The dynamic responses of mood and sleep physiology to chronic sleep restriction and subsequent recovery sleep

Healthy sleep of sufficient duration preserves mood and disturbed sleep is a risk factor for a range of psychiatric disorders. As adults commonly experience chronic sleep restriction (SR), an enhanced understanding of the dynamic relationship between sleep and mood is needed, including whether susceptibility to SR-induced mood disturbance differs between sexes. To address these gaps, data from N=221 healthy adults who completed one of two multi-day laboratory studies with identical 9-day SR protocols were analyzed. Participants randomized to the SR (n=205) condition underwent 5 nights of SR to 4 h time-in-bed and were then randomized to one of seven sleep doses that ranged from 0 h to 12 h in 2 h increments; participants randomized to the control (n=16) condition received 10 h time-in-bed on all study nights. The Profile of Mood States (POMS) was used to assess mood every 2 h during wakefulness and markers of sleep homeostasis (EEG slow-wave activity) were derived via polysomnography. Mood progressively deteriorated across SR with marked disturbances in somatic mood components. Altered sleep physiology contributed to mood disturbance whereby increased EEG slow-wave activity was associated with increased POMS Total Mood Disturbance scores, a finding specific to males. Mood was restored in a dose-response fashion where improvements were greater with longer sleep doses. These findings suggest that when lifestyle and environmental factors are inhibited in the laboratory, the affective consequences of chronic sleep loss are primarily somatic mood disturbances. Altered sleep homeostasis may contribute to mood disturbance, yet sleep-dependent mechanisms may be sex-specific.

Long-term influence of sleep/wake history on the dynamic neurobehavioural response to sustained sleep restriction

Chronic sleep restriction, common in today's 24/7 society, causes cumulative neurobehavioural impairment, but the dynamics of the build-up and dissipation of this impairment have not been fully elucidated. We addressed this knowledge gap in a laboratory study involving two, 5-day periods of sleep restriction to 4 hr per day, separated by a 1-day dose-response intervention sleep opportunity. We measured sleep physiological and waking neurobehavioural responses in 70 healthy adults, each randomized to one of seven dose-response intervention sleep doses ranging from 0 to 12 hr, or a non-sleep-restricted control group. As anticipated, sleep physiological markers showed homeostatic dynamics throughout the study, and waking neurobehavioural impairment accumulated across the two sleep restriction periods. Unexpectedly, there was only a slight and short-lived effect of the 1-day dose-response intervention sleep opportunity. Whether the dose-response intervention sleep opportunity involved extension, further restriction or total deprivation of sleep, neurobehavioural functioning during the subsequent second sleep restriction period was dominated by prior sleep-wake history. Our findings revealed a profound and enduring influence of long-term sleep-wake history as a fundamental aspect of the dynamic regulation of the neurobehavioural response to sleep loss.

Acute sleep deprivation induces synaptic remodeling at the soleus muscle neuromuscular junction in rats

Sleep is important for cognitive and physical performance. Sleep deprivation not only affects neural functions but also results in muscular fatigue. A good night's sleep reverses these functional derangements caused by sleep deprivation. The role of sleep in brain function has been extensively studied. However, its role in neuromuscular junction (NMJ) or skeletal muscle morphology is sparsely addressed although skeletal muscle atonia and suspended thermoregulation during rapid eye movement sleep possibly provide a conducive environment for the muscle to rest and repair; somewhat similar to slow-wave sleep for synaptic downscaling. In the present study, we have investigated the effect of 24 h sleep deprivation on the NMJ morphology and neurochemistry using electron microscopy and immunohistochemistry in the rat soleus muscle. Acute sleep deprivation altered synaptic ultra-structure viz. mitochondria, synaptic vesicle, synaptic proteins, basal lamina, and junctional folds needed for neuromuscular transmission. Further acute sleep deprivation showed the depletion of the neurotransmitter acetylcholine and the overactivity of its degrading enzyme acetylcholine esterase at the NMJ. The impact of sleep deprivation on synaptic homeostasis in the brain has been extensively reported recently. The present evidence from our studies shows new information on the role of sleep on the NMJ homeostasis and its functioning.

Correlation of Various Sleep Patterns on Different Types of Memory Retention: A Systematic Review

Sleep has a substantial impact on memory consolidation, although the link between specific sleep patterns and different forms of memory retention is not well-understood. The purpose of this systematic review is to investigate the correlation between varying sleep habits and memory recall. To identify pertinent research published between 2017 and 2023, a thorough check of electronic databases was carried out. Inclusion criteria encompassed peer-reviewed articles published in English, focusing on human participants, and investigating the relationship between sleep patterns and memory retention. Data extraction and quality assessment were performed on selected studies. This research used different strategies and examined several forms of memory retention, including declarative memory, procedural memory, and emotional memory. Several sleep patterns, including sleep duration, sleep stages, and sleep continuity, were investigated. This comprehensive study demonstrated the relationship between adequate sleep duration and memory consolidation, particularly in regard to declarative memory. Furthermore, deep sleep, characterized by slow-wave sleep (SWS), has been associated with superior procedural memory retention. Sleep continuity, as evaluated by reduced sleep fragmentation or undisturbed sleep, influenced memory consolidation across multiple categories of memory. However, the relationship between rapid eye movement (REM) sleep and memory retention remains inconclusive due to conflicting findings. This systematic review emphasizes the significance of various sleep patterns in memory retention. Memory consolidation corresponds with adequate sleep length, deep sleep (or SWS), and sleep continuity. Future research ought to investigate the connection between REM sleep and memory retention. Understanding the impact of specific sleep patterns on memory processes might help guide therapies and interventions to improve memory consolidation and overall cognitive functioning.

Investigating the relationship between objective measures of sleep and self-report sleep quality in healthy adults: a review

STUDY OBJECTIVES

Sleep is one of the most common factors related to health, yet a standard definition of sleep quality has not been identified. Polysomnography provides important information about objective sleep variables. However, the relationship between objective sleep variables and perception of sleep quality remains unclear. The purpose of this review was to (1) summarize the current methods of measuring objective sleep macrostructure and microstructure, including electroencephalography arousals, spectral frequency, cyclic alternating pattern, and self-report sleep quality, and (2) investigate the relationship between objective measures of sleep physiology and self-report sleep quality in healthy adults.

METHODS

A literature search was conducted using Medline, PubMed, and PsycInfo databases and cited reference searches. Eligible studies included a comparison between self-report sleep quality and polysomnography sleep measures in healthy adults.

RESULTS

Thirteen studies were identified. Measurement of self-report sleep quality varied widely across studies. Total sleep time and sleep efficiency were most consistently related to sleep quality, while other objective sleep variables, including electroencephalography spectral analysis, were not reliably predictive of self-report sleep quality in healthy adults. There is preliminary support that microstructural sleep analysis with cyclic alternating pattern may be related to self-reported sleep quality.

CONCLUSIONS

Further research is needed to define and standardize self-report measures of sleep quality and investigate the microstructure of sleep. Objective measures of sleep and experiences of "quality" sleep are not as closely related as one may expect in healthy individuals, and understanding this relationship further is necessary to improve the clinical utility of sleep physiology.

CITATION

Cudney LE, Frey BN, McCabe RE, Green SM. Investigating the relationship between objective measures of sleep and self-report sleep quality in healthy adults: a review. J Clin Sleep Med. 2022;18(3):927-936.

From sleep medicine to medicine during sleep-a clinical perspective

Objective. In this perspective paper, we aim to highlight the potential of sleep as an auspicious time for diagnosis, management and therapy of non-sleep-specific pathologies.Approach. Sleep has a profound influence on the physiology of body systems and biological processes. Molecular studies have shown circadian-regulated shifts in protein expression patterns across human tissues, further emphasizing the unique functional, behavioral and pharmacokinetic landscape of sleep. Thus, many pathological processes are also expected to exhibit sleep-specific manifestations. Modern advances in biosensor technologies have enabled remote, non-invasive recording of a growing number of physiologic parameters and biomarkers promoting the detection and study of such processes.Main results. Here, we introduce key clinical studies in selected medical fields, which leveraged novel technologies and the advantageous period of sleep to diagnose, monitor and treat pathologies. Studies demonstrate that sleep is an ideal time frame for the collection of long and clean physiological time series data which can then be analyzed using data-driven algorithms such as deep learning.Significance.This new paradigm proposes opportunities to further harness modern technologies to explore human health and disease during sleep and to advance the development of novel clinical applications - from sleep medicine to medicine during sleep.

SNORAP: A Device for the Correction of Impaired Sleep Health by Using Tactile Stimulation for Individuals with Mild and Moderate Sleep Disordered Breathing

Sleep physiology and sleep hygiene play significant roles in maintaining the daily lives of individuals given that sleep is an important physiological need to protect the functions of the human brain. Sleep disordered breathing (SDB) is an important disease that disturbs this need. Snoring and Obstructive Sleep Apnea Syndrome (OSAS) are clinical conditions that affect all body organs and systems that intermittently, repeatedly, with at least 10 s or more breathing stops that decrease throughout the night and disturb sleep integrity. The aim of this study was to produce a new device for the treatment of patients especially with position and rapid eye movement (REM)-dependent mild and moderate OSAS. For this purpose, the main components of the device (the microphone (snore sensor), the heart rate sensor, and the vibration motor, which we named SNORAP) were applied to five volunteer patients (male, mean age: 33.2, body mass index mean: 29.3). After receiving the sound in real time with the microphone, the snoring sound was detected by using the Audio Fingerprint method with a success rate of 98.9%. According to the results obtained, the severity and the number of the snoring of the patients using SNORAP were found to be significantly lower than in the experimental conditions in the apnea hypopnea index (AHI), apnea index, hypopnea index, in supine position’s AHI, and REM position’s AHI before using SNORAP (Paired Sample Test, p < 0.05). REM sleep duration and nocturnal oxygen saturation were significantly higher when compared to the group not using the SNORAP (Paired Sample Test, p < 0.05).

Diet and Sleep Physiology: Public Health and Clinical Implications

This mini-review examines the complex relationship between diet and sleep and explores the clinical and public health implications of the current evidence. Dietary quality and intake of specific nutrients can impact regulatory hormonal pathways to alter sleep quantity and quality. Sleep, in turn, affects the intake of total energy, as well as of specific foods and nutrients, through biological and behavioral mechanisms. Initial research in this field focused primarily on the effects of short sleep duration on nutritional quality. However, more recent studies have explored the dynamic relationship between long sleep duration and diet. Current evidence suggests that extremes of sleep duration alter sleep patterns, hormonal levels, and circadian rhythms, which contribute to weight-related outcomes and obesity, and other risk factors for the development of chronic disease such as type 2 diabetes and cardiovascular disease. These patterns may begin as early as childhood and have impacts throughout the life course. Given that non-communicable diseases are among the leading causes of death globally, deeper understanding of the interactions between sleep and nutrition has implications for both public health and clinical practice.

Understanding the physiology of sleep and promoting effective routines with infants in hospital and at home

Sleep is a biological necessity. Infants are unique individuals and what can be regarded as normal for one infant and his or her family may be considered a problem for another. Genetics, lifestyles, roles and responsibilities all influence sleep. This article explores the physiology of infant sleep and reviews how sleep is influenced by culture, events such as a hospital admission and parenting styles. It considers how the children's nurse can help and support a family who may feel that they have infant sleep-related issues. A good sleep pattern is essential for a child to succeed at school, reach their full potential and maintain their health and well-being.

Interictal Hippocampal Spiking Influences the Occurrence of Hippocampal Sleep Spindles

OBJECTIVES

The significance of hippocampal sleep spindles and their relation to epileptic activity is still a matter of controversy. Hippocampal spindles have been considered a physiological phenomenon, an evoked response to afferent epileptic discharges, or even the expression of an epileptic manifestation. To address this question, we investigated the presence and rate of hippocampal spindles in focal pharmacoresistant epilepsy patients undergoing scalp-intracerebral electroencephalography (EEG).

DESIGN

Sleep recording with scalp-intracerebral EEG.

SETTING

Tertiary referral epilepsy center.

PATIENTS

Twenty-five epilepsy patients (extratemporal: n = 6, temporal: n = 15, and multifocal including the temporal lobe: n = 4).

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

We analyzed associations between hippocampal spindles and hippocampal electrophysiological findings (interictal spiking, seizure onset zone) and magnetic resonance imaging volumetry. Sixteen of 25 patients (64%) had hippocampal spindles (extratemporal epilepsy: 6/6; temporal epilepsy: 10/15; and multifocal epilepsy: 0/4; P = 0.005). Median spindle rate was 0.6 (range, 0.1-8.6)/min in nonrapid eye movement sleep. Highest spindle rates were found in hippocampi of patients with extratemporal epilepsy (P < 0.001). A negative association was found between hippocampal spiking activity and spindle rate (P = 0.003). We found no association between the presence (n = 21) or absence (n = 17) of hippocampal seizure onset zone and hippocampal spindle rate (P = 0.114), and between a normal (n = 30) or atrophic (n = 8) hippocampus and hippocampal spindle rate (P = 0.195).

CONCLUSIONS

Hippocampal spindles represent a physiological phenomenon, with an expression that is diminished in epilepsy affecting the temporal lobe. Hippocampal spiking lowered the rate of hippocampal spindles, suggesting that epileptic discharges may at least in part be a transformation of these physiological events, similar to the hypothesis considering generalized spike-and-waves a transformation of frontal spindles.

Sleep physiology, abnormal States, and therapeutic interventions

Sleep is essential. Unfortunately, a significant portion of the population experiences altered sleep states that often result in a multitude of health-related issues. The regulation of sleep and sleep-wake cycles is an area of intense research, and many options for treatment are available. The following review summarizes the current understanding of normal and abnormal sleep-related conditions and the available treatment options. All clinicians managing patients must recommend appropriate therapeutic interventions for abnormal sleep states. Clinicians' solid understanding of sleep physiology, abnormal sleep states, and treatments will greatly benefit patients regardless of their disease process.

Interplay between spontaneous and induced brain activity during human non-rapid eye movement sleep

Humans are less responsive to the surrounding environment during sleep. However, the extent to which the human brain responds to external stimuli during sleep is uncertain. We used simultaneous EEG and functional MRI to characterize brain responses to tones during wakefulness and non-rapid eye movement (NREM) sleep. Sounds during wakefulness elicited responses in the thalamus and primary auditory cortex. These responses persisted in NREM sleep, except throughout spindles, during which they became less consistent. When sounds induced a K complex, activity in the auditory cortex was enhanced and responses in distant frontal areas were elicited, similar to the stereotypical pattern associated with slow oscillations. These data show that sound processing during NREM sleep is constrained by fundamental brain oscillatory modes (slow oscillations and spindles), which result in a complex interplay between spontaneous and induced brain activity. The distortion of sensory information at the thalamic level, especially during spindles, functionally isolates the cortex from the environment and might provide unique conditions favorable for off-line memory processing.

Sleep and its importance in adolescence and in common adolescent somatic and psychiatric conditions

Restoring sleep is strongly associated with a better physical, cognitive, and psychological well-being. By contrast, poor or disordered sleep is related to impairment of cognitive and psychological functioning and worsened physical health. These associations are well documented not only in adults but also in children and adolescents. Importantly, adolescence is hallmarked by dramatic maturational changes in sleep and its neurobiological regulation, hormonal status, and many psychosocial and physical processes. Thus, the role of sleep in mental and physical health during adolescence and in adolescent patients is complex. However, it has so far received little attention. This review first presents contemporary views about the complex neurobiology of sleep and its functions with important implications for adolescence. Second, existing complex relationships between common adolescent somatic/organic, sleep-related, and psychiatric disorders and certain sleep alterations are discussed. It is concluded that poor or altered sleep in adolescent patients may trigger and maintain many psychiatric and physical disorders or combinations of these conditions, which presumably hinder recovery and may cross into later stages of life. Therefore, timely diagnosis and management of sleep problems appear critical for growth and development in adolescent patients.

Sleep physiology and sleep disorders in childhood

Sleep has long been considered as a passive phenomenon, but it is now clear that it is a period of intense brain activity involving higher cortical functions. Overall, sleep affects every aspect of a child's development, particularly higher cognitive functions. Sleep concerns are ranked as the fifth leading concern of parents. Close to one third of all children suffer from sleep disorders, the prevalence of which is increased in certain pediatric populations, such as children with special needs, children with psychiatric or medical diagnoses and children with autism or pervasive developmental disorders. The paper reviews sleep physiology and the impact, classification, and management of sleep disorders in the pediatric age group.

Effect of continuous positive airway pressure on sleep structure in heart failure patients with central sleep apnea

STUDY OBJECTIVES

At termination of obstructive apneas, arousal is a protective mechanism that facilitates restoration of upper airway patency and airflow. Treating obstructive sleep apnea (OSA) by continuous positive airway pressure (CPAP) reduces arousal frequency indicating that such arousals are caused by OSA. In heart failure (HF) patients with central sleep apnea (CSA), however, arousals frequently occur several breaths after apnea termination, and there is uncertainty as to whether arousals from sleep are a consequence of CSA. If so, they should diminish in frequency when CSA is attenuated. We therefore sought to determine whether attenuation of CSA by CPAP reduces arousal frequency.

DESIGN

Randomized controlled clinical trial.

PATIENTS AND SETTING

We examined data from 205 HF patients with CSA (apnea-hypopnea index [AHI] > or =15, > 50% were central) randomized to CPAP or control who had polysomnograms performed at baseline and 3 months later.

MEASUREMENTS AND RESULTS

In the control group, there was no change in AHI or frequency of arousals. In the CPAP-treated group, the AHI decreased significantly (from [mean +/- SD] 38.9 +/- 15.0 to 17.6 +/- 16.3, P < 0.001) but neither the frequency of arousals nor sleep structure changed significantly.

CONCLUSION

These data suggest that attenuation of CSA by CPAP does not reduce arousal frequency in HF patients. We conclude that arousals were not mainly a consequence of CSA, and may not have been acting as a defense mechanism to terminate apneas in the same way they do in OSA.

Response Surface Mapping of Neurobehavioral Performance: Testing the Feasibility of Split Sleep Schedules for Space Operations

The demands of sustaining high levels of neurobehavioral performance during space operations necessitate precise scheduling of sleep opportunities in order to best preserve optimal performance. We report here the results of the first split-sleep, dose-response experiment involving a range of sleep/wake scenarios with chronically reduced nocturnal sleep, augmented with a diurnal nap. To characterize performance over all combinations of split sleep in the range studied, we used response surface mapping methodology. Waking neurobehavioral performance was studied in N=90 subjects each assigned to one of 18 sleep regimens consisting of a restricted nocturnal anchor sleep period and a diurnal nap. Psychomotor vigilance task performance and subjective assessments of sleepiness were found to be primarily a function of total time in bed per 24 h regardless of how sleep was divided among nocturnal anchor sleep and diurnal nap periods. Digit symbol substitution task performance was also found to be primarily a function of total time in bed per 24 h; however, accounting for nocturnal sleep duration and nap duration separately provided a small but significant enhancement in the variance explained. The results suggest that reductions in total daily sleep result in a near-linear accumulation of impairment regardless of whether sleep is scheduled as a consolidated nocturnal sleep period or split into a nocturnal anchor sleep period and a diurnal nap. Thus, split sleep schedules are feasible and can be used to enhance the flexibility of sleep/work schedules for space operations involving restricted nocturnal sleep due to mission-critical task scheduling. These results are generally applicable to any continuous industrial operation that involves sleep restriction, night operations, and shift work.