bluuebunny/crossref_metadata_2025_split huggingface dataset:
225 Sleep Timing and Chronotype in Mothers: Longitudinal Changes and Associations with Wellbeing from Pregnancy to 2 Years Postpartum
Authors: Verma Sumedha , Pinnington Donna , Manber Rachel , Bei Bei 
Published: May 2021

Abstract

Introduction
Women experience significant changes to sleep during perinatal periods. Existing research focuses on sleep duration and quality, but not sleep timing or chronotype (i.e., preferred timing for activity and sleep). This study investigated change trajectories of sleep timing and chronotype from late pregnancy to two years postpartum, and examined longitudinal associations between chronotype and insomnia, sleep-related daytime impairment, and mood.

Methods
Data were from a 2-arm randomized controlled trial testing behavioral sleep and diet interventions. A community sample of nulliparous women without severe sleep/mental health conditions participated. Women self-reported bedtime, risetime, chronotype (reduced Morningness-Eveningness Questionnaire), Insomnia Severity Index, and PROMIS Depression, Anxiety, and Sleep-Related Impairment over 7 time points: 30 and 35 weeks’ gestation, and postpartum months 1.5, 3, 6, 12 and 24.

Results
163 women (mean age 33.35 ± 3.42 years) took part. Mixed effects models controlling for age and group allocation showed that both bed- and risetimes became progressively earlier over time by approximately 20-30 minutes on average (p &lt; .001); chronotype also shifted progressively towards morningness (p &lt; .01). After controlling for covariates (sleep duration and efficiency, mental health history, social support, age, group allocation), greater morningness was significantly associated with lower symptoms of insomnia and sleep-related impairment over time (p-values &lt; .001); longitudinal associations between chronotype and symptoms of depression and anxiety were non-significant (p-values &gt; .65).

Conclusion
This is one of the first studies to examine longitudinal changes in sleep timing and chronotype from pregnancy to two years postpartum. Sleep timing and chronotype became progressively earlier over the first two postpartum years. The magnitude of changes is beyond what is expected with increasing age. Greater morningness was associated with lower sleep complaints and sleep-related daytime impairment during the postpartum period. The mechanisms underlying these associations require further research.

Support (if any)
Australasian Sleep Association, Monash University, Australian Government RTP Scholarship and National Health and Medical Research Council.
237 Sleep disturbances, online instruction, and learning during COVID-19: evidence from 4148 adolescents in the NESTED study
Authors: Saletin Jared , Owens Judith , Wahlstrom Kyla , Honaker Sarah , Wolfson Amy , Seixas Azizi , Wong Patricia , Carskadon Mary , Meltzer Lisa 
Published: May 2021

Abstract

Introduction
COVID-19 fundamentally altered education in the United States. A variety of in-person, hybrid, and online instruction formats took hold in Fall 2020 as schools reopened. The Nationwide Education and School in TEens During COVID (NESTED) study assessed how these changes impacted sleep. Here we examined how instruction format was associated with sleep disruption and learning outcomes.

Methods
Data from 4148 grade 6-12 students were included in the current analyses (61% non-male; 34% non-white; 13% middle-school). Each student’s instructional format was categorized as: (i) in-person; (ii) hybrid [≥1 day/week in-person]; (iii) online/synchronous (scheduled classes); (iv) online/asynchronous (unscheduled classes); (v) online-mixed; or (vi) no-school. Sleep disturbances (i.e., difficulty falling/staying asleep) were measured with validated PROMIS t-scores. A bootstrapped structural equation model examined how instructional format and sleep disturbances predict school/learning success (SLS), a latent variable loading onto 3 outcomes: (i) school engagement (ii) likert-rated school stress; and (iii) cognitive function (PROMIS t-scores). The model covaried for gender, race-ethnicity, and school-level

Results
Our model fit well (RMSEA=.041). Examining total effects (direct + indirect), online and hybrid instruction were associated with lower SLS (b’s:-.06 to -.26; p’s&lt;.01). The three online groups had the strongest effects (synchronous: b=-.15; 95%CI: [-.20, -.11]; asynchronous: b=-.17; [-.23, -.11]; mixed: b=-.14; [-.19, -.098]; p’s&lt;.001). Sleep disturbance was also negatively associated with SLS (b=-.02; [-.02, -.02], p&lt;.001). Monte-carlo simulations confirmed sleep disturbance mediated online instruction’s influence on SLS. The strongest effect was found for asynchronous instruction, with sleep disturbance mediating 24% of its effect (b = -.042; [-0.065, -.019]; p&lt;.001). This sleep-mediated influence of asynchronous instruction propagated down to each SLS measure (p’s&lt;.001), including a near 3-point difference on PROMIS cognitive scores (b = -2.86; [-3.73, -2.00]).

Conclusion
These analyses from the NESTED study indicate that sleep disruption may be one mechanism through which online instruction impacted learning during the pandemic. Sleep disturbances were unexpectedly influential for unscheduled instruction (i.e., asynchronous). Future analyses will examine specific sleep parameters (e.g., timing) and whether sleep’s influence differs in teens who self-report learning/behavior problems (e.g., ADHD). These nationwide data further underscore the importance of considering sleep as educators and policy makers determine school schedules.
Support (if any):
252 Non-Invasive Quantification of Human Brain Lactate Concentrations Across Sleep-Wake Cycles
Authors: Yildiz Selda , Lim Miranda , Sammi Manoj , Powers Katherine , Murchison Charles , Iliff Jeffrey , Rooney William 
Published: May 2021

Abstract

Introduction
Cellular mechanisms underlying changes in small animal brain lactate concentrations have been investigated for more than 70 years and report sharp reductions in lactate (12-35%) during sleep or anesthesia relative to wakefulness. The goal of this study was to investigate alterations in human cerebral lactate concentrations across sleep-wake cycles. Toward this goal, we developed a novel non-invasive methodology, quantified changes in human cerebral lactate during sleep stages, and investigated potential mechanisms associated with changes in lactate.

Methods
Nine subjects (four females, five males; 21-27 y-o, mean age 24.2 ±2) were sleep deprived overnight, and underwent (5:45~11:00 am) experiments combining simultaneous MR-spectroscopy (MRS) and polysomnography (PSG) in a 3 T MR instrument using a 64-channel head/neck coil. A single voxel MRS (1H-MRS) acquired signals from a volume of interest (12~24 cm3) for every 7.5-s for 88~180-min. Lactate signal intensity was determined from each 7.5-s spectrum, normalized to corresponding water signal, and averaged over 30-s for each PSG epochs. Artifact corrected PSG data were scored for each 30-s epoch using the standard criteria and classified into one of four stages: W, N1, N2 and N3. Group mean lactate levels were quantified using LCModel. Three subjects returned for lactate diffusivity measurements using diffusion-sensitized PRESS MRS sequence.

Results
Compared to W, group mean lactate levels within each sleep stage showed a reduction of [4.9 ± 4.9] % in N1, [10.4 ± 5.2] % in N2, and [24.0 ± 5.8] % in N3. We observed a significant decrease in lactate apparent diffusion coefficient (ADC) accompanied by reduced brain lactate in sleep compared to wake (P&lt;0.002). There were no differences in ADC values between wake and sleep for H2O, NAA, tCr, or Cho.

Conclusion
This is the first in-vivo report of alterations in human brain lactate concentrations across sleep-wake cycles. Observed decline in lactate levels during sleep compared to wakefulness is consistent with, and extends results from invasive small animal brain studies first reported more than 70 years ago, and support the notion of altered lactate metabolism and/or increased glymphatic activity in sleeping human brain.

Support (if any)
The Paul. G. Allen Family Foundation funded the study.
260 Beyond Validation Testing: A Sleep Tracker for Longitudinal Data Collection in Operational Environments
Authors: Devine Jaime , Chinoy Evan , Markwald Rachel , Devine Jaime , Hursh Steven 
Published: May 2021

Abstract

Introduction
Sleep tracking wearables are increasingly being validation tested against polysomnography (PSG) and actigraphy, but they may not be ideal for long-term epidemiological sleep studies, or for use in operational environments. A given device’s short battery life, limited data storage capacity, inability to detect naps or estimate sleep architecture, or privacy concerns may discourage researchers from using wearables to collect objective sleep data in real-world settings. The Zulu watch (Institutes for Behavior Resources) is designed to collect longitudinal sleep data in operational populations with irregular sleep patterns, such as long-haul pilots or shift workers. It is capable of on-wrist sleep-wake determination, nap detection, on-wrist sleep depth scoring (i.e., interrupted sleep, light sleep, or deep sleep), on-wrist data storage up to 80 sleep intervals, and year-long battery life. Laboratory testing is an important initial step toward establishing the performance of a device for longitudinal real-world sleep evaluation; therefore, the Zulu watch sleep tracking was subjected to testing against gold-standard PSG and actigraphy.

Methods
Eight healthy young adult participants (30.4±3.2 years; mean±SD) wore a Zulu watch and Philips Respironics Actiwatch 2 simultaneously over a 3-day laboratory PSG sleep study, with 8 hours time-in-bed each night. Overall epoch-by-epoch agreement of sensitivity (for sleep), specificity (for wake), and accuracy of Zulu watch data were tested against PSG and Actiwatch 2.

Results
Compared with either PSG or actigraphy, both accuracy and sensitivity for Zulu watch sleep-wake determination were &gt;90% while specificity was low (~26% vs. PSG, ~33% vs. actigraphy). Accuracy for sleep scoring vs. PSG was ~87% for interrupted sleep, ~52% for light sleep, and ~49% for deep sleep.

Conclusion
The Zulu watch showed mixed results but may be a viable candidate for sleep evaluation based on initial laboratory performance testing in healthy adults. The next steps will be to compare the Zulu watch against self-report of sleep in operational and substance use disorder populations. Longitudinal epidemiological sleep studies can become more feasible if technology is tailored to the specific needs of the real-world environment.

Support (if any)
Medical Technology Enterprise Consortium award MTEC-17-08-Multi-Topic-0104; Office of Naval Research, Code 34.
280 Is blue-enriched light more effective than red light to enhance vigilance and cognitive performance in Parkinson’s Disease?
Authors: Rosinvil Thaïna , Daneault Veronique , Vanderwalle Gilles , Desaultels Alex , Forcier Pierre , Gaudet-Fex Benjamin , Apinis-Deshaies Amélie , Aumont Tomy , Constantin Ioana Medeleine , Matute Andrea , Gagnon Jean-Francois , Gosselin Nadia , Lina Jean-Marc , Carrier Julie 
Published: May 2021

Abstract

Introduction
Approximately 50% (between 16–74%) of adults with Parkinson’s disease (PD) show excessive daytime sleepiness. Besides its important role for vision, light conveys a powerful stimulating signal for alertness and cognition. Recent research has demonstrated that the blue part of light spectrum is the most efficient in enhancing vigilance and cognitive performance in young and older healthy individuals, thanks to a specific photoreception system within the eye which is particularly sensitive to blue wavelength. The aim of this pilot study was to compare the effects of blue-enriched light exposure (BL) and red-light placebo exposure (RL) on psychomotor vigilance and cognitive performance in adults with PD.

Methods
Sixteen participants with idiopathic PD (64.0±5.5 yrs, 6 women, Hoehn and Yahr status: 2) completed a brief neuropsychological assessment to exclude dementia, self-reported questionnaires and a complete eye examination in screening visits. The one-day experimental procedure included 1.25 h period of baseline dim-light exposition, followed by two light conditions presented in a counterbalanced design and separated by 15 minutes in dim-light: 1.25 h of BL at 959lux and 1.25 h of placebo RL condition at 472lux. Both light conditions were delivered by Luminette®. Data were normalized according to baseline dim-light evaluation. Mixed analyses of variance (2 light conditions X 2 orders) were performed to compare performance on an auditory psychomotor vigilance task (A-PVT) and an auditory 2-back cognitive tasks (A-2-back) during light exposure.

Results
We observed no significant effect of light conditions, orders and no interaction on reaction time (RT) and number of correct answers for the A-2-Back task. Furthermore, there was no significant difference between BL and RL on A-PVT performance including median RT, shift in optimum RT (i.e.,mean RT from fastest 10% RT), and duration of response in the lapse domain (i.e.,mean RT from slowest 10% RT).

Conclusion
These preliminary results do not support the notion that blue-enriched white light exposure is more efficient than red light exposure to stimulate psychomotor vigilance and cognitive performance in adults with PD. Next steps of analyses will compare the effects of BL and RL on subjective sleepiness and EEG cortical activation in the same population.

Support (if any)
CIHC & QPN
284 Cognitive Deficits due to Insufficient Sleep are Mitigated Following Strenuous Physical Exertion in Firefighters
Authors: Stepan Michelle , Wilckens Kristine , Hostler Dave , Franzen Peter 
Published: May 2021

Abstract

Introduction
Insufficient sleep impairs cognitive function which results in costly errors. Firefighter shifts regularly exceed 24-hrs with little to no sleep. Nevertheless, firefighters must maintain and flexibly shift attention in high-pressure scenarios. Firefighters also engage in strenuous physical exertion during fire suppression activities. However, it is unclear whether physical exertion acts as another stressor, exasperating cognitive deficits due to insufficient sleep, or whether physical exertion enhances arousal to reduce cognitive deficits. Moreover, the effects of physical exertion may depend on the type of cognitive process and extent of sleep loss. We examined the effect of physical exertion on vigilant attention and task-switching in firefighters who underwent sleep-deprivation or sleep-disruption.

Methods
Participants were 17 healthy young adult males who participated in a within-subjects crossover design with three experimental lab visits: sleep-deprivation, sleep-disruption (woken 3 times for 60-min each), and normal sleep. The next day, participants completed a 50-min treadmill exercise task in a heated room in firefighter protective clothing. Participants completed a vigilant attention task (Psychomotor Vigilance Task, PVT) and a task-switching task five to nine times each visit. The five timepoints of interest–before and after the sleep manipulation night, before and after the treadmill exercise task, and recovery (approximately 180-min following exercise)–were examined using linear mixed effects models.

Results
We analyzed lapses (reaction times [RT]&gt;500ms) on the PVT and switch-trial RT and accuracy on the task-switching task for sleep-deprivation and sleep-disruption conditions relative to normal sleep. Sleep-disruption, p=.001, and sleep-deprivation, p&lt;.001, increased lapses. Sleep-disruption increased switch-trial RT, p=.01, and sleep-deprivation reduced switch-trial accuracy, p=.01. Only switch-trial accuracy improved immediately after the treadmill exercise task and only for the sleep-deprivation condition, p=.01. During recovery, lapses lessened for the sleep-deprivation condition, p=.049, and switch-trial accuracy improved for both sleep-deprivation, p=.01, and sleep-disruption conditions, p=.049.

Conclusion
Physical exertion reduced task-switching and attentional deficits caused by insufficient sleep, with more benefits observed during recovery. We found no evidence for performance decrements due to physical exertion. Physical exertion may interact with the extent of sleep loss–primarily benefitting performance under conditions of total sleep-deprivation.

Support (if any)
DSF Charitable Foundation and University of Pittsburgh Clinical and Translational Science Institute UL1TR001857.
286 Pilot Sleep During Brazil-to-China COVID-19 Humanitarian Mission Flights Compared to Biomathematical Predictions of Sleep
Authors: Devine Jaime , Garcia Caio , Simoes Audrey , Choynowski Jake , Guelere Marina , de Godoy Bruno , Pacheco Philipe , Hursh Steven 
Published: May 2021

Abstract

Introduction
n response to the COVID-19 pandemic, Azul Airlines organized and conducted five separate humanitarian missions to China between May and July, 2020. Each mission consisted of 4 flight legs between 11-15 hours long crewed by a team of 8 pilots. Each pilot was given a 9-hour sleep opportunity during the flight period. Prior to conducting the missions, a sleep-prediction algorithm (AutoSleep) within the Sleep, Activity, Fatigue, and Task Effectiveness (SAFTE) model Fatigue Avoidance Scheduling Tool (FAST) was used to predict in-flight time in bed (TIB) and total sleep time (TST). During missions, pilots wore a wrist actigraph and completed a sleep diary. These analyses compare the accuracy of SAFTE-FAST AutoSleep predictions against pilots’ sleep diary and actigraphy from Azul’s COVID-19 humanitarian missions.

Methods
Pilots wore a sleep-tracking actigraphy device (Zulu Watch, Institutes for Behavior Resources), and reported the TIB and sleep quality of their in-flight rest periods using a sleep diary. Diary TST was estimated from TIB and sleep quality. AutoSleep, diary, and actigraphy measures were compared using paired samples t-tests. Agreement was compared using intraclass correlation coefficients (ICC).

Results
Twenty (n=20) pilots flying across 5 humanitarian missions provided sleep diary and actigraphy data. AutoSleep predictions of TIB (235±20 minutes) and TST (193±16 minutes) were significantly lower than diary (TIB: 330±123, t=6.80, p≤0.001; TST: 262±108, t=5.60, p≤0.001) and comparable to actigraphy (TIB: 246±127, t=0.78, p=0.43; TST: 212±113, t=1.59, p=0.12). ICC values were &gt;0.90, indicating excellent agreement, for TIB (0.94) and TST (0.91).

Conclusion
Biomathematical predictions of in-flight sleep during unprecedented humanitarian missions were in agreement with actual sleep patterns during flights. These findings indicate that biomathematical models may retain accuracy even under extreme circumstances like the COVID-19 pandemic. Pilots may overestimate the amount of sleep that they receive during extreme flights-duty periods, which could constitute a fatigue risk.

Support (if any)
NA
304 The relationship between basic personality, subjective sleep duration, and psychological distress during a military deployment
Authors: Sowden Walter , Bessey Alexxa , Merrill Julie , Mckeon Ashlee , Choynowski Jake , Mantua Janna 
Published: May 2021

Abstract

Introduction
Extended, overseas operations (deployments) increase the likelihood that military personnel will experience psychological distress. Reduced sleep during deployments is a key correlate of psychological distress. Thus, it is imperative to identify mechanisms that adaptively modulate the relationship between insufficient sleep and psychological distress. Research has recently connected basic personality traits (i.e., the Big Five: extraversion, agreeableness, conscientiousness, neuroticism, and openness) to more sleep. The current project aimed to examine the relationship between basic personality traits, subjective sleep duration (SSD), and psychological distress during an operational deployment.

Methods
488 soldiers took surveys both prior to and half-way through a nine-month deployment. The pre-deployment survey included the Big Five Index, and three standardized measures of psychological distress commonly used to screen military personnel for anxiety (Generalized Anxiety Disorder; GAD-7), depression (Patient Health Questionnaire; PHQ-8), and post-traumatic stress (Posttraumatic Symptom Disorder Checklist; PCL-4). The mid-deployment survey included an item from the Pittsburgh Sleep Quality Index measuring SSD and the same psychological distress measures from the pre-deployment survey. General linear models were used to test the interaction between SSD and each basic personality trait on each measure of psychological distress at mid-deployment while accounting for psychological distress at pre-deployment.

Results
Of the Big Five, conscientiousness was the only trait to significantly moderate the relationship between SSD and anxiety, t = 2.11, p = .035, where higher conscientiousness weakened the relationship. Further only agreeableness attenuated the relationship between depression and SSD, t = 2.10, p = .036. Interestingly, the only Big Five trait that moderated the relationship between SSD and PTS was openness, insomuch that openness strengthened the relationship, t = -1.92, p = .055.

Conclusion
The relationship between SSD and psychological distress was uniquely impacted by different personality traits. These results reinforce the age-old concept that behavior is the product of a complex, nuanced, and puzzling interaction between the individual and the environment. The current research motivates further research into personality as an adaptive mechanism for optimizing military wellbeing.

Support (if any)
Support for this study came from the Military Operational Medicine Research Program (MOMRP) of the United States Army Medical Research and Development Command (USAMRDC).