has revealed a noticeable shift in the overnight polysomnography (PSG) power spectrum. To better quantify the effects of OSA on brain function and to identify the most reliable predictors of pathological cortical activation, this study quantified the PSG power and its association with the degree of hypoxia in OSA patients. This retrospective study recruited 93 patients with OSA. OSA patients were divided into three groups based on their apnea-hypopnea index (AHI) scores. The clinical characteristics and sleep macrostructure of these patients were examined, followed by an analysis of PSG signals. Power spectral density (PSD) in five frequency bands was analyzed during nonrapid eye movement (NREM) sleep, rapid eye movement (REM) sleep, and wakefulness. Finally, correlation analysis was conducted to assess the relationships among PSD, PSG parameters, and serum levels of S100β and uric acid. Obstructive sleep apnea occurred during both the NREM and REM sleep phases. Except for a decrease in the duration of N2 sleep and an increase in the microarousal index, there were no significant differences in sleep architecture based on disease severity. Compared to the mild OSA group, the theta and alpha band PSD in the frontal and occipital regions during NREM sleep and wakefulness were significantly decreased in the moderate and severe OSA groups. Correlation analysis revealed that theta PSD in N1 and N3 stages were negatively correlated the AHI, oxygen desaturation index, SaO2<90% and microarousal index. These findings imply that patients with more severe OSA exhibited considerable NREM hypoxia and abnormal brain activity in the frontal and occipital regions. Therefore, sleep EEG oscillation may be a useful neurophysiological indicator for assessing brain function and disease severity in patients with OSA.

On illusion of flying dreams. the mechanism of their occurrence

It is shown that there is no need to resort to exoteric hypotheses to explain flying in a dream. From a biophysical point of view, the phenomenon of "flying in a dream" is based on the already studied adaptive mechanisms and daily rhythms of the human body. During sleep, the brain's arousal thresholds are lowered, making it easier to arouse the brain with weak signals. This study considers one of the mechanisms of such excitation with a change in body position, which is perceived by the brain in the rapid eye movement sleep phase as a decrease in body weight, which, under certain conditions, can cause the illusion of flying in the brain.

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.

Algorithm for the classification of phases and stages of sleep in patients with chronic disorders of consciousness based on logical artificial intelligence

BACKGROUND: The analysis of sleep patterns in patients with chronic disorders of consciousness is attracting increasing attention in terms of diagnosis, prognosis, and treatment of severe brain damage. The study describes a software package based on an artificial intelligence (AI) expert system designed to classify the phases and stages of sleep, taking into account the characteristics of impaired cortical rhythm in such patients.&#x0D; AIM: To develop a specialized AI-based software package focused on patients with chronic impairment of consciousness for automatic classification of sleep phases and stages, with an emphasis on identifying sleep spindles and non-rapid eye movement (REM) and REM sleep phases.&#x0D; MATERIALS AND METHODS: To ensure the correct operation of the software package, receiver operating characteristic (ROC) curves were analyzed considering the binary classification of slow sleep, REM sleep, and wakefulness.&#x0D; RESULTS: The average sensitivity and specificity of the algorithm were 87.9 and 70.1, respectively. The average area under the ROC curve was 0.790. The algorithm for determining the REM phase demonstrates low specificity with high sensitivity, and its graph was similar to that of wakefulness, as well as the irregularity of the presence of REMs in the REM sleep phase in patients with CNS and the frequent presence of nystagmus in the waking state. Information about the presence of nystagmus, entered at the start of the program, allowed us to slightly increase the efficiency of the algorithm; however, this aspect probably needs further improvement.&#x0D; CONCLUSION: A software package that takes into account the features of electroencephalography of patients with chronic disorders of consciousness and analyzes sleep and wakefulness automatically is not only useful as a diagnostic tool for neurologists and somnologists but also contributes to a wider dissemination of this technique in clinical practice.

Relação entre sono e memória: Mais próximos do que você imagina

Hypnology (the study of sleep) is an area of medicine that permeates all others, because sleep is a fundamental part of everyone's life, since we spend a third of it asleep. This is due to its circadian rhythm. For this to happen, the action of modulating neurons is fundamental, each with different neuromediators that send out axons, establishing synapses in large areas of the cerebral cortex and regions that extend from the thalamus to the spinal cord. In addition, there is an interaction between the organism and the environment that regulates the sleep-wake cycle more effectively. This interaction characterizes the timer systems, which have cells capable of detecting environmental variations - sensory cells, especially light variations, and the so-called oscillator cells or pacemakers, which are responsible for the cycle regardless of external influences. In addition, there are hormonal interactions that influence both the sleep-wake cycle and organic functions. It is essential to study these relationships in order to understand the different states and stages of sleep, namely: slow-wave sleep, also known as non-REM sleep, and fast-wave sleep or REM sleep. Non-REM sleep is further subdivided into 4 stages, in which the human being starts from wakefulness and plunges into the various stages of depth. REM sleep is the deepest sleep, the stage of dreams, in which it is more difficult to wake the individual. Numerous nerve circuits are formed in this last stage of sleep, and it is this stage that is partly responsible for memory consolidation. There are various types of memory: those acquired throughout life, whether conscious or not, are essential for human beings to live well in society and form their individuality. The storage and recall of memories depends on the emotions experienced by each person. This changes the storage process and the places where memories are stored in each person's brain. There are regions that are essential and common to everyone, such as the hippocampus and amygdala, but the place where long-term memories are stored depends on each person's reaction to a given situation, and this will happen during the REM sleep phase. Becoming aware of this topic is fundamental to understanding the importance of good sleep hygiene, which is essential for achieving a substantial improvement in sleep quality and, consequently, quality of life, whether in terms of mood, health, cognition, memory and its consequences, or aspects related to work or academicism.

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.

0788 Sleep Profile of Adolescents Following Posterior Spinal Fusion

Abstract Introduction Major musculoskeletal operations can have a prolonged impact on patients’ quality of life during the postoperative period. Sleep patterns can be affected by general anesthesia, complex and prolonged operations, and post-surgical care. Sleep disturbance can be considered a determinant of poor postsurgical outcomes. In this study, we examined the sleep profile of adolescents who underwent Posterior Spine Fusion (PSF) utilizing the FitBit Charge 4TM wearable device. Methods Patients were approached at the time of their evaluation in the orthopedic office once they had been scheduled for PSF. Patients received a Fitbit Charge 4TM at the time of enrollment. Total sleep time (TST), the duration of REM and Deep Sleep phases, and sleep efficiency were obtained from patients’ FitBit4 data and were calculated by averaging data recorded over a 2-4-day period during the week prior to surgery, during the hospital stay, one-two-three weeks, and 3 months after patients were discharged home. Patients were given a PROMIS sleep questionnaire delivered to their cellular phone using Qualtrics the week before the hospitalization, during hospitalization, and 3 months after surgery. Pain scores were obtained every 4-6 hours during the patient’s hospital stay using the self-reporting numeric scale. Results 16 patients (10 female (62%)) completed the 3 months study period. Mean age was 16±1.9 years. The average length of hospitalization was 3 days. The average TST, REM, and DEEP sleep at baseline was 387±111, 74±28, 75±25 minutes respectively. TST, REM, and DEEP sleep decreased during the acute post-operative period and gradually increased during the follow-up period going to baseline values by the 3rd post-surgery week in 72% of the cases. Perception of sleep showed mild disturbance at baseline and worsened during the hospital stay based on PROMIS scores with improvement or return to baseline by the 3rd month post-operatively in 86% of patients. Conclusion Sleep phases of adolescents are affected after a major surgery. Similar to patients of other major surgeries, these changes are short-lived and returned to baseline by the 3rd post-operative week. There was a broad range of changes among subjects during the study period. Support (if any)

Sleep quality and polysomnographic changes in patients with chronic pain with and without central sensitization signs

BackgroundInsufficient sleep is common nowadays and it can be associated with chronic pain. ObjectiveTo describe the main polysomnographic findings in patients with chronic musculoskeletal pain and to estimate the association between sleep quality, polysomnography variables and chronic musculoskeletal pain. MethodsThis cross-sectional research analyzed a database from polysomnography type 1 exams results and then collected data via an electronic form from these patients. The form collected sociodemographic data and presented clinical questionnaires for measuring sleep quality, sleepiness, pain intensity and central sensitization signs. Pearson's correlation coefficient and odds ratio were used to estimate the associations. ResultsThe mean age of the respondents was 55.1 (SD 13.4) years. The mean score of the Central Sensitization Inventory showed signs of central sensitization (50.1; SD 13.4) in the participants. Most patients (86%) had 1 or more nocturnal awakenings, 90% had one or more episodes of sleep apnea, 47% had Rapid Eye Movement sleep phase latency greater than 70–120 min and the mean sleep efficiency among all participants was 81.6%. The Pittsburgh Sleep Quality Index score was correlated with the CSI score (r = 0.55; 95% CI: 0.45, 0.61). People with central sensitization signs have 2.6 times more chance to present sleep episodes of blood oxygen saturation below 90% (OR = 2.62; 95% CI:1.23, 6.47). ConclusionMost people with central sensitization signs had poor sleep quality, night waking episodes and specific disturbances in sleep phases. The findings showed association between central sensitization, sleep quality, nocturnal awakening, and changes in blood oxygen saturation during sleep.

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.