Alterations of pain pathways by experimental sleep disturbances in humans: central pain-inhibitory, cyclooxygenase, and endocannabinoid pathways

STUDY OBJECTIVES

There is strong evidence that sleep disturbances are an independent risk factor for the development of chronic pain conditions. The mechanisms underlying this association, however, are still not well understood. We examined the effect of experimental sleep disturbances (ESDs) on three pathways involved in pain initiation/resolution: (1) the central pain-inhibitory pathway, (2) the cyclooxygenase (COX) pathway, and (3) the endocannabinoid (eCB) pathway.

METHODS

Twenty-four healthy participants (50% females) underwent two 19-day long in-laboratory protocols in randomized order: (1) an ESD protocol consisting of repeated nights of short and disrupted sleep with intermittent recovery sleep; and (2) a sleep control protocol consisting of nights with an 8-hour sleep opportunity. Pain inhibition (conditioned pain modulation, habituation to repeated pain), COX-2 expression at monocyte level (lipopolysaccharide [LPS]-stimulated and spontaneous), and eCBs (arachidonoylethanolamine, 2-arachidonoylglycerol, docosahexaenoylethanolamide [DHEA], eicosapentaenoylethanolamide, docosatetraenoylethanolamide) were measured every other day throughout the protocol.

RESULTS

The central pain-inhibitory pathway was compromised by sleep disturbances in females, but not in males (p < 0.05 condition × sex effect). The COX-2 pathway (LPS-stimulated) was activated by sleep disturbances (p < 0.05 condition effect), and this effect was exclusively driven by males (p < 0.05 condition × sex effect). With respect to the eCB pathway, DHEA was higher (p < 0.05 condition effect) in the sleep disturbance compared to the control condition, without sex-differential effects on any eCBs.

CONCLUSIONS

These findings suggest that central pain-inhibitory and COX mechanisms through which sleep disturbances may contribute to chronic pain risk are sex specific, implicating the need for sex-differential therapeutic targets to effectively reduce chronic pain associated with sleep disturbances in both sexes.

CLINICAL TRIALS REGISTRATION

NCT02484742: Pain Sensitization and Habituation in a Model of Experimentally-induced Insomnia Symptoms. https://clinicaltrials.gov/ct2/show/NCT02484742.

Treatment-related changes in insomnia, anticipatory pleasure, and depression symptoms: A proof-of-concept study with cancer survivors

OBJECTIVE/BACKGROUND

Cancer survivors have elevated rates of insomnia and depression. Insomnia increases risk for depression onset, and the Integrated Sleep and Reward (ISR) Model suggests that impairments in reward responding (e.g., ability to anticipate and/or experience pleasure) plays a central role in this relationship. Cognitive behavioral therapy for insomnia (CBT-I) is efficacious for treating chronic insomnia and reducing depression in cancer survivor populations. The effects of CBT-I on anticipatory and consummatory pleasure are theoretically and clinically meaningful, yet remain unexamined.

PATIENTS/METHODS

This secondary analysis of a pilot RCT (N = 40 cancer survivors with insomnia) explicated changes in anticipatory and consummatory pleasure and depression symptoms following a 4-session, synchronous, virtual CBT-I program versus enhanced usual care (referral to a behavioral sleep medicine clinic + sleep hygiene handout). Linear mixed models examined changes in anticipatory and consummatory pleasure and depression symptoms as predictors of changes in insomnia severity from baseline to post-intervention and 1-month follow-up.

RESULTS

CBT-I buffered against deterioration in anticipatory pleasure but not consummatory pleasure or depression symptoms. Across conditions, increased anticipatory pleasure was associated with insomnia reduction through 1-month follow-up, even after adjusting for changes in depression symptoms.

CONCLUSION

CBT-I may improve reward processing deficits in cancer survivors with insomnia. Findings provide support for the ISR Model and implicate pleasure as an important target for insomnia and depression.

Dismantling the Component-Specific Effects of Yogic Breathing: Feasibility of a Fully Remote Three-Arm RCT with Virtual Laboratory Visits and Wearable Physiology

Despite the growing research base examining the benefits and physiological mechanisms of slow-paced breathing (SPB), mindfulness (M), and their combination (as yogic breathing, SPB + M), no studies have directly compared these in a "dismantling" framework. To address this gap, we conducted a fully remote three-armed feasibility study with wearable devices and video-based laboratory visits. Eighteen healthy participants (age 18-30 years, 12 female) were randomized to one of three 8-week interventions: slow-paced breathing (SPB, N = 5), mindfulness (M, N = 6), or yogic breathing (SPB + M, N = 7). The participants began a 24-h heart rate recording with a chest-worn device prior to the first virtual laboratory visit, consisting of a 60-min intervention-specific training with guided practice and experimental stress induction using a Stroop test. The participants were then instructed to repeat their assigned intervention practice daily with a guided audio, while concurrently recording their heart rate data and completing a detailed practice log. The feasibility was determined using the rates of overall study completion (100%), daily practice adherence (73%), and the rate of fully analyzable data from virtual laboratory visits (92%). These results demonstrate feasibility for conducting larger trial studies with a similar fully remote framework, enhancing the ecological validity and sample size that could be possible with such research designs.

Improvements in well-being and cardiac metrics of stress following a yogic breathing workshop: Randomized controlled trial with active comparison

ObjectiveCompare two distinct psychosocial stress-management workshops.ParticipantsUndergraduate and graduate students (n = 69 for analysis, completed April 2017).MethodsParticipants were randomized to one of two workshops (Sudarshan Kriya Yoga, SKY; Wisdom On Wellness, WOW), matched in terms of duration, group size, etc. Outcomes were questionnaires and psychophysiological response to laboratory stress induction at pre, post, and 3-month follow-up.ResultsSKY and WOW participants demonstrated similar workshop ratings and retention rates. SKY demonstrated greater improvements on a number of self-report measures relative to WOW, including perceived stress, sleep, social connectedness, distress, anxiety, depression, conscientiousness, self-esteem, and life satisfaction. Both groups improved in terms of heart rate measures of stress reactivity, however, these outcomes were partially related to changes in resting values at post-workshop and follow-up.ConclusionsThese findings offer insight into unique patterns of change between yogic breathing, acceptance-based approaches to stress management versus cognitively based approaches.

Differential effects of an experimental model of prolonged sleep disturbance on inflammation in healthy females and males

Sleep disturbances, including disrupted sleep and short sleep duration, are highly prevalent and are prospectively associated with an increased risk for various widespread diseases, including cardiometabolic, neurodegenerative, chronic pain, and autoimmune diseases. Systemic inflammation, which has been observed in populations experiencing sleep disturbances, may mechanistically link disturbed sleep with increased disease risks. To determine whether sleep disturbances are causally responsible for the inflammatory changes reported in population-based studies, we developed a 19-day in-hospital experimental model of prolonged sleep disturbance inducing disrupted and shortened sleep. The model included delayed sleep onset, frequent nighttime awakenings, and advanced sleep offset, interspersed with intermittent nights of undisturbed sleep. This pattern aimed at providing an ecologically highly valid experimental model of the typical sleep disturbances often reported in the general and patient populations. Unexpectedly, the experimental sleep disturbance model reduced several of the assessed proinflammatory markers, namely interleukin(IL)-6 production by monocytes and plasma levels of IL-6 and C-reactive protein (CRP), presumably due to intermittent increases in the counterinflammatory hormone cortisol. Striking sex differences were observed with females presenting a reduction in proinflammatory markers and males showing a predominantly proinflammatory response and reductions of cortisol levels. Our findings indicate that sleep disturbances causally dysregulate inflammatory pathways, with opposing effects in females and males. These results have the potential to advance our mechanistic understanding of the pronounced sexual dimorphism in the many diseases for which sleep disturbances are a risk factor.

Diagnostic and public health investigation of Mycobacterium tuberculosis infection in a dog in Ontario, Canada

A 4-y-old, female mixed-breed dog was presented to the Ontario Veterinary College for further evaluation of multiple pulmonary and hepatic masses, intrathoracic lymphadenitis, and recent development of a pyogranulomatous pleural effusion. Along with other comprehensive tests, a thoracic lymph node biopsy was performed, and Mycobacterium tuberculosis complex infection was confirmed by real-time PCR. The dog’s condition declined post-operatively, and euthanasia was elected. Postmortem examination confirmed severe granulomatous pneumonia, hepatitis, intrathoracic and intraabdominal lymphadenitis, omentitis, and nephritis. Line-probe assays performed on samples collected postmortem confirmed the species as M. tuberculosis. 24-loci MIRU-VNTR genotyping, spoligotyping, and whole-genome sequencing revealed relations to known human isolates, but no epidemiologic link to these cases was investigated. Given the concern for potential human exposure during this animal’s disease course, a public health investigation was initiated; 45 individuals were tested for M. tuberculosis exposure, and no subsequent human infections related to this animal were identified. Our case highlights the need for more readily available, minimally invasive testing for the diagnosis of canine mycobacteriosis, and highlights the ability of canid species to act as potential contributors to the epidemiology of M. tuberculosis infections.

The Survivorship Sleep Program (SSP): A synchronous, virtual cognitive behavioral therapy for insomnia pilot program among cancer survivors

BACKGROUND

For cancer survivors, insomnia is prevalent, distressing, and persists for years if unmanaged. Cognitive behavioral therapy for insomnia (CBT-I) is an effective treatment yet can be difficult to access and may require modification to address survivorship-specific barriers to sleep. In this 2-phase study, the authors adapted and assessed the feasibility, acceptability, and preliminary effects of synchronous, virtual CBT-I adapted for cancer survivors (the Survivorship Sleep Program [SSP]).

METHODS

From April to August 2020, cancer survivors with insomnia (N = 10) were interviewed to refine SSP content and delivery. From October 2020 to March 2021, 40 survivors were recruited for a randomized controlled trial comparing 4 weekly SSP sessions with enhanced usual care (EUC) (CBT-I referral plus a sleep hygiene handout). Feasibility and acceptability were assessed by enrollment, retention, attendance, fidelity, survey ratings, and exit interviews. Insomnia severity (secondary outcome), sleep quality, sleep diaries, and fatigue were assessed at baseline, postintervention, and at 1-month follow-up using linear mixed models.

RESULTS

The SSP included targeted content and clinician-led, virtual delivery to enhance patient centeredness and access. Benchmarks were met for enrollment (56% enrolled/eligible), retention (SSP, 90%; EUC, 95%), attendance (100%), and fidelity (95%). Compared with EUC, the SSP resulted in large, clinically significant improvements in insomnia severity (Cohen d = 1.19) that were sustained at 1-month follow-up (Cohen d = 1.27). Improvements were observed for all other sleep metrics except sleep diary total sleep time and fatigue.

CONCLUSIONS

Synchronous, virtually delivered CBT-I targeted to cancer survivors is feasible, acceptable, and seems to be efficacious for reducing insomnia severity. Further testing in larger and more diverse samples is warranted.

Profile of subjective-objective sleep discrepancy in patients with insomnia and sleep apnea

STUDY OBJECTIVES

Although subjective-objective sleep discrepancy has long been observed in patients with insomnia, the profiles of this discrepancy are poorly understood. Further, sleep discrepancy in insomnia with sleep comorbidities remains underexplored. We sought to better characterize sleep discrepancy among patient groups with and without insomnia and comorbid conditions such as obstructive sleep apnea (OSA).

METHODS

Using data from the Sleep Heart Health Study, we conducted a secondary analysis describing (1) the profile of self-reported and objective sleep measures in patients with insomnia (IS group; n = 73) and comorbid OSA (IS + OSA group; n = 143), compared with individuals with OSA only (OSA group; n = 296) and normal sleep control patients (NSC group; n = 126); (2) the comparative magnitude of sleep misperception between these 4 groups; and (3) the self-reported quality of life (QOL) in the 4 groups.

RESULTS

Subjective-objective sleep discrepancy existed in all 4 groups, including the NSC group. Controlling for age, sex, mental health conditions, sleep apnea severity, and objectively measured sleep time, the presence of self-reported insomnia had the strongest association with sleep discrepancy. In patients with insomnia, sleep onset latency was overestimated (7.8 ± 36.8 min in the IS group; P < .001 when compared to the NSC and OSA groups), with the largest differences seen in the comorbid IS + OSA group (15.0 ± 56.8 min). Insomnia conferred the most negative impact on QOL, with the combined IS + OSA group reporting the lowest QOL.

CONCLUSIONS

Self-reported insomnia is associated with sleep discrepancy and negative QOL. Those with comorbid OSA reported the greatest sleep discrepancy and the lowest QOL. Future research is warranted to further understand individual profiles of misperception and insomnia phenotypes.

CITATION

Ma Y, Goldstein MR, Davis RB, Yeh GY. Profile of subjective-objective sleep discrepancy in patients with insomnia and sleep apnea. J Clin Sleep Med. 2021;17(11):2155-2163.

Treatment of chronic primary sleep onset insomnia with Kundalini Yoga: a randomized controlled trial with active sleep hygiene comparison

STUDY OBJECTIVES

Prior studies have suggested a benefit of yoga for alleviating sleep disturbance; however, many studies have had methodological limitations. This trial study aimed to extend that literature by including an active sleep hygiene (SH) comparison.

METHODS

Participants aged 25-59 with a primary complaint of sleep onset insomnia lasting at least six months were block randomized to 8-week Kundalini Yoga or SH intervention, both consisting of initial 60-minute instruction and weekly check-ins. Daily sleep diaries and questionnaires were collected at baseline, throughout intervention, and at 6-month follow-up. Data were analyzed using linear mixed models (N=20 in each group).

RESULTS

Participant ratings of the interventions did not significantly differ. SH improved several diary and questionnaire outcomes, however, yoga resulted in even greater improvements corresponding to medium-to-large between-group effect sizes. Total sleep time increased progressively across yoga treatment (d=0.95, p=.002), concurrent with increased sleep efficiency (SE; d=1.36, p<.001) and decreased sleep onset latency (SOL; d=-1.16, p<.001), but without changes in pre-sleep arousal (d=-0.30, p=.59). Remission rates were also higher for yoga compared to SH, with ≥80% of yoga participants reporting average SOL<30 minutes and SE>80% at 6-month follow-up. For over 50% of yoga participants, the insomnia severity index decreased by at least 8 points at end of treatment and follow-up.

CONCLUSIONS

Yoga, taught in a self-care framework with minimal instructor burden, was associated with self-reported improvements above and beyond an active sleep hygiene comparison, sustained at 6-month follow-up. Follow-up studies are needed to assess actigraphy and polysomnography outcomes, as well as possible mechanisms of change.

CLINICAL TRIAL REGISTRATION

Yoga as a Treatment for Insomnia (ClinicalTrials.gov, NCT00033865).

Comparing the Impact of COVID-19-Related Social Distancing on Mood and Psychiatric Indicators in Sexual and Gender Minority (SGM) and Non-SGM Individuals

Empirical evidence demonstrates mental health disparities between sexual and gender minority individuals (SGM) compared with cisgender heterosexual individuals. SGM individuals report elevated rates of emotional distress, symptoms related to mood and anxiety disorders, self-harm, and suicidal ideation and behavior. Social support is inversely related to psychiatric symptoms, regardless of SGM status. The COVID-19 pandemic-with its associated limited social interactions-represents an unprecedented period of acute distress with potential reductions in accessibility of social support, which might be of particular concern for SGM individuals' mental well-being. In the present study, we explored the extent to which potential changes in mental health outcomes (depressive symptoms, worry, perceived stress, positive and negative affect) throughout the duration of the pandemic were related to differences in perceptions of social support and engagement in virtual social activity, as a function of SGM status. Utilizing a large sample of US adults (N = 1,014; 18% reported SGM status), we assessed psychiatric symptoms, perceptions of social isolation, and amount of time spent socializing virtually at 3 time windows during the pandemic (between March 21 and May 21). Although SGM individuals reported greater levels of depression compared with non-SGM individuals at all 3 time points, there was no interaction between time and SGM status. Across all participants, mental health outcomes improved across time. Perceived social isolation was associated with poorer mental health outcomes. Further, time spent engaging in virtual socialization was associated with reduced depression, but only for those in self-reported quarantine. We discuss these results in terms of the nature of our sample and its impact on the generalizability of these findings to other SGM samples as well as directions for future research aimed at understanding potential health disparities in the face of the COVID-19 pandemic.

0233 Pain, Fatigue, and Altered Reactivity to a Repeated Physiological Stressor in Insomnia Patients: An Explanatory-Driven Analysis

Introduction

Fatigue and pain are prominent features of functional impairment in insomnia. This study aimed to better understand behavioral and physiological mechanisms of these complex relationships.

Methods

22 participants with insomnia disorder (DSM-5 criteria, 18 female, age 18-49yrs) and 22 good-sleeper controls (19 female, age 18-47yrs) completed two-weeks sleep logs and actigraphy recordings prior to coming to the laboratory for overnight polysomnography and subsequent daytime testing that included questionnaires, three trials of cold pressor test (CPT), and pain testing with blood draws collected throughout. Insomnia diagnosis was determined by a board-certified sleep specialist, and exclusion criteria included psychiatric history within past 6 months, other sleep disorder, significant medical conditions, and any medications within past two weeks with significant effects on inflammation, autonomic function, or other psychotropic effects. For CPT, participants were instructed to immerse hand in ice cold water for at least one minute and rate pain intensity throughout the immersion and 3-minute recovery. Data were analyzed with linear mixed models.

Results

Per inclusion criteria, PSQI scores were differed between groups (insomnia: 10.2±2.7, range 7–16; control: 1.9±1.3, range 0–5; p&lt;.001). Insomnia consistently reported higher daily fatigue ratings compared to controls (p&lt;.001), as well as higher spontaneous pain globally and across several specific domains (p’s: .007-.03). In response to CPT, groups did not differ in their initial tolerance (i.e. immersion duration, p=.41) or intensity ratings during immersion (p=.88), however insomnia showed blunted recovery in intensity ratings (p&lt;.01). Control participants then showed an ability to habituate to repeated CPT by increasing immersion duration, whereas insomnia slightly decreased in tolerance across trials (Group effect: p&lt;.05).

Conclusion

These data indicate that habituation to and acute recovery from pain is deteriorated in chronic insomnia, which may be a key contributor to maintained pathophysiology over time and mechanism to target with comprehensive treatment.

Support

Merck Inc. MISP# 51971 (investigator-initiated), NIH/National Center for Research Resources UL1-RR02758 and M01-RR01032 to the Harvard Clinical and Translational Science Center.

0279 Fatigue and Pain Responses Across Repeated Exposure to Experimentally Induced Sleep Disturbance and Intermittent Recovery Sleep: Sex Differences

Introduction

Sleep disturbances are more common in women than in men, as are many chronic pain disorders characterized by inflammation and fatigue. This study investigated sex differences in fatigue and pain responses to sleep disruption and whether such responses recover with uninterrupted sleep.

Methods

24 healthy young individuals (12 women; ages 18–42 yrs) participated in a study consisting of two counterbalanced 19-day experimental in-hospital stays, separated by two months. Following 3 baseline nights, participants were exposed to 3 nights of sleep disruption (SD) involving delayed sleep onset, hourly awakenings, and early-morning awakenings without return to sleep, followed by 1 night of recovery sleep. This 4-day cycle was repeated three times and finished with 3 additional nights of recovery sleep. Total sleep opportunity on SD nights was 4 hrs, and on recovery/sleep control (SC) nights was 8 hrs. Light exposure, ambient temperature, food and fluid intake, and physical activity were controlled. Self-reported fatigue and pain, pain sensitivity, and habituation were collected throughout. Data were analyzed with linear mixed models.

Results

For women but not men, fatigue in response to SD recovered incompletely starting after the 2nd sleep disruption-recovery cycle and remained elevated after the final 3 recovery nights in women (p&lt;.05). Additionally, women became more sensitive to pressure pain in response to SD (p&lt;.001) with incomplete return to baseline after the final 3 recovery nights. Whereas men habituated to cold pain across SC and even more so across SD (p=.045 Day, p=.021), women did not habituate.

Conclusion

These results indicate that incomplete recovery in both fatigue and pressure pain, alongside a lack of habituation to cold pain, in response to sleep disruption may explain the common co-occurrence of insomnia, fatigue, and pain observed as more prevalent in women.

Support

NIH/NINDS R01-NS091177; NIH/National Center for Research Resources UL1-RR02758 and M01-RR01032 to the Harvard Clinical and Translational Science Center.

Establishing the objective sleep phenotype in hypersomnolence disorder with and without comorbid major depression

STUDY OBJECTIVES

To clarify whether hypersomnolence disorder is associated with a specific sleep phenotype and altered neurophysiological function in persons with and without hypersomnolence disorder and major depressive disorder (MDD).

METHODS

Eighty-three unmedicated persons with and without hypersomnolence disorder and/or MDD underwent ad libitum high-density EEG polysomnography. Clinical and sleep architecture variables were compared between groups. Topographic patterns of slow-wave activity (SWA) relative to healthy controls were compared, with correlations between topographic SWA and daytime sleepiness assessed. Reductions in SWA in hypersomnolence disorder were mapped to specific cortical areas using source localization.

RESULTS

Regardless of the presence or absence of comorbid MDD, persons with hypersomnolence disorder had increased sleep duration relative to both controls and persons with MDD without hypersomnolence. Participants with hypersomnolence disorder also demonstrated reduced bilateral centroparietal low-frequency activity during nonrapid eye movement sleep relative to controls, a pattern not observed in persons with MDD but without hypersomnolence. SWA in these regions was negatively correlated with subjective measures of daytime sleepiness. Source localization demonstrated reductions in SWA in the supramarginal gyrus, somatosensory, and transverse temporal cortex in participants with hypersomnolence disorder.

CONCLUSIONS

Hypersomnolence disorder is characterized by increased sleep duration with normal sleep continuity, regardless of the presence or absence of comorbid depression. Reduced local SWA may be a specific neurophysiological finding in hypersomnolence disorder. Further research is warranted to elucidate the mechanisms through which these cortical changes are related to clinical complaints of daytime sleepiness.

Increased high-frequency NREM EEG power associated with mindfulness-based interventions for chronic insomnia: Preliminary findings from spectral analysis

OBJECTIVE

Mindfulness-based interventions (MBI) have been shown to reduce subjective symptoms of insomnia but the effects on objective measures remain unclear. The purpose of this study was to examine sleep EEG microarchitecture patterns from a randomized controlled trial of Mindfulness-Based Stress Reduction (MBSR) and Mindfulness-Based Therapy for Insomnia (MBTI).

METHODS

Sleep EEG spectral analysis was conducted on 36 participants with chronic insomnia (>6 months) randomized to 8-week MBSR, MBTI, or self-monitoring control (SM). Overnight polysomnography with 6-channel EEG was conducted at baseline, post-treatment, and 6-month follow-up. Spectral power averaged from channels C3/C4 across NREM epochs (excluding N1) was examined for within-group changes and relationships with self-report measures.

RESULTS

Increases in absolute NREM beta (16-25 Hz) power were observed from baseline to post-treatment (p = .02, d = 0.53) and maintained at 6-month follow-up (p = .01, d = 0.57) in the combined MBI groups, and additionally in the gamma (25-40 Hz) range at follow-up for the MBTI group only. No significant changes in these frequency bands were observed for SM. Following mindfulness intervention, NREM beta was positively associated with Five-Facet Mindfulness (FFM) score (rho = 0.37, p = .091) and negatively associated with Insomnia Severity Index (rho = -0.43, p = .047).

CONCLUSION

These results in people with insomnia corroborate prior reports of increased high-frequency sleep EEG power associated with mindfulness training. This change in beta EEG pattern merits further evaluation as a potential marker of the effects of mindfulness meditation on sleep, especially given the paradoxical findings in the context of insomnia.

CLINICAL TRIAL REGISTRATION

clinicaltrials.gov, NCT00768781.

Objective measures of sleep duration and continuity in major depressive disorder with comorbid hypersomnolence: a primary investigation with contiguous systematic review and meta-analysis

Hypersomnolence plays an important role in the presentation, treatment and course of mood disorders. However, there has been relatively little research that examines objective measures of sleep duration and continuity in patients with depression and hypersomnolence, despite the use of these factors in sleep medicine nosological systems. This study compared total sleep time and efficiency measured by naturalistic actigraphic recordings followed by ad libitum polysomnography (PSG; without prescribed wake time) in 22 patients with major depressive disorder and co-occurring hypersomnolence against age- and sex-matched healthy sleeper controls. The major depressive disorder and co-occurring hypersomnolence group demonstrated significantly longer sleep duration compared with healthy sleeper controls quantified by sleep diaries, actigraphy and ad libitum PSG. No between-group differences in sleep efficiency (SE), latency to sleep or wake after sleep onset were observed when assessed using objective measures. To further contextualize these findings within the broader scientific literature, a systematic review was performed to identify other comparable investigations. A meta-analysis of pooled data demonstrated patients with mood disorders and co-occurring hypersomnolence have significantly greater sleep duration and similar SE compared with healthy controls when assessed using ad libitum PSG. These results suggest current sleep medicine nosology that distinguishes hypersomnia associated with psychiatric disorders primarily as a construct characterized by low SE and increased time in bed may not be accurate. Future studies that establish the biological bases hypersomnolence in mood disorders, as well as clarify the accuracy of nosological thresholds to define excessive sleep duration, are needed to refine the diagnosis and treatment of these disorders.

Sleep confers a benefit for retention of statistical language learning in 6.5month old infants

Infants show robust ability to track transitional probabilities within language and can use this information to extract words from continuous speech. The degree to which infants remember these words across a delay is unknown. Given well-established benefits of sleep on long-term memory retention in adults, we examine whether sleep similarly facilitates memory in 6.5month olds. Infants listened to an artificial language for 7minutes, followed by a period of sleep or wakefulness. After a time-matched delay for sleep and wakefulness dyads, we measured retention using the head-turn-preference procedure. Infants who slept retained memory for the extracted words that was prone to interference during the test. Infants who remained awake showed no retention. Within the nap group, retention correlated with three electrophysiological measures (1) absolute theta across the brain, (2) absolute alpha across the brain, and (3) greater fronto-central slow wave activity (SWA).

Regional Patterns of Elevated Alpha and High-Frequency Electroencephalographic Activity during Nonrapid Eye Movement Sleep in Chronic Insomnia: A Pilot Study

STUDY OBJECTIVES

To examine nonrapid eye movement (NREM) sleep in insomnia using high-density electroencephalography (EEG).

METHODS

All-night sleep recordings with 256 channel high-density EEG were analyzed for 8 insomnia subjects (5 females) and 8 sex and age-matched controls without sleep complaints. Spectral analyses were conducted using unpaired t-tests and topographical differences between groups were assessed using statistical non-parametric mapping. Five minute segments of deep NREM sleep were further analyzed using sLORETA cortical source imaging.

RESULTS

The initial topographic analysis of all-night NREM sleep EEG revealed that insomnia subjects had more high-frequency EEG activity (> 16 Hz) compared to good sleeping controls and that the difference between groups was widespread across the scalp. In addition, the analysis also showed that there was a more circumscribed difference in theta (4-8 Hz) and alpha (8-12 Hz) power bands between groups. When deep NREM sleep (N3) was examined separately, the high-frequency difference between groups diminished, whereas the higher regional alpha activity in insomnia subjects persisted. Source imaging analysis demonstrated that sensory and sensorimotor cortical areas consistently exhibited elevated levels of alpha activity during deep NREM sleep in insomnia subjects relative to good sleeping controls.

CONCLUSIONS

These results suggest that even during the deepest stage of sleep, sensory and sensorimotor areas in insomnia subjects may still be relatively active compared to control subjects and to the rest of the sleeping brain.

Improvements in well-being and vagal tone following a yogic breathing-based life skills workshop in young adults: Two open-trial pilot studies

Background:

While efficacy of Sudarshan Kriya Yoga (SKY) has been demonstrated in a number of prior studies, little is known about the effects of SKY taught as part of the Your Enlightened Side (YES+) workshop designed for college students and other young adults.

Aims:

This study aimed to assess the effects of YES+, a yogic breathing-based life skills workshop, on multiple measures of well-being and physiological stress response.

Materials and Methods:

Two nonrandomized open-trial pilot studies were conducted with a total of 74 young adults (age 25.4 ± 6.6 years; 55% female). Study 1 collected a variety of self-report questionnaires at baseline, postworkshop, and 1-month follow-up. Study 2 collected self-report questionnaires in addition to electrocardiography with a stationary cycling challenge at baseline and 1-month follow-up.

Results:

Study 1: Improvements in self-reported depression (P's ≤ 0.010), perceived stress (P's ≤ 0.002), life satisfaction (P's ≤ 0.002), social connectedness (P's ≤ 0.004), and gratitude (P's ≤ 0.090) were observed at postworkshop and 1-month after workshop relative to baseline. Study 2: Improvements in self-reported emotion regulation were observed at 1-month follow-up relative to baseline (P = 0.019). Positive and Negative Affect Schedule-Expanded Form positive affect increased (P = 0.021), while fatigue and sadness decreased (P's ≤ 0.005). During the stationary cycling challenge, rate to recovery of electrocardiography inter-beat interval also increased from baseline to 1-month follow-up (P = 0.077).

Conclusions:

These findings suggest that a life skills workshop integrating yogic breathing techniques may provide self-empowering tools for enhancing well-being in young adults. Future research is indicated to further explore these effects, particularly in regards to vagal tone and other aspects of stress physiology.

Effects of oral temazepam on slow waves during non-rapid eye movement sleep in healthy young adults: A high-density EEG investigation

Slow waves are characteristic waveforms that occur during non-rapid eye movement (NREM) sleep that play an integral role in sleep quality and brain plasticity. Benzodiazepines are commonly used medications that alter slow waves, however, their effects may depend on the time of night and measure used to characterize slow waves. Prior investigations have utilized minimal scalp derivations to evaluate the effects of benzodiazepines on slow waves, and thus the topography of changes to slow waves induced by benzodiazepines has yet to be fully elucidated. This study used high-density electroencephalography (hdEEG) to evaluate the effects of oral temazepam on slow wave activity, incidence, and morphology during NREM sleep in 18 healthy adults relative to placebo. Temazepam was associated with significant decreases in slow wave activity and incidence, which were most prominent in the latter portions of the sleep period. However, temazepam was also associated with a decrease in the magnitude of high-amplitude slow waves and their slopes in the first NREM sleep episode, which was most prominent in frontal derivations. These findings suggest that benzodiazepines produce changes in slow waves throughout the night that vary depending on cortical topography and measures used to characterize slow waves. Further research that explores the relationships between benzodiazepine-induced changes to slow waves and the functional effects of these waveforms is indicated.

The 5α-reductase inhibitor finasteride is not associated with alterations in sleep spindles in men referred for polysomnography

OBJECTIVE

Endogenous neurosteroids that potentiate the gamma-aminobutyric acid type A (GABAA ) receptor are thought to enhance the generation of sleep spindles. This study tested the hypothesis that the 5α-reductase inhibitor finasteride, an agent associated with reductions in neurosteroids, would be associated with reduced sleep spindles in men referred for polysomnography.

METHODS

Spectral analysis and spindle waveform detection were performed on electroencephalographic (EEG) sleep data in the 11-16 Hz sigma band, as well as several subranges, from 27 men taking finasteride and 27 matched comparison patients (ages 18 to 81 years).

RESULTS

No significant differences between groups were observed for spectral power or sleep spindle morphology measures, including spindle density, amplitude, duration, and integrated spindle activity.

CONCLUSIONS

Contrary to our hypothesis, these findings demonstrate that finasteride is not associated with alterations in sleep spindle range activity or spindle morphology parameters.

Effects of partial sleep deprivation on slow waves during non-rapid eye movement sleep: A high density EEG investigation

OBJECTIVE

Changes in slow waves during non-rapid eye movement (NREM) sleep in response to acute total sleep deprivation are well-established measures of sleep homeostasis. This investigation utilized high-density electroencephalography (hdEEG) to examine topographic changes in slow waves during repeated partial sleep deprivation.

METHODS

Twenty-four participants underwent a 6-day sleep restriction protocol. Spectral and period-amplitude analyses of sleep hdEEG data were used to examine changes in slow wave energy, count, amplitude, and slope relative to baseline.

RESULTS

Changes in slow wave energy were dependent on the quantity of NREM sleep utilized for analysis, with widespread increases during sleep restriction and recovery when comparing data from the first portion of the sleep period, but restricted to recovery sleep if the entire sleep episode was considered. Period-amplitude analysis was less dependent on the quantity of NREM sleep utilized, and demonstrated topographic changes in the count, amplitude, and distribution of slow waves, with frontal increases in slow wave amplitude, numbers of high-amplitude waves, and amplitude/slopes of low amplitude waves resulting from partial sleep deprivation.

CONCLUSIONS

Topographic changes in slow waves occur across the course of partial sleep restriction and recovery.

SIGNIFICANCE

These results demonstrate a homeostatic response to partial sleep loss in humans.

Topographic deficits in alpha-range resting EEG activity and steady state visual evoked responses in schizophrenia

Deficits in both resting alpha-range (8-12Hz) electroencephalogram (EEG) activity and steady state evoked potential (SSVEP) responses have been reported in schizophrenia. However, the topographic specificity of these effects, the relationship between resting EEG and SSVEP, as well as the impact of antipsychotic medication on these effects, have not been clearly delineated. The present study sought to address these questions with 256 channel high-density EEG recordings in a group of 13 schizophrenia patients, 13 healthy controls, and 10 non-schizophrenia patients with psychiatric diagnoses currently taking antipsychotic medication. At rest, the schizophrenia group demonstrated decreased alpha EEG power in frontal and occipital areas relative to healthy controls. With SSVEP stimulation centered in the alpha band (10Hz), but not with stimulation above (15Hz) or below (7Hz) this range, the occipital deficit in alpha power was partially reverted. However, the frontal deficit persisted and contributed to a significantly reduced topographic relationship between occipital and frontal alpha activity for resting EEG and 10Hz SSVEP alpha power in schizophrenia patients. No significant differences were observed between healthy and medicated controls or between medicated controls and schizophrenia. These findings suggest a potential intrinsic deficit in frontal eyes-closed EEG alpha oscillations in schizophrenia, whereby potent visual stimulation centered in that frequency range results in an increase in the occipital alpha power of these patients, which however does not extend to frontal regions. Future research to evaluate the cortical and subcortical mechanisms of these effects is warranted.

Effects of oral temazepam on sleep spindles during non-rapid eye movement sleep: A high-density EEG investigation

Benzodiazepines are commonly used medications that alter sleep spindles during non-rapid eye movement (NREM) sleep, however the topographic changes to these functionally significant waveforms have yet to be fully elucidated. This study utilized high-density electroencephalography (hdEEG) to investigate topographic changes in sleep spindles and spindle-range activity caused by temazepam during NREM sleep in 18 healthy adults. After an accommodation night, sleep for all participants was recorded on two separate nights after taking either placebo or oral temazepam 15 mg. Sleep was monitored using 256-channel hdEEG. Spectral analysis and spindle waveform detection of sleep EEG data were performed for each participant night. Global and topographic data were subsequently compared between temazepam and placebo conditions. Temazepam was associated with significant increases in spectral power from 10.33 to 13.83 Hz. Within this frequency band, temazepam broadly increased sleep spindle duration, and topographically increased spindle amplitude and density in frontal and central-posterior regions, respectively. Higher frequency sleep spindles demonstrated increased spindle amplitude and a paradoxical decrease in spindle density in frontal and centroparietal regions. Further analysis demonstrated temazepam both slowed the average frequency of spindle waveforms and increased the relative proportion of spindles at peak frequencies in frontal and centroparietal regions. These findings suggest that benzodiazepines have diverse effects on sleep spindles that vary by frequency and cortical topography. Further research that explores the relationships between topographic and frequency-dependent changes in pharmacologically-induced sleep spindles and the functional effects of these waveforms is indicated.

Breathing-based meditation decreases posttraumatic stress disorder symptoms in U.S. military veterans: a randomized controlled longitudinal study

Given the limited success of conventional treatments for veterans with posttraumatic stress disorder (PTSD), investigations of alternative approaches are warranted. We examined the effects of a breathing-based meditation intervention, Sudarshan Kriya yoga, on PTSD outcome variables in U.S. male veterans of the Iraq or Afghanistan war. We randomly assigned 21 veterans to an active (n = 11) or waitlist control (n = 10) group. Laboratory measures of eye-blink startle and respiration rate were obtained before and after the intervention, as were self-report symptom measures; the latter were also obtained 1 month and 1 year later. The active group showed reductions in PTSD scores, d = 1.16, 95% CI [0.20, 2.04], anxiety symptoms, and respiration rate, but the control group did not. Reductions in startle correlated with reductions in hyperarousal symptoms immediately postintervention (r = .93, p < .001) and at 1-year follow-up (r = .77, p = .025). This longitudinal intervention study suggests there may be clinical utility for Sudarshan Kriya yoga for PTSD.

Medroxyprogesterone acetate is associated with increased sleep spindles during non-rapid eye movement sleep in women referred for polysomnography

Sleep spindles are characteristic electroencephalographic waveforms that may play functionally significant roles in sleep-dependent memory consolidation, cortical development, and neuropsychiatric disorders. Circumstantial evidence has connected endogenous progesterone and its metabolites to the production of sleep spindles; however, the effects of exogenous progestins on sleep spindles have not been described in women. We examined differences in sleep spindle frequency and morphology in a clinical sample of women (n=21) referred for polysomnography taking depot medroxyprogesterone acetate (MPA), relative to a matched comparison group. Consistent with our hypotheses, women taking MPA demonstrated significantly higher sleep spindle density and maximal amplitude relative to comparison patients. Our results suggest that progestins potentiate the generation of sleep spindles, which may have significant implications for research that examines the role of these waveforms in learning, development, and mental illness.

Might the beneficial effects of statin drugs be related to their action on iron metabolism?

Although the cholesterol-heart hypothesis is often regarded as a dogmatic belief, controversy continues to surround the aetiology and pathogenesis of atherosclerosis. In fact, lowering cholesterol with statin drugs has been shown to reduce cardiovascular risk. However, statins have pleiotropic effects independent of their capacity to lower cholesterol. We highlight that statin drugs exert an important action on iron metabolism, which in turn may prevent progression and destabilization of atherosclerotic plaque. If it is found that the effect of statins on iron metabolism is a mechanism of their beneficial action, this consequence of statin use can be clinically replicated by other methods, such as controlled reduction of body iron stores. This might allow the use of lower doses or even obviate the use of statins in primary cardiovascular prevention, and therefore avoid the side effects and expense of these drugs.

Detection and characterization of Clostridium perfringens in the feces of healthy and diarrheic dogs

Clostridium perfringens has been implicated as a cause of diarrhea in dogs. The objectives of this study were to compare 2 culture methods and to evaluate a multiplex polymerase chain reaction (PCR) assay to detect C. perfringens toxin genes alpha (α), beta (β ), beta 2 (β2), epsilon (ɛ), iota (ι), and C. perfringens enterotoxin (cpe) from canine isolates. Fecal samples were collected from clinically normal non-diarrheic (ND) dogs, (n = 105) and diarrheic dogs (DD, n = 54). Clostridium perfringens was isolated by directly inoculating stool onto 5% sheep blood agar (SBA) and enrichment in brain-heart infusion (BHI) broth, followed by inoculation onto SBA. Isolates were tested by multiplex PCR for the presence of α, β, β2, ɛ, ι, and cpe genes. C. perfringens was isolated from 84% of ND samples using direct culture and from 87.6% with enrichment (P = 0.79). In the DD group, corresponding isolation rates were 90.7% and 93.8% (P = 0.65). All isolates possessed the α toxin gene. Beta (β), β2, ɛ, ι, and cpe toxin genes were identified in 4.5%, 1.1%, 3.4%, 1.1%, and 14.8% of ND isolates, respectively. In the DD group, β and β2 were identified in 5%, ɛ and ι were not identified, and the cpe gene was identified in 16.9% of isolates. Enrichment with BHI broth did not significantly increase the yield of C. perfringens, but it did increase the time and cost of the procedure. C. perfringens toxin genes were present in equal proportions in both the ND and DD groups (P ≤ 0.15 to 0.6). Within the parameters of this study, culture of C. perfringens and PCR for toxin genes is of limited diagnostic usefulness due to its high prevalence in normal dogs and the lack of apparent difference in the distribution of toxin genes between normal and diarrheic dogs.

Overnight changes in waking auditory evoked potential amplitude reflect altered sleep homeostasis in major depression

OBJECTIVE

Sleep homeostasis is altered in major depressive disorder (MDD). Pre- to postsleep decline in waking auditory evoked potential (AEP) amplitude has been correlated with sleep slow wave activity (SWA), suggesting that overnight changes in waking AEP amplitude are homeostatically regulated in healthy individuals. This study investigated whether the overnight change in waking AEP amplitude and its relation to SWA is altered in MDD.

METHOD

Using 256-channel high-density electroencephalography, all-night sleep polysomnography and single-tone waking AEPs pre- and postsleep were collected in 15 healthy controls (HC) and 15 non-medicated individuals with MDD.

RESULTS

N1 and P2 amplitudes of the waking AEP declined after sleep in the HC group, but not in MDD. The reduction in N1 amplitude also correlated with fronto-central SWA in the HC group, but a comparable relationship was not found in MDD, despite equivalent SWA between groups. No pre- to postsleep differences were found for N1 or P2 latencies in either group. These findings were not confounded by varying levels of alertness or differences in sleep variables between groups.

CONCLUSION

MDD involves altered sleep homeostasis as measured by the overnight change in waking AEP amplitude. Future research is required to determine the clinical implications of these findings.

Prevention of postpartum smoking relapse in mothers of infants in the neonatal intensive care unit

OBJECTIVE

Approximately 40% of women who smoke tobacco quit smoking during pregnancy, yet up to 85% relapse after delivery. Those who resume smoking often do so by 2 to 8 weeks postpartum. Smoking mothers are more than twice as likely to quit breastfeeding by 10 weeks postpartum. The hospitalization of a newborn, while stressful, is an opportunity to emphasize the importance of a smoke-free environment for babies. Supporting maternal-infant bonding may reduce maternal stress and motivate mothers to remain smoke free and continue breastfeeding. The objective of this study was to reduce postpartum smoking relapse and prolong breastfeeding duration during the first 8 weeks postpartum in mothers who quit smoking just before or during pregnancy and have newborns admitted to the Neonatal Intensive Care Unit (NICU).

STUDY DESIGN

This study was an Institutional Review Board-approved prospective randomized clinical trial. After informed consent, mothers of newborns admitted to the NICU were randomized to a control or intervention group. Both groups received weekly encouragement to remain smoke free and routine breastfeeding support. Mothers in the intervention group were also given enhanced support for maternal-infant bonding including information about newborn behaviors, and were encouraged to frequently hold their babies skin-to-skin.

RESULT

More mothers were smoke free (81 vs 46%, P<0.001) and breastfeeding (86 vs 21%, P<0.001) in the intervention than in the control group at 8 weeks postpartum.

CONCLUSION

Interventions to support mother-infant bonding during a newborn's hospitalization in the NICU are associated with reduced rates of smoking relapse and prolonged duration of breastfeeding during the first 8 weeks postpartum.

Altered slow wave activity in major depressive disorder with hypersomnia: a high density EEG pilot study

Hypersomnolence in major depressive disorder (MDD) plays an important role in the natural history of the disorder, but the basis of hypersomnia in MDD is poorly understood. Slow wave activity (SWA) has been associated with sleep homeostasis, as well as sleep restoration and maintenance, and may be altered in MDD. Therefore, we conducted a post-hoc study that utilized high density electroencephalography (hdEEG) to test the hypothesis that MDD subjects with hypersomnia (HYS+) would have decreased SWA relative to age- and sex-matched MDD subjects without hypersomnia (HYS-) and healthy controls (n=7 for each group). After correction for multiple comparisons using statistical non-parametric mapping, HYS+ subjects demonstrated significantly reduced parieto-occipital all-night SWA relative to HYS- subjects. Our results suggest hypersomnolence may be associated with topographic reductions in SWA in MDD. Further research using an adequately powered prospective design is indicated to confirm these findings.

Surgery and cancer promotion: are we trading beauty for cancer?

It is well-known that cancer surgery can actually promote the growth of some tumors by a variety of mechanisms. There are observational data suggesting that surgery per se can increase the risk of cancer among individuals without a history of clinical cancer. Occult microscopic cancers are exceedingly common in the general population and are held in a dormant state by a balance between cell proliferation and cell death and also an intact host immune surveillance. The catecholamine surge from the stress of surgery and resulting β(2)-adrenergic signaling culminates in a transient and robust increased vascular endothelial growth factor expression locally and systemically that is enough to start tumor angiogenesis and end dormancy. The same catecholamine surge and β(2)-adrenergic signaling impairs cell-mediated immunity at a crucial time. Elegant animal studies have demonstrated that perioperative nonselective β-blockade abrogates surgical stress-induced angiogenesis and tumor growth. Prospective human trials are desperately needed and clinical implications are discussed.

Antidepressant effects of selective slow wave sleep deprivation in major depression: a high-density EEG investigation

Sleep deprivation can acutely reverse depressive symptoms in some patients with major depression. Because abnormalities in slow wave sleep are one of the most consistent biological markers of depression, it is plausible that the antidepressant effects of sleep deprivation are due to the effects on slow wave homeostasis. This study tested the prediction that selectively reducing slow waves during sleep (slow wave deprivation; SWD), without disrupting total sleep time, will lead to an acute reduction in depressive symptomatology. As part of a multi-night, cross-over design study, participants with major depression (non-medicated; n = 17) underwent baseline, SWD, and recovery sleep sessions, and were recorded with high-density EEG (hdEEG). During SWD, acoustic stimuli were played to suppress subsequent slow waves, without waking up the participant. The effects of SWD on depressive symptoms were assessed with both self-rated and researcher-administered scales. Participants experienced a significant decrease in depressive symptoms according to both self-rated (p = .007) and researcher-administered (p = .010) scales, while vigilance was unaffected. The reduction in depressive symptoms correlated with the overnight dissipation of fronto-central slow wave activity (SWA) on baseline sleep, the rebound in right frontal all-night SWA on recovery sleep, and the amount of REM sleep on the SWD night. In addition to highlighting the benefits of hdEEG in detecting regional changes in brain activity, these findings suggest that SWD may help to better understand the pathophysiology of depression and may be a useful tool for the neuromodulatory reversal of depressive symptomatology.

Electrophysiological traces of visuomotor learning and their renormalization after sleep

OBJECTIVE

Adapting movements to a visual rotation involves the activation of right posterior parietal areas. Further performance improvement requires an increase of slow wave activity in subsequent sleep in the same areas. Here we ascertained whether a post-learning trace is present in wake EEG and whether such a trace is influenced by sleep slow waves.

METHODS

In two separate sessions, we recorded high-density EEG in 17 healthy subjects before and after a visuomotor rotation task, which was performed both before and after sleep. High-density EEG was recorded also during sleep. One session aimed to suppress sleep slow waves, while the other session served as a control.

RESULTS

After learning, we found a trace in the eyes-open wake EEG as a local, parietal decrease in alpha power. After the control night, this trace returned to baseline levels, but it failed to do so after slow wave deprivation. The overnight change of the trace correlated with the dissipation of low frequency (<8 Hz) NREM sleep activity only in the control session.

CONCLUSIONS

Visuomotor learning leaves a trace in the wake EEG alpha power that appears to be renormalized by sleep slow waves.

SIGNIFICANCE

These findings link visuomotor learning to regional changes in wake EEG and sleep homeostasis.