Sleep Stages Research Articles

Magnetic Garments Promote Parasympathetic Dominance and Improve Sleep Quality in Male Long-Distance Runners Following a 30 km Run

This study aimed to investigate the effects of high-intensity running on the autonomic nervous system and sleep quality of male long-distance runners and to examine the impact of wearing magnetic garments on these parameters. Fifteen highly trained male collegiate long-distance runners participated in a randomized, double-blind crossover study. Participants completed two 30 km runs (30k-RUN) during a 10-day training camp. After each run, they wore either magnetic (MAG) or non-magnetic control (CTRL) garments. Sleep quality and heart rate variability (HRV) were assessed using a wrist-worn device before and after each 30k-RUN. Wearing MAG garments post-30k-RUN resulted in significantly longer deep sleep duration compared to CTRL. HRV analysis revealed that the MAG condition led to a significantly higher root mean square of successive RR interval differences and high-frequency power, indicating enhanced parasympathetic activity. The low-frequency to high-frequency ratio was significantly lower in MAG than in CTRL. Perceived recovery scores were significantly higher in MAG than in CTRL. The findings of this study suggest that wearing magnetic garments following high-intensity endurance running may promote parasympathetic dominance and improve sleep quality in male long-distance runners. These findings indicate that magnetic garments may be a practical method for enhancing recovery in athletes following intense training.

Wakefulness Induced by TAAR1 Partial Agonism in Mice Is Mediated Through Dopaminergic Neurotransmission

Trace amine-associated receptor 1 (TAAR1) is a negative regulator of dopamine (DA) release. The partial TAAR1 agonist RO5263397 promotes wakefulness and suppresses NREM and REM sleep in rodents and non-human primates. We tested the hypothesis that the TAAR1-mediated effects on sleep/wake regulation were due, in part, to DA release. Male C57BL6/J mice (n = 8) were intraperitoneally administered the D1R antagonist SCH23390, the D2R antagonist eticlopride, a combination of D1R + D2R antagonists, or saline at ZT5.5, followed 30 min later by RO5263397 or vehicle per os. EEG, EMG, subcutaneous temperature, and activity were recorded across the 8 treatments and sleep architecture was analyzed for 6 h post-dosing. As described previously, RO5263397 increased wakefulness and delayed NREM and REM sleep onset. D1, D2, and D1 + D2 pretreatment reduced RO5263397-induced wakefulness for 1–2 h after dosing but only the D1 antagonist significantly reduced the TAAR1-mediated increase in NREM latency. Neither the D1 nor the D2 antagonist affected the TAAR1-mediated suppression of REM sleep. These results suggest that, whereas the TAAR1 effects on wakefulness are mediated, in part, through the D2R, D1R activation plays a role in reversing the TAAR1-mediated increase in NREM sleep latency. In contrast, the TAAR1-mediated suppression of REM sleep appears not to involve D1R or D2R mechanisms.

Characteristics of clinical descriptive variables and polysomnographic findings of catathrenia.

Catathrenia has been classified as a sleep-related breathing disorder variant in the third edition of the International Classification of Sleep Disorders, but its validity remains unverified. We analyzed the clinical descriptive variables and polysomnographic findings of catathrenia and discussed the similarities and differences to those of obstructive sleep apnea (OSA), non-REM parasomnias, and sleep bruxism (SB). A retrospective analysis was conducted on 47 patients diagnosed with nocturnal groaning through polysomnography. We examined sex, body mass index, age at symptom onset, weekly symptom frequency, and presence/absence of comorbidities, including OSA, periodic limb movement disorder, non-REM parasomnia, and SB. The groaning event (GE) index was calculated according to sleep position and sleep stage. The distribution of patients with catathrenia did not show sex difference (male/female = 20:27), body mass index was 20.6 ± 3.0 kg/m2, and age of onset was 18.2 ± 7.4 years. The GE index was higher in stages N1 and R than in stage N3 and in the supine position than in the lateral position. There were no cases complicated with non-REM parasomnia, but the complication of SB was observed in 30% of the participants, and SB events appeared immediately before or during the interictal period of the GE episodes in these cases. Given the clinical background, posture- and sleep stage-dependent appearance of GEs, and the relatively high complication rate of SB, catathrenia pathogenesis may be heterogeneous or comprise elements of different sleep disorders.

Sleep in the dromedary camel: features of the 'first night effect'.

The 'first night effect' (FNE) is a well-known phenomenon in polysomnographic (PSG) sleep studies, resulting in significant variations in the macrostructure of wakefulness and sleep states, particularly between the initial and subsequent sleep recording sessions. The FNE phenomenon during sleep has been studied in various species, revealing complex variations between several sessions of sleep recording. The present study used a non-invasive PSG method to examine differences between various vigilance states in four adult female dromedary camels during 4 consecutive nights and days of sleep recording. The results indicate the presence of a FNE in the architecture of the dromedary camel's vigilance states. On the first night, the proportions of wakefulness and light non-rapid eye movment (NREM) sleep (drowsiness) were higher, at a mean (standard error of the mean [SEM]) of 40.92% (0.88%) and 14.93% (0.37%), respectively; while the proportion of rumination (mean [SEM] 29.55% [0.92%]) was lower compared to consecutive nights. No FNE was found on deep NREM sleep, while night-time REM sleep had a shorter proportion during the first night compared to subsequent consecutive nights. A significantly lower REM/total sleep time (TST) ratio was observed on the first night. Daytime comparisons did not show any significant differences for the different vigilance states. The increase in wakefulness and light NREM sleep and the reduction in REM sleep and REM/TST sleep on the first night indicate a decline in sleep quality in the dromedary camel due to the FNE. Thus, we recommend excluding from a PSG sleep study at least the first session/night of the recordings to ensure accurate results.

Hubungan Kualitas Tidur Dengan Kejadian Hipertensi Pada Lansia di Desa Sukadaya Kecamatan Sukawangi Kabupaten Bekasi 2023

Hypertension is a non-communicable disease caused by various risk factors. One of the factors that causes hypertension is sleep quality. Sleep quality is a process when a person is sleeping, which is done to maintain a state of sleep and to obtain the appropriate Rapid Eye Movement (REM) and Non Rapid Eye Movement (NREM) stages. A person's habit of not sleeping enough or having poor quality sleep can increase the risk of increased blood pressure or hypertension. The aim of this research is to determine the relationship between sleep quality in the elderly and the incidence of hypertension in the elderly in Sukadaya Village, Sukawangi District, Bekasi Regency in 2023. The type of research used is quantitative research with observational methods (cross sectional), a sample of 170 people aged 60 years. tThe sampling technique uses simple random sampling. Sleep quality data was collected using the PSQI questionnaire directly and blood pressure measurements. This research stated that the sleep quality of the respondents was in the poor category, 86 respondents 50.6%, and the blood pressure of the respondents was categorized as high, 98 respondents 57.6%. The statistical test results showed that the p-value = 0.000 (α < 0.05). So this shows that H0 is rejected, which means that there is a relationship between sleep quality and the incidence of hypertension in the elderly in Sukadaya Sukawangi Bekasi 2023.

Local sleep in songbirds: different simultaneous sleep states across the avian pallium.

Wakefulness and sleep have often been treated as distinct and global brain states. However, an emerging body of evidence on the local regulation of sleep stages challenges this conventional view. Apart from unihemispheric sleep, the current data that support local variations of neural oscillations during sleep are focused on the homeostatic regulation of local sleep, i.e., the role preceding awake activity. Here, to examine local differences in brain activity during natural sleep, we recorded the electroencephalogram and the local field potential across multiple sites within the avian pallium of zebra finches without perturbing the previous awake state. We scored the sleep stages independently in each pallial site and found that the sleep stages are not pallium-wide phenomena but rather deviate widely across electrode sites. Importantly, deeper electrode sites had a dominant role in defining the temporal aspects of sleep state congruence. Altogether, these findings show that local regulation of sleep oscillations also occurs in the avian brain without prior awake recruitment of specific pallial circuits and in the absence of mammalian cortical neural architecture.

Gender-specific associations between sleep stages and cardiovascular risk factors.

Sleep characteristics are associated with cardiovascular disease (CVD) risk and both sleep and CVD risk vary by gender. Our objective was to examine associations between polysomnographic sleep characteristics and CVD risk after excluding moderate-severe sleep apnea, and whether gender modifies these associations. This was a cross-sectional study with at-home polysomnography in adults in Brazil (n= 1,102 participants with apnea-hypopnea index (AHI)<15 events/hour). Primary exposures were N3, REM, wake after sleep onset (WASO), arousal index (AI) and AHI, and outcomes were blood pressure (BP) and lipid levels. Associations between sleep and BP varied by gender. In women, more N3 was associated with lower systolic BP (-0.40 mmHg per 10 minutes, 95%CI -0.71, -0.09), lower diastolic BP (-0.29 mmHg per 10 minutes, 95%CI -0.50, -0.07), and lower odds of hypertension (OR 0.94, 95%CI 0.89, 0.98). In men, more WASO was associated with higher systolic BP (0.41 mmHg per 10 minutes, 95%CI 0.08, 0.74) and higher odds of hypertension (OR 1.07, 95%CI 1.01, 1.14). No interactions by gender were observed for lipids. More WASO was associated with lower total cholesterol (-0.71 per 10 minutes, 95%CI -1.37, -0.05). Higher AHI was associated with higher total cholesterol (+0.97 per event/hour, 95%CI 0.24, 1.70) and higher LDL (+0.84 per event/hour, 95%CI 0.04, 1.64). N3 is more strongly associated with BP in women, which is consistent with other studies demonstrating gender differences in BP control and CVD risk and adds a novel risk factor. Longitudinal and interventional studies are required to determine whether changes in N3 result in BP changes.

A Randomized-Controlled Trial Targeting Cognition in Early Alzheimer's Disease by Improving Sleep with Trazodone (REST).

Alzheimer's disease (AD) is a leading cause of mortality and morbidity among aging populations worldwide. Despite arduous research efforts, treatment options for this devastating neurodegenerative disease are limited. Sleep disturbances, through their link to changes in neural excitability and impaired clearance of interstitial abnormal protein aggregates, are a key risk factor for the development of AD. Research also suggests that the neuroprotective effects of sleep are particularly active during slow wave sleep. Given the strong link between sleep disturbance and AD, targeting sleep in the prodromal stages of AD, such as in mild cognitive impairment (MCI), represents a promising avenue for slowing the onset of AD-related cognitive decline. In efforts to improve sleep in older individuals, several pharmacologic approaches have been employed, but many pose safety risks, concern for worsening cognitive function, and fail to effectively target slow wave sleep. Trazodone, a safe and widely used drug in the older adult population, has shown promise in inducing slow wave sleep in older adults, but requires more rigorous research to understand its effects on sleep and cognition in the prodromal stages of AD. In this review, we present the rationale and study design for our randomized, double-bind, placebo-controlled, crossover trial (NCT05282550) investigating the effects of trazodone on sleep and cognition in 100 older adults with amnestic MCI and sleep complaints.

Impaired Sleep-Dependent Memory Consolidation in Pediatric Narcolepsy Type 1.

Disrupted nighttime sleep (DNS) is common in pediatric Narcolepsy type 1, yet its cognitive impact is unknown. As N2 sleep spindles are necessary for sleep-dependent memory consolidation, we hypothesized that Narcolepsy Type 1 impairs memory consolidation via N2 sleep fragmentation and N2 sleep spindle alterations. We trained 28 pediatric Narcolepsy Type 1 participants and 27 healthy controls (HC) on a spatial declarative memory task before a nocturnal in-lab polysomnogram and then gave them a cued recall test upon awakening in the morning. We extracted wake and sleep stage bout numbers and N2 spindle characteristics from the polysomnogram and conducted mixed model analysis of sleep-dependent memory consolidation to identify group differences. Narcolepsy Type 1 participants had shorter N2 bout durations and associated shorter N2 spindles vs. HC, but other N2 spindle features were similar. Narcolepsy Type 1 participants had worse memory performance post-sleep than HCs after adjusting for age and gender (mean memory consolidation HC: -3.1% ± 18.7, NT1: -15.6 ± 24.8, main effect group x time of testing F=5.3, p=0.03). We did not find significant relationships between sleep-dependent memory consolidation and N2 spindle characteristics. Notably, increased N1% was associated with worse sleep-dependent memory consolidation with results driven by the Narcolepsy Type 1 group. Sleep-dependent memory consolidation is mildly impaired in youth with Narcolepsy Type 1 and findings may be attributed to increases in N1 sleep. Further studies are needed to determine if these findings are generalizable and reversible with sleep-based therapies.

The human claustrum tracks slow waves during sleep

Slow waves are a distinguishing feature of non-rapid-eye-movement (NREM) sleep, an evolutionarily conserved process critical for brain function. Non-human studies suggest that the claustrum, a small subcortical nucleus, coordinates slow waves. We show that, in contrast to neurons from other brain regions, claustrum neurons in the human brain increase their spiking activity and track slow waves during NREM sleep, suggesting that the claustrum plays a role in coordinating human sleep architecture.

Overnight changes in performance fatigability and their relationship to modulated deep sleep oscillations via auditory stimulation.

Deep sleep oscillations are proposed to be central in restoring brain function and to affect different aspects of motor performance such as facilitating the consolidation of motor sequences resulting in faster and more accurate sequence tapping. Yet, whether deep sleep modulates performance fatigability during fatiguing tasks remains unexplored. We investigated overnight changes in tapping speed and resistance against performance fatigability via a finger tapping task. During fast tapping, fatigability manifests as a reduction in speed (or "motor slowing") which affects all tapping tasks, including motor sequences used to study motor memory formation. We further tested whether overnight changes in performance fatigability are influenced by enhancing deep sleep oscillations using auditory stimulation. We found an overnight increase in tapping speed alongside a reduction in performance fatigability and perceived workload. Auditory stimulation led to a global enhancement of slow waves and both slow and fast spindles during the stimulation window and a local increase in slow spindles in motor areas across the night. However, overnight performance improvements were not significantly modulated by auditory stimulation and changes in tapping speed or performance fatigability were not predicted by individual changes in deep sleep oscillations. Our findings demonstrate overnight changes in fatigability but revealed no evidence suggesting that this effect is causally linked to temporary augmentation of slow waves or sleep spindles. Our results are important for future studies using tapping tasks to test the relationship between sleep and motor memory consolidation, as overnight changes in objectively measured and subjectively perceived fatigue likely impact behavioural outcomes.

Optimization of Desalting Conditions for the Green Seaweed Codium fragile for Use as a Functional Food with Hypnotic Effects.

Codium fragile (CF) contains various bioactive compounds, but its high salt content (39.8%) makes its use as a functional food challenging. Here, we aimed to optimize the desalination process and verify changes in functionality based on variations in salt and total phenolic contents. To optimize the CF immersion conditions for the lowest salt content and monitor the total phenolic content, a response surface methodology was used. The optimal immersion conditions were as follows: X1 (immersion temperature) = 42.8 °C; X2 (immersion time) = 1.0 h. An inverse correlation was noted between salt content and total phenolic content. Among the post-desalination processes, desalination with centrifugal dehydration (CD) significantly reduced salt content. CD ethanol extract (CD-E) induced the longest sleep duration in the pentobarbital-induced sleep test in ethanol extracts. Moreover, 1000 mg/kg CD-E had a significant effect on non-rapid eye movement sleep but did not affect delta activity. These findings highlight the potential of industrializing CF as a functional food through desalination and its promise as a natural aid for sleep promotion.

Pharmacological Management of Sleep-Wake Disturbances in Delirium.

Delirium is a heterogeneous syndrome primarily characterized by fluctuations in attention and awareness. Sleep-wake disturbances are a common and significant feature of delirium and can manifest as circadian rhythm inversion, sleep fragmentation, and reduced rapid eye movement (REM) and slow-wave sleep. Some literature suggests that the relationship between sleep disruption and delirium is reciprocal wherein the two reinforce one another and may share an underlying etiology. As there are no FDA-approved medications for delirium or delirium-related sleep disturbances, management is primarily focused on addressing underlying medical concerns and promoting physiologic circadian patterns with non-pharmacological behavioral interventions. In practice, however, medications are often used, albeit with limited evidence to support their use. This literature review explores the pharmacology and pharmacokinetics of several medications with literature investigating their use in delirium: melatonin, ramelteon, dual orexin receptor antagonists (DORAs), and dexmedetomidine. Current evidence suggests a possible benefit of ramelteon or melatonin, dexmedetomidine for patients in the ICU setting, and DORAs as therapeutic options for the re-regulation of sleep-wake cycle disruption in delirium. We discuss pertinent pharmacokinetic and pharmacodynamic factors that may influence clinical decision-making regarding these interventions.

The temporal asymmetry of cortical dynamics as a signature of brain states

The brain is a complex non-equilibrium system capable of expressing many different dynamics as well as the transitions between them. We hypothesized that the level of non-equilibrium can serve as a signature of a given brain state, which was quantified using the arrow of time (the level of irreversibility). Using this thermodynamic framework, the irreversibility of emergent cortical activity was quantified from local field potential recordings in male Lister-hooded rats at different anesthesia levels and during the sleep-wake cycle. This measure was carried out on five distinct brain states: slow-wave sleep, awake, deep anesthesia–slow waves, light anesthesia–slow waves, and microarousals. Low levels of irreversibility were associated with synchronous activity found both in deep anesthesia and slow-wave sleep states, suggesting that slow waves were the state closest to the thermodynamic equilibrium (maximum symmetry), thus requiring minimum energy. Higher levels of irreversibility were found when brain dynamics became more asynchronous, for example, in wakefulness. These changes were also reflected in the hierarchy of cortical dynamics across different cortical areas. The neural dynamics associated with different brain states were characterized by different degrees of irreversibility and hierarchy, also acting as markers of brain state transitions. This could open new routes to monitoring, controlling, and even changing brain states in health and disease.

The functional activity of the brain in patients with occupational chronic mercury intoxication against background of the treatment of insomnia disorders

Introduction. In patients with chronic mercury intoxication, insomnia disorders are much more common than in the general population. Persistent emotional disorders in combination with severe sleep disturbances may contribute to the progression of cognitive dysfunction in patients in the late post-exposure period of chronic mercury intoxication. The purpose of the study was to analyze the trend in electroencephalography indices and study cognitive evoked potentials in patients with occupational chronic mercury intoxication to optimize the treatment of insomnia. Materials and methods. Two groups of 30 patients with occupational chronic mercury intoxication, who worked at the enterprises of Usolyekhimprom LLC and Sayanskhimplast OJSC, were examined. In the first group of patients received the first treatment option, the average age was 56±0.71 years, in the second group, cases received the second treatment regimen, were of 57.1±3 years. Before and after treatment, there were carried out neurophysiological studies including polysomnography, electroencephalography, and a study of cognitive evoked potentials P300. Results. After the implementation of the treatment regimen in the first group, positive changes in the main indices of polysomnography were revealed as follows: decrease in the time of falling asleep and time of wakefulness in the bed, increase in total sleep time and the representation of delta sleep, increase in the sleep efficiency index, etc., electroencephalography (decrease in the delta index – rhythm and an increase in the alpha rhythm index), and cognitive evoked potentials (decreased latency and increased P300 amplitude). In the second group, there were registered positive alterations only in three neurophysiological indices: a decrease in the latent period of the 1st stage of sleep, a decline in the delta rhythm index and a fall in P300 latency. Limitations. The results cannot be generalized to workers as the group included only men. Conclusion. According to neurophysiological studies, improvement in polysomnography parameters during the treatment of insomnia in patients in the late post-contact period of chronic mercury intoxication was accompanied by an improvement in concentration and an increase in the rate of psychomotor response.

The importance of including both sexes in preclinical sleep studies and analyses

A significant effort in biomedical sciences has been made to examine relationships between sex and the mechanisms underlying various disease states and behaviors, including sleep. Here, we investigated biological sex differences in sleep using male and female C57BL/6J mice (n = 267). Physiological parameters were recorded for 48-h using non-invasive piezoelectric cages to determine total sleep, non-rapid eye movement (NREM) sleep, rapid eye movement (REM)-like sleep, and wakefulness (WAKE). We fit hierarchical generalized linear mixed models with nonlinear time effects and found substantial sex differences in sleep. Female mice slept less overall, with less NREM sleep compared to males. Females also exhibited more REM-like sleep and WAKE and had shorter NREM sleep bout lengths. We also conducted a simulation exercise where we simulated a hypothetical treatment that altered the sleep of female mice, but not male mice. In models that included an appropriate sex by treatment interaction, a female-specific treatment response was accurately estimated when sample sizes were equal but was not detected when sample sizes were unequal, and females were underrepresented. Failure to include both sexes in experimental designs or appropriately account for sex during analysis could lead to inaccurate translational recommendations in pre-clinical sleep studies.

A whole-brain model of the aging brain during slow wave sleep.

Age-related brain changes affect sleep and are reflected in properties of sleep slow-waves, however the precise mechanisms behind these changes are still not completely understood. Here, we adapt a previously established whole-brain model relating structural connectivity changes to resting state dynamics, and extend it to a slow-wave sleep brain state. In particular, starting from a representative connectome at the beginning of the aging trajectory, we have gradually reduced the inter-hemispheric connections, and simulated sleep-like slow-wave activity. We show that the main empirically observed trends, namely a decrease in duration and increase in variability of the slow waves are captured by the model. Furthermore, comparing the simulated EEG activity to the source signals, we suggest that the empirically observed decrease in amplitude of the slow waves is caused by the decrease in synchrony between brain regions.Significance Statement Aging is characterized by changes in slow wave (SW) sleep features, yet the precise mechanisms driving these alterations remain elusive. Employing a connectome-based model, we implement the established age- related reductions in inter-hemispheric connectivity, successfully replicating the SW changes in the simulated activity. Our simulation of EEG activity also suggests that observed decreases in SW amplitude stems from diminished synchrony between brain regions. Our results support the notion that alterations in SW characteristics result from reductions in cortical excitatory drive-here facilitated by the inter-hemispheric connections. Our model serves as a robust foundation for extensions to population studies and interventional work in animal models of aging aimed at disentangling the contributions of network alterations, changes to local neural mass properties, and neuromodulation.

THE ROLE OF PHYSICAL ACTIVITY IN IMPROVING THE QUALITY OF SLEEP OF PATIENTS WITH VARIOUS SLEEP DISORDERS

Sleep is an important human behavior and difficulties with sleep are closely related to health, potentially leading to the development of diseases and a reduced quality of life. Sleep disorders cover a wide range of problems associated with mental health disorders, such as anxiety and depression, and contribute to an increased tendency to become overweight or obese. In addition, sleep difficulties can lead to more serious sleep disorders, such as problems with sleep maintenance, poor sleep efficiency, and reduced daytime attention. The purpose of the study is to highlight the role of physical activity in improving the quality of sleep in patients with various sleep disorders. Materials and methods. To better understand the impact of physical activity on sleep quality and its positive effect on sleep onset and duration, a search of scientific literature was conducted between 2019 and 2024 in the PubMed, Scopus, Web of Science, and Google Scholar databases using the terms “exercise,” “sleep,” “quality of life,” “insomnia,” and “activity.” The search resulted in the selection of publications that examined the relationship between daily sleep and physical activity and will be discussed in this review. Results. The study identified potential biological pathways that explain the possible interactions between sleep and physical activity in the short and long term. Acute or repetitive physical activity increases total sleep time by reducing insulin resistance and the concentration of inflammatory markers, better regulation of circadian rhythm, and the release of brain-derived neurotrophic factor. In turn, sleep deprivation can alter physical performance or contribute to fatigue during physical activity by increasing cortisol concentrations, decreasing growth hormone and prolactin concentrations, and stimulating inflammatory markers. Scientific studies have established the beneficial effects of physical activity in alleviating sleep problems. Numerous studies show that moderate to vigorous physical activity has a positive effect on sleep quality. Physical activity has pluripotential beneficial effects on bodily functions. These benefits include a reduction in the incidence of cardiovascular disease, coronary heart disease, hypertension, type 2 diabetes, and death. In addition to these effects, physical activity has a significant beneficial effect on the onset, duration, and quality of sleep, which complements its beneficial effects. In contrast, lack of sleep is associated with an increased incidence of cardiovascular complications and death. In this regard, physical activity serves as a non-pharmacological means of improving sleep, especially in older people who often have difficulty falling asleep. Regarding the time of exercise and its effect on sleep, there was no difference between morning and evening exercise in terms of sleep onset and quality. In addition, the multifaceted benefits of physical activity go beyond improving sleep to contribute to overall well-being and longevity, offering a comprehensive health solution that is comparatively better than alternative treatments. Conclusions. Based on the research presented here, it can be concluded that the scientific literature has identified an improvement in sleep quality after physical activity, and empirical evidence confirms its positive impact, regardless of type or intensity. Increased physical activity was found to be associated with improved total sleep duration, reduced sleep latency, and improved sleep efficiency. Exercise can improve sleep by reducing sleep latency and increasing slow wave sleep.

Exploring bispectral index as an alternative to polysomnography for long-term sleep monitoring in disorders of consciousness.

Sleep plays a crucial role in neuroplasticity and recovery from brain injury, particularly in disorders of consciousness (DoC), including unresponsive wakefulness syndrome (UWS) and minimally conscious state (MCS). Traditional sleep monitoring methods like polysomnography (PSG) are complex and often impractical for long-term use in clinical settings. This study aimed to explore the utility of the Bispectral Index (BIS) as a more practical alternative for monitoring sleep patterns in DoC patients. We conducted simultaneous PSG and BIS monitoring on 38 DoC patients (19 UWS and 19 MCS). The study focused on analyzing sleep timing distribution, the effectiveness of BIS in differentiating sleep stages, and its correlation with consciousness levels. Our findings revealed that DoC patients exhibited irregular and fragmented sleep patterns, necessitating extended monitoring periods. The BIS effectively differentiated various sleep stages, with significant differences in BIS values observed across these stages. However, BIS values did not show significant differences between UWS and MCS patients, indicating that BIS primarily indicates wakefulness rather than cognitive awareness. DoC patients have disturbed sleep-wake cycles that require prolonged monitoring. BIS can well distinguish sleep stages in DoC patients, and the distribution of values is similar to that of normal subjects. However, BIS could not distinguish the level of consciousness of DoC patients. The study demonstrates the potential of BIS as a practical tool for long-term sleep monitoring in DoC patients, offering a less intrusive alternative to traditional methods.

Recent Evidence of Non-Rapid Eye Movement Sleep Oscillation Abnormalities in Psychiatric Disorders.

We review recent studies published from 2019 to 2024 examining slow waves and sleep spindles abnormalities across neurodevelopmental, mood, trauma-related, and psychotic disorders using polysomnography and Electroencephalogram (EEG). Individuals with attention-deficit/hyperactivity disorder (ADHD) showed higher slow-spindle activity, while findings on slow-wave activity were mixed. Individuals with autism spectrum disorder (ASD) showed inconsistent results with some evidence of lower spindle chirp and slow-wave amplitude. Individuals with depression displayed lower slow-wave and spindle parameters mostly in medicated patients. Individuals with post-traumatic stress disorder (PTSD) showed higher spindle frequency and activity, which were associated with their clinical symptoms. Psychotic disorders demonstrated the most consistent alterations, with lower spindle density, amplitude, and duration across illness stages that correlated with patients' symptom severity and cognitive deficits, whereas lower slow-wave measures were present in the early phases of the disorders. Sleep spindle and slow-wave abnormalities are present across psychiatric populations, with the most consistent alterations observed in psychotic disorders. Larger studies with standardized methodologies and longitudinal assessments are needed to establish the potential of these oscillations as neurophysiological biomarkers and/or treatment targets.