Sleep and Pain in Veterans with Chronic Pain: Effects of Psychological Pain Treatment and Temporal Associations

Introduction

Chronic pain is highly prevalent in US military Veterans. Non-opioid and non-pharmacologic treatments are recommended when clinically appropriate, but research on the mechanisms underlying benefits of these treatments is lacking. Here, we examined the role of sleep in the effects of three non-pharmacologic pain treatments in Veterans. Specifically, we investigated whether treatment effects on sleep predicted treatment effects on pain occurring later, or vice versa.

Methods

Veterans enrolled in a randomized controlled trial were invited to participate in this supplementary sleep study. A total of 174 Veterans were randomized to one of three 8-session, in-person, group-based pain treatments: hypnosis, mindfulness meditation, or education control. Measurements included self-reported sleep disturbance, pain intensity, and pain catastrophizing; sleep duration was assessed with actigraphy. Sleep and pain measurements were obtained at baseline, posttreatment, and 3-month posttreatment follow-up.

Results

At baseline, average pain intensity was moderate (mean ± SD: 5.7 ± 1.7 on the 0-10 Numeric Rating Scale), pain catastrophizing was just below the clinically relevant threshold (mean ± SD: 28.6 ± 12.2 on the Pain Catastrophizing Scale), and subjective sleep disturbance exceeded the US population average (mean ± SD: 58.5 ± 8.1 on the Patient Reported Outcomes Measurement Information System Sleep Disturbance - Short Form). By contrast, objective sleep duration was consistent with the recommended daily sleep amount of 7-8 h for adults (mean ± SD: 8.3 ± 1.4 h). Across treatment conditions, pain intensity, pain catastrophizing, and subjective sleep disturbance were significantly less at posttreatment and 3-month follow-up than at baseline (p < 0.001). Actigraphic sleep duration did not differ significantly as a function of time. There was a high degree of covariation among the measures of pain intensity, pain catastrophizing, and sleep disturbance (p < 0.05). However, self-reported sleep disturbance was not significantly correlated with actigraphic sleep duration (|r| <= 0.13, p > 0.05). Sleep and pain variables observed at prior assessments predicted these same variables at subsequent assessments. There was no significant evidence that changes in pain preceded changes in sleep or that changes in sleep preceded changes in pain (all p > 0.05).

Discussion

For this study's Veterans, treatment-related changes in sleep and pain appeared to occur in parallel. The concomitant changes in sleep and pain suggest that therapies improving pain in Veterans may yield attendant benefits for the treatment of sleep, and possibly vice versa.

Nighttime Sleep and Respiratory Disturbances in Individuals Receiving Methadone to Treat Opioid Use Disorder

ABSTRACT

Opioids are a leading cause of drug overdose deaths in the United States. Methadone used as medication for opioid use disorder (MOUD) reduces drug cravings and promotes abstinence. However, individuals in methadone-based MOUD treatment commonly report subjective sleep complaints and are at risk for respiratory depression from opioids. We investigated nighttime sleep and respiratory function in eight individuals (six women, two men; ages 31-68 years) in their first 90 days of methadone-based MOUD treatment. Participants underwent overnight cardiorespiratory polysomnography. Sleep and respiratory variables were characterized with descriptive statistics for comparison to reference data from similarly aged healthy adults. Although participants spent 8.1 ± 0.3 hours (mean ± SD ) in bed, their total sleep time was only 6.8 ± 1.3 hours. They exhibited longer sleep latency and intermittent wakefulness. Sleep structure was irregular, with disrupted sleep cycles. Participants also displayed a decreased amount of N1 sleep and an increased amount of N3 sleep, compared with reference data. Participants showed respiratory depression, with an average apnea-hypopnea index of 16.5 ± 8.9 events per hour. Central sleep apneas comprised 69.1% ± 20.9% of the respiratory events. A Cheyne-Stokes-like breathing pattern, consisting of 30-second cycles of three central sleep apneas, was observed in 75% of participants. Our results suggest that individuals early in methadone-based MOUD treatment experience disordered sleep and respiratory disturbances. Such nighttime physiological changes may have serious long-term health consequences and contribute to unintended overdose rates. Identifying and treating MOUD individuals with sleep apnea could reduce risk of death.

Effects of total sleep deprivation on components of top-down attentional control using a flexible attentional control task

Sleep deprivation consistently decreases vigilant attention, which can lead to difficulty in performing a variety of cognitive tasks. However, sleep-deprived individuals may be able to compensate for degraded vigilant attention by means of top-down attentional control. We employed a novel task to measure the degree to which individuals overcome impairments in vigilant attention by using top-down attentional control, the Flexible Attentional Control Task (FACT). The FACT is a two-choice task that has trials with valid, invalid, and neutral cues, along with an unexpected switch in the probability of cue validity about halfway in the task. The task provides indices that isolate performance components reflecting vigilant attention and top-down attentional control. Twelve healthy young adults completed an in-laboratory study. After a baseline day, the subjects underwent 39 hours of total sleep deprivation (TSD), followed by a recovery day. The FACT was administered at 03:00, 11:00, and 19:00 during sleep deprivation (TSD condition) and at 11:00 and 19:00 after baseline sleep and at 11:00 after recovery sleep (rested condition). When rested, the subjects demonstrated both facilitation and interference effects on cued trials. While sleep deprived, the subjects showed vigilant attention deficits on neutral cue trials, and an impaired ability to reduce these deficits by using predictive contextual cues. Our results indicate that the FACT can dissociate vigilant attention from top-down attentional control. Furthermore, they show that during sleep deprivation, contextual cues help individuals to compensate partially for impairments in vigilant attention, but the effectiveness of top-down attentional control is diminished.

Drug-Drug Interaction Between Orally Administered Hydrocodone-Acetaminophen and Inhalation of Cannabis Smoke: A Case Report

Objective

To determine if a 2-day protocol measuring pharmacokinetic and pharmacodynamic characteristics can demonstrate drug-drug interactions when smoked cannabis is added to orally administered hydrocodone/acetaminophen combination products.

Case Summary

A 51-year-old non-Hispanic white male with chronic pain diagnoses participated in a 2-day pilot protocol. The participant attended two 7-hour in-lab days where he received 10 blood draws each day and completed self-administered pain and anxiety surveys. For both days, the participant took his prescribed dose of hydrocodone/acetaminophen (1/2 tablet of 7.5 mg/325 mg combination product) with the addition of 1 smoked pre-rolled marijuana cigarette (labeled as 0.5 g; 22.17% Δ9-tetrahydrocannabinol; 0.12% cannabidiol) on Day 2. Blood specimens were analyzed using mass spectrometry to quantify the difference of plasma hydrocodone levels between Day 1 and Day 2.

Results

Compared to Day 1, lower levels of pain and anxiety were reported during Day 2 with the addition of cannabis to oral hydrocodone/acetaminophen. Day 2 pharmacokinetic analysis also revealed more rapid absorption and overall lower levels of hydrocodone in plasma.

Discussion

Lower hydrocodone plasma levels in Day 2 may indicate cannabis's effect on metabolism and reduce the risk of opioid toxicity. The quicker absorption rate of hydrocodone could explain lower pain and anxiety scores reported on the second day.

Conclusion and Relevance

A 2-day protocol was able to capture differences across time in pharmacokinetic and pharmacodynamic measurements. Larger studies can be designed to better characterize the potential drug-drug interaction of cannabis and opioids.

0477 Comparison of a Non-Contact Sleep Monitoring Device with Wrist Actigraphy in a Sample of Individuals with Chronic Insomnia

Introduction

Non-contact devices (NCDs) have been developed to measure sleep longitudinally and unobtrusively in the naturalistic home setting. We compared longitudinal measurements from a wrist actigraph (Actiwatch-2, Philips Respironics) and from a NCD (SleepScore Max, SleepScore Labs) in a sample of adults with insomnia

Methods

N=71 adults (ages 39.0±13.0y; 50 women) who met ICSD-3 criteria for chronic insomnia and were otherwise healthy participated in an at-home sleep monitoring study. Participants continuously wore the actigraph for one week, then used the NCD to record only nightly sleep periods for the next 8 weeks. Week-by-week within-subject averages and standard deviations (SDs) over days were assessed for five major sleep parameters: total sleep time (TST), sleep onset latency (SOL), wake after sleep onset (WASO), time in bed (TIB), and sleep efficiency (SE). These sleep parameters were analyzed with mixed-effects ANOVA comparing week one (actigraphy) to the next 8 weeks (NCD), and correlations between the first week (actigraphy) and second week (NCD) were calculated.

Results

Significant differences for actigraphy versus NCD were found for the weekly averages of SOL and WASO (F&gt;25.8, p&lt;0.001). The NCD measured longer average SOL (M±SEM=25.0±1.5min) than actigraphy (12.6±2.0min) and less average WASO (40.5±2.7min) than actigraphy (51.1±3.2min). Further, significant differences were found for the weekly within-subject SDs of TST and WASO (F&gt;7.52, p&lt;0.01). The NCD measured greater SD for TST (71.6±2.8min) than actigraphy (60.0±4.7min) and greater SD for WASO (25.0±1.4min) than actigraphy (19.2±2.2min). Actigraphy and NCD weekly averages were positively correlated for TST, WASO, TIB, and SE (p&lt;0.001), but not SOL (r=0.03, p=0.80). Similarly, weekly within-subject SDs were positively correlated for TST, WASO, TIB, and SE (p≤0.05), but not SOL (r=–0.03, p=0.81).

Conclusion

Actigraphy and NCD were not used simultaneously, precluding a direct comparison between these measurement modalities. Nonetheless, in this ecologically valid context, significant differences were only found for the weekly averages of SOL and WASO and for the weekly within-subject variability of SOL and TST, with significant correlations between the devices for all variables except SOL. Although actigraphy tends to underestimate SOL, NCD validation against polysomnography in chronic insomnia is warranted.

Support (If Any)

NIH grant KL2TR002317; research devices provided by SleepScore Labs.

0296 Vigilant Attention Performance Advantage Conferred by TNFα G308A Polymorphism is Associated with Diminished Delta and Theta Power in the Non-REM Sleep EEG

Introduction

Carriers of the A allele of a single nucleotide polymorphism of the TNFα gene (G308A, rs1800629) are relatively resilient to vigilant attention performance impairment from total sleep deprivation (TSD), as compared to G/G homozygotes, and even exhibit a small performance advantage at baseline. The mechanism underlying this effect remains unclear. As TNFα is a sleep regulatory substance, we investigated whether TNFα G308A genotype is associated with systematic differences in markers of sleep homeostasis.

Methods

N=168 healthy young adults (ages 27.4±5.4y; 86 women) participated in one of seven in-laboratory TSD studies. During TSD, performance was assessed every 2–3h using a psychomotor vigilance test (PVT). The TSD period was preceded and followed by nocturnal sleep opportunities (baseline and recovery, respectively), which were recorded polysomnographically and scored according to AASM criteria. The EEG (C3-M2 derivation) of stages N2 and N3 non-REM sleep was investigated using spectral analysis.

Results

The genotype distribution of the sample was 0.6% A/A, 26.8% A/G, 72.6% G/G, in Hardy-Weinberg equilibrium (P=0.14). As documented previously, A allele carriers, compared to G/G homozygotes, had fewer PVT lapses (RTs&gt;500ms) at baseline and during TSD, indicating greater resilience to sleep deprivation. During both baseline and recovery sleep, A allele carriers, compared to G/G homozygotes, displayed reduced power in the delta (0.8–4.0Hz; P=0.017) and theta (4.2–8.0Hz; P=0.004) bands of the non-REM sleep EEG.

Conclusion

The performance advantage of the A allele carriers brings to mind the “banking sleep” phenomenon previously observed in sleep deprivation studies with prior sleep extension, suggesting that the A allele carriers gained this advantage by essentially being able to bank sleep. If this interpretation is correct, then the diminished power in the delta and theta bands of the non-REM sleep EEG in the A allele carriers, which suggests reduced homeostatic sleep pressure during both baseline and recovery sleep, may imply that the A allele carriers operate at a lower homeostatic setpoint due to an underlying advantage in the recuperative efficiency of sleep.

Support (If Any)

NIH R01HL070154, R21CA167691, R01HL105768; ONR N00014-13-C-0063, N00014-13-1-0302, FAA DTFAAC-11-A-00003, CDMRP W81XWH-16-1-0319, USAMRDC W81XWH-05-1-0099, and an SRS Elliot D. Weitzman, M.D. Research Grant.

0024 ARC Genotype Modulates EEG Spectral Power Following Total Sleep Deprivation

Introduction

Sleep homeostasis is manifested by a robust increase in slow wave sleep (SWS) following acute total sleep deprivation (TSD), with concomitant changes in spectral power of the non-REM (NREM) sleep EEG marked by substantial interindividual differences. We previously found that a single nucleotide polymorphism of the activity-regulated cytoskeleton associated protein (ARC) gene modulates SWS rebound following TSD. Here we sought to determine whether ARC genotype is also associated with interindividual differences in spectral power of the NREM sleep EEG.

Methods

50 healthy adults (27.3±4.9 years; 28 females) participated in one of two in-laboratory studies. Each participant had a 10h baseline sleep opportunity (22:00–08:00), 38h TSD, and a 10h recovery sleep opportunity (22:00–08:00). Sleep periods were recorded polysomnographically and visually scored according to AASM criteria. Genomic DNA was assayed for the ARC c.*742 + 58C&gt;T non-coding SNP, rs35900184. Log-transformed NREM sleep EEG spectral power (C3-M3 derivation) over 0.2 Hz frequency bins in each of four frequency bands – delta (0.8–4.0 Hz), theta (4.2–8.0 Hz), alpha (8.2–12.0 Hz), and beta (12.2–16.0 Hz) – was analyzed by band using mixed-effects ANOVA with fixed effects for ARC genotype, night (baseline, recovery), frequency bin, and their interactions. Analyses included study and age as covariates and a random effect over subjects on the intercept.

Results

The genotype distribution in this sample was 33 C/C homozygotes, 11 C/T heterozygotes, and 6 T/T homozygotes. There was a significant ARC by night interaction in the theta (F2,1833=5.94, p=0.003) and alpha (F2,1833=8.58, p&lt;0.001) bands. Compared to baseline sleep, during recovery sleep C/C homozygotes had 18.9% more theta power and 8.7% more alpha power, C/T heterozygotes had 17.9% more theta power and 7.6% more alpha power, and T/T homozygotes had 20.0% more theta power and 15.1% more alpha power.

Conclusion

Our results show that ARC genotype mediates the NREM sleep EEG response to TSD; compared to C allele carriers, homozygosity for the T allele is associated with a much more pronounced increase in alpha power, as well as a larger increase in theta power. The functional implications of this ARC effect remain to be determined.

Support (If Any)

ONR N00014-13-1-0302, NIH R21CA167691, and USAMRDC W81XWH-18-1-0100.

Pain Catastrophizing Mediates the Relationship Between Pain Intensity and Sleep Disturbances in U.S. Veterans With Chronic Pain

INTRODUCTION

Veterans with chronic pain frequently report comorbid disruptions in sleep and psychological dysfunction. The purpose of this study was to investigate whether psychological function variables mediate the sleep-pain relationship. Knowledge regarding such contributing factors can inform the development and optimization of treatments for sleep disturbances and pain.

MATERIALS AND METHODS

In an IRB-approved, registered clinical trial, we collected objective sleep data from U.S. military Veterans with chronic pain (N = 184, ages 23-81) using wrist actigraphy for 7 days and self-reported survey data assessing sleep quality, pain intensity, and psychological function (depression, anxiety, post-traumatic stress disorder, and pain catastrophizing). We investigated the associations between objectively measured and self-reported sleep quality and self-reported pain intensity. In addition, using parallel mediation analyses, we examined whether psychological function variables mediated these associations.

RESULTS

Actigraphy showed suboptimal sleep duration (less than 7 hours) and sleep fragmentation for most participants. Self-reported poor sleep quality and pain intensity were significantly correlated. Pain catastrophizing was found to mediate the association between self-reported sleep quality and pain intensity.

CONCLUSIONS

Sleep disturbances in this sample of Veterans with chronic pain included insufficient sleep, fragmented sleep, and perceived poor sleep quality. Analyses suggest that poor perceived sleep quality and pain intensity are mediated via pain catastrophizing. The finding highlights the potential importance of pain catastrophizing in Veterans with chronic pain. Future longitudinal research is needed to determine the extent to which treatments that reduce pain catastrophizing might also improve both sleep and pain outcomes.

727 Impact of Washington State COVID-19 Lockdown on Sleep

Introduction

The COVID-19 pandemic caused a global disruption to daily routines. Studies using surveys and sleep-related applications on mobile devices suggest that the pandemic has contributed to increases in sleep disruption or onset of new sleep disturbances. We present results from a naturalistic at-home study in which objective sleep measurements were made using both a wrist actigraph (Actiwatch-2, Philips Respironics) and a non-contact monitoring device (SleepScore Max, SleepScore Labs), comparing sleep measurements obtained immediately before and after the start of the first mandatory COVID-19 stay-at-home order in Washington State.

Methods

As part of a larger study, nine Washington State residents (ages 22–48, 5 female, 4 male; 6 insomniacs, 3 normal sleeper) were enrolled in a 10-week at-home sleep monitoring study, which involved 1 week of actigraphy, 8 weeks of non-contact monitoring (data available for 6 subjects), and 1 week of actigraphy. During the study, the Washington State governor issued a stay-at-home order, effective March 15, 2020. We compared sleep measurements obtained before this date (mean ± SD: 25.0 ± 15.0 nights) and after this date (25.2 ± 13.9 nights) using mixed-effects ANOVA.

Results

Non-contact monitoring measurements indicated that after the start of the lockdown, participants woke up later by 63.2 ± 12.1 min (mean ± SE; F[1,299]=27.40, p<0.001) without significant change in bedtime (F[1,299]=0.29, p=0.59). Sleep latency lengthened by 4.0 ± 2.3 min (F[1,295]=4.92, p=0.027), and there were increases in number of awakenings (F[1,295]=6.22, p=0.013) and wake after sleep onset (F[1,295]=12.58, p<0.001). Actigraphy data complemented these results, showing delayed sleep onset by 53.4 ± 15.1 min (F[1,101]=12.46, p<0.001) and delayed final awakening by 104.3 ± 19.6 min (F[1,101]=28.43, p<0.001), with longer sleep duration (F[1,101]=6.06, p=0.016), increased number of awakenings (F[1,101]=13.00, p<0.001), and a trend for increased intermittent wakefulness (F[1,101]=3.88, p=0.052) post-lockdown.

Conclusion

In this sample, we found evidence of increased sleep disruption following the first Washington State stay-at-home order related to COVID-19. Our findings are consistent with previous studies based on self-report data, which observed later wake times and decreases in sleep quality post-lockdown.

Support (if any)

NIH grant KL2TR002317. Non-contact monitoring devices provided by SleepScore Labs.

332 Non-REM EEG Spectral Power at Baseline and After Total Sleep Deprivation in Individuals with Sleep-Onset Insomnia

Introduction

The baseline non-REM sleep EEG of individuals with insomnia has been found to display increased spectral power at frequencies &gt;14Hz, which may reflect hyperarousal. There is some evidence in this population of reduced slow wave activity after total sleep deprivation (TSD), potentially indicating altered sleep homeostasis. We investigated non-REM sleep EEG spectra at baseline and after TSD in individuals with sleep-onset insomnia.

Methods

10 individuals with sleep-onset insomnia and 5 healthy controls (ages 22-40y, 11 females) completed a 5-day laboratory study with an adaptation night, baseline night, assignment to 38h TSD (n=5 insomnia, n=5 control) or equivalent non-TSD control (n=5 insomnia), and recovery night. Sleep periods were 10h (22:00-08:00) with digital polysomnography (250Hz; Nihon Kohden). Following artifact rejection, 5s subepochs of the non-REM (stages N2, N3) sleep EEG (C3-M2 derivation) in baseline and recovery nights were subjected to spectral analysis. Spectra (0.2Hz bins) were averaged over subepochs in 30s epochs. Repeated-measures ANOVA compared baseline spectra between insomnia and controls, and baseline-recovery difference spectra between TSD insomnia, non-TSD insomnia, and TSD controls.

Results

Average non-REM sleep amount was 5.9 at baseline, increasing by 1.1h after TSD, with no differences between groups (p≥0.20). At baseline, the insomnia group showed increased power in theta/alpha (~4–12Hz), reaching significance in the lower spindle range, compared to controls (p&lt;0.05). As anticipated, no differences emerged between baseline and recovery nights in the non-TSD insomnia group. However, the TSD insomnia group showed increased delta (~1–3Hz) and theta/alpha (~6–10Hz) power (p&lt;0.05) during recovery. Healthy controls showed expected power increases in delta and lower spindle range, and decreases in upper spindle range (~14–15Hz), after TSD (p&lt;0.05).

Conclusion

Compared to healthy controls, individuals with sleep-onset insomnia showed increased non-REM sleep EEG power in the theta/alpha bands and low spindle frequency range, with further significant increases in theta/alpha in addition to delta power following TSD, despite small sample size. The increase in delta power following TSD was equivalent to that in healthy controls, suggesting no sleep homeostasis abnormality. Whether the elevated theta/alpha power may be related to hyperarousal is unclear.

Support (if any)

ONR grant N00014-13-C-0063

784 Naturalistic Measurement of Sleep/Wake Disturbance in Adults Receiving Methadone Treatment for Opioid Use Disorder

Introduction

Individuals with opioid use disorder (OUD) report significant sleep/wake disturbance, which continues even after stabilization on medication-assisted treatment (MAT). However, the nature of sleep/wake disturbance in this population has not been well documented objectively. Here we analyze naturalistic wrist actigraphy recordings in individuals with OUD receiving methadone-based MAT.

Methods

Seven adults undergoing methadone treatment for OUD (ages 26–50; 4 women) wore a wrist actigraph (Actiwatch-2, Philips Respironics) continuously for 7 days. They were asked to adhere to their normal sleep schedule in order to obtain naturalistic observations. Reference data were collected in a separate study of healthy controls, in which 14 hospital nurses (ages 20–60; 13 women) wore a wrist actigraph continuously for 7 days. In this reference group, 7 participants had a day shift schedule (07:00–19:00) and 7 had a night shift schedule (19:00–07:00), with six 12h shifts in a 2-week period. Actigraphic data were collected in 1min epochs, and the sleep/wake status for each epoch was estimated using Actiware 6.0.9 (Philips Respironics). The estimated sleep/wake patterns were subjected to cosinor analysis to assess 24h rhythmicity and analysis of the distribution of inactive periods to assess sleep continuity.

Results

For the reference group, nurses working day shifts displayed strong 24h rhythmicity, whereas nurses working night shifts showed blunted 24h rhythmicity (F[1,12]=66.11, p&lt;0.001). However, both day and night nurses exhibited high sleep continuity (KS test, p=0.82). By contrast, for the group with OUD receiving methadone, the strength of 24h rhythmicity was reduced to between that of the day and night shift nurses in the reference group, indicating weak regularity of sleep/wake patterns (F[2,18]=33.79, p&lt;0.001). Furthermore, individuals with OUD receiving methadone experienced low sleep continuity compared to the reference group (KS test, p=0.030).

Conclusion

These naturalistic observations confirm the presence of sleep/wake disturbance, resulting from both irregular sleep/wake patterns and low sleep continuity, in individuals receiving methadone-based MAT for OUD. Sleep/wake disturbance may interfere with the ability to achieve OUD recovery goals, and comparing sleep disturbance in MAT populations to reference data highlights the need to consider sleep in these populations as a clinical priority.

Support (if any)

State of Washington Initiative Measure No. 171

Robustness of inter-individual differences in slow wave sleep for daytime sleep periods after total sleep deprivation with or without caffeine administration: potential implications for around-the-clock operations

There are large inter-individual differences in slow wave sleep, which constitute a trait or phenotype. We investigated whether the manifestation of this trait is impacted by daytime sleeping after sleep deprivation, and to what extent it is robust to prior caffeine intake. N = 12 subjects underwent three 48 h periods of total sleep deprivation with different caffeine dosing regimens. There were significant, considerable, and robust inter-individual differences in slow wave sleep across nighttime sleep opportunities before, and daytime sleep after, total sleep deprivation, regardless of caffeine dosing. The robustness of this phenotype may have functional implications for individuals in around-the-clock operational settings.

TNFα G308A genotype, resilience to sleep deprivation, and the effect of caffeine on psychomotor vigilance performance in a randomized, double-blind, placebo-controlled, crossover study

The TNFα G308A gene polymorphism has been reported to influence performance impairment during total sleep deprivation (TSD). We investigated this effect in a randomized, double-blind, crossover laboratory study of repeated exposure to 48 h TSD with caffeine administration at different doses. In a retrospective analysis, we replicated the finding that the A allele of TNFα G308A, found in 4 of 12 study participants, confers resilience to performance impairment during TSD. There was no evidence of an interaction of TNFα genotype with the beneficial effect of caffeine (200 or 300 mg) on performance during TSD, suggesting distinct underlying mechanisms.

0297 Relationship Between Sleepiness Symptoms Questionnaire Ratings and Psychomotor Vigilance Performance in a Total Sleep Deprivation Study

Introduction

While measuring the neurobehavioral consequences of sleepiness is arguably best done with performance tasks providing objective assessments of impairment, this often proves challenging in real-world operational settings. Self-report instruments measuring subjective sleepiness provide a practical alternative, but field studies generally fail to show high correlation between objective and subjective assessments of impairment. The Sleepiness Symptoms Questionnaire (SSQ) is a self-report instrument developed to address this issue by asking about observable symptoms of sleepiness and (motor vehicle driving) performance impairment. In a laboratory sleep deprivation study, we compared SSQ sleepiness ratings to performance impairment on a 10min psychomotor vigilance test (PVT).

Methods

N=12 healthy normal sleepers (ages 21-39y, 6 females) participated in a 4-day in-laboratory study. After a baseline day (9h time in bed; 22:00-07:00), subjects underwent 38h total sleep deprivation (TSD) followed by a recovery day (9h time in bed; 22:00-07:00). As part of neurobehavioral testing throughout the experiment, subjects completed the SSQ and PVT back to back at 6.5h, 14.5h, 22.5h, and 30.5h TSD, and 6.5h after recovery sleep. Data from one subject were incomplete and discarded prior to analysis.

Results

As TSD progressed, the SSQ sleepiness ratings and the number of lapses (RTs&gt;500ms) on the PVT were elevated, with sleepiness and performance impairment peaking at 22.5h TSD. Both measures returned to baseline levels after recovery sleep. Mixed-effects analysis of covariance showed moderate correlation between SSQ ratings and PVT lapses (r=0.44, F1,43=24.1, p&lt;0.001).

Conclusion

Self-reported sleepiness on the SSQ reflected the expected homeostatic and circadian changes in sleep pressure during TSD and following recovery sleep, as did PVT performance impairment. The moderate correlation between subjective ratings on the SSQ, with its emphasis on observable sleepiness symptoms, and objective impairment on the PVT suggests that the SSQ may be a reasonably reliable instrument for measuring sleepiness under conditions of acute sleep deprivation.

Support

Jazz Pharmaceuticals

0274 Associations of TNFα Gene Polymorphism with Resilience to Sleep Deprivation and Caffeine Sensitivity

Introduction

Sleep deprivation degrades the fidelity of human brain information processing, leading to cognitive impairment. Carriers of the A allele of a single nucleotide polymorphism of the TNFα gene (G308A, rs1800629) have been found to be resilient to cognitive impairment due to sleep deprivation as compared to individuals homozygous for the G allele. Caffeine mitigates the cognitive impairment associated with sleep deprivation. We investigated whether the effects of caffeine and TNFα genotype interact.

Methods

In an 18-day, controlled, in-laboratory study, 12 healthy adults (age 27.4±6.9; 6 females) underwent three sessions of 48-hour total sleep deprivation (TSD), with each TSD session preceded and followed by three nights of baseline and/or recovery sleep (10 hours time in bed). In randomized, counterbalanced, double-blind, placebo-controlled fashion, during each TSD session a specific dose of caffeine (0, 200, or 300 mg) was administered four times at 12-hour intervals. Vigilant attention was measured every 2 hours during each TSD session with a psychomotor vigilance test (PVT), for which the log of the signal-to-noise ratio (LSNR) derived from the RT distribution was determined as a measure of the fidelity of information processing. Each subject’s TNFα genotype was assessed from a blood sample.

Results

Subjects homozygous for the TNFα G allele showed greater PVT impairment during sleep deprivation in the 0 mg caffeine (i.e., placebo) condition as compared to carriers of the A allele and as compared to the 200 and 300 mg caffeine conditions (mixed-effects ANOVA, genotype by dose interaction: F2,566=5.23, p=0.005). There was no appreciable caffeine-related difference in performance for carriers of the A allele, who were relatively resilient to TSD regardless of caffeine dose.

Conclusion

These results suggest non-additive, interacting effects of TNFα genotype and caffeine and a potentially shared mechanism of action with regard to the fidelity of information processing during sleep deprivation.

Support

This research was supported by ONR. AJB, TJB, VFC, RHR were supported by DoD MOMRP-USAMRDC. The views expressed here are those of the authors and do not represent the official policy or position of the DoD.

0308 DRD2 C957T Genotype Influences Vigilant Attention Performance Impairment During Total Sleep Deprivation

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&gt;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&lt;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.

Self-Reported Sleep Need, Subjective Resilience, and Cognitive Performance Following Sleep Loss and Recovery Sleep

Objective

Individuals vary in response to sleep loss: some individuals are “vulnerable” and demonstrate cognitive decrements following insufficient sleep, while others are “resistant” and maintain baseline cognitive capability. Physiological markers (e.g., genetic polymorphisms) have been identified that can predict relative vulnerability. However, a quick, cost-effective, and feasible subjective predictor tool has not been developed. The objective of the present study was to determine whether two factors—“subjective sleep need” and “subjective resilience”—predict cognitive performance following sleep deprivation.

Methods

Twenty-seven healthy, sleep-satiated young adults participated. These individuals were screened for sleep disorders, comorbidities, and erratic sleep schedules. Prior to 40 hours of in-laboratory total sleep deprivation, participants were questioned on their subjective sleep need and completed a validated resilience scale. During and after sleep deprivation, participants completed a 5-minute psychomotor vigilance test every 2 hours.

Results

Both subjective resilience and subjective sleep need individually failed to predict performance during sleep loss. However, these two measures interacted to predict performance. Individuals with low resilience and low sleep need had poorer cognitive performance during sleep loss. However, in individuals with medium or high resilience, psychomotor vigilance test performance was not predicted by subjective sleep need. Higher resilience may be protective against sleep loss-related neurobehavioral impairments in the context of subjective sleep need.

Conclusions

Following sleep loss (and recovery sleep), trait resilient individuals may outperform those with lower resiliency on real-world tasks that require continuous attention. Future studies should determine whether the present findings generalize to other, operationally relevant tasks and additional cognitive domains.

Sleep problems and functioning during initial training for a high-risk occupation

OBJECTIVES

The current study sought to characterize the sleep problems of soldiers entering Basic Combat Training and to identify the link between sleep problems and subsequent performance, psychological distress, anger reactions, and attention.

DESIGN

Soldiers were surveyed at 4 time points throughout the standard 10 weeks of Basic Combat Training. Surveys were administered at weeks 1, 3, 6, and 9. Sleep problems were identified as either present or absent at each time point using a sleep problem screening questionnaire. Four sleep patterns were identified and then used to evaluate outcomes throughout training (n = 1577).

RESULTS

When compared to those who never had a sleep problem ("healthy "; 60.6%), those who recovered from their initial sleep problem ("recovered"; 12.8%) started training with higher psychological distress and anger reactions and lower attention but steadily improved throughout training. Those who developed a sleep problem during training ("new onset"; 20.0%) and those who had a sleep problem throughout training ("chronic"; 6.6%) also started off significantly worse than the healthy group. The new-onset and chronic groups saw slower psychological distress improvement and a decline in attention throughout the course compared to the healthy group. The chronic group also significantly increased their anger reactions throughout training compared to the healthy group.

CONCLUSION

Sleep problems during Basic Combat Training may be an indicator for difficulties managing entry into the military. These findings highlight the importance of improving sleep health for soldiers throughout Basic Combat Training and for others with similar training in high-risk occupations.

Objective changes in activity levels following sleep extension as measured by wrist actigraphy

OBJECTIVE/BACKGROUND

It is widely established that insufficient sleep can lead to adverse health outcomes. Paradoxically, epidemiologic research suggests that individuals who report habitual nightly sleep greater than 9 h also are at risk for adverse health outcomes. Further, studies have shown that long sleepers have decreased activity levels, which may partially explain the relationship between long sleep duration and mortality. The influence of sleep extension (longer time in bed) on levels of daily activity has not yet been established. The current study examined whether a week of sleep extension altered activity levels within the subsequent daily waking active and sleep period in order to determine whether increased time in bed indeed is related to decreased activity levels.

METHODS

A total of 26 healthy volunteers wore wrist accelerometer devices (Actiwatch 2.0, Philips) in order to objectively measure sleep and activity for six days during their normal schedules and for six days during a sleep extension (10 h time in bed) intervention.

RESULTS

There were no significant or clinically-relevant differences in 24-h activity or activity during the active or sleep period between baseline and sleep extension conditions. There were no main or interaction effects of day and condition when daily activity counts were compared between baseline and sleep extension conditions for the 24 h period (Day: F_{(5, 21)} = 1.92, p = 0.12; Condition: F_(1,25) = 2.93, p = 0.09; Day by Condition: F_(5,21) = 0.32, p = 0.83), Active Waking Period (Day: F_(5,25) = 1.53, p = 0.18; Condition: F_(1,25) = 0.26, p = 0.61; Day by Condition: F_(5,21) = 0.55, p = 0.74) or Nightly Sleep (Day: F_(5,21) = 0.86, p = 0.51; Condition: F_(1,25) = 1.78, p = 0.19; Day by Condition: F_(5,21) = 0.79, p = 0.56) periods. In contrast, there was a main effect of condition when examining sleep duration by day between conditions (Day: F_(5,21) = 1.60, p = 0.16; Condition: F_(1,25) = 167.31, p < 0.001; Day by Condition: F_(5,21) = 2.31, p = 0.07), such that sleep duration was longer during the sleep extension condition.

DISCUSSION

Sleep duration increased during six days of a sleep extension protocol but activity levels remained similar to their baseline (normal) sleep schedule. The current findings suggest that extending time in bed alone does not alter waking activity counts in young healthy adults. The link between extended sleep and adverse health outcomes may be attributable to other phenotypic factors, or other biological correlates of extended sleep and poor health.

Sleep extension reduces fatigue in healthy, normally-sleeping young adults

Objective

To assess the effects of one week of sleep extension on mood, fatigue and subjective sleepiness in normal-sleeping young adults.

Methods

Twenty-seven adults (age 24.4±5.4 years, 11 female) participated. At-home baseline sleep/wake patterns were recorded with wrist actigraphy for 14 days. This was followed by two nights of in-lab baseline sleep with 8 hours time in bed (TIB), then 7 nights with TIB extended to 10 hours (2100-0700 hours). Fatigue, mood, and sleepiness were assessed following the 2^nd and 9^th nights of in-laboratory sleep (i.e., 2 nights with 8hTIB and 7 nights with 10 hours TIB, respectively) using the Automated Neuropsychological Assessment Metric and Karolinska Sleepiness Scale. Paired t-tests were used to compare mood, fatigue, and sleepiness ratings between conditions.

Results

At-home wrist actigraphy revealed a mean nightly total sleep time (TST) of 7.53 +/- 0.88 hours of sleep per night. Mean in-lab baseline sleep duration (7.76 +/- 0.59) did not differ from at-home sleep. However, during sleep extension, mean TST was 9.36 +/- 0.37 hours per night, significantly more than during the in-lab baseline (p < .001). Following sleep extension, fatigue ratings were significantly reduced, relative to baseline (p = .03). However, sleep extension had no other significant effects on subjective ratings of mood or sleepiness.

Conclusions

Sleep extension resulted in reduced fatigue in healthy, normal-sleeping young adults, although subjective sleepiness and mood were not improved. Implications include the possibility that (a) the effects of sleep extension on various aspects of mood depend upon the extent to which those aspects of mood are made salient by the study design and methodology; and (b) sleep extension may prove beneficial to fatigue-related conditions such as “burnout.”