Sleep Phenomena Research Articles

The Insomnia Plague in Fictional Macondo.

Disease and medicine are found throughout Gabriel García Márquez's work. This article examines the insomnia plague described in the novel One Hundred Years of Solitude and performs a differential diagnosis exercise with conditions that affect both sleep and memory. The main finding is that the insomnia plague narrated by García Márquez, with its clinical manifestations, the sequence of symptoms, and its resolution, cannot be associated with any specific diagnosis. However, similarities to and differences from several clinical conditions are discussed, as well as the relation between the neurophysiologic phenomena of sleep and memory.

0746 Dynamics of Sleep Stage Transitions in Patients with Narcolepsy and Other Hypersomnias

Abstract Introduction Narcolepsy is a chronic sleep disorder characterized by excessive daytime sleepiness and abnormal REM sleep phenomena. Narcolepsy can be distinguished into type 1 (NT1; with cataplexy) and type 2 (NT2; without cataplexy). It has been reported that sleep stage sequences at sleep-onset as well as sleep-wake dynamics across the night may be useful in the differential diagnosis of hypersomnia. Here we studied dynamic features of sleep stage transitions during whole night sleep in patients with NT1, NT2, and other types of hypersomnia (o-HS). Methods Twenty patients with NT1, 14 patients with NT2, and 35 patients with o-HS underwent overnight PSG. Transition probabilities between sleep stages (wake, N1, N2, N3, and REM) and survival curves of continuous runs of each sleep stage were compared between groups. Transition-specific survival curves of continuous runs of each sleep stage, dependent on the subsequent stage of the transition, were also compared. Results The probability of transitions from N1-to-wake was significantly greater in NT1 than in NT2 and o-HS while that from N1-to-N2 was significantly smaller in NT1 than in NT2 and o-HS. The probability of transitions from N2-to-REM was significantly smaller in NT1 than in o-HS. Wake and N1 were significantly more continuous in NT1 than in NT2; specifically, N1 followed by N2 was significantly more continuous in NT1 than in NT2 and o-HS. N2 was significantly less continuous in NT1 and NT2 than in o-HS; this was specifically confirmed for N2 followed by N1/wake. REM sleep was significantly less continuous in NT1 than in NT2 and o-HS; specifically, REM sleep followed by wake was significantly less continuous in NT1 than in o-HS. Continuity of N3 did not differ significantly between groups. Conclusion Dynamics of sleep stage transitions differed between NT1, NT2, and o-HS. Dynamic features of sleep such as sleep instability, persistency of wake/N1, and REM fragmentation may differentiate NT1 from NT2, while N2 continuity may differentiate narcolepsy from o-HS. The results suggest that sleep transition analysis may be of clinical utility and provide insights into the underlying pathophysiology of hypersomnia and narcolepsy. Support JSPS KAKENHI (18K17891 to AK).

Sleepiness on the flight deck: Reported rates of occurrence and predicted fatigue risk exposure associated with UK airline pilot work schedules

Survey and field studies conducted with commercial airline pilots suggest that in-flight sleepiness and related involuntary sleep phenomena are experienced by pilots during their duties. However, for methodological, practical and commercial reasons, there is a lack of publicly available research data of per-flight hour rates of sleepiness experienced by pilots or predicted fatigue risk rates associated with pilots’ hours of work. This empirical field study sought to address this gap by collecting self-reported sleepiness/alertness ratings from pilots from 18 different UK airlines via a mobile phone app over the period of August 2017. In tandem, predicted sleepiness levels and sleep opportunities associated with participants’ flown rosters were investigated using biomathematical fatigue modelling. Findings indicated that a quarter of all flying duty periods were predicted to be preceded by a main sleep opportunity shorter than six hours, whilst 10% of all flying hours were associated with elevated fatigue risk levels. Pilots reported 7.3 reports of involuntary sleep on the flight deck per 1000 flying hours, which represents a rate far greater than that previously reported to the regulator. By comparison, the rates of predicted and recorded fatigue-related incapacitations greatly exceeded the target rate of medical incapacitation permissible under the medical incapacitation safety standard for commercial aviation of less than one occurrence per 1,000,000 h.

The history of observations and some methodological features of the studies on local sleep

The phenomenon of local sleep, a concept that has come into somnology relatively recently, has been attracting more and more attention of researchers. Under this name, two groups of phenomena are considered. The first is the appearance in different parts of the cerebral cortex of different EEG patterns during general sleep. The second is the disconnection of certain cortical areas from the processing of extero- or proprioceptive signals and their transition to spiking and slow wave electrical activity, which is typical for sleep, while awake. The authors believe that it is the second phenomenon that can be called real local sleep. The appearance of local cortical sleep is inseparably linked with the occurrence of local wakefulness. It can be expected that the occurrence of local sleep will have detrimental consequences for behavior in urgent and complicated situations, while local wakefulness can adversely affect the visceral health of the body. A possible way of early detection of the local sleep development is proposed. In conclusion, some methodological problems on the way of electrophysiological studies of the local aspects of sleep and wakefulness are considered.

DEFINITION, EXPLANATION, AND SCIENTIFIC METHOD IN ARISTOTLE’S DE SOMNO

Abstract Exploring the systematic connections between Aristotle’s theory and practice of science has emerged as an important concern in recent years. On the one hand, we can invoke the theory of the Posterior Analytics to motivate specific moves that Aristotle makes in the course of his actual investigation of the natural world. On the other, we can use Aristotle’s practice of science to illuminate the theory of the Posterior Analytics, which is presented in a notoriously abstract, and at times also elliptical, way. I would like to contribute to this interpretative tradition with a study of how Aristotle explains the phenomenon of sleep and waking.

Better Sleep Experience for the Critically Ill: A Comprehensive Strategy for Designing Hospital Soundscapes

In this paper, the sleep phenomenon is considered in relation to critical care soundscapes with the intention to inform hospital management, medical device producers and policy makers regarding the complexity of the issue and possible modes of design interventions. We propose a comprehensive strategy based on soundscape design approach that facilitates a systematic way of tackling the auditory quality of critical care settings in favor of better patient sleep experience. Future research directions are presented to tackle the knowledge deficits in designing for critical care soundscapes that cater for patient sleep. The need for scientifically-informed design interventions for improving patient sleep experience in critical care is highlighted. The value of the soundscape design approach for resolving other sound-induced problems in critical care and how the approach allows for patient-centred innovation that is beyond the immediate sound issue are further discussed.

Correlation Between Sleep-Time Masseter Muscle Activity and Tooth Wear: An Electromyographic Study.

To assess the correlation between tooth wear and sleep-time masseter muscle activity (sMMA) in a group of healthy young adults who underwent home electromyographic/electrocardiographic (EMG/ECG) recordings with a portable device. A total of 41 healthy volunteers (23 women, 18 men; mean age 28.8 years, range 25 to 40) with good natural dentition underwent a 2-night in-home evaluation with a portable device that allowed a simultaneous sleep-time recording of EMG signals from both masseter muscles and heart rate. The number of sleep bruxism (SB) episodes per sleep hour (SB index), the number of phasic, tonic, and mixed sMMA events per hour, and the total number of sMMA events per night were calculated. All individuals also underwent an assessment of tooth wear on digital casts with the adoption of a six-degree rating scale. Correlations between sMMA variables and tooth wear were assessed using Pearson test. The null hypothesis was that correlation between the two conditions would not be significant. On average, the SB index was 4.5 ± 2.6, while the total number of sleep-time masseter contractions was 97.2 ± 55.2. Of those contractions, almost 60% were phasic. Average tooth wear was 1.5 ± 0.7, with the canines and mandibular incisors showing the highest wear scores. For all pairwise analyses, correlation values were not significant (P values .11 to .69), with r values ranging from 0.064 to 0.253. The null hypothesis of an absence of correlation between tooth wear and sMMA could not be rejected, implying that tooth wear cannot be used as an indicator of ongoing SB or sMMA. Future studies taking into account the multifaceted nature of tooth wear and the complex natural course of sleep phenomena are encouraged to investigate the issue further, at the individual level.

Unraveling the genetic underpinnings of sleep deprivation-induced impairments in human cognition.

The biobehavioral phenomena of sleep and cognition involve complex phenotype-genotype associations, i.e., complex relationships between observable traits and the genetic variants that contribute to the expression of those traits. There is a general belief that investigating such relationships requires large sample sizes. However, sleep- and cognition-related phenotype-genotype associations may be strengthened through carefully controlled laboratory studies that amplify a given cognitive phenotype by perturbing the biobehavioral system through sleep deprivation and/or pharmacogenetic interventions. Utilization of performance tasks that dissociate cognitive processes allows for cognitive endophenotyping, that is, making precise measurements that capture the essence of a cognitive phenotype. This enables assessment of the genetic underpinnings of cognitive impairment due to sleep deprivation without necessarily requiring large samples. Theory-driven gene selection, selective population sampling techniques to avoid underrepresentation of rare genetic variants, and modern statistical techniques informed by prior knowledge further enhance statistical power. Here we illustrate these approaches on the basis of recent findings, supplemented with some new results, as well as a discussion of modern regression methods for statistical analysis. Ongoing research employing these methods is driving advancements in the understanding of the genetic underpinnings of cognitive impairment associated with sleep loss.

A five-year longitudinal study reveals progressive cortical thinning in narcolepsy and faster cortical thinning in relation to early-onset.

Narcolepsy with cataplexy is characterized by excessive daytime sleepiness, cataplexy, and other REM sleep phenomena. Previous MRI studies were cross-sectional in design and could not adequately address if disease progression leads the brain structural abnormalities in narcolepsy. Our analysis in patients using longitudinally collected brain MRIs (n = 17; 2 scans per patient; scan interval: 4.7 ± 1.9years) revealed widespread progressive cortical thinning in bilateral dorsolateral frontal and fusiform cortices, right anterior cingulate (corrected p < 0.05). Cross-sectional analyses showed faster progressive cortical thinning in patients than controls (n = 83, one scan per subject available), which we confirmed significant in the analysis of a small-set of longitudinal control data (n = 10). The pattern of progressive thinning in patients was overlapped well with those found in structural and functional studies of narcolepsy. We also found a faster progression of cortical thinning and worse disease severity (decreased sleep efficiency, increased sleep latency and arousal index) over time in a subgroup of patients with earlier disease onset (n = 9, onset age: 15.9 ± 2.5years old) compared to later disease onset (n = 8, 25.3 ± 4.9). The faster progressive cortical thinning and worse disease severity over time in the patients with early-onset suggest compelling evidence of disease progression existing in this phenotype of narcolepsy syndrome. Our result based on a small dataset, however, demands a more careful investigation of the underlying mechanism.

Noise and delay sustained chimera state in small world neuronal network

Chimera state in neuronal network means the coexistence of synchronized and desynchronized firing patterns. It attracts much attention recently due to its possible relevance to the phenomenon of unihemispheric sleep in mammals. In this paper, we search for chimera state in a noisy small-world neuronal network, in which the neurons are delayed coupled. We found both transient and permanent chimera state when time delay is close to a critical value. The chimera state occurs due to the competition between the synchronized and desynchronized patterns in the neuronal network. On the other hand, intermediate intensity of noise facilitates the occurrence of delay-sustained chimera states. Comparison between noise and delay shows that time delay is the key factor determining the chimera state, whereas noise is a subordinate one.

Sleep spindles are altered in early- but not late-onset nightmare recallers

Nightmares are a common sleep disorder, defined as highly disturbing mentation which usually awakens the individual from rapid eye movement (REM) sleep. While nightmares are mainly a REM sleep phenomenon, Picard-Deland et al., (2017) recently showed an association between nightmare recall and sleep spindles, which are a non-rapid eye movement (NREM) oscillatory feature. Their results pointed to fewer slow spindles and a higher oscillatory frequency for fast spindles among frequent nightmare recallers compared with controls. To test the suggestion that nightmares stem from changes to emotional neural circuits arising in early childhood (Nielsen, 2017), including early changes in sleep spindles (Scholle et al., 2007), we investigated if the spindle features of early-onset nightmare recallers (ie, recalling nightmares since childhood) (N = 22), differed from those of late-onset nightmare recallers (ie, since adolescence or adulthood) (N = 11), or from those of controls (N = 23). A retrospective analysis of the sleep spindles of 56 participants who had undergone a polysomnographically-recorded morning nap revealed that Early starters uniquely exhibited lower slow spindle densities in five of six derivations (all p < 0.045) and higher fast spindle frequencies in all six derivations (all p < 0.015). These results add precision to previously reported findings for Nightmare recallers: spindle differences are shown to hold only for Early starters. The lifelong occurrence of nightmares may be closely tied to disruptions in the normal development of spindle generation processes occurring early in development.

Examining Unihemispheric Sleep and its Potential Relation to Lateral Resting Behaviour and Unipedal Resting Stance in Caribbean Flamingos

While much recent research has examined flamingo unipedal resting, as well as laterality in the resting behaviours of these birds, the phenomenon of unihemispheric sleep is not well documented in flamingos, and the potential relationship between unihemispheric sleep and these other aspects of flamingo resting behaviour has not been thoroughly explored. In the present report, unihemispheric sleep was studied in Caribbean Flamingos (Phoenicopterus ruber) (n=17) at the Philadelphia Zoo (Philadelphia, PA, USA). Specifically, we examined whether unihemispheric sleep, as measured by contralateral eye closure, is associated with unipedal resting and lateral behavioural side choice in resting Caribbean Flamingos. Results over three studies evidenced that Caribbean Flamingos do engage in unihemispheric sleep, and suggested that unihemispheric sleep is not related to unipedal resting or lateral neck-resting behaviour. Moreover, Harker and Harker's (2010) hypothesis that unipedal resting in flamingos is brought on by the impending onset of unihemispheric sleep was tested, with results failing to support this notion.

Sleep-Related Movement Disorders: Hypnic Jerks

Hypnic jerks represent a benign physiological phenomenon of sleep, which must be differentiated from other sleep-related movement disorders and epilepsy. A comprehensive review of hypnic jerks is presented with emphasis on recognition, physiology, evaluation, and treatment. The recent edition of the International Classification of Sleep Disorders (ICSD-3) has classified hypnic jerks as a sleep-related movement disorder under the subheading isolated symptoms and normal variants. Although generally benign, there have been increasing reports of excessive hypnic jerks in neurological disorders such as Parkinsonism, migraine, and brainstem lesions and children with neurologic disorders. Recent research identifying changes in the polysomnogram has led to a better understanding of the physiology of hypnic jerks. A variety of different motor patterns have been described; however, the origin and physiology of hypnic jerks remain enigmatic. Hypnic jerks represent a fascinating phenomenon of sleep; however, additional studies are needed to clarify their physiology and origin.

Coordination of cortical and thalamic activity during non-REM sleep in humans

Every night, the human brain produces thousands of downstates and spindles during non-REM sleep. Previous studies indicate that spindles originate thalamically and downstates cortically, loosely grouping spindle occurrence. However, the mechanisms whereby the thalamus and cortex interact in generating these sleep phenomena remain poorly understood. Using bipolar depth recordings, we report here a sequence wherein: (1) convergent cortical downstates lead thalamic downstates; (2) thalamic downstates hyperpolarize thalamic cells, thus triggering spindles; and (3) thalamic spindles are focally projected back to cortex, arriving during the down-to-upstate transition when the cortex replays memories. Thalamic intrinsic currents, therefore, may not be continuously available during non-REM sleep, permitting the cortex to control thalamic spindling by inducing downstates. This archetypical cortico-thalamo-cortical sequence could provide the global physiological context for memory consolidation during non-REM sleep.

Gender characteristics of the structural organization of sleep in obstructive sleep apnea syndrome

To reveal gender characteristics of the sleep structure in obstructive sleep apnea syndrome (OSAS) during polysomnographic monitoring (PSGM). According to the results of a pre-survey using an apnea screening questionnaire, the investigation included 58 women (body mass index (BMI), 38.2±2.1 kg/m2) and 75 men (BMI, 34.2±1.8 kg/m2), aged 50-55 years, who complained about snoring, sleep apnea, and daytime hypersomnia. Copy-pair groups were formed and compared after objectively confirming the diagnosis by PSGM made at a specialized sleep laboratory, by applying the GRASS-TELEFACTOR Twin PSG system (Comet) with an integrated SPM-1 sleep module (USA) in accordance with the standard procedure. The International Sleep Disorder Classification (2005) was used to diagnose apnea and to estimate its severity. According to the results of PSGM, the men and women were divided into 3 groups, by using the generally accepted OSAS severity scale. Comparative analysis revealed differences in sleep structure parameters with the equal severity of OSAS in the men and women. These differences were characterized by a more marked fragmentariness, impaired cyclicity, and the appearance of the basic specific phenomenon of impaired integrated activity of somnogenic structures - an alpha-delta sleep phenomenon in the men versus the women. There were increases in the time of rapid eye movement (REM) sleep, in that of awakening at night after falling asleep, and in sleep latency in the women with a simultaneous decrease in the total effectiveness of sleep compared to that in the men with the equal-severity OSAS. The found gender differences in the sleep structure may be ascribed to the compensatory mechanisms in the function of brain somnogenic structures in the women and the preponderance of REM sleep is a compensatory adaptive response of the sleep homeostatic system, which necessitates further investigations in this area.

Chimera states in a Hodgkin-Huxley model of thermally sensitive neurons.

Chimera states occur when identically coupled groups of nonlinear oscillators exhibit radically different dynamics, with one group exhibiting synchronized oscillations and the other desynchronized behavior. This dynamical phenomenon has recently been studied in computational models and demonstrated experimentally in mechanical, optical, and chemical systems. The theoretical basis of these states is currently under active investigation. Chimera behavior is of particular relevance in the context of neural synchronization, given the phenomenon of unihemispheric sleep and the recent observation of asymmetric sleep in human patients with sleep apnea. The similarity of neural chimera states to neural "bump" states, which have been suggested as a model for working memory and visual orientation tuning in the cortex, adds to their interest as objects of study. Chimera states have been demonstrated in the FitzHugh-Nagumo model of excitable cells and in the Hindmarsh-Rose neural model. Here, we demonstrate chimera states and chimera-like behaviors in a Hodgkin-Huxley-type model of thermally sensitive neurons both in a system with Abrams-Strogatz (mean field) coupling and in a system with Kuramoto (distance-dependent) coupling. We map the regions of parameter space for which chimera behavior occurs in each of the two coupling schemes.

Sleep Problems as Consequence, Contributor, and Comorbidity: Introduction to the Special Issue on Sleep, Published in Coordination With Special Issues in Clinical Practice in Pediatric Psychology and Journal of Developmental and Behavioral Pediatrics.

Despite long-standing public and scientific interest in the phenomenon of sleep, the current decade has shown tremendous growth in our understanding of the sleep of children who have medical or developmental conditions. To accommodate, promote, and guide that growth, Journal of Pediatric Psychology, Clinical Practice in Pediatric Psychology, and Journal of Developmental and Behavioral Pediatrics have published coordinated special issues, encompassing >30 relevant articles. This article introduces the special issue in Journal of Pediatric Psychology, highlighting papers that illustrate how sleep problems are not only commonly comorbid with childhood medical and developmental conditions; they are also likely caused by and contribute to these conditions. In doing so, these coordinated special issues guide clinical care and reveal opportunities for future research.

Prevalence and determinants of periodic limb movements in the general population.

Periodic limb movements during sleep (PLMS) are sleep phenomena characterized by periodic episodes of repetitive stereotyped limb movements. The aim of this study was to describe the prevalence and determinants of PLMS in a middle to older aged general population. Data from 2,162 subjects (51.2% women, mean age = 58.4 ± 11.1 years) participating in a population-based study (HypnoLaus, Lausanne, Switzerland) were collected. Assessments included laboratory tests, sociodemographic data, personal and treatment history, and full polysomnography at home. PLMS index (PLMSI) was determined, and PLMSI > 15/h was considered as significant. Prevalence of PLMSI > 15/h was 28.6% (31.3% in men, 26% in women). Compared to subjects with PLMSI ≤ 15/h, subjects with PLMSI > 15/h were older (p < 0.001), were predominantly males (p = 0.007), had a higher proportion of restless legs syndrome (RLS; p < 0.001), had a higher body mass index (p = 0.001), and had a lower mean glomerular filtration rate (p < 0.001). Subjects with PLMSI > 15/h also had a higher prevalence of diabetes, hypertension, and beta-blocker or hypnotic treatments. The prevalence of antidepressant use was higher, but not statistically significant (p = 0.07). Single nucleotide polymorphisms (SNPs) within BTBD9 (rs3923809), TOX3 (rs3104788), and MEIS1 (rs2300478) genes were significantly associated with PLSMI > 15/h. Conversely, mean hemoglobin and ferritin levels were similar in both groups. In the multivariate analysis, age, male gender, antidepressant intake, RLS, and rs3923809, rs3104788, and rs2300478 SNPs were independently associated with PLMSI > 15/h. PLMS are highly prevalent in our middle-aged European population. Age, male gender, RLS, antidepressant treatment, and specific BTBD9, TOX3, and MEIS1 SNP distribution are independent predictors of PLMSI > 15/h.

Sleepwalking Through the Neutral

My interest in the phenomenon of sleep and its relation to an experience of the ‘neutral’ is part of an ongoing exploration of the poetics of negative performance (not-doing, waiting, letting be … ...

Sharing Our Time with the Time of the World

Studying the Bernau manuscripts, we find that because protentions are motivated by the sedimentation of retentions and retention is the retaining of fulfilled protentions, the problem of the birth of consciousness arises. I argue that the phenomenon of sleep and awakening is not fundamental enough to understand the problem of the birth of consciousness, since “far” retentions can here serve as motivations. Consciousness at its birth seems to require a pre-consciousness of hyletic unities, such as manuscript C 4 described, to provide these first motivations. I will show that this model of time-consciousness therefore already requires a rethinking of consciousness according to an open (horizontal) affection-and-action model instead of the absolute (vertical) sensation model. As such, the transcendental solidarity between objectivity of knowledge and subjectivity of experience comes to be founded in the primordial transcendence that the pre-consciousness of C 4 implies. Time-constitution at its core is already motivated by the world to constitute it and itself.