Subjective Sleepiness Research Articles

The Influence of Emergency Call Volume on Occupational Workload and Sleep Quality in Urban Firefighters.

The aim of the study is to determine the impact of emergency call volume on exertion, autonomic activity, and sleep among urban structural firefighters. Thirty-four firefighters wore a wrist-based monitor to track sleep and autonomic parameters and rated their level of perceived exertion (Borg Rating of Perceived Exertion) and subjective sleepiness after a 24-hour shift. Predictive variables included total run time and total run time after 11:59 PM. Total run time and sleep duration accounted for Borg Rating of Perceived Exertion and subjective sleepiness, while total run time and total run time after 11:59 PM accounted for sleep durations on-duty. The current results suggest that emergency call volume is associated with indicators of exertion and sleep. As such, call volume tracking is an important consideration for departments to ensure personnel readiness and wellness and provide a method of tracking the occupational demands experienced by firefighters on-duty.

Reverse Sleep State Misperception: a Rare Clinical Presentation in Sleep Clinics

Reverse Sleep State Misperception: a Rare Clinical Presentation in Sleep Clinics

Inverse association between slow-wave sleep and low-grade inflammation in children and adolescents with major depressive disorder

ObjectiveTo investigate the relationship between both self-reported and objective sleep variables and low-grade inflammation in children and adolescents with major depressive disorder (MDD) of moderate to severe symptom severity. MethodsIn this cross-sectional study, we examined twenty-nine children and adolescents diagnosed with MDD and twenty-nine healthy controls (HC). Following a one-week actigraphy assessment, comprehensive sleep evaluations were conducted, including a one-night sleep EEG measurement and self-reported sleep data. Plasma high-sensitivity C-reactive protein (hsCRP) was employed as a marker to assess low-grade inflammation. ResultsNo significant difference in hsCRP levels was observed between participants with MDD and HC. Furthermore, after adjusting for sleep difficulties, hsCRP exhibited no correlation with the severity of depressive symptoms. In HC, levels of hsCRP were not linked to self-reported and objective sleep variables. In contrast, depressed participants showed a significant correlation between hsCRP levels and increased subjective insomnia severity (Insomnia Severity Index; r = 0.41, p < 0.05), increased time spent in the N2 sleep stage (r = 0.47, p < 0.01), and decreased time spent in slow-wave sleep (r = − 0.61, p < 0.001). Upon additional adjustments for body mass index, tobacco use and depression severity, only the inverse association between hsCRP and time spent in slow-wave sleep retained statistical significance. Moderation analysis indicated that group status (MDD vs. HC) significantly moderates the association between slow-wave sleep and hsCRP. ConclusionOur findings suggest that alterations in the architecture of slow-wave sleep may have a significant influence on modulating low-grade inflammatory processes in children and adolescents with MDD.

The Role of Sleep for Age-Related Differences in Neurobehavioral Performance.

This study investigated developmental changes from childhood to adulthood in neurobehavioral performance and sleep measures. While many studies have examined age-related changes between childhood and adolescence and from mid-to-late adulthood, young adulthood has been overlooked. The main aim of this study was to investigate the effects of sleep loss on developmental changes in neurobehavioral performance and sleepiness in a natural setting. A total of 119 children, adolescents, and young adults (38 children aged 6-9; 38 adolescents aged 13-19; and 43 young adults aged 20-27) wore an actigraph for a continuous five-weekday night. Subjective sleepiness (Karolinska Sleepiness Scale) and neurobehavioral performance (using the psychomotor vigilance test and the digit symbol substitution test) were measured on five school days. The results showed that adolescents and young adults outperformed children on both the digit symbol substitution test and the psychomotor vigilance test measures. However, adolescents committed more errors of commission on the psychomotor vigilance test and reported higher levels of subjective sleepiness. The results are discussed in relation to brain maturation in various cognitive functions.

The dynamics of neurobehavioral impairment and recovery sleep: improved biomathematical modeling for fatigue risk management in operational settings

Adequate sleep is essential for maintaining health, safety, and neurobehavioral functioning in 24/7 operational settings. Loss of sleep causes fatigue, which results in neurobehavioral impairment. Neurobehavioral impairment builds up disproportionately under conditions of total sleep deprivation compared to sustained sleep restriction; and recuperation due to recovery sleep is disproportionately fast after total sleep deprivation compared to sustained sleep restriction. These sleep schedule-dependent dynamics have been captured in a previously published, biomathematical model of fatigue, which includes positive feedback regulation of a relatively fast (hours to days) sleep/wake homeostatic process by a slower (days to weeks) allostatic process—a feature that suggests adenosinergic mechanisms are involved. However, the previously published model underestimates the rate of recuperation due to recovery sleep after acute total sleep deprivation as well as after consecutive days of sleep restriction. The objective of the present research is to modify the model to improve the accuracy of its predictions for recuperation due to recovery sleep. This can be accomplished by including in the model an additional, reciprocal feedback mechanism, presumed to be predominantly adenosinergic in nature, which provides feedback from the faster homeostatic process back onto the slower allostatic process. Adding a single new model parameter and refitting three existing model parameters significantly improves the predictions for recuperation due to recovery sleep after both acute total sleep deprivation and sustained sleep restriction. This model modification also improves the predictions of the build-up of neurobehavioral impairment across days of sustained sleep restriction, without adversely affecting the accuracy of the model in other scenarios including circadian misalignment and sleep inertia. The modified model preserves the previously developed capability to predict the differential dynamics of fatigue for objective performance impairment and subjective sleepiness. With the improved predictions for recuperation due to recovery sleep, the expanded model can be used to provide quantitative estimates for potentially impactful work scheduling decisions, such as the duration of time off needed before workers would be safe to return to the work floor. This enhances the usefulness of the model as a tool for predicting and managing neurobehavioral functioning and safety in 24/7 operational settings.

Association between sleep quality and dry eye disease: a literature review and meta-analysis

ObjectiveThe purpose of this article is to systematically review the association between dry eye and sleep quality.MethodsPubMed, EMBASE, Cochrane, Web of Science, and grey literature databases were searched for observational studies published before April 2023. Meta-analysis was performed using STAT15 software.ResultsA total of 21 studies with 419,218 participants were included. The results showed that the dry eye subjects had a worse sleep quality than the healthy population, with poorer subjective sleep quality, longer sleep latency, and a higher risk of unhealthy sleep duration such as insufficient sleep or excessive sleep. The Pittsburgh Sleep Quality Index (PSQI) scores of the dry eye subjects were significantly higher than those of the control subjects (WMD = 1.78, 95%CI: 1.06, 2.50, P < 0.001). The dry eye subjects scored higher than the control subjects in sleep quality, sleep latency, and sleep disturbance in PSQI; there was no difference between the dry eye individuals and control subjects in sleep duration, sleep efficiency, daytime dysfunction, and sleep medication scores. The risk of sleep disorders in the dry eye subjects was significantly higher than that in the non-dry eye subjects (RR = 2.20, 95%CI: 1.78, 2.72, P < 0.001); the risk of insufficient sleep in the dry eye subjects was higher than that in the control subjects (RR = 3.76, 95%CI: 3.15, 4.48, P < 0.001), and the prevalence of excessive sleepiness in dry eye subjects was higher than that in the control subjects (RR = 5.53, 95%CI: 3.83, 7.18, P < 0.001). The ESS scores of the dry eye subjects were significantly higher than those of the control subjects (WMD = 3.02, 95%CI: 2.43, 3.60, P < 0.01).ConclusionOur meta-analysis suggests that individuals with dry eye have a worse sleep quality than the healthy population, with poorer subjective sleep quality, longer sleep latency, and higher risk of unhealthy sleep duration such as insufficient sleep or excessive sleepiness.

Abstract 25: Association Between Household Sleep Environment and Sleep Health Characteristics: The Coronary Artery Risk Development in Young Adults (CARDIA)—Sleep Study

Introduction: Household environmental factors and sleep behaviors may contribute to poor sleep health. We identified associations between household sleep environment (HHSE) and sleep health characteristics. Hypothesis: Individuals with adverse HHSE will have poorer sleep health. Methods: We used cross-sectional data from the CARDIA sleep ancillary study at Year 35. HHSE (i.e., sleep disruptors and sleep behaviors) scores were derived from responses to questions in the questionnaire (see Table footnote), where a higher score indicated higher sleep disruptors or more detrimental sleep behaviors. Sleep outcomes were: 1) sleep quality assessed with the Pittsburgh Sleep Quality Index (PSQI) and daytime sleepiness assessed with the Epworth Sleepiness Scale (ESS) (N=699) and 2) sleep duration (minutes) and efficiency (%) measured by 7-day wrist actigraphy (N=574). Robust regression estimated differences in sleep outcomes corresponding to each 1-score increment in HHSE. We adjusted for age, sex, race, education, smoking status, body mass index, depressive symptoms, and comorbidities. Racial differences in associations of interest were examined by testing for interaction. Results: Participants mean age was 61.5 years, 63.1% were female and 35.9% were Black. Means (SD) of PSQI, ESS scores, sleep duration, and sleep efficiency were 6.2 (3.7), 5.5 (3.7), 414.6 minutes (SD=60.4), and 84.4% (SD= 6.7), respectively. After multivariable adjustment, both higher sleep disruptors and more detrimental sleep behaviors were associated with poorer sleep quality and greater daytime sleepiness. HHSE showed no association with sleep duration and efficiency (Table 1). Sleep disruptors were only significantly associated with daytime sleepiness among Black participants (p-interaction= 0.01). Conclusions: Adverse household sleep environment was related to poorer subjective sleep quality and daytime sleepiness. Future studies should investigate reasons why Black adults appear more susceptible to household sleep disruptors.

Tagesschläfrigkeit bei Patienten mit unbehandeltem Restless-Legs-Syndrom

Abstract Background Restless legs syndrome (RLS), a disorder characterized by an urge to move one’s legs during sleep or rest, leads to impaired sleep quality. Many patients with RLS report increased daytime sleepiness, but this has seldom been the focus of clinical research. The current study empirically investigated the prevalence and severity of daytime sleepiness in RLS. Methods This prospective study included 29 newly diagnosed treatment-naïve patients with RLS and 31 healthy controls and assessed standardized subjective (tiredness symptom scale [TSS], Stanford Sleepiness Scale [SSS], Epworth Sleepiness Scale [ESS]), cognitive (psychomotor vigilance task [PVT], Mackworth Clock Test [MCT]), and physiological measures (pupillary unrest index [PUI]). RLS symptom severity was assessed, and the effects of RLS on general health aspects and subjective sleep quality (Pittsburgh Sleep Quality Index) were compared to control data. Results Patients had moderate to severe RLS with significant negative effects on general health, quality of life, and sleep quality. Patients with RLS showed more subjective daytime sleepiness (ESS) and current sleepiness (TSS, SSS) than controls. The objective performance of patients in sustained attention tasks (P VT, MCT) was significantly worse than that of controls. Additionally, patients showed higher PUI scores. Conclusion In the present study, RLS was associated with markedly impaired subjective sleep quality and with subjectively and objectively increased daytime sleepiness. Since daytime sleepiness can be a major factor leading to compromised quality of life, assessing and treating sleepiness should be incorporated into standard diagnostics and treatment.

Assessment of Psychometric Characteristics of Parkinson's Disease Sleep Scale 2 and Analysis of a Cut-Off Score for Detecting Insomnia in Italian Patients with Parkinson's Disease: A Validation Study.

Sleep disorders are frequent non-motor symptoms affecting patients with Parkinson's disease (PD). Insomnia represents the most common sleep disorder. Parkinson's disease Sleep Scale 2 (PDSS-2) is a specific tool to investigate sleep problems in PD. The General Sleep Disturbances Scale (GSDS) was a general scale validated for the Italian population. Our goal was to assess the psychometric characteristics of PDSS-2 and the GSDS in this population, calculating a cut-off score for insomnia symptoms by using subitems of PDSS-2. Patients admitted at the PD Unit of the Hospital of Rome Tor Vergata outpatient clinic and those afferent to PD associations were asked to complete PDSS-2 and GSDS to be correlated to identify a cut-off for insomnia symptoms. Items 1,2,3,8,13 of PDSS-2 were used to detect insomnia. An ROC curve to assess a cut-off score for insomnia was determined. A cross-cultural analysis of PD population characteristics was performed. In total, 350 PD patients were recruited. Cronbach's alpha was high for the total score (0.828 for PDSS-2 and 0.832 for GSDS). A cross-cultural analysis did not show any significant p-value. The ROC curve yielded an AUC of 0.79 (CI: 0.75-0.84). The cut-off value for insomnia disorder based on items 1,2,3,8,13 of PDSS-2 was >10, demonstrating a sensitivity of 76% and a specificity of 69% in determining the presence of subjective insomnia symptoms in PD. PDSS-2 is demonstrated to be a valid, specific tool to address sleep disturbances in PD patients. A cut-off score of 10 for items 1,2,3,8,13 was identified for detecting insomnia symptoms in PD patients.

Investigating Fatigue in Operational Nightshifts

Abstract: The study investigated sleepiness and fatigue in a single split nightshift arrangement in air traffic control. The arrangement included two mirrored nightshift types, with sleep and operational phases alternating once mid-shift. Sleep duration, subjective sleepiness, and fatigue as well as sustained attention, which have not been thoroughly studied to date, were examined. The findings suggest different sleep strategies. Working during the second part of the night resulted in reduced sleep duration before the shift. Subjective fatigue exhibited varying patterns depending on the shift type and time, with elevated fatigue observed at the start and middle of the shift. However, subjective sleepiness and sustained attention were primarily influenced by the passage of time.

Effects of daylight and darkness at daytime versus nighttime on driver sleepiness: A driving simulator study

The study explores the impact of light conditions on driver sleepiness. In a driving simulator experiment, 20 drivers drove both during daytime in an alert condition and then later at night after being awake since early morning. Light conditions were manipulated by driving in a simulated nighttime scenario in a dark room (1 lx) versus driving in simulated daylight in a room lit with light emitting diodes combining blue light with a yellow phosphor giving a two peaked spectrum (212 lx). Both the daylight and the darkness scenarios were driven daytime and nighttime in a 2 × 2 design. Sleepiness was measured during the four 1-hour drives in terms of subjective sleepiness ratings, divided attention ability, driving performance, heart rate variability and blink behaviour. Significant differences were found in all measured sleepiness indicators between the daytime and nighttime drives, and in most indicators for time-on- task. No significant main effects were found between simulated daylight and darkness. A psychomotor vigilance test conducted before and after each drive also showed no significant effects for lighting condition. Further research, preferably using longitudinal studies in more realistic settings on real roads, is needed to determine which behaviours and which cognitive processes that are affected when driving in daylight versus darkness.

Determinants of physical activity in newly diagnosed obstructive sleep apnea patients: testing the health action process approach.

This study aims to identify the determinants associated with physical activity (PA) behavior in newly diagnosed obstructive sleep apnea (OSA) patients by applying the Health Action Process Approach (HAPA) with a longitudinal design. Anthropometric and clinical (OSA severity, subjective somnolence, use of continuous positive airway pressure (CPAP)) variables, the determinants of physical activity specified in the HAPA (motivational self-efficacy, outcome expectancies, risk perception, intention, maintenance self-efficacy, action planning, coping planning, social support), as well as physical activity behavior were assessed using a longitudinal (T1 and T2) design in a sample of 57 OSA patients in routine care. Applying regression analyses, regarding the motivation phase, the amount of explained variance in intention was 77% and 39% of the variance in physical activity. In the motivational phase, motivational self-efficacy, risk perception and outcome expectancies were associated with intention. In the volitional phase, physical activity at T1 and social support (family) were related with physical activity at T2. In conclusion, the assumptions of HAPA were partially found in the context of newly diagnosed OSA patients. This study provided additional evidence regarding the role of motivational self-efficacy, outcome expectancies and risk perception during motivational phase, and highlighted the important role of social support from the family in the PA in this population.

Prolonged theoretical classes impact students' perceptions: an observational study.

Mental fatigue (MF) arises during prolonged demanding cognitive activity and results in acute feelings of tiredness and a decreased physical and/or cognitive performance capacity. An often-overlooked population that is significantly at risk for the development of MF are university students. The current study investigated the impact of prolonged in-person theoretical classes on the perceptions of MF, boredom, and sleepiness among 27 Slovenian university students (first-year physiotherapy). Their subjective experiences at various time points during a 4-h class interspersed with a 20 min break were assessed with a repeated measures ANOVA and consequent Bonferroni post-hoc tests (significance set at <0.05). Subjective MF and sleepiness significantly increased during the first and the second part of the class (p < 0.05), while they significantly decreased during the break (p < 0.05). Boredom levels only increased significantly during the second part of the class (p < 0.05). Additionally, students who had inadequate sleep the night before the class reported higher levels of MF at the beginning of the class. This study highlighted a significant impact of a theoretical class on subjective feelings of mental fatigue and showed that a break in the middle of the class temporarily alleviated this negative impact. These results emphasize the importance of adequate sleep, effective breaks, and strategies to manage cognitive workload in optimizing students' cognitive well-being and academic performance. Further research is needed to better understand the underlying factors and develop targeted interventions to support students' cognitive functioning and well-being during prolonged academic sessions.

Brain structural correlates of subjective sleepiness and insomnia symptoms in shift workers.

Studies on the brain structures of shift workers are limited; thus, this cross-sectional study aimed to compare the brain structures and the brain structural correlates of subjective sleepiness and insomnia symptoms between shift workers and non-shift workers. Shift workers (n = 63) and non-shift workers (n = 58) completed questionnaires assessing subjective sleepiness and insomnia symptoms. Cortical thickness, cortical surface area, and subcortical volumes were measured by magnetic resonance imaging. The brain morphometric measures were compared between the groups, and interaction analyses using the brain morphometric measures as the dependent variable were performed to test the interactions between the study group and measures of sleep disturbance (i.e., subjective sleepiness and insomnia symptoms). No differences in cortical thickness, cortical surface area, or subcortical volumes were detected between shift workers and non-shift workers. A single cluster in the left motor cortex showed a significant interaction between the study group and subjective sleepiness in the cortical surface area. The correlation between the left motor cortex surface area and the subjective sleepiness level was negative in shift workers and positive in non-shift workers. Significant interaction between the study group and insomnia symptoms was present for the left/right putamen volumes. The correlation between the left/right putamen volumes and insomnia symptom levels was positive in shift workers and negative in non-shift workers. Left motor cortex surface area and bilateral putamen volumes were unique structural correlates of subjective sleepiness and insomnia symptoms in shift workers, respectively.

Sleepy without stimulation: subjective and objective sleepiness in actigraphy-verified natural short sleepers.

Natural short sleepers (NSS)-individuals who report minimal sleepiness or daytime dysfunction despite habitually sleeping less than the recommended amount (i.e., <7 h)-are a focus of growing interest in sleep research. Yet, the predominance of research on NSS has relied on subjective reports of functionality. The present study examined subjective and objective sleepiness among actigraphy-verified NSS in comparison with recommended (7-9 h/day) length sleepers (RLS) who reported similarly minimal daytime dysfunction. The study tested the hypothesis that under conditions of low environmental stimulation, NSS have increased risk of drowsiness and sleep onset, regardless of perceived alertness. The NSS and RLS groups were identified via screening and verified with a 14 day assessment with actigraphy, sleep diaries, and morning ratings of sleep restoration. In-laboratory resting electroencephalography (EEG) data were analysed using a computerised EEG-based algorithm (Vigilance Algorithm Leipzig; VIGALL) to classify second-by-second changes in objective sleepiness ranging from cognitively active alertness to sleep onset. Results demonstrated that NSS exhibited significantly higher drowsiness and sleep onset ('microsleeps') across 15 min of resting EEG despite perceptions of lower subjective sleepiness compared to RLS. Findings suggest that irrespective of perceived sleep restoration and alertness, NSS appear to be at high risk of objective sleepiness that is rapidly unmasked under conditions of low environmental stimulation. Such apparent discrepancy between subjective and objective sleepiness has potentially important public health implications. Future research directions, including tests of mechanisms and tailored sleep extension intervention, are discussed.

Sleep deprivation detected by voice analysis.

Sleep deprivation has an ever-increasing impact on individuals and societies. Yet, to date, there is no quick and objective test for sleep deprivation. Here, we used automated acoustic analyses of the voice to detect sleep deprivation. Building on current machine-learning approaches, we focused on interpretability by introducing two novel ideas: the use of a fully generic auditory representation as input feature space, combined with an interpretation technique based on reverse correlation. The auditory representation consisted of a spectro-temporal modulation analysis derived from neurophysiology. The interpretation method aimed to reveal the regions of the auditory representation that supported the classifiers' decisions. Results showed that generic auditory features could be used to detect sleep deprivation successfully, with an accuracy comparable to state-of-the-art speech features. Furthermore, the interpretation revealed two distinct effects of sleep deprivation on the voice: changes in slow temporal modulations related to prosody and changes in spectral features related to voice quality. Importantly, the relative balance of the two effects varied widely across individuals, even though the amount of sleep deprivation was controlled, thus confirming the need to characterize sleep deprivation at the individual level. Moreover, while the prosody factor correlated with subjective sleepiness reports, the voice quality factor did not, consistent with the presence of both explicit and implicit consequences of sleep deprivation. Overall, the findings show that individual effects of sleep deprivation may be observed in vocal biomarkers. Future investigations correlating such markers with objective physiological measures of sleep deprivation could enable "sleep stethoscopes" for the cost-effective diagnosis of the individual effects of sleep deprivation.

Subjective sleepiness better predicts effort-related cardiovascular response than sleep duration per se

Subjective sleepiness better predicts effort-related cardiovascular response than sleep duration per se

The association between Superwoman schema and subjective sleep quality among Black women

ObjectivesSimilar to women overall, Black women are socialized to be communal and “self-sacrificing,” but unlike women from other racial/ethnic backgrounds, Black women are also socialized to be “strong” and “invulnerable.” This phenomenon is labeled Superwoman schema. This study examined associations between Superwoman schema endorsement and subjective sleep quality. MethodsParticipants included 405 Black women (ages 30-46). Superwoman schema was measured using a 35-item scale capturing five dimensions: obligation to present strength, suppress emotions, resistance to vulnerability, motivation to succeed, and obligation to help others. Superwoman schema overall and the five dimensions/subscales were analyzed. The Pittsburgh Sleep Quality Index (PSQI) was used to investigate overall subjective sleep quality (range: 0-19), poor sleep quality (PSQI >5), and specific sleep domains (eg, sleep duration, sleep disturbances). We fit linear and binary logistic regression models, adjusting for health-related and sociodemographic factors. ResultsSuperwoman schema dimension obligation to help others was associated with lower overall subjective sleep quality (β: .81, 95%CI=0.29, 1.32) and poor sleep quality (OR: 1.55, 95%CI=1.10, 2.19), as well as bad subjective sleep quality (OR: 1.76, 95%CI=1.18, 2.66), sleep disturbances (β: .73, 95%CI =0.07, 1.41), and daytime sleepiness (OR: 2.01, 95%CI=1.25, 3.26). Suppress emotions (OR: 1.41, 95%CI=1.01, 1.99) was associated with poor subjective sleep quality. Superwoman schema overall was associated with daytime sleepiness (OR: 2.01, 95%CI=1.06, 3.82). ConclusionSuperwoman schema endorsement, especially obligation to help others and suppress emotions, may be important psychosocial risk factors for Black women’s sleep health.

Subjective sleep quality and sleepiness dynamics on a group of military submariners: before, during and after a mission

Subjective sleep quality and sleepiness dynamics on a group of military submariners: before, during and after a mission

A novel analytic framework to identify the neural signatures of sleep state misperception from polysomnographic recordings

A novel analytic framework to identify the neural signatures of sleep state misperception from polysomnographic recordings