Insomnia is Associated with Cortical Hyperarousal as Early as Adolescence

Interactions of Obstructive Sleep Apnea With the Pathophysiology of Cardiovascular Disease, Part 1: JACC State-of-the-Art Review

The American Heart Association considers sleep health an essential component of cardiovascular health, and sleep is generally a time of cardiovascular quiescence, such that any deviation from normal sleep may be associated with adverse cardiovascular consequences. Many studies have shown that both impaired quantity and quality of sleep, particularly with obstructive sleep apnea (OSA) and comorbid sleep disorders, are associated with incident cardiometabolic consequences. OSA is associated with repetitive episodes of altered blood gases, arousals, large negative swings in intrathoracic pressures, and increased sympathetic activity. Recent studies show that OSA is also associated with altered gut microbiota, which could contribute to increased risk of cardiovascular disease. OSA has been associated with hypertension, atrial fibrillation, heart failure, coronary artery disease, stroke, and excess cardiovascular mortality. Association of OSA with chronic obstructive lung disease (overlap syndrome) and morbid obesity (obesity hypoventilation syndrome) increases the odds of mortality.

Individualized approaches to pediatric chronic insomnia: Advancing precision medicine in sleep disorders

The manifestations of chronic insomnia undergo age-related changes. In younger infants and children, behavioral insomnia emerges as the most prevalent form and typically responds to behavioral interventions. However, distinct clusters of clinical presentations suggest the presence of various phenotypes, potentially implicating the primary involvement of specific neurotransmitters. These conceptualizations, coupled with genetic studies on pleiotropy and polygenicity, may aid in identifying individuals at risk of persistent insomnia into adulthood and shed light on novel treatment options. In school-age children, the predominant presentation is sleep-onset insomnia, often linked with nighttime fears, anxiety symptoms, poor sleep hygiene, limit-setting issues, and inadequate sleep duration. The manifestations of insomnia in adolescence correlate with the profound changes occurring in sleep architecture, circadian rhythms, and homeostatic processes. The primary symptoms during adolescence include delayed sleep onset, sleep misperception, persistent negative thoughts about sleep, and physiological hyperarousal-paralleling features observed in adult insomnia. An approach centered on distinct presentations may provide a framework for precision-based treatment options. Enhanced comprehension of insomnia's manifestations across diverse developmental stages can facilitate accurate assessment. Efforts to subtype insomnia in childhood align with this objective, potentially guiding the selection of appropriate treatments tailored to individual neurobiological, clinical, and familial features.

Toward better outcome measurement for insomnia in children with autism spectrum disorder

LAY ABSTRACT

Insomnia, trouble falling asleep or staying asleep, is common in autistic children. In a previous report, we described the results of focus groups with parents of autistic children toward the development of the Pediatric Autism Insomnia Rating Scale. In this article, we report on the steps taken to complete the Pediatric Autism Insomnia Rating Scale. With help from the Simons Foundation registry, we collected information from parents on 1185 children with autism spectrum disorder to test the new measure. These results were evaluated using standard statistical methods such as factor analysis. To confirm the validity of the new measure, we enrolled a separate sample of 134 autistic children for a detailed assessment by video conference. This step showed that the Pediatric Autism Insomnia Rating Scale is clearly measuring symptoms of insomnia in children with autism spectrum disorder and not related problems such as hyperactivity, repetitive behavior, or anxiety. We also showed that the total score on the Pediatric Autism Insomnia Rating Scale is stable when repeated over a brief period of time. This is important because a measure that is not stable over a brief period of time would not be suitable as an outcome measure. In summary, the Pediatric Autism Insomnia Rating Scale is a brief and valid measure of insomnia in children with autism spectrum disorder that provides reliable scores.

Association Between EEG Power During Sleep and Attention Levels in Patients with Major Depressive Disorder

Purpose

Major depressive disorder (MDD) is associated with cognitive impairment through unclear mechanisms. We examined the relationship between sleep electroencephalogram (EEG) power and attention level in MDD.

Patients and Methods

Forty-seven untreated patients with MDD and forty-seven age- and sex-matched controls were included. We examined relative EEG power during non-rapid eye movement (NREM) sleep and rapid eye movement (REM) sleep by fast Fourier transform. The Attention Network Test (ANT) was performed to evaluate attention levels.

Results

Compared to controls, patients with MDD had lower theta power during NREM (P = 0.018) and REM (P = 0.002) sleep, while higher beta power (P = 0.050) during NREM sleep and delta power (P = 0.018) during REM sleep. Regarding attention level, patients with MDD had lower levels of accuracy (P = 0.021), longer mean reaction time (P < 0.001), poorer manifestations of the alerting effect (P = 0.038) and worse executive control (P = 0.048). Moreover, decreased theta power during NREM sleep was correlated with worsened accuracy (β = 0.329, P = 0.040), decreased theta power during REM sleep was correlated with worsened alerting effect (β = 0.355, P = 0.020), and increased delta power during REM sleep was correlated with longer mean reaction time (β = 0.325, P = 0.022) in patients with MDD. No association between ANT performance and other frequency bands was observed in patients with MDD.

Conclusion

Our findings suggest that patients with MDD manifest impaired selective attention function that is associated with decreased theta power during NREM/REM sleep and increased delta power during REM sleep.

Depressive symptoms, sleep-wake features, and insomnia among female students: The role of rumination

Depression symptoms are prevalent among nursing students, especially those in Asia. This study assessed the association between rumination and depression symptoms among female nursing students (N = 148) and the chain mediation role of sleep-wake indexes and insomnia symptoms. The data were collected from a battery of questionnaires and consecutive 7-day actigraphy data for analyzing sleep-wake indexes. About 54.1% of the participants had either mild or moderate depression symptoms. Most students (89.2%) had a delayed circadian phase, and circadian activity rhythm (CAR) was not ideal. The path mediation model underwent analysis using the PROCESS macros. The results showed that rumination in students is directly positively correlated with depressive symptoms (b = 4.831). Moreover, the association between rumination and depressive symptoms is sequent (moderating effect = 0.12, 95% CI [0.017, 0.410]). The proposed model in this study provides a foundation for improving educational programs on sleep hygiene and promoting mental wellness.

High stability of EEG spectral power across polysomnography and multiple sleep latency tests in good sleepers and chronic insomniacs

To assess the stability of electroencephalographic (EEG) spectral features across overnight polysomnography (PSG) and daytime multiple sleep latency tests (MSLTs) in chronic insomniacs (CIs) and normal controls (NCs). A total of 20 NCs and 22 CIs underwent standard PSG and MSLTs. Spectral analyses were performed on EEG data from PSG and MSLTs and absolute and relative power in central, frontal and occipital channels were obtained for wake (W) and non-rapid eye movement sleep stage 1 and 2 (N1, N2). Intraclass correlation coefficients (ICCs) were used to assess the stability of EEG spectral power across PSG and MSLTs for W, N1 and N2. The absolute power of all frequency bands except delta exhibited high stability across PSG and MSLTs in both NCs and CIs (ICCs ranged from 0.430 to 0.978). Although delta absolute power was stable in NCs during N1 and N2 stages (ICCs ranged from 0.571 to 0.835), it tended to be less stable in CIs during W and sleep stages (ICCs ranged from 0.042 to 0.807). We also observed lower stability of relative power compared to absolute power though the majority of relative power outcomes maintained high stability in both groups (ICCs in relative power ranged from 0.044 to 0.962). Most EEG spectral bandwidths across PSG and MSLT in W, N1 and N2 show high stability in good sleepers and chronic insomniacs. EEG signals from either an overnight PSG or a daytime MSLT may be useful for reliably exploring EEG spectral features during wakefulness or sleep.

Associations between Sleep Disturbances, Personality Traits and Self-Regulation in a Sample of Healthy Adults

Background: Scientific evidence and everyday experience show that sleep disturbances and self-regulation as a proxy of stress reactivity are linked. Particular personality traits such as neuroticism, internalizing and externalizing problems are also associated with sleep disturbances. Here, we combined self-regulation and personality traits and associated these variables with subjective sleep disturbances. Methods: A total of 846 adults (mean age: 33.7 years; 78.7% females) completed questionnaires covering sleep disturbances, self-regulation and personality traits. Results: Higher scores for sleep disturbances were associated with higher scores for externalization, internalization, and instability and with lower scores for stability (all trait variables) and with poorer self-regulation (state variable). The regression model showed that higher scores for externalization and internalization (traits), and lower scores for self-regulation (state) predicted higher scores for sleep disturbance. Next, self-regulation had both a direct effect on sleep disturbance, and an indirect effect via personality traits. Conclusions: Sleep disturbances were related to both state (i.e., self-regulation) and trait (e.g., internalization and instability) dimensions. The current data analysis leapfrogs the state-trait dichotomy discussion and reconciles the state-and-trait approach in the prediction of poor sleep, though self-regulation appeared to have both direct and indirect effects on sleep disturbances.

Embracing sleep-onset complexity

Sleep is crucial for many vital functions and has been extensively studied. By contrast, the sleep-onset period (SOP), often portrayed as a mere prelude to sleep, has been largely overlooked and remains poorly characterized. Recent findings, however, have reignited interest in this transitional period and have shed light on its neural mechanisms, cognitive dynamics, and clinical implications. This review synthesizes the existing knowledge about the SOP in humans. We first examine the current definition of the SOP and its limits, and consider the dynamic and complex electrophysiological changes that accompany the descent to sleep. We then describe the interplay between internal and external processing during the wake-to-sleep transition. Finally, we discuss the putative cognitive benefits of the SOP and identify novel directions to better diagnose sleep-onset disorders.

Edward O. Bixler, PhD: from the Apollo project and chimpanzees to sleep epidemiology

What an honor to write about Dr. Edward O. Bixler's contributions to the sleep field. In 1967, Dr. Bixler published a case report on a chimpanzee with implanted brain electrodes while working at an Air Force base in New Mexico. A few years later, in 1971, he published on the sleep effects of flurazepam in individuals with insomnia together with Dr. Anthony Kales, data that he had collected when the Sleep Research & Treatment Center (SRTC) was housed at the University of California Los Angeles. Dr. Bixler, a meticulous scientist, learned from Dr. Kales, a devoted clinician, to study "the whole patient, and all aspects of sleep," a legacy that continued when the SRTC moved to Penn State in Hershey. Indeed, Dr. Bixler's tenure at Penn State from 1971 until 2019 kept the science of the SRTC focused on that premise and helped translate scientific evidence into clinical care. He not only contributed early to the pharmacology of sleep and the effects of hypnotics, but he was also a pioneer in "sleep epidemiology." His "Prevalence of sleep disorders in the Los Angeles metropolitan area" study of 1979 was the first rigorous epidemiological study on sleep disturbances. Starting in 1990, he established the Penn State Adult Cohort to estimate the prevalence and natural history of sleep-disordered breathing and other sleep disorders in adults. Inspired by life-course epidemiology, he established in 2001 the Penn State Child Cohort to estimate the same phenomena in children. This Living Legend paper captures and highlights Dr. Bixler's enduring legacy to sleep science.

Pediatric Insomnia

Insomnia is the most common sleep disorder among all ages; unfortunately, however, child and adolescent insomnia is infrequently addressed. Given the importance of adequate sleep for proper brain development, pediatric populations are particularly vulnerable to the negative effects of insomnia. Therefore, proper clinical assessment and treatment of pediatric insomnia is crucial. This article is the result of a comprehensive literature review and serves as a guide to the disorder and how it presents differently across child development.

Transcranial Magnetic Stimulation of the Default Mode Network to Improve Sleep in Individuals With Insomnia Symptoms: Protocol for a Double-Blind Randomized Controlled Trial

BACKGROUND

Cortical hyperarousal and ruminative thinking are common aspects of insomnia that have been linked with greater connectivity in the default mode network (DMN). Therefore, disrupting network activity within the DMN may reduce cortical and cognitive hyperarousal and facilitate better sleep.

OBJECTIVE

This trial aims to establish a novel, noninvasive method for treating insomnia through disruption of the DMN with repetitive transcranial magnetic stimulation, specifically with continuous theta burst stimulation (cTBS). This double-blind, pilot randomized controlled trial will assess the efficacy of repetitive transcranial magnetic stimulation as a novel, nonpharmacological approach to improve sleep through disruption of the DMN prior to sleep onset for individuals with insomnia. Primary outcome measures will include assessing changes in DMN functional connectivity before and after stimulation.

METHODS

A total of 20 participants between the ages of 18 to 50 years with reported sleep disturbances will be recruited as a part of the study. Participants will then conduct an in-person screening and follow-on enrollment visit. Eligible participants then conduct at-home actigraphic collection until their first in-residence overnight study visit. In a double-blind, counterbalanced, crossover study design, participants will receive a 40-second stimulation to the left inferior parietal lobule of the DMN during 2 separate overnight in-residence visits. Participants are randomized to the order in which they receive the active stimulation and sham stimulation. Study participants will undergo a prestimulation functional magnetic resonance imaging scan and a poststimulation functional magnetic resonance imaging scan prior to sleep for each overnight study visit. Sleep outcomes will be measured using clinical polysomnography. After their first in-residence study visit, participants conduct another at-home actigraphic collection before returning for their second in-residence overnight study visit.

RESULTS

Our study was funded in September 2020 by the Department of Defense (W81XWH2010173). We completed the enrollment of our target study population in the October 2022 and are currently working on neuroimaging processing and analysis. We aim to publish the results of our study by 2024. Primary neuroimaging outcome measures will be tested using independent components analysis, seed-to-voxel analyses, and region of interest to region of interest analyses. A repeated measures analysis of covariance (ANCOVA) will be used to assess the effects of active and sham stimulation on sleep variables. Additionally, we will correlate changes in functional connectivity to polysomnography-graded sleep.

CONCLUSIONS

The presently proposed cTBS protocol is aimed at establishing the initial research outcomes of the effects of a single burst of cTBS on disrupting the network connectivity of the DMN to improve sleep. If effective, future work could determine the most effective stimulation sites and administration schedules to optimize this potential intervention for sleep problems.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04953559; https://clinicaltrials.gov/ct2/show/NCT04953559.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/51212.

Sleep-EEG in comorbid pain and insomnia: implications for the treatment of pain disorders

Introduction

Patients with chronic pain experience a high prevalence of comorbid insomnia, which is associated with functional impairment. Recent advances in sleep electroencephalography (sleep-EEG) may clarify the mechanisms that link sleep and chronic pain. In this clinical update, we outline current advancements in sleep-EEG assessments for pain and provide research recommendations.

Results

Promising preliminary work suggests that sleep-EEG spectral bands, particularly beta, gamma, alpha, and delta power, may create candidate neurophysiological signatures of pain, and macro-architectural parameters (e.g., total sleep time, arousals, and sleep continuity) may facilitate EEG-derived sleep phenotyping and may enable future stratification in the treatment of pain.

Conclusion

Integration of measures obtained through sleep-EEG represent feasible and scalable approaches that could be adopted in the future. We provide research recommendations to progress the field towards a deeper understanding of their utility and potential future applications in clinical practice.

Insomnia nosology: a systematic review and critical appraisal of historical diagnostic categories and current phenotypes

Insomnia nosology has significantly evolved since the Diagnostic and Statistical Manual (DSM)-III-R first distinguished between 'primary' and 'secondary' insomnia. Prior International Classification of Sleep Disorders (ICSD) nosology 'split' diagnostic phenotypes to address insomnia's heterogeneity and the DSM nosology 'lumped' them into primary insomnia, while both systems assumed causality for insomnia secondary to health conditions. In this systematic review, we discuss the historical phenotypes in prior insomnia nosology, present findings for currently proposed insomnia phenotypes based on more robust approaches, and critically appraise the most relevant ones. Electronic databases PsychINFO, PubMED, Web of Science, and references of eligible articles, were accessed to find diagnostic manuals, literature on insomnia phenotypes, including systematic reviews or meta-analysis, and assessments of the reliability or validity of insomnia diagnoses, identifying 184 articles. The data show that previous insomnia diagnoses lacked reliability and validity, leading current DSM-5-TR and ICSD-3 nosology to 'lump' phenotypes into a single diagnosis comorbid with health conditions. However, at least two new, robust insomnia phenotyping approaches were identified. One approach is multidimensional-multimethod and provides evidence for self-reported insomnia with objective short versus normal sleep duration linked to clinically relevant outcomes, while the other is multidimensional and provides evidence for two to five clusters (phenotypes) based on self-reported trait, state, and/or life-history data. Some approaches still need replication to better support whether their findings identify true phenotypes or simply different patterns of symptomatology. Regardless, these phenotyping efforts aim at improving insomnia nosology both as a classification system and as a mechanism to guide treatment.

Cognitive factors and processes in models of insomnia: A systematic review

Cognition is central to the experience of insomnia. Although unhelpful thoughts about and around insomnia are a primary treatment target of cognitive behaviour therapy for insomnia, cognitive constructs are termed and conceptualised differently in different theories of insomnia proposed over the past decades. In search of consensus in thinking, the current systematic review identified cognitive factors and processes featured in theoretical models of insomnia and mapped any commonality between models. We systematically searched PsycINFO and PubMed for published theoretical articles on the development, maintenance and remission of insomnia, from inception of databases to February, 2023. A total of 2458 records were identified for title and abstract screening. Of these, 34 were selected for full-text assessment and 12 included for analysis and data synthesis following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We identified nine distinguishable models of insomnia published between 1982 and 2023 and extracted 20 cognitive factors and processes featured in these models; 39 if sub-factors were counted. After assigning similarity ratings, we observed a high degree of overlap between constructs despite apparent differences in terminologies and measurement methods. As a result, we highlight shifts in thinking around cognitions associated with insomnia and discuss future directions.

Mechanisms of cognitive behavioural therapy for insomnia

Although much is known now about behavioural, cognitive and physiological consequences of insomnia, little is known about changes after cognitive behavioural therapy for insomnia on these particular factors. We here report baseline findings on each of these factors in insomnia, after which we address findings on their changes after cognitive behavioural therapy. Sleep restriction remains the strongest determinant of insomnia treatment success. Cognitive interventions addressing dysfunctional beliefs and attitudes about sleep, sleep-related selective attention, worry and rumination further drive effectiveness of cognitive behavioural therapy for insomnia. Future studies should focus on physiological changes after cognitive behavioural therapy for insomnia, such as changes in hyperarousal and brain activity, as literature on these changes is sparse. We introduce a detailed clinical research agenda on how to address this topic.

Change in Insomnia and Depressive Symptoms During COVID-19: A Prospective Longitudinal Study of Iranian Women with Multiple Sclerosis

BACKGROUND

There is some evidence that sleep patterns and psychological health have worsened in the general population as a result of the COVID-19-pandemic. Persons with multiple sclerosis (MS) represent a particularly vulnerable population for COVID-19 infections and effects of restrictions. The present study investigated whether insomnia and depressive symptoms, as well as other MS-related symptoms (i.e. fatigue and paresthesia), changed from before to during the COVID-19-pandemic among persons with diagnosed MS.

METHOD

A sample of 90 Iranian females with MS (mean age; 37.62 years; median EDSS score: 2.5) completed a series of self-rating scales at two time points: Nine months before the COVID-19 outbreak in May 2019 (baseline) and then again during the COVID-19 pandemic in May 2020 (study end). Self-rating questionnaires covered sociodemographic and disease-related information, insomnia, depressive symptoms, fatigue, and paresthesia.

RESULTS

Depressive symptoms increased over time with a significant p-value and medium effect size. Symptoms of insomnia increased over time (significant p-value, but small effect size), while no significant changes were observed in fatigue and paresthesia (very small effect sizes). The only predictor for insomnia during the COVID-19 pandemic was insomnia before the COVID-19 pandemic; the only predictor for depressive symptoms during the COVID-19 pandemic was insomnia before the COVID-19 pandemic.

CONCLUSIONS

Overall, the COVID-19 pandemic and its related social restrictions had significant effects on symptoms of depression and insomnia in this sample of Iranian women with MS, but had no effect on fatigue and paresthesia.

Amygdala resting-state functional connectivity alterations in patients with chronic insomnia disorder: correlation with electroencephalography beta power during sleep

STUDY OBJECTIVES

This study investigated alterations in resting-state functional connectivity (RSFC) and hyperarousal biomarkers in patients with chronic insomnia disorder (CID), compared with good sleepers (GS). We also examined the relationships between altered RSFC and hyperarousal biomarkers.

METHODS

Fifty patients with CID and 52 GS completed self-reporting questionnaires, and then underwent polysomnography and resting-state functional magnetic resonance imaging. We analyzed RSFC in the amygdala (AMG) and anterior insula (aINS), which are core regions of the salience network that are likely to be involved in hyperarousal. We also analyzed electroencephalography (EEG) relative beta power and heart rate variability (HRV) parameters (e.g. low and high frequency) during sleep. We then tested between-group differences in the RSFC and hyperarousal biomarkers; we examined correlations of RSFC with EEG beta power and HRV.

RESULTS

Compared with GS, patients with CID showed more negative RSFC between the right amygdala (R.AMG) and left supramarginal gyrus (L.SMG), but less positive RSFC between the left aINS and bilateral lateral prefrontal cortex. The R.AMG-L.SMG RSFC was negatively correlated with EEG beta power in central regions (C3: r = -0.336, p = 0.012; C4: r = -0.314, p = 0.024).

CONCLUSIONS

Decreased RSFC between the R.AMG and L.SMG in patients with insomnia may reflect the difficulty in cortical top-down regulation of the AMG, indicating daytime hyperarousal. Individuals who experience hyperarousal during the daytime may also exhibit cortical hyperarousal during sleep, as indicated by increased EEG beta power.

Sub-types of insomnia in adolescents: Insights from a quantitative/molecular twin study

Background

Insomnia with short sleep duration has been postulated as more severe than that accompanied by normal/long sleep length. While the short duration subtype is considered to have greater genetic influence than the other subtype, no studies have addressed this question. This study aimed to compare these subtypes in terms of: (1) the heritability of insomnia symptoms; (2) polygenic scores (PGS) for insomnia symptoms and sleep duration; (3) the associations between insomnia symptoms and a wide variety of traits/disorders.

Methods

The sample comprised 4000 pairs of twins aged 16 from the Twins Early Development Study. Twin models were fitted to estimate the heritability of insomnia in both groups. PGS were calculated for self-reported insomnia and sleep duration and compared among participants with short and normal/long sleep duration.

Results

Heritability was not significantly different in the short sleep duration group (A = 0.13 [95%CI = 0.01, 0.32]) and the normal/long sleep duration group (A = 0.35 [95%CI = 0.29, 0.40]). Shared environmental factors accounted for a substantial proportion of the variance in the short sleep duration group (C = 0.19 [95%CI = 0.05, 0.32]) but not in the normal/long sleep duration group (C = 0.00 [95%CI = 0.00, 0.04]). PGS did not differ significantly between groups although results were in the direction expected by the theory. Our results also showed that insomnia with short (as compared to normal/long) sleep duration had a stronger association with anxiety and depression (p < .05)-although not once adjusting for multiple testing.

Conclusions

We found mixed results in relation to the expected differences between the insomnia subtypes in adolescents. Future research needs to further establish cut-offs for 'short' sleep at different developmental stages and employ objective measures of sleep.

Effects on resting-state EEG phase-amplitude coupling in insomnia disorder patients following 1 Hz left dorsolateral prefrontal cortex rTMS

Despite burgeoning evidence for cortical hyperarousal in insomnia disorder, the existing results on electroencephalography spectral features are highly heterogeneous. Phase-amplitude coupling, which refers to the modulation of the low-frequency phase to a high-frequency amplitude, is probably a more sensitive quantitative measure for characterizing abnormal neural oscillations and explaining the therapeutic effect of repetitive transcranial magnetic stimulation in the treatment of patients with insomnia disorder. Sixty insomnia disorder patients were randomly divided into the active and sham treatment groups to receive 4 weeks of repetitive transcranial magnetic stimulation treatment. Behavioral assessments, resting-state electroencephalography recordings, and sleep polysomnography recordings were performed before and after repetitive transcranial magnetic stimulation treatment. Forty good sleeper controls underwent the same assessment. We demonstrated that phase-amplitude coupling values in the frontal and temporal lobes were weaker in Insomnia disorder patients than in those with good sleeper controls at baseline and that phase-amplitude coupling values near the intervention area were significantly enhanced after active repetitive transcranial magnetic stimulation treatment. Furthermore, the enhancement of phase-amplitude coupling values was significantly correlated with the improvement of sleep quality. This study revealed the potential of phase-amplitude coupling in assessing the severity of insomnia disorder and the efficacy of repetitive transcranial magnetic stimulation treatment, providing new insights on the abnormal physiological mechanisms and future treatments for insomnia disorder.

Longitudinal associations between pandemic post-traumatic stress symptoms and subsequent non-suicidal self-injury in adolescents: A multiple mediation model

BACKGROUNDS

PTSD is one of the most common conditions after people have experienced trauma. While previous studies have found a link between PTSD and non-suicidal self-injury, (NSSI), few studies have longitudinally explored this relationship and the underlying mechanisms.

AIMS

This study explored adolescent NSSI frequency after COVID-19 lockdown experiences, the relationship with early PTSD symptoms, and the mediating role of depression and sleep problems.

METHODS

A cohort of 1609 adolescents completed two surveys during and after the national lockdown in China; one month into the lockdown and six months later; which assessed demographic and pandemic-related exposure variables; PTSD, depression, sleep, and NSSI. Mediation analyses and hierarchical regression were employed to examine the relationships and the paths between these variables.

RESULTS

The NSSI rate was found to be 31.9 % after the three-month lockdown, with 20.6 % of adolescent participants reporting sleeping disorders, and 33.9 % indicating probable depression. Adolescents who had earlier PTSD symptoms, often smoked and/or drank, and had current depression and sleep disorders reported greater NSSI. Early PTSD symptoms were found to predict later NSSI and were mediated by sleep problems and depressive symptoms. Specifically, PTSD avoidance and numbing symptoms were significantly associated with NSSI above and beyond the depressive symptoms, sleeping problems, and the other covariables.

CONCLUSION

It is necessary to be vigilant about the increased risk of NSSI in adolescents who have experienced extended pandemic lockdowns. Preventing early adolescent PTSD symptoms, especially avoidance and numbness, and helping teenagers quit smoking and drinking could reduce the risk of sleep disorders, depression, and NSSI.

Wearable and mobile technology to characterize daily patterns of sleep, stress, presleep worry, and mood in adolescent insomnia

OBJECTIVES

Characterizing daily patterns of sleep, stress, presleep worry, and mood in adolescents with and without insomnia symptomatology.

DESIGN

Two months of continuous wearable tracking and daily diary ratings.

SETTING

Free-living conditions.

PARTICIPANTS

Ninety-three adolescents (59 girls; 16-19 years old) with (N = 47; 26 with clinical and 21 with sub-clinical) and without (N = 46; control) DSM-5 insomnia symptomatology.

MEASUREMENTS

Fitbit Charge 3 tracked sleep, heart rate, and steps. Evening electronic diaries collected ratings of daily stress, presleep worry, and mood.

RESULTS

While sleep duration (control: 6.88 ± 1.41 hours; insomnia: 6.92 ± 1.28 hours), architecture, timing, and night-to-night variability were similar between groups, the insomnia group reported higher levels of stress and worry, being mainly related to "school". At the intraindividual level, stress and worry predicted shorter sleep duration and earlier wake up times, which, in turn, predicted higher stress the following day. Moreover, higher-than-usual stress predicted higher sleep-time heart rate, with a more consistent effect in adolescents with insomnia. Results were overall consistent after controlling for covariates and several robustness checks.

CONCLUSIONS

There is a bidirectional relationship between daily stress and sleep, with daily stress negatively impacting sleep, which in turn leads to more stress in adolescents with and without insomnia symptoms. Findings also highlight the complexity of insomnia in adolescence, in which the core clinical features (perceived sleep difficulties) and the critical factors (stress/worry) implicated in the pathophysiology of the disorder are not necessarily reflected in objective sleep indicators.

Insomnia in Infancy, Childhood, and Adolescence

Insomnia is the most prevalent sleep disorder in youth, tends to persist over time, and is associated with a myriad of adverse outcomes. This paper synthesizes the current evidence regarding the phenomenology, prevalence, assessment, consequences, cause, and treatment of pediatric insomnia, highlighting areas that warrant further research and addressing the unique characteristics of this disorder in infants, children, and adolescents.

Identification of discriminative neuroimaging markers for patients on hemodialysis with insomnia: a fractional amplitude of low frequency fluctuation-based machine learning analysis

BACKGROUND AND OBJECTIVE

Insomnia is one of the common problems encountered in the hemodialysis (HD) population, but the mechanisms remain unclear. we aimed to (1) detect the spontaneous brain activity pattern in HD patients with insomnia (HDWI) by using fractional fractional amplitude of low frequency fluctuation (fALFF) method and (2) further identify brain regions showing altered fALFF as neural markers to discriminate HDWI patients from those on hemodialysis but without insomnia (HDWoI) and healthy controls (HCs).

METHOD

We compared fALFF differences among HDWI subjects (28), HDWoI subjects (28) and HCs (28), and extracted altered fALFF features for the subsequent discriminative analysis. Then, we constructed a support vector machine (SVM) classifier to identify distinct neuroimaging markers for HDWI.

RESULTS

Compared with HCs, both HDWI and HDWoI patients exhibited significantly decreased fALFF in the bilateral calcarine (CAL), right middle occipital gyrus (MOG), left precentral gyrus (PreCG), bilateral postcentral gyrus (PoCG) and bilateral temporal middle gyrus (TMG), whereas increased fALFF in the bilateral cerebellum and right insula. Conversely, increased fALFF in the bilateral CAL/right MOG and decreased fALFF in the right cerebellum was observed in HDWI patients when compared with HDWoI patients. Moreover, the SVM classification achieved a good performance [accuracy = 82.14%, area under the curve (AUC) = 0.8202], and the consensus brain regions with the highest contributions to classification were located in the right MOG and right cerebellum.

CONCLUSION

Our result highlights that HDWI patients had abnormal neural activities in the right MOG and right cerebellum, which might be potential neural markers for distinguishing HDWI patients from non-insomniacs, providing further support for the pathological mechanism of HDWI.

Elevated beta activity in the nighttime sleep and multiple sleep latency electroencephalograms of chronic insomnia patients

Aim

To examine the 24-h hyperarousal hypothesis of insomnia using electroencephalographic (EEG) spectral analysis of overnight polysomnography (PSG) and daytime multiple sleep latency tests (MSLTs).

Methods

Standard PSG and MSLT were recorded in 31 chronic insomniacs (CIs) (21 females, mean age 36.19) and in 21 normal controls (NCs) (18 females, mean age 34.76). EEG spectral analyses were conducted and relative power was obtained for each sleep stage during PSG and each session during MSLTs. Subsequently, CIs were subdivided based on sleep efficiency (SE < or ≥ 85%) or mean sleep latency (MSL) of MSLT (< or ≥ 15 min), and beta power was compared among NCs and CIs subgroups. General liner regression analyses of beta power and PSG parameters were conducted.

Results

CIs had significantly greater beta power in nighttime W, N1, N2, NREM, and in total overnight and in MSLT sessions compared with NCs. CIs with lower PSG-SE or longer MSLT-MSL showed higher beta power at nighttime. Compared with NCs, increased beta power was limited to CIs with lower PSG-SE or longer MSLT-MSL during MSLT sessions. In all subjects, total daytime beta was positively correlated to total overnight beta and MSL, total overnight beta was negatively related to SE. In CIs, total daytime beta and total overnight beta were positively correlated.

Conclusion

Our results support the hypothesis of 24-h cortical hyperarousal in insomnia. We conclude that 24-h cortical hyperarousal is clearly present in insomnia and is greater in insomnia with objective findings.

The role of ascending arousal network in patients with chronic insomnia disorder

The ascending arousal system plays a crucial role in individuals' consciousness. Recently, advanced functional magnetic resonance imaging (fMRI) has made it possible to investigate the ascending arousal network (AAN) in vivo. However, the role of AAN in the neuropathology of human insomnia remains unclear. Our study aimed to explore alterations in AAN and its connections with cortical networks in chronic insomnia disorder (CID). Resting-state fMRI data were acquired from 60 patients with CID and 60 good sleeper controls (GSCs). Changes in the brain's functional connectivity (FC) between the AAN and eight cortical networks were detected in patients with CID and GSCs. Multivariate pattern analysis (MVPA) was employed to differentiate CID patients from GSCs and predict clinical symptoms in patients with CID. Finally, these MVPA findings were further verified using an external data set (32 patients with CID and 33 GSCs). Compared to GSCs, patients with CID exhibited increased FC within the AAN, as well as increased FC between the AAN and default mode, cerebellar, sensorimotor, and dorsal attention networks. These AAN-related FC patterns and the MVPA classification model could be used to differentiate CID patients from GSCs with 88% accuracy in the first cohort and 77% accuracy in the validation cohort. Moreover, the MVPA prediction models could separately predict insomnia (data set 1, R²  = .34; data set 2, R²  = .15) and anxiety symptoms (data set 1, R²  = .35; data set 2, R²  = .34) in the two independent cohorts of patients. Our findings indicated that AAN contributed to the neurobiological mechanism of insomnia and highlighted that fMRI-based markers and machine learning techniques might facilitate the evaluation of insomnia and its comorbid mental symptoms.

IL-1α and TNF-α as an inducer for ROS-mediated NLRP1/NLRP3 inflammasomes activation in mononuclear blood cells from individuals with chronic insomnia disorder

BACKGROUND

There are some evidence that cytokines may play an important role in sleep deprivation; however, the underlying mechanisms are still unknown. So, the present study aim to evaluate the relationship between NLRP1 and NLRP3 inflammasomes activation of blood cells and serum levels of cytokines in individuals with chronic insomnia disorder (CID).

METHODS

Blood samples were collected from 24 individuals with CID and 24 healthy volunteers. The inflammasomes activation was evaluated using real time PCR of NLRP1, NLRP3, ASC, and Caspase-1; western blot of NLRP1 and NLRP3; caspase-1 activity assay; and serum levels of IL-1β, IL-18 and other cytokines using enzyme-linked immunosorbent assay (ELISA). ROS generation in blood cells were detected by flow cytometry assay. As well, MRI scans were obtained on a Siemens Magnetom Avanto 1.5 T MRI whole body scanner using an 8-channel head coil.

RESULTS

We found the increased activity of NLRP1 and NLRP3 inflammasomes in blood cells; the increased serum levels of pro-inflammatory cytokines; and the decreased serum levels of IL-10 and TGF-β in individuals with CID. We observed significant correlation between increased serum concentration of IL-1β and the severity of insomnia in individuals with CID. The levels of ROS in blood cells was found to be correlated with IL-1α and TNF-α concentrations in serums from individuals with CID. Moreover, the included individuals with CID demonstrated the increased right-cerebellum-cortex and lateral ventricle MD bilaterally compared to controls.

CONCLUSIONS

This study provided new insights on the pathogenesis of CID and the effects of cytokines on inflammasome activation.

Temporal relations between peripheral and central arousals in good and poor sleepers

Good sleepers and patients with insomnia symptoms (poor sleepers) were tracked with two measures of arousal; conventional polysomnography (PSG) for electroencephalogram (EEG) assessed cortical arousals, and a peripheral arterial tonometry device was used for the detection of peripheral nervous system (PNS) arousals associated with vasoconstrictions. The relationship between central (cortical) and peripheral (autonomic) arousals was examined by evaluating their close temporal dynamics. Cortical arousals almost invariably were preceded and followed by peripheral activations, while large peripheral autonomic arousals were followed by cortical arousals only half of the time. The temporal contiguity of these two types of arousals was altered in poor sleepers, and poor sleepers displayed a higher number of cortical and peripheral arousals compared with good sleepers. Given the difference in the number of peripheral autonomic arousals between good and poor sleepers, an evaluation of such arousals could become a means of physiologically distinguishing poor sleepers.

Management of Chronic Insomnia Using Cognitive Behavior Therapy for Insomnia (CBT-I) During COVID-19 Pandemic: Does One Shoe Fit All?

Purpose

Insomnia is a highly prevalent disorder that is seen across all age groups causing significant morbidity to the patients. Its prevalence has further risen during COVID-19 pandemic. It is widely acknowledged that untreated insomnia can lead to significant health risks and socio-occupational dysfunction.

Methods

A narrative review was conducted following focused search of databases.

Results

Available guidelines mention two different approaches for the management of insomnia-pharmacological and non-pharmacological. Non-pharmacological therapies like multicomponent cognitive behavior therapy for insomnia (CBT-I) have been advocated for the management of acute as well as chronic insomnia in the literature as it has been found efficacious and useful. Multiple variants of CBT-I, e.g., digitally delivered CBT-I, brief CBT-I have been tested during pandemic owing to closure of clinics. However, there are certain issues to be considered while choosing CBT-I as therapy. For example, like other forms of psychotherapies, is there a need for assessing the candidature of patient before administering CBT-I; is CBT-I free of adverse effects as commonly thought; is CBT-I more efficacious than hypnotics; and at last, how to manage cases that are not candidate for CBT-I.

Conclusion

This narrative review addresses the scientific robustness of evidence for issues related to adherence, efficacy and adverse effects of non-pharmacological therapies. Available literature suggests that data related to adherence and efficacy of CBT-I suffer from methodological shortcomings and careful selection of patient is important for the successful therapy. At the same time, attempts have been made to shed light to the areas where CBT-I can be helpful in the management of insomnia.

Association of a novel EEG metric of sleep depth/intensity with attention-deficit/hyperactivity, learning, and internalizing disorders and their pharmacotherapy in adolescence

STUDY OBJECTIVES

Psychiatric/learning disorders are associated with sleep disturbances, including those arising from abnormal cortical activity. The odds ratio product (ORP) is a standardized electroencephalogram metric of sleep depth/intensity validated in adults, while ORP data in youth are lacking. We tested ORP as a measure of sleep depth/intensity in adolescents with and without psychiatric/learning disorders.

METHODS

Four hundred eighteen adolescents (median 16 years) underwent a 9-hour, in-lab polysomnography. Of them, 263 were typically developing (TD), 89 were unmedicated, and 66 were medicated for disorders including attention-deficit/hyperactivity (ADHD), learning (LD), and internalizing (ID). Central ORP during non-rapid eye movement (NREM) sleep was the primary outcome. Secondary/exploratory outcomes included central and frontal ORP during NREM stages, in the 9-seconds following arousals (ORP-9), in the first and second halves of the night, during REM sleep and wakefulness.

RESULTS

Unmedicated youth with ADHD/LD had greater central ORP than TD during stage 3 and in central and frontal regions during stage 2 and the second half of the sleep period, while ORP in youth with ADHD/LD on stimulants did not significantly differ from TD. Unmedicated youth with ID did not significantly differ from TD in ORP, while youth with ID on antidepressants had greater central and frontal ORP than TD during NREM and REM sleep, and higher ORP-9.

CONCLUSIONS

The greater ORP in unmedicated youth with ADHD/LD, and normalized levels in those on stimulants, suggests ORP is a useful metric of decreased NREM sleep depth/intensity in ADHD/LD. Antidepressants are associated with greater ORP/ORP-9, suggesting these medications induce cortical arousability.

Clinical characterization of insomnia in adolescents - an integrated approach to psychopathology

OBJECTIVES/BACKGROUND

Insomnia in adolescence is common and debilitating yet it remains poorly understood. Here, we examine the complexity of clinical, behavioral, and psychosocial factors characterizing insomnia in adolescents.

METHODS

Ninety-five adolescents (16-19 years) with (N = 47, 31 female) and without (N = 48, 28 female) insomnia symptoms participated. In the insomnia group, 26 (20 female) met full DSM-5 criteria for insomnia disorder, while 21 (11 female) met partial criteria. Participants completed a clinical interview and assessments of clinical, behavioral, and psychosocial dimensions associated with insomnia. GLMs and network analyses were used to evaluate group and sex differences in severity and inter-relationships between symptoms.

RESULTS

Adolescents with insomnia symptomatology had lower sleep hygiene and thought control, more depressive symptoms and dysfunctional sleep-related cognitions, and more substance use as a coping behavior than healthy controls. They also indicated higher neuroticism, stress levels, and sleep stress reactivity (p < 0.05), but no difference in adverse childhood experiences, than controls. Girls compared to boys with insomnia reported lower sleep quality, and more pre-sleep cognitive activity and sleep stress reactivity (p < 0.05). Compared to healthy girls, girls in the insomnia group reported lower sleep hygiene and higher agreeableness. Network analyses confirmed profound group differences in network topology, with the insomnia group having different levels of centrality and relationships between clinical characteristics compared with controls.

CONCLUSIONS

Findings highlight clinical and sex-specific characteristics of adolescent insomnia, with network analyses revealing a complex interplay between clinical, behavioral, and psychosocial domains. Adolescents with insomnia symptoms, particularly girls, may benefit from interventions to improve negative cognition, mood, and stress, and behavioral strategies to counteract sleep-related maladaptive behaviors.

Trajectories of Insomnia Symptoms From Childhood Through Young Adulthood

OBJECTIVES

Insomnia symptoms are transdiagnostic to physical and mental health disorders. Given the lack of population-based cohorts with objective sleep measures and long-term follow-ups, little is known about the chronicity of childhood insomnia symptoms. We determined the developmental trajectories of insomnia symptoms, their evolution into adult insomnia, and the role of objective sleep duration in the transition to adulthood.

METHODS

A total of 502 children (median 9 years old, 71.7% response rate) were studied 7.4 years later as adolescents (median 16 years old) and 15 years later as adults (median 24 years old). Insomnia symptoms were ascertained as moderate-to-severe difficulties initiating and/or maintaining sleep via parent- or self reports at all 3 time points, adult insomnia via self-report in young adulthood, and objective short-sleep duration via polysomnography in childhood and adolescence.

RESULTS

Among children with insomnia symptoms, the most frequent trajectory was persistence (43.3%), followed by remission (26.9% since childhood, 11.2% since adolescence) and a waxing-and-waning pattern (18.6%). Among children with normal sleep, the most frequent trajectory was persistence (48.1%), followed by developing insomnia symptoms (15.2% since adolescence, 20.7% in adulthood) and a waxing-and-waning pattern (16.0%). The odds of insomnia symptoms worsening into adult insomnia (22.0% of children, 20.8% of adolescents) were 2.6-fold and 5.5-fold among short-sleeping children and adolescents, respectively.

CONCLUSIONS

Early sleep interventions are a health priority because pediatricians should not expect insomnia symptoms to developmentally remit in a high proportion of children. Objective sleep measures may be clinically useful in adolescence, a critical period for the adverse prognosis of the insomnia with short-sleep duration phenotype.

Association between sleep quality and anxiety in South Korean adolescents

Objectives

Anxiety disorder is among the most prevalent mental illnesses among adolescents. Early detection and proper treatment are important for preventing sequelae such as suicide and substance use disorder. Studies have suggested that sleep duration is associated with anxiety disorder in adolescents. In the present study, we investigated the association between sleep quality and anxiety in a nationally representative sample of Korean adolescents.

Methods

This cross-sectional study was conducted using data from the 2020 Korea Youth Risk Behavior Web-based Survey. The Generalized Anxiety Disorder-7 questionnaire was used to evaluate anxiety. The chi-square test was used to investigate and compare the general characteristics of the study population, and multiple logistic regression analysis was used to analyze the relationship between sleep quality and anxiety.

Results

In both sexes, anxiety was highly prevalent in participants with poor sleep quality (adjusted odds ratio [aOR], 1.56; 95% confidence interval [CI], 1.43 to 1.71 in boys; aOR, 1.30; 95% CI, 1.19 to 1.42 in girls). Regardless of sleep duration, participants with poor sleep quality showed a high aOR for anxiety.

Conclusions

This study identified a consistent relationship between sleep quality and anxiety in Korean adolescents regardless of sleep duration.

[Characteristics of Sleep Electroencephalographic Power in Chronic Insomnia Patients]

OBJECTIVE

To study the sleep electroencephalogram (EEG) power features of patients with chronic insomnia.

METHODS

Retrospective analysis was performed with patients who met the ICD-10 diagnostic criteria for chronic insomnia, using polysomnography (PSG) to examine the overnight sleep EEG. The sleep architectures and relative EEG power across five frequency bands during overnight sleep were compared to study the differences between the insomnia and control groups. Furthermore, the correlation between EEG power and various PSG measures was also analyzed.

RESULTS

Forty-five subjects were enrolled in the study, including 25 chronic insomniacs (18 females, aged [36.2±10.7] years) and 20 controls (18 females, aged [36.1±7.6] years). Compared to those of the control group, insomnia patients had significantly lower value of delta power ([38.0±6.1] vs. [43.2±5.8], P<0.05) in the NREM1 stage, and increased value of beta power during total NREM, NREM1 and NREM2 (NREM sleep [5.4±2.3] vs. [3.8±1.4], NREM1 [11.3±3.5] vs. [8.7±2.8], and NREM2 [5.7±2.3] vs. [4.4±1.4], all P<0.05). For correlation analyses, in the insomnia group, a significantly positive correlation was found between the delta value during NREM sleep and the duration of NREM3 sleep ( r=0.527). The beta value during NREM sleep was found to be negatively correlated to the duration of NREM3 sleep ( r=－0.767). A positive correlation was found between the beta value during NREM sleep and the duration of NREM1 and NREM2 sleep ( r=0.486 and 0.589, respectively).

CONCLUSION

The results suggest that patients with chronic insomnia have decreased low-frequency EEG power, but increased high-frequency EEG power during NREM sleep. The findings indicate that cortex arousal level is elevated in chronic insomniacs during NREM sleep.

A virtual reality-based mind-body approach to downregulate psychophysiological arousal in adolescent insomnia

Objective

In this study, we describe the rationale, supported by preliminary data, for a novel, digital, immersive virtual reality (VR)-based mind-body approach, designed to reduce bedtime arousal in adolescents with insomnia.

Methods

Fifty-two high-school students (16-20 years; 32 female) with (N = 18) and without (N = 34) DSM-5 insomnia symptoms engaged with 20 min of immersive VR-guided meditation and paced breathing (0.1 Hz) (intervention condition) and 20 min of quiet activity (control condition), right before bedtime, on two separate evenings.

Results

The intervention resulted in acute autonomic and cortical modulation (p < 0.05), leading to reduced physiological arousal (↓heart rate, ↓cortisol) compared with the control condition, with similar effects in adolescents with and without insomnia. No significant changes were detected for cognitive arousal levels. During the intervention, all participants were able to achieve the targeted 0.1 Hz breathing rate, and the majority experienced no discomfort associated with the VR exposure. However, 30-40% of the participants experienced some trouble slowing down their breathing.

Conclusions

The study provides supporting preliminary evidence for the mechanism behind a novel VR-based digital approach, designed to regulate psychophysiological arousal levels by acting on neurocognitive and autonomic pathways. Further studies (e.g. randomized clinical trials) are needed to evaluate the isolated and synergistic effects of its components (e.g. VR vs. VR + paced breathing), and its efficacy, acceptance, and feasibility in alleviating insomnia symptoms in adolescents.

When Non-Suicidal Self-Injury Predicts Non-Suicidal Self-Injury and Poor Sleep-Results from a Larger Cross-Sectional and Quasi-Longitudinal Study

Poor sleep is associated with a higher risk of non-suicidal self-injury (NSSI) as a proxy of unfavorable emotion regulation. In the present study, we tested the hypothesis that past non-suicidal self-injury was associated with current non-suicidal self-injury and with current subjective sleep patterns. To this end, a larger sample of young adults were assessed. A total of 2374 adults (mean age: 27.58 years; 39.6% females) completed a series of self-rating questionnaires covering sociodemographic information, past and current NSSIs, suicide attempts, and current sleep patterns, including experiencing nightmares. Past NSSIs predicted current NSSIs. Current sleep patterns had a modest impact on the association between past and current NSSIs. Compared to male participants, female participants did not report more sleep complaints or more current NSSIs, but more past NSSIs. Past NSSIs predicted the occurrences of nightmares and suicide attempts. The best predictor of current NSSI was the remembered past NSSI, while current poor sleep was only modestly associated with current NSSI. Further indicators of current NSSI and poor sleep were suicide attempts and nightmares within the last six months. Overall, it appears that poor emotion regulation should be considered as underlying factor to trigger and maintain non-suicidal self-injury-related behavior and poor sleep. Further, unlike previous studies, which focused on the possible influence of sleep patterns on NSSIs, the aim of the present study paradigm was to investigate NSSIs on sleep patterns.

Presleep physiological stress is associated with a higher cortical arousal in sleep and more consolidated REM sleep

How sleep regulates physiological stress in healthy individuals is not well understood. We explored the associations between naturally occurring pre-sleep physiological arousal and EEG power spectral density together with rapid eye movement sleep (REMS) continuity. One hundred and fifty-four individuals (mean age 16.9, SD 0.1 years) collected five samples of saliva between the evening (mean time 18:20) and bedtime (mean 23:00) by using swabs, and underwent an overnight in-home polysomnography. We calculated spectral density for REMS and non-rapid eye movement sleep (non-REMS), and the number and duration of REMS arousals (<15 s) during sleep. An observational design allowed for measurement of natural variation in physiological and sleep arousal. Increasing cortisol levels toward bedtime were associated with higher EEG power spectral density at all frequency ranges in frontal locations, the highest association being for the beta1 frequency band. In central locations, the associations were pronounced for beta1 and beta2 bands. Higher overall cortisol levels in the evening were associated with less fragmented REMS. Presleep arousal was not associated with sleep staging. Physiological arousal toward bedtime was associated with EEG power spectral density values during sleep specifically at high EEG frequencies. This may represent a compensatory mechanism that serves as an adaptation to stress, since the REMS was more continuous along a higher physiological arousal level in the evening. Although causality cannot be inferred, a design with nonmanipulated physiological stress followed by naturally timed sleep at home provides new insights into stress regulation homeostasis.

Effect of trazodone versus cognitive-behavioural treatment on high- and slow-frequency activity during non-rapid eye movement sleep in chronic insomnia: A pilot, randomized clinical trial

Trazodone and cognitive-behavioural treatment for insomnia (CBT-I) are widely used to treat patients with chronic insomnia. Although both treatments improve sleep continuity, no study has compared their comparative effectiveness in modifying spectral electroencephalographic (EEG) activity during sleep in humans. In this study, participants included 19 men and women with chronic insomnia who were randomized to either trazodone (n = 8) or CBT-I (n = 11) treatment for 3 months. We examined delta (0.39-3.91 Hz), theta (4.30-7.81 Hz), alpha (8.20-11.72 Hz), sigma (12.11-14.84 Hz), beta (15.23-35.16 Hz) and gamma (35.55-49.61 Hz) relative power during non-rapid eye movement (NREM) sleep at pre-treatment, 3- month post-treatment and 6-month follow-up. This study was registered in Clinical Trials (NCT01348542). We found trazodone but not CBT-I significantly decreased sigma (p = .041, d = 0.88; time × group p = .009) and beta (p = .005, d = 1.41; time × group p = .016) power during NREM sleep at post-treatment. Compared to CBT-I, trazodone increased delta (p = .018) and decreased sigma (p = .013) and beta (p = .023) power during NREM sleep at post-treatment. At follow-up, we did not observe significant changes in relative EEG power during NREM sleep in either the CBT-I or trazodone group compared to pre-treatment. Compared to CBT-I, trazodone decreased alpha (p = .039) and sigma (p = .009) power during NREM sleep at follow-up. In conclusion, trazodone, but not CBT-I, decreased fast-frequency EEG activity during NREM sleep. Compared to CBT-I, trazodone appears to have a stronger impact on cortical and physiological hyperarousal in patients with chronic insomnia.

Relationship between Sleep Problems and Self-Injury: A Systematic Review

Objective/Background: Previous studies suggested that sleep problems were related to non-suicidal self-injury. The current systematic review investigated more thoroughly this relationship.Methods: PubMED and Embase databases were searched. The keywords were "self-injury" OR "self-harm" OR "non-suicidal self-injury" OR "self-injurious behavior" OR "self-destructive behavior" OR "self-mutilation" AND "sleep problem" OR "sleep disturbance" OR insomnia OR nightmare OR "poor sleep quality" or "sleep disorders." A total of 16 studies were included in the present review.Results: The pattern of results indicated that sleep problems such as short sleep duration, sleep disturbances, and poor sleep quality were associated with non-suicidal self-injury. Additionally, emotional dysregulation, depression, and post-traumatic stress disorder appeared to mediate this relationship. Above all adolescents and young adults with sleep disruptions were at higher risk of non-suicidal self-injury.Conclusions:g Interventions to improve sleep quality and sleep duration might concomitantly decrease the risk of non-suicidal self-injury.

Sex and Pubertal Differences in the Maturational Trajectories of Sleep Spindles in the Transition from Childhood to Adolescence: A Population-Based Study

Sleep spindles, bursts of electroencephalogram (EEG) activity in the σ-frequency (11–16 Hz) range, may be biomarkers of cortical development. Studies capturing the transition to adolescence are needed to delineate age-related, sex-related, and pubertal-related changes in sleep spindles at the population-level. We analyzed the sleep EEG of 572 subjects 6–21 years (48% female) and 332 subjects 5–12 years (46% female) followed-up at 12–22 years. From 6 to 21 years, spindle density (p quadratic = 0.019) and fast (12–16 Hz) spindle percent (p quadratic = 0.016) showed inverted U-shaped trajectories, with plateaus after 15 and 19 years, respectively. Spindle frequency increased (p linear < 0.001), while spindle power decreased (p linear < 0.001) from 6 to 21 years. The trajectories of spindle density, frequency, and fast spindle percent diverged between females and males, in whom density plateaued by 14 years, fast spindle percent by 16 years, and frequency by 18 years, while fast spindle percent and spindle frequency continued to increase until 21 years in females. Males experienced a longitudinal increase in spindle density 31% greater than females by 12–14 years (p = 0.006). Females experienced an increase in spindle frequency and fast spindle percent 2% and 41% greater, respectively, than males by 18–22 years (both p = 0.004), while males experienced a 14% greater decline in spindle power by 18–22 years (p = 0.018). Less mature adolescents (86% male) experienced a longitudinal increase in spindle density 36% greater than mature adolescents by 12–14 years (p = 0.002). Overall, males experience greater maturational changes in spindle density in the transition to adolescence, driven by later pubertal development, and sex differences become prominent in early adulthood when females have greater spindle power, frequency, and fast spindle percent.

Immunization with a heat-killed bacterium, Mycobacterium vaccae NCTC 11659, prevents the development of cortical hyperarousal and a PTSD-like sleep phenotype after sleep disruption and acute stress in mice

STUDY OBJECTIVES

Sleep deprivation induces systemic inflammation that may contribute to stress vulnerability and other pathologies. We tested the hypothesis that immunization with heat-killed Mycobacterium vaccae NCTC 11659 (MV), an environmental bacterium with immunoregulatory and anti-inflammatory properties, prevents the negative impacts of 5 days of sleep disruption on stress-induced changes in sleep, behavior, and physiology in mice.

METHODS

In a 2 × 2 × 2 experimental design, male C57BL/6N mice were given injections of either MV or vehicle on days -17, -10, and -3. On days 1-5, mice were exposed to intermittent sleep disruption, whereby sleep was disrupted for 20 h per day. Immediately following sleep disruption, mice were exposed to 1-h social defeat stress or novel cage (control) conditions. Object location memory (OLM) testing was conducted 24 h after social defeat, and tissues were collected 6 days later to measure inflammatory markers. Sleep was recorded using electroencephalography (EEG) and electromyography (EMG) throughout the experiment.

RESULTS

In vehicle-treated mice, only the combination of sleep disruption followed by social defeat (double hit): (1) increased brief arousals and NREM beta (15-30 Hz) EEG power in sleep immediately post-social defeat compared to baseline; (2) induced an increase in the proportion of rapid-eye-movement (REM) sleep and number of state shifts for at least 5 days post-social defeat; and (3) induced hyperlocomotion and lack of habituation in the OLM task. Immunization with MV prevented most of these sleep and behavioral changes.

CONCLUSIONS

Immunization with MV ameliorates a stress-induced sleep and behavioral phenotype that shares features with human posttraumatic stress disorder.

Objective REM sleep characteristics of recurrent isolated sleep paralysis: a case-control study

STUDY OBJECTIVES

Recurrent isolated sleep paralysis (RISP) is a rapid eye movement (REM) parasomnia characterized by a dissociative state with characteristics of REM sleep and wakefulness. Pathophysiology has not yet been clarified and very little research has been performed using objective polysomnographic measures with inconsistent results. The main aim of our study was to find whether higher REM sleep fragmentation is consistent with the theory of state dissociation or whether signs of dissociation can be detected by spectral analysis.

METHODS

Nineteen participants in the RISP group and 19 age- and gender-matched participants in the control group underwent two consecutive full-night video-polysomnography recordings with 19-channel electroencephalography. Apart from sleep macrostructure, other REM sleep characteristics such as REM arousal index, percentage of wakefulness and stage shifts within REM sleep period were analyzed, as well as power spectral analysis during REM sleep.

RESULTS

No difference was found in the macrostructural parameters of REM sleep (percentage of REM sleep and REM latency). Similarly, no significant difference was detected in REM sleep fragmentation (assessed by REM sleep arousal index, percentage of wakefulness and stage shifts within REM sleep). Power spectral analysis showed higher bifrontal beta activity in the RISP group during REM sleep.

CONCLUSIONS

The results showed an underlying persistent trait of higher cortical activity that may predispose patients with SP to be more likely to experience recurrent episodes, without any apparent macrostructural features including higher REM sleep fragmentation.

Sources of Sleep Disturbances and Psychological Strain for Hospital Staff Working during the COVID-19 Pandemic

Hospital staff members reported increased stress-related workload when caring for inpatients with COVID-19 (“frontline hospital staff members”). Here, we tested if depression, anxiety, and stress were associated with poor sleep and lower general health, and if social support mediated these associations. Furthermore, we compared current insomnia scores and general health scores with normative data. A total of 321 full-time frontline hospital staff members (mean age: 36.86; 58% females) took part in the study during the COVID-19 pandemic. They completed a series of questionnaires covering demographic and work-related information, symptoms of depression, anxiety, stress, social support, self-efficacy, and symptoms of insomnia and general health. Higher symptoms of depression, anxiety, and stress were associated with higher symptoms of insomnia and lower general health. Higher scores of depression, anxiety, and stress directly predicted higher insomnia scores and lower general health scores, while the indirect effect of social support was modest. Compared to normative data, full-time frontline hospital staff members had a 3.14 higher chance to complain about insomnia and a significantly lower general health. Symptoms of insomnia and general health were unrelated to age, job experience, educational level, and gender. Given this background, it appears that the working context had a lower impact on individuals’ well-being compared to individual characteristics.

Maturational trajectories of non-rapid eye movement slow wave activity and odds ratio product in a population-based sample of youth

BACKGROUND

Brain maturation is reflected in the sleep electroencephalogram (EEG) by a decline in non-rapid eye movement (NREM) slow wave activity (SWA) throughout adolescence and a related decrease in sleep depth. However, this trajectory and its sex and pubertal differences lack replication in population-based samples. We tested age-related changes in SWA (0.4-4 Hz) power and odds ratio product (ORP), a standardized measure of sleep depth.

METHODS

We analyzed the sleep EEG of 572 subjects aged 6-21 y (48% female, 26% racial/ethnic minority) and 332 subjects 5-12 y followed-up at 12-22 y. Multivariable-adjusted analyses tested age-related cross-sectional and longitudinal trajectories of SWA and ORP.

RESULTS

SWA remained stable from age 6 to 10, decreased between ages 11 and 17, and plateaued from age 18 to 21 (p-cubic<0.001); females showed a longitudinal decline 23% greater than males by 13 y, while males experienced a steeper slope after 14 y and their longitudinal decline was 21% greater by 19 y. More mature adolescents (75% female) experienced a greater longitudinal decline in SWA than less mature adolescents by 14 y. ORP showed an age-related increasing trajectory (p-linear<0.001) with no sex or pubertal differences.

CONCLUSIONS

We provide population-level evidence for the maturational decline and sex and pubertal differences in SWA in the transition from childhood to adolescence, while introducing ORP as a novel metric in youth. Along with previous studies, the distinct trajectories observed suggest that age-related changes in SWA reflect brain maturation and local/synaptic processes during this developmental period, while those of ORP may reflect global/state control of NREM sleep depth.

Sleep structure and electroencephalographic spectral power of middle-aged or older adults: Normative values by age and sex in the Korean population

The fine structure of sleep electrocortical activity reflects health and disease. The current study provides normative data for sleep structure and electroencephalography (EEG) spectral power measures derived from overnight polysomnography (PSG) and examines the effect of age and sex among Korean middle-aged and older adults with or without obstructive sleep apnea (OSA). We analysed home PSG data from 1,153 adult participants of an ongoing population-based cohort study, the Korean Genome and Epidemiology Study. Sleep stages were visually scored and spectral power was measured on a single-channel EEG (C4-A1). We computed spectral power for five frequency ranges. The EEG power was reported in relative (%) and log-transformed absolute values (µV² ). With ageing, the proportion of N1 sleep increased, whereas N3 decreased, which is more noticeable in men than in women. The amount of N3 was relatively low in this cohort. With ageing, relative delta power decreased and alpha and sigma power increased for the whole sleep period, which was more pronounced during REM sleep in non-OSA. For men compared with women, relative theta power was lower during REM and sigma and beta were higher during N1 sleep. The differences of relative powers by age and sex in OSA were comparable to those in non-OSA. In a community-based Korean population, we present normative data of sleep structure and spectral power for middle-aged or older adults of a non-Caucasian ethnicity. The values varied with age and sex and were not influenced by sleep apnea.