bluuebunny/crossref_metadata_2025 huggingface dataset:
0156 Activation of Glutamatergic PPT Neurons and Their Projections Promotes Arousal, and Distinct Wake Behaviors
Authors: Kroeger D , Thundercliffe J A , Phung A , Geraci C , DeLuca R , Bragg S , Arrigoni E , Scammell T E
Published: May 2020

Introduction

The pedunculopontine tegmental (PPT) region in the brainstem is crucial for the regulation of sleep/wake states. We recently showed that chemogenetic activation of glutamatergic PPT neurons promotes wakefulness for several hours. Here we used optogenetic activation of these neurons to further investigate the mechanisms and pathways through which PPT glutamatergic neurons produce wakefulness.

Methods

Using vGlut2-cre mice, we transfected neurons in the PPT region with a viral vector coding for cre-dependent ChR2 tagged with fluorescent mCherry and implanted bilateral optical fibers above the PPT nuclei as well as EEG/EMG leads. Two weeks later, we administered blue laser light to activate ChR2-expressing neurons and recorded sleep/wake states.

Results

Activation of ChR2-expressing glutamatergic neurons during NREM sleep rapidly elicited wakefulness in a stimulation-frequency dependent manner, with higher frequencies producing wake more quickly and with longer duration. Random, automated stimulation for 10 s at 5 Hz over 24 h revealed that activation of glutamatergic PPT neurons produces rapid arousals form NREM sleep. Importantly, stimulation did not wake mice from REM sleep, suggesting that glutamatergic PPT signaling does not interfere with REM sleep. To map the target areas through which PPT glut neurons produce wakefulness, we used a viral tracer to visualize PPT glutamatergic projections, and then optogenetically stimulated terminals in 1) basal forebrain, 2) lateral hypothalamus, 3) thalamus, and 4) substantia nigra. We found that stimulating terminals in all of these regions woke mice from NREM sleep, and stimulating terminals in the basal forebrain and lateral hypothalamus produced a number of active wake behaviors such as locomotion. In contrast, stimulation of PPT glut soma and terminals in the thalamus and substantia nigra results mainly in quiet wakefulness.

Conclusion

Glutamatergic PPT neurons potently promote arousal from NREM sleep but not REM sleep, and the resulting wake behavior is modulated by different projection targets.

Support

NIH grant P01 - HL095491
0171 The Impact of Short-Term Bright Green Light Exposure in Partially Sleep-Deprived Persons
Authors: Pilcher J J , Bisson J B , Scircle E J
Published: May 2020

Introduction

Many workers and students experience regular sleep deprivation and daytime sleepiness when they are expected to be performing at their best. The purpose of the current research was to investigate the potential effect of short-term bright green light exposure on daytime performance and sleepiness in partially sleep-deprived persons.

Methods

Participants were 30 students (19.4±0.89 years; 20 females). On Day 1, participants were loaned a Fitbit to provide an objective measure of activity/sleep and were instructed to sleep no more than 5 hours that night. On Day 2, participants provided information on their sleep time for the previous night and were randomly assigned to a bright light condition (bright green light, 381 Lux) or a standard light condition (control condition, indoor florescent light, 139 Lux). They completed a simple reaction time task, the Arrow Flankers task to measure cognitive inhibition, and the Stanford Sleepiness Scale during three testing periods (baseline, after 20 minutes of light exposure, and after 60 minutes of light exposure). Between the testing periods, participants read a non-fiction book while exposed to their respective light condition. At the end of the study, participants returned their FitBit.

Results

The Fitbit and self-report sleep data indicated that participants slept 4.9 hours the night between Day 1 and Day 2. Mixed 2 (light condition) x 3 (testing period) ANOVAs indicated that the bright green light condition resulted in a significant decrease in reaction time on the Flankers task but had no significant effect on simple reaction time or subjective sleepiness.

Conclusion

The current findings suggest that 60 minutes of bright green light exposure could improve performance on a cognitive inhibition task. This suggests that bright green light exposure could be a useful countermeasure for cognitive performance decrements in settings where sleep deprivation is common.

Support

None to report.
0194 Bedtime Technology Use and New Questions for the Sleep Hygiene Index
Authors: Mastin D , Abu-Halimeh N , Collins B T , Critton J , Henderson M , Michelle S , Quattom M , Sanders M , Moore B , Peszka J
Published: May 2020

Introduction

We examined the relationship between bedtime active and passive social technology use (self and bedpartner) and daytime sleepiness/sleep. We generated questions to differentiate participants with and without bedpartners and updated passive personal, active bedpartner, and passive bedpartner social technology questions of the Sleep Hygiene Index.

Methods

327 students (age: M=19.7 years, SD=3.78) recruited through psychology courses and campus newsletters received extra credit or chances to win $25 gift cards. Participants completed demographic information, the Epworth Sleepiness Scale (ESS), the Pittsburgh Sleep Quality Index, questions regarding associated features of inadequate sleep hygiene, and the Sleep Hygiene Index. Five questions assessed active and passive social technology use, presence of a bedpartner, and awareness of bedpartner active and passive social technology use during sleep time.

Results

61.8% and 62.7% of students reported frequently or always using active and passive bedtime social technology, respectively; and 23.5% and 29.1% reported noticing a partner’s active or passive use. More frequent active technology use was significantly related to greater daytime sleepiness (ESS) (r(305)=.193, p<.05), sleep disturbances (PSQI-global: r(302)=.120, p<.05), and associated features of inadequate sleep hygiene (daytime sleepiness, worry about sleep, mood disturbance, avolition, and reduced cognition (r(306)=.212, p<.05)). Neither passive use nor passive or active partner use was significantly related to any sleep/sleepiness variables.

Conclusion

We continue to find students are frequent users of bedtime social technology which is related to daytime sleepiness, disrupted sleep, and related complaints. Passive and partner active/passive bedtime technology use may not have a significant impact on daytime sleepiness. It is possible younger participants are not good judges of passive or partner technology use or this younger population is resilient to these disruptions.

Support

none
0198 Psychomotor/Cognitive Effects, Pharmacokinetics and Safety of V117957, a Novel, Highly Potent and Selective Partial Agonist for Nociceptin/Orphanin-FQ Peptide (NOP) Receptors, Administered in Combination with Alcohol in Healthy Subjects
Authors: Zhou M , Harris S , Cipriano A , Kapil R , He E , Shet M , Apseloff G
Published: May 2020

Introduction

V117957 is an investigational nociceptin/orphanin-FQ peptide (NOP) receptor partial agonist designed to treat insomnia by promoting sleep onset and maintenance with minimal residual next-day somnolence or psychomotor impairment. The satisfactory safety/tolerability profile of V117957 has been previously established in ~200 healthy subjects with maximum doses at 30mg following a single oral administration and 10mg once daily for 2 weeks. The present study was conducted to assess the safety/tolerability and pharmacokinetics (PK) of V117957 with co-administered alcohol.

Methods

A randomized, double-blind, double-dummy, placebo-controlled, balanced six-period crossover design was employed. Single doses (2mg, 6mg) of V117957 and placebo were administered orally to healthy subjects in the morning with and without alcohol (0.7g/kg). Pharmacodynamic (PD) effects of V117957 were assessed, and safety/tolerability and PK interactions were also characterized. The primary PD endpoints (body sway, Digit Vigilance Test, and numeric working memory) were measured through 12 hours postdosing.

Results

Forty-eight subjects were enrolled and randomized; 46 completed. Compared with placebo, alcohol alone showed an impairment on psychomotor/cognitive performances through 2 hours postdose. V117957 alone showed a dose-dependent impairment. Compared with V117957 alone and alcohol alone, co-administration of alcohol and V117957 showed greater impairment until 8 hours postdose. No subject discontinued due to an adverse event (AE). No clinically meaningful treatment-emergent (TE) changes in clinical laboratory values, vital signs, SpO2 measurements, or 12-lead ECG results were observed. The most common TEAE was somnolence. All plasma and urine PK parameters for V117957 and alcohol were comparable when V117957 or alcohol was administered alone or in combination.

Conclusion

Single oral doses of V117957, 2mg or 6mg, administered alone or in combination with alcohol in healthy subjects resulted in no notable PK interaction between V117957 and alcohol. A dose-effect relationship in the magnitude and duration of impairment was observed for most psychomotor/cognitive performance parameters. Greater effects of V117957 with alcohol were observed for most psychomotor/cognitive performance parameters up to 8 hours post-dose.

Support

Funded by Imbrium Therapeutics, a subsidiary of Purdue Pharma L.P.
0214 The Relationship Between Work Stress and Sleep Quality in Shift Working Nurses: The Intermediate Effect of Circadian Rhythm Amplitude and Stability
Authors: Wu S , Wu C , Wang X , Fei W , Ma Y , Fu Y
Published: May 2020

Introduction

Research suggests that work stress may be an important factor in poor sleep in shift working nurses. However, evidence is limited about the underlying mechanism. Circadian rhythm might be effective. The purpose of this study was to explore the relationship between work stress and sleep quality in shift working nurses and the mediation effect of circadian rhythm amplitude and stability respectively.

Methods

A total of 529 nurses working in shifts from seven hospitals were selected by convenient sampling in Shanghai, China. Participants were assessed with the Circadian Type Inventory (CTI), Chinese Nursing Stressor Scale (CNSS), Pittsburgh Sleep Quality Index (PSQI). The Amos24.0 software was applied to construct structural equation models with circadian rhythm amplitude (LV) and circadian rhythm stability (FR) as intermediate variables respectively.

Results

About 73.3% (388/529) of the nurses’ PSQI scores were above 5, indicating poor sleep quality. The correlations between work stress, circadian rhythm amplitude, circadian rhythm amplitude and sleep quality were all significant (all P<0.01).Sleep quality total score was positively correlated with work stress(γ=0.348) and circadian rhythm amplitude (γ=0.330). Work stress was positively correlated with circadian rhythm amplitude (γ=0.297,P<0.01). Sleep quality total score was negatively correlated circadian rhythm amplitude (γ=-0.204,P<0.01);Work stress was negatively correlated with circadian rhythm amplitude (γ= -0.284,P<0.01).Work stress showed significant indirect effects on sleep quality through the mediating effect of circadian rhythm amplitude (β=0.188,P<0.01) and circadian rhythm amplitude (β= 0.082,P<0.05).

Conclusion

It suggests that nurses working in shifts have poor sleep quality. Work stress and the amplitude and stability of circadian rhythm could affect sleep quality, and circadian rhythm amplitude and stability could mediate the relationship between work stress and sleep quality.

Support

The work was supported by Xinglin Young Talent Program of Shanghai University of Traditional Chinese Medicine(to Caiqin Wu) and The 12th Innovative activities of college students of Shanghai Traditional Chinese Medicine(2019SHUTCM094).
0223 Interactions Between Home, Work, and Sleep Among Full-Time Firefighters
Authors: Watkins S L , Shannon M A , Hurtado D , Shea S A , Bowles N P
Published: May 2020

Introduction

Firefighters endure large occupational burdens (e.g., heat, exposure to toxic fumes, witnessed trauma) and generally operate under conditions of chronic sleep deficiency due to long shifts plus disrupted sleep and circadian disruption due to emergency calls during the night. A typical shift for firefighters is 24-hours on/48-hours off, and firefighters are expected to use time-off to recover from any sleep debt. However, firefighters need to balance that recovery with social/family needs and home maintenance. We conducted focus groups and qualitative analysis of responses to understand how firefighters’ sleep recoverability is affected by occupational burdens and home/family dynamics.

Methods

Focus groups were conducted via convenience sampling in Portland, Oregon, with full-time firefighters, battalion chiefs, and spouses of firefighters to assess current strategies and coping mechanisms used to manage occupational burdens, home/family obligations, and sleep loss based on their 24-hours on/48-hours off shift schedule. Grounded theory, using NVivo 12 plus, was used to code focus group transcripts to reveal reoccurring concepts that were further grouped into themes.

Results

Major themes that emerged among firefighters and spouses (n=48) centered on spousal resentment of firefighters, driven by understanding a firefighters’ heroic occupation and need to recover from accumulated sleep loss and shift schedule, but also wanting a partner physically/emotionally present to share home/social responsibilities. While married firefighters discussed choosing family/home obligations over reducing sleep debt to maintain social/family relationships, single and divorced firefighters spoke of fewer conflicts impeding their ability to prioritize sleep at home.

Conclusion

This study improves our understanding of how work impacts home life in firefighters and can inform future strategies to address work-family conflict and sleep loss concerns, and highlights the importance of managing expectations of time-off to promote a healthier work-life balance.

Support

Oregon Healthy Workforce Center
0229 Exploring the Relationships Between Sleep, Stress, and Performance in Simulation-Based Learning
Authors: McGuire K , Lorenz R
Published: May 2020

Introduction

Sleep deprivation and stress may affect performance among students. Simulation-based learning (SBL) in undergraduate nursing programs provides the opportunity for students to practice critical decision-making without fear of patient harm; however, students still report experiencing stress during SBL. Current research is unclear on the effect of sleep deprivation combined with stress on performance in SBL. The purpose of this study was to explore the association between stress, functional outcomes of sleep, and performance in SBL.

Methods

Elements of the Theory of Stress, Appraisal, and Coping and the National League for Nursing Jeffries Nursing Education Simulation Framework guided this study. Baccalaureate nursing students consented to participate in a 1-hour SBL experience that included the collection of one hair and 4 saliva samples for cortisol concentration. Participants completed the Functional Outcomes of Sleep- Short Form and the Perceived Stress Questionnaire. An experienced faculty member evaluated student performance using the Creighton Competency Evaluation Inventory.

Results

Participants (N=35) were mainly female (n=32, 91.4%), white (n=29, 82.9%), with ages ranging between 18–22 years (n=32, 91.4%), and employed outside of nursing school (n=32, 91.4%). Other ethnicities represented include Asian and African American. Kendall’s Tau correlations revealed a significant relationship between functional outcomes of sleep and perceived stress (r=-.281, p=.020). Although not significant, a small relationship was observed between functional outcomes of sleep and performance (r=.145, p=.236). No significant relationship between performance and perceived stress (r=-.099, p=.423) was identified.

Conclusion

This study suggests that daytime dysfunction related to sleep is related to perceived stress and performance in undergraduate nursing students during participation in SBL. Due likely to small sample size, the relationship between sleep and performance was unable to achieve significance. These findings support the need for future research exploring the effects of sleep on stress and performance with larger more heterogeneous samples of students.

Support

This researcher would like to acknowledge and thank the following funding sources for their generous support of this work: Marion Bender Scholarship (Saint Louis University School of Nursing), Dissertation Award from Sigma Theta Tau International-Epsilon Eta Chapter, and Southern Illinois University Edwardsville School of Nursing Faculty Scholar Award.
0240 College Football Players Compared to Other Collegiate Athletes: Symptoms of Insufficient Sleep Duration, Insomnia, and Sleep Apnea
Authors: Abdi H , Athey A , Auerbach A , Turner R , Killgore W D , Wills C C , Grandner M A
Published: May 2020

Introduction

College athletes experience frequent sleep disturbances. Data from professional football players suggests high rates of sleep apnea symptoms. Little data is available on college football players, especially compared to other athletes.

Methods

Data were obtained from N=189 NCAA Division-I student athletes, including N=45 football players). Outcomes of interest came from the Sleep Disorders Symptom Check List (SDSCL) which rated symptoms on a frequency scale of 0: never and 4: >5 times/week. Symptoms evaluated were daytime tiredness, any snoring, loud snoring, breathing pauses during sleep, and waking up choking/gasping sleep apnea), as well as difficulty falling asleep, difficulty with nighttime awakenings, and early morning awakenings (insomnia). Other outcomes include self-reported sleep duration, Insomnia Severity Index, frequency of caffeine use, and frequency of use of medications to help with sleep. Linear and ordinal logistic regression analyses were adjusted for age, sex, year in school, socioeconomic status, and mood. Post-hoc analyses examined men only.

Results

Regarding sleep apnea symptoms, football players reported more snoring (oOR=3.14, p=0.01), loud snoring (oOR=4.38, p=0.008), breathing pauses (oOR=5.42, p=0.0499), and choking/gasping (oOR=8.51), but not daytime tiredness. Regarding insufficient sleep, football players reported no difference in sleep duration but decreased caffeine use (oOR=0.27, p=0.002). Regarding insomnia, football players showed no difference in ISI scores or insomnia symptoms, but increased likelihood of sleeping pill use (oOR=3.01, p=0.03). When analyses were restricted to men only, all of these relationships were maintained.

Conclusion

College football athletes may exhibit different sleep symptoms than other college athletes, as they exhibit more sleep apnea-related symptoms, without the increase in daytime symptoms, such as tiredness.

Support

The REST study was funded by an NCAA Innovations grant.

Dr. Grandner is supported by R01MD011600
0242 Efficient Perception-Action Coupling Relates to More Slow Wave Sleep in Military Personnel
Authors: LaGoy A D , Eagle S R , Sinnott A M , Beckner M E , Conkright W R , Flanagan S D , Martin B J , Nindl B C , Germain A , Ferrarelli F , Connaboy C
Published: May 2020

Introduction

The ability to adapt actions to perceptions of environmental constraints, perception-action coupling, may be compromised by military operational stress (caloric restriction, sleep disruption, physical exertion). Differences in sleep may influence susceptibility to these stressors. We investigated perception-action coupling during simulated military operational stress and the influence of sleep on perception-action coupling.

Methods

During a 5-day simulated military operational stress protocol, thirty-six (6 female) service members (25.8 ± 4.7 years) completed three trials of a perception-action coupling task (PACT) in the evening after a night of baseline sleep (BASE), two nights of sleep restriction (T1) and a night of recovery sleep (T2). Participants had 8-hr for baseline and recovery sleep (2300-0700) and 4-hr disturbed sleep on sleep restriction nights (0100-0300 and 0500-0700). Polysomnography was used to determine time spent in different sleep stages: stage 2 (N2), slow wave (SWS) and rapid-eye movement (REM). The tablet-based PACT requires participants make quick, accurate perceptual judgments and responses about the ability of virtual balls to fit through virtual apertures. Linear mixed models were used to assess interaction and main effects of study day and prior sleep on PACT response time (RT) and accuracy (ACC).

Results

No significant sleep x time interactions or significant main effect of time were found for RT or ACC. A significant main effect of SWS was found for RT (F1,88.307 = 4.331, p = .04). Higher SWS was related to lower (faster) RT. No significant main effects of other sleep stages were found.

Conclusion

Perception-action coupling was maintained during simulated military operational stress. Participants with more SWS across the study responded faster during the PACT but N2 and REM sleep did not relate to perception-action coupling performance, suggesting a specific effect of SWS on perception-action coupling abilities and behaviors.

Support

Department of Defense Award #W81XWH-17-2-0070 (PI: Nindl)
0258 Early Semester Sleep Variability Predicts Depression Among College Students
Authors: Price S , Chikersal P , Doryab A , Villalba D , Dutcher J , Tumminia M , Cohen S , Creswell K , Mankoff J , Dey A , Creswell D
Published: May 2020

Introduction

Sleep is a critical behavior predicting mental health and depressive symptomatology in young adults.The extant scientific literature generally focuses on self-reported sleep measures over relatively short time frames. Here, we examine whether actigraphy-measured sleep variables early in the academic semester predict depressive symptomatology at the end of the semester among first and second year college students. There is currently debate in the sleep literature about which sleep variables are the most robust predictors of depression among young adults. In this study, we evaluate total sleep time, midpoint sleep time, and sleep variability where variability is defined by the mean-squared successive difference (MSSD) of midpoint sleep as predictors of depression.

Methods

The sample consisted of 160 first and second year college students at a private American university. The students completed a beginning and end of semester assessment of depressive symptomatology using the Center for Epidemiologic Studies Depression Scale (CES-D), and wore a Fitbit throughout the semester to capture sleep features of interest: total sleep time (TST), midpoint sleep, and midpoint MSSD.

Results

When controlling for beginning of semester CES-D, early semester (weeks 3–6) midpoint sleep MSSD significantly (p < 0.05) predicted increased end of semester CES-D. These effects were specific to the sleep variability measure (MSSD). Total sleep time and sleep chronotype (i.e. midpoint sleep) were not significant predictors of end of semester depressive symptomatology.

Conclusion

Early semester sleep window variability among college freshmen, particularly during stressful midterm exams, is a robust risk factor for depression among college students. This work contributes to initial actigraphy studies suggesting that MSSD measures of sleep window variability foster increased mental health risks among young people. This work calls for further investigation to understand possible causal relationships between sleep variability and mental health.

Support

This work was supported by the Life@CMU project funded by the Carnegie Mellon University Provost’s Office.
0259 Shiftworkers are at Increased Risk of Developing Chronic Pain and Opioid Use Disorders: A Study of 116,000 UK Biobank Participants Over a Decade
Authors: Gao L , Li P , Cui L , Luo Y , Vetter C , Saxena R , Scheer F A , Johnson-Akeju O , Hu K
Published: May 2020

Introduction

In the current epidemic of opioid-related deaths, and widespread use of opioids to treat chronic pain, there is a pressing need to understand the underlying risk factors that contribute to such devastating conditions. Shiftwork has been associated with adverse health outcomes. We tested whether shiftwork during middle age is linked to the development of chronic pain and opioid misuse.

Methods

We studied 116,474 participants in active employment between 2006–2010 (mean age 57±8; range 37–71) from the UK Biobank, who have been followed for up to 10 years until 2017. We included participants who were free from all forms of self-reported pain, and were not taking opioid medications at baseline. Chronic pain and opioid use disorder diagnoses were determined using hospitalization records and diagnostic coding from ICD-10. Multivariate logistic regression models were performed to examine the associations of shiftwork status (yes/no) and nightshift frequency (none/occasional/permanent) and with incident chronic pain and/or opioid use disorder during follow-up. Models were adjusted for demographics, education, Townsend deprivation index, major confounders (BMI, diabetes, bone fractures/injuries, operations, peripheral vascular disease, joint/inflammatory diseases, cancer, standing/manual labor at work) and covariates (smoking, alcohol, high cholesterol, depression/anxiety, and cardiovascular diseases).

Results

In total, 190 (1.6/1,000) developed chronic pain or opioid use disorders. Shiftworkers (n=17,673) saw a 1.5-fold increased risk (OR 1.56, 95% CI: 1.08–2.24, p=0.01) relative to day workers. Within shiftworkers, those who reported occasional nightshift work (n=3,966) were most vulnerable (OR 1.57, 95% CI: 1.06–2.34, p=0.02). Results remained similar after adjusting for baseline sleep duration, chronotype and insomnia.

Conclusion

Shiftwork, and in particular rotating nightshift work is associated with increased risk for developing chronic pain and opioid use disorders. Replication is required to confirm the findings and to examine underlying mechanisms.

Support

This work was supported by NIH grants T32GM007592, RF1AG064312, and RF1AG059867.
0264 The Effects of Previous Night’s Sleep, 12-Hour Shift, and Workload on Sleepiness in Emergency Medical Service Providers
Authors: Pavuluri H , Schmidt W M , Amalean A , Fowler L
Published: May 2020

Introduction

Shift-work has been shown to be detrimental to workers in many ways, including having negative effects on sleep. Many factors related to shift-work can contribute to these negative effects, including increased workload and less sleep the previous night. The effects of shift-work on sleep have been studied extensively in nurses and physicians, but this research is lacking in paramedics and emergency medical technicians (EMTs). This study assessed the effects of previous night’s sleep, day- versus night-shift, and workload on sleepiness in paramedics and EMTs.

Methods

Thirty-three EMTs and paramedics were tested before and after their 12-hour (either day- or night-) shift. Testing consisted of questions about previous night’s sleep, pupillometry to assess pupillary response for physiological sleepiness, and the Stanford Sleepiness Scale for subjective sleepiness. The number of calls made per shift was used to quantify workload/call volume.

Results

An analysis of variance assessed the effect of shift (day/night), previous night’s sleep, and workload on post-shift sleepiness. Pupillometry demonstrated that participants were sleepier after 12-hour shifts, but those who slept 8–9 hours the night before were less affected. Pupillary response indicated higher levels of sleepiness following the night-shift compared to the day-shift. This was contrary to perceived sleepiness, which was higher after the day-shift than the night-shift. Higher call volume resulted in a sleepier physiological response, and this effect was shown to be dependent upon the shift.

Conclusion

Performing shift-work results in increased sleepiness in workers, especially after a night shift. However, physiological sleepiness does not always correspond to perceived sleepiness. In addition, increased workload results in increased sleepiness, especially during the day shift. This highlights the importance of obtaining 8–9 hours of sleep before a 12-hour shift to protect against the effects of sleepiness on patient care and EMS workers themselves.

Support

This was funded in part by a UofSC Provost Grant.
0270 Somnolence Profiles in Mice Submitted to Acute and Chronic Sleep Deprivation
Authors: Fernandes G L , Araujo P , Tufik S , Andersen M
Published: May 2020

Introduction

Sleepiness is a behavioral marker of homeostatic sleep regulation and is related to several negative outcomes with interindividual variation, which may amount to central sleep mechanisms. However, there is a lack of evidence linking progressive sleep need and sleepiness with factors of individual variability, which could be tested by acute and chronic sleep deprivation. Thus, the study objective was to investigate the development of sleepiness in sleep deprived mice.

Methods

C57BL/6J male mice (n=340) were distributed in 5 sleep deprivation groups, 5 sleep rebound groups and 10 control groups. Animals underwent acute total sleep deprivation for 3, 6, 9 or 12 hours or chronic sleep deprivation for 6 hours for 5 consecutive days. Sleep rebound groups had the opportunity to sleep for 1, 2, 3, 4 hours after acute sleep deprivation or 24 hours after chronic sleep deprivation. During the protocol, sleep attempts were counted as a sleepiness index. After euthanasia, blood was collected for corticosterone assessment.

Results

Using the average group sleep attempts, it was possible to differentiate between sleepy (mean>group average) and resistant to sleepiness animals (mean<group average). Frequency of resistant mice was 65%, 56%, 56% and 53% for 3, 6, 9 and 12 hours of acute sleep deprivation, respectively, and 74% in chronic sleep deprivation. 52% of the sleepiness variance might be explained by individual variation during chronic sleep deprivation and 68% of sleepiness variance during acute sleep deprivation was attributed to extended wakefulness. A normal corticosterone zenith was observed at the start of the dark phase, independent of sleep deprivation.

Conclusion

Different degrees of sleepiness in sleep deprived mice were verified. Sleep deprivation per se was the main factor explaining sleepiness during acute sleep deprivation whereas in chronic deprivation individual variation was more relevant.

Support

This work was financially supported by Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) (#2017/18455-5), Coordenação de Aperfeiçoamento de Pessoal Nível Superior (CAPES) - grant code 001, ConselhoNacional de Desenvolvimento Científico e Tecnológico (CNPq) (#169040/2017–8)and Associação Fundo de Incentivo à Pesquisa (AFIP).
0284 The Effects of a Circadian-Aligned Watchbill Shift Work Schedule on Sleep Quality and Quantity in U.S. Navy Submarine Personnel
Authors: Dahlquist D T , Chinoy E D , Markwald R R , Chabal S A
Published: May 2020

Introduction

Prior to 2014, the U.S. Navy Submarine Force operated on a non-circadian-aligned watchbill shift work schedule (18-hour day-length) that resulted in insufficient sleep. For instance, prior research reported that submariners received insufficient sleep on this schedule, and modest sleep restrictions can adversely affect performance, alertness, and, ultimately, negatively impact mission outcomes. Thus, the present study characterized sleep patterns of submariners operating on a newer, circadian-aligned 24-hour day-length watchbill.

Methods

Submariners (n=58; 27.8±5.9 years) of various ranks volunteered from a U.S. Navy submarine. Submariners wore a research-grade actigraphy watch over a 30-day underway mission, for objective sleep measurement of time in bed (TIB), total sleep time (TST), and sleep efficiency (SE). Subjective sleep was measured from questionnaires (Pittsburgh Sleep Quality Index [PSQI], Insomnia Severity Index [ISI], Profile of Mood States [POMS-fatigue subscale]) that were taken pre- and post-underway.

Results

Compared with pre-underway, at post-underway submariners reported significantly higher scores on the ISI, PSQI global sleep quality, and POMS-fatigue (all p<0.05, indicating worse sleep and fatigue ratings). According to actigraphy, submariners acquired on average 6.7±1.0 hours TST, 7.5±1.1 hours TIB, and 88.9±3.9 % SE per day throughout the underway mission. Actigraphy-determined TIB and TST were variable compared with PSQI self-reported TIB and TST.

Conclusion

Study results indicate that submariners experience modest sleep restriction on a newly implemented 24-hour watchbill, which is an improvement in sleep relative to prior assessments of the former standard 18-hour watchbill. However, submariners endorsed lower sleep quality and higher fatigue levels from a month-long underway mission. This study is one of the first examinations of sleep under the 24-hour watchbill mandate that was instated in 2014. Future studies should further evaluate sleep and test fatigue mitigation strategies in different shift configurations of the 24-hour watchbill.

Support

Joint Program Committee-5 Fatigue Mechanisms and Countermeasures Working Group
0308 DRD2 C957T Genotype Influences Vigilant Attention Performance Impairment During Total Sleep Deprivation
Authors: Muck R A , Skeiky L , Schmidt M A , Satterfield B C , Wisor J P , Honn K A , Van Dongen H
Published: May 2020

Introduction

There are substantial, phenotypical individual differences in the adverse impact of total sleep deprivation (TSD) on vigilant attention performance. Dopaminergic genotypes have been found to contribute to these phenotypical differences. Here we investigated the association between a single nucleotide polymorphism (SNP) of the dopamine receptor D2 (DRD2) gene, C957T (rs6277), on vigilant attention performance measured with the psychomotor vigilance test (PVT) in a laboratory TSD study.

Methods

N=46 healthy adults (ages 26.0±5.3y; 25 females) completed a 4-day in-laboratory study with a baseline day (10h time in bed: 22:00-08:00), a 38h TSD period, and a recovery day (10h time in bed: 22:00-08:00). DNA isolated from whole blood was assayed for DRD2 C957T genotype using real-time polymerase chain reaction. PVT performance was measured during TSD at 2-4h intervals, and analyzed for genotype using mixed-effects analysis of covariance of lapses of attention (RTs>500ms).

Results

The genotype distribution in this sample - 28.3% C/C, 50.0% C/T, 21.7% T/T - was found to be in Hardy-Weinberg Equilibrium (X21=0.0008, p=0.98). As expected, there was a significant effect of time awake on PVT performance (F14,602=26.67, p<0.001). There was a significant main effect of DRD2 genotype (F2,602=3.24, p=0.040) and a significant interaction of time awake by DRD2 genotype (F28,602=1.96, p=0.003). Subjects homozygous for the T allele showed greater impairment during extended wakefulness than carriers of the C allele. Genotype explained 7.6% of the variance in the PVT data observed during the 38h TSD period.

Conclusion

Subjects homozygous for the T allele of DRD2 C957T were considerably more vulnerable to TSD-induced PVT performance impairment than carriers of the C allele. A recent study showed that DRD2 C957T influences PVT performance in interaction with a SNP of the DAT1 gene. Here, DRD2 genotype was by itself also associated with PVT performance impairment during TSD.

Support

CDMRP awards W81XWH-16-1-0319 and W81XWH-18-1-0100.
0313 Is Healthy Sleep Possible for Professional Firefighters? A Comparison of “On-Duty” and “Off-Duty” Sleep Quantity and Quality
Authors: Dautovich N D , Dzierzewski J , Sabet S , Soto P , Donovan E , Kleva C
Published: May 2020

Introduction

Healthy sleep is vital for firefighter safety, health, wellness, and for public well-being. However, professional firefighters experience disturbed sleep at disproportionately high rates. The current study investigated whether firefighters can obtain healthy sleep by identifying (1) differences in sleep while “on-duty” and “off-duty” and (2) risk factors for poor sleep.

Methods

Professional firefighters in Richmond, Virginia’s Department of Fire and Emergency Services (N=268), reported their sleep using the Pittsburgh Sleep Quality Index (PSQI) both on- and off-duty. Good and poor sleepers were identified using the PSQI global score cutoff of 5. Demographic and STOP-BANG questionnaires were also completed.

Results

Using a repeated measures MANOVA, on-duty sleep was significantly worse compared to off-duty sleep across PSQI component and global scores F(7, 253)=45.24 p<.001, η²=.56. On-duty, 76.1% of firefighters were classified as poor sleepers compared to 42.9% off-duty. 34.7% were reclassified as good sleepers or stayed good sleepers (22.4%) when off-duty. A sizeable minority experienced consistently poor sleep while on- and off-duty (41.4%), and a small number reported worse sleep when off-duty (1.5%). More night calls and poorer self-rated mental health predicted worse on-duty sleep (p<.001) and poorer self-rated mental health predicted worse off-duty sleep (p<.001).

Conclusion

Healthy sleep is possible for professional firefighters. Almost a quarter of the sample was classified as “good sleepers” on-duty and over half were classified as “good sleepers” off-duty. Nonetheless, sleep on-duty was significantly worse overall, with over a third of the sample experiencing consistently poor sleep. When working a 24-hour variable shift schedule, it appears that poor sleep may “carryover” from on-duty to off-duty. Poorer self-rated mental health and more night calls were identified as risk factors. Further research is needed to probe risk and protective factors within this population.

Support

N/A
0321 Increased Slow-Wave Activity Predicts Slower Processing Speed in Toddlers
Authors: Waddle A E , Kurth S , Harsh J , Lassonde J M , Lee D , LeBourgeois M K
Published: May 2020

Introduction

Slow-wave activity (SWA) shows an inverted U-shaped time course during development. Specifically, maximal SWA undergoes a posteroanterior shift from 2 to 20 years of age, which may reflect cortical maturation. Previously, we showed that greater slow sigma power during sleep predicted faster reaction time in preschool-aged children. To date, little is known about the relationship between SWA and processing speed (PS), a basic fundament underlying complex cognitive skills in early development.

Methods

This project examined the relationship between SWA and PS in 2.5-3.0-year-old children (n=26, 50% males) via home-based assessments. After a 5-day stabilization sleep schedule, a baseline sleep EEG recording was performed on participants at 4 electrode placements: Fz, Oz, C3, and C4. SWA EEG spectral power was quantified in the 0.75-4.5 Hz rangeduring the first 60 minutes of NREM sleep. PS was obtained as part of a standard cognitive assessment via a computer-based task one hour after waking from a midday nap.

Results

On average, reaction time (PS) was 2111 ± 08 ms and SWA was 856.4 ± 300.7 µV2/Hz. Increased SWA in the occipital region was predictive of a longer reaction time and therefore slower PS (r = 0.44, p = 0.03). This relationship showed differences between sexes, suggesting that females (r = 0.26, p = 0.07) may show a stronger association between SWA in the occipital brain region and PS than males (r = 0.09, p = 0.33).

Conclusion

Interestingly, these findings contradict our hypothesis based on previous data with older children indicating that greater SWA was associated with more advanced behavioral and cognitive skills. This discrepancy may reflect the stark individual differences present within this rapidly maturing age group.

Support

Research support from NIH R01-MH086566 to MKL.
0326 Daily Sleep and Affect in Adolescents: Differential Associations During Constrained Versus Unconstrained Sleep
Authors: Shen L , Wiley J F , Bei B
Published: May 2020

Introduction

Few studies have examined bi-directional associations between daily sleep and affect in adolescents, and even fewer assessed both high and low arousal affect under naturalistically-occurring constrained (school) and unconstrained (vacation) sleep opportunities.

Methods

205 adolescents (54.1% females, age M±SD=16.9±0.87 years) completed daily measures of sleep and affect over 28 continuous days (2-week school and 2-week vacation). Total sleep time (TST) and sleep efficiency (SE) were measured using actigraphy and sleep diary. High- and low-arousal positive and negative affect (PA, NA) were self-reported each afternoon. Cross-lagged, multilevel models were conducted: affect predicted same-night sleep controlling for previous-night sleep; sleep predicted next-day affect controlling for previous-day affect. Day of week, study day, and sociodemographics were controlled.

Results

During both school and vacation, adolescents with overall higher low-arousal PA also had greater self-reported SE. Other aspects of sleep-affect associations differ between school and vacation (all p<.05). During school, significant associations were between, not within individuals. Bi-directional associations were found between longer actigraphy-TST and greater high-arousal PA, and between higher self-reported SE and lower low-arousal NA. High-arousal PA and NA were associated with self-reported TST (positive and negative respectively). During vacation, between-individuals, higher NA was bi-directionally associated with lower self-reported SE, regardless of arousal. Longer self-reported TST was associated with lower low-arousal NA. On the within-person level, regardless of sleep measurement, nights with longer-than-average TST were associated with lower NA the next day (high- and low- arousal). Nights with higher-than-average SE predicted lower next-day low-arousal NA.

Conclusion

Sleep-affect associations differed based on sleep opportunity and arousal, suggesting potentially different mechanisms of action. When sleep is typically constrained, overall levels of sleep-affect associations were stronger than daily fluctuations. When sleep is typically unconstrained, significant associations were found both between- and within- persons. In particular, daily fluctuations in sleep were predictive of next-day NA, rather than the other direction.

Support

Monash International Postgraduate Research Scholarship and Monash Graduate Scholarship
0328 The Associations Between Self-Reported Symptoms of Sleep Disorders, Objective Sleep Patterns and Affect in Adolescence
Authors: Dimakos J , Gauthier-Gagne G , Somerville G , Boursier J , Gruber R
Published: May 2020

Introduction

Developmental changes in adolescence make adolescents prone to experiencing negative mood and increased emotional lability. Experimental studies employing sleep restriction paradigms have shown that decreased sleep increased negative affect, but a gap exists regarding the association between sleep disorders and negative affect in adolescence. The objective of this study was to examine this association. It was hypothesized that higher levels of reported symptoms of sleep disorders would be associated with lower positive affect and higher negative affect in adolescents.

Methods

Participants: 101 adolescents (65 females) aged between 13 and 18 years old (M=14.69, SD=1.16). Measures: Sleep Disorders Inventory for Students was used to measure symptoms of sleep disorders and sleep patterns were measured objectively using actigraphy. Positive and Negative Affect Schedule (PANAS) was used to measure positive and negative affect.

Results

Correlational analyses were conducted to assess the relationship between symptoms of sleep disorders, sleep patterns, and positive and negative affect. Higher levels of reported symptoms of sleep disorders were associated with later bedtimes (r= .26, p< .01), shorter sleep durations (r= -.20, p< .05), increased sleep onset latency (r= .21, p< .05), decreased sleep efficiency (r= -.23, p< .05), and less immobile minutes (r= -.23, p< .05) measured by actigraphy. Higher levels of reported symptoms of sleep disorders were associated with lower levels of positive affect (r= -.20, p< .05) and higher levels of negative affect (r= .39, p< .001)

Conclusion

Reported symptoms of sleep disorders were associated with overall poorer sleep patterns in adolescents as well as decreased positive affect and increased negative affect. Sleep specialists assisting adolescents with sleep disorders should inquire about mood regulation.

Support

Social Sciences and Humanities Research Council
0329 Poor Prenatal Sleep and Postpartum Depression are Associated with Infant Sleep Problems
Authors: Chen I Y , Glynn L M , Benca R M
Published: May 2020

Introduction

Childhood sleep problems are associated with increased risk of psychiatric conditions later in life. Sleep disturbances are prevalent during pregnancy and associated with postpartum depression and persistent sleep disturbance. Although maternal sleep and mood likely contribute to infant sleep problems, relationships between these factors are understudied. The present study examined associations of prenatal maternal sleep and postpartum depression with infant sleep patterns.

Methods

The sample included 235 women (29.2±5.8 years old), who were enrolled in a longitudinal study beginning in the first trimester of pregnancy. Maternal sleep and mood were assessed with the Pittsburgh Sleep Quality Index, the Center for Epidemiologic Studies Depression Scale, and the Edinburgh Postnatal Depression Scale during 3 prenatal and 2 postpartum visits. Infant sleep patterns were assessed with the Brief Infant Sleep Questionnaire at 2-, 6-, and 12-months. Mixed model repeated measure analyses were conducted to examine changes in maternal and infant sleep across time. Partial correlation adjusted for age, depression, and postpartum maternal sleep was performed to estimate the association between prenatal maternal sleep and infant sleep. ANCOVAs controlling for age were conducted to assess the effect of postpartum depression on infant sleep.

Results

Maternal sleep quality deteriorated during the third trimester and 2-months postpartum, and improved at 6-months postpartum (ps< .001). Infant sleep became more consolidated with age, with decreased nocturnal awakenings (frequency and duration) and increased nighttime sleep duration (ps< .001). Poorer prenatal maternal sleep was associated with shorter infant sleep duration at 6 months (r=-0.33, p<.001). Mothers with persistent postpartum depression reported their child as having longer daytime sleep compared to their counterparts (F=3.55, p<.05).

Conclusion

Prenatal sleep problems and persistent postpartum depression are associated with poorer infant sleep. Our findings suggest that screening and preventive interventions for sleep problems during pregnancy may have beneficial impact on infant sleep.

Support

Research supported by National Institutes of Health MH-96889.