Lower Daytime Sleepiness Research Articles

Less daytime sleepiness and slow wave activity during sleep predict better physical readiness in military personnel

BackgroundMilitary personnel must maintain physical performance despite exposure to operational stressors such as sleep loss, caloric restriction and high cognitive load. Habitual sleep and specific sleep features are positively associated with fitness and may contribute to physical performance in operational settings. Further, by affecting muscle recovery, sleep may contribute to the ability to maintain performance across multiple days of exposure to operational stressors. ObjectivesWe examined the role of individual differences in baseline sleep on baseline physical performance and on change in physical performance throughout exposure to simulated military operational stress (SMOS). MethodsMilitary personnel (36 male, 9 female, 26.3 ± 5.3 years) completed a 5-day SMOS protocol during which they completed a tactical mobility test daily. Sleep questionnaires were administered at intake and sleep was monitored each night with polysomnography. Lasso regressions were used to identify meaningful predictors of physical performance at baseline and of change in physical performance across SMOS. ResultsBetter aerobic fitness, lower daytime sleepiness (Epworth Sleepiness Scale), and lower absolute slow wave activity (0.5-4 Hz) predicted better physical performance at baseline (66.1% of variance explained), but did not relate to changes in performance. ConclusionsCollectively, higher daytime sleepiness and slow wave activity may reflect more chronic exposure to insufficient sleep and higher baseline sleep drive, which in turn led to compromised physical performance. The findings suggest that low self-report sleepiness and low objective slow wave activity may reflect two quantifiable markers of healthy sleep behaviors that have implications for operational performance.

The Effect of Smartphone Use and Nomophobia on Sleep Quality and Daytime Sleepiness in Turkey

Abstract Background Smartphones used unconsciously and in an uncontrolled manner make young people experience sleep problems. This study aimed to investigate the effects of university students’ smartphone addiction and nomophobia levels on sleep quality and excessive daytime sleepiness. Methods This study, which had a cross-sectional design, was conducted with 390 people who were first-year and senior students at Inonu University between November and December 2019. The Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale, Nomophobia Scale, and Smartphone Addiction Scale were used in the present study used. For statistical analysis, the chi-squared test, the Student’s t-test, one-way ANOVA, Spearman’s rank correlation coefficient and binomial logistic regression analysis were used. The research has ethics committee approval.The error level was chosen as p = 0.05. Results The smartphone use time of the students was finded to be 5.4±2.6 years, daily online time was 4.3±2.6 hours, and daily sleep time was 7.4±1.5 hours. The students received 78.3±25.8 points from the Nomophobia Scale, 90.3±29.7 from the Smartphone Addiction Scale, 7.2±2.8 from the Pittsburgh Sleep Quality Index, and 5.9±4.1 points from the Epworth Sleepiness Scale. A total of 54.4% of students had moderate, and 22.8% had severe nomophobic symptoms; 83.6% of the group had poor sleep quality, and 14.6% had excessive daytime sleepiness. A positive, moderate and significant relation was detected between the mean Nomophobia score and the mean Smartphone Addiction Scale score. It was also determined that those with less than 30 minutes of smartphone use before sleeping had low nomophobia, smartphone addiction and daytime sleepiness scores, and better sleep quality. Conclusions Nomophobic symptoms and smartphone addiction were observed to be high in university students. Most students had poor sleep quality. The awareness of students on healthy sleep, and conscious and controlled smartphone use should be increased. Key messages • Smartphone addiction increases the level of nomophobia moderately in university students. • Those who use a smartphone less than 30 minutes before going to sleep have better sleep quality and lower daytime sleepiness.

Personalized sleep-wake patterns aligned with circadian rhythm relieve daytime sleepiness

SummaryShift workers and many other groups experience irregular sleep-wake patterns. This can induce excessive daytime sleepiness that decreases productivity and elevates the risk of accidents. However, the degree of daytime sleepiness is not correlated with standard sleep parameters like total sleep time, suggesting other factors are involved. Here, we analyze real-world sleep-wake patterns of shift workers measured with wearables by developing a computational package that simulates homeostatic sleep pressure – physiological need for sleep – and the circadian rhythm. This reveals that shift workers who align sleep-wake patterns with their circadian rhythm have lower daytime sleepiness, even if they sleep less. The alignment, quantified by the sleep parameter, circadian sleep sufficiency, can be increased by dynamically adjusting daily sleep durations according to varying bedtimes. Our computational package provides flexible and personalized real-time sleep-wake patterns for individuals to reduce their daytime sleepiness and could be used with wearables to develop smart alarms.

An Exploratory Assessment of Sleep Patterns, Burnout and Perceived Stress of a Cohort of Active Duty Military Physicians.

This article was migrated. The article was marked as recommended. Introduction: Physician well-being is crucial and has the potential to impact patient safety. Many physicians across different stages of their careers experience stress, burnout, and/or decreased sleep. These factors can negatively affect physician well-being and performance and contribute to medical errors. The purpose of this study is to further understand physician well-being by examining a single cohort for patterns of sleep, burnout, and perceived stress across gender, training level, and specialty. Materials and methods: A cohort of 32 practicing military physicians ranging from first-year residents to experienced attendings continuously wore an actigraphy watch for a duration of at least 5 days to capture baseline sleep patterns. On the last day of data collection, participants completed a self-reported assessment of their daytime sleepiness using the Epworth Sleepiness Scale (ESS), a two-item burnout scale adapted from the Maslach Burnout Inventory, and a 10-item perceived stress questionnaire. Data for the entire cohort were descriptively analyzed. Results: The cohort had a mean sleep duration of 6.69 hours across the 5 days, with a maximum mean sleep duration of 7.90 hours, and a minimum mean sleep duration of 5.69 hours per day. Analysis stratified by gender and level of training revealed an average sleep duration of at least 6 hours across these groups. Overall, the cohort reported low perceived stress levels, low daytime sleepiness, and low burnout. Conclusion: The cohort of physicians examined in the present study did not show signs of significant sleep deprivation, feelings of perceived stress, or burnout. This may be due to military culture and the structure of military training facilities that emphasize duty hour regulations. In addition, these findings may be related to the fact that military health professionals are salaried, as opposed to being on a fee-for-service schedule, and military facilities offer well-being programs.

0091 Sleep as a Mediator of the Relationship Between Exercise and Self-Reported Cognitive Function

Abstract Introduction Insufficient sleep and sedentary behavior are associated with cognitive decline. How sleep and physical activity interact to influence cognition is not fully understood. This study sought to examine whether self-reported sleep and exercise impact subjective cognitive complaints across adulthood. Methods Self-report questionnaire data from 2,744 adults (μ=56.18 yrs/old; 63.8% F; μ=16.36 yrs/edu) in the University of California Irvine Consent-to-Contact Registry were analyzed. Multiple regression models, analysis of covariance, and ordinary least squares path analysis were conducted to investigate relationships among the Cognitive Function Instrument (CFI), Medical Outcome Study Sleep Scale (MOS-SS) Subscales, and exercise frequency. All models adjusted for education, sex, age, BMI, medical comorbidities, depression, cancer diagnosis, and antidepressant usage. Individuals taking medications known to affect sleep or with a diagnosis major psychiatric illness were excluded from analyses. Results All MOS-SS Subscales significantly predicted CFI score (all p<0.001). Individuals who exercise >3times/week had significantly lower scores on the CFI (p<0.05), Sleep Problems Index I & II (both p<0.05), Somnolence Subscale (p<0.01), and higher scores on the Sleep Adequacy Subscale (p=0.001). Mediation analyses revealed that all subscales, aside from the Sleep Disturbance Subscale, mediated the relationship between exercise frequency and CFI Score (Bootstrapped CI’s did not include zero). Conclusion More self-reported sleep disturbance and greater daytime sleepiness are associated with more subjective cognitive complaints. Individuals who exercise more frequently report lower daytime sleepiness and higher quality sleep. The effects of exercise frequency on cognitive complaints appear to be mediated by the impact of exercise on sleep. These results suggest that sleep health may be a crucial consideration when evaluating outcomes of exercise-based therapies aimed at delaying the onset of cognitive impairment. Support The C2C registry was made possible by a donation from HCP, Inc. and is supported by NIA AG016573 and NCATS UL1 TR001414.

Cognitive Functions Predict Trajectories of Sleepiness Over 10 Years: A Population-Based Study.

Excessive daytime sleepiness is associated with chronic disorders of aging and mortality. Because longitudinal data are limited on the development of sleep disturbances and cognitive changes in older adults, we investigated the demographic, clinical, and cognitive predictors of self-reported daytime sleepiness over a period of 10 years. We jointly modeled latent trajectories over time of sleepiness, cognitive domains, and informative attrition and then fit models to identify cognitive trajectories and baseline characteristics that predicted the trajectories of sleepiness. Three latent trajectory groups were identified: emerging sleepiness, persistent sleepiness, and consistently low daytime sleepiness accounting for attrition in all groups. Compared with low sleepiness, emerging sleepiness was significantly associated with declining attention and subjective memory complaints; persistent sleepiness was associated with lower baseline scores in all cognitive domains, declining language trajectory, and more subjective memory complaints. These findings suggest that persistent sleepiness and emerging daytime sleepiness are associated with cognitive decline and multiple morbidities, albeit more subtly in emerging daytime sleepiness. Furthermore, these data suggest that change in the cognitive domain of attention and subjective memory complaints may be early indicators of future sleep disturbance.

Self-Reported Daytime Sleepiness and Sleep-Disordered Breathing in Patients With Atrial Fibrillation: SNOozE-AF

BackgroundAtrial fibrillation (AF) management guidelines recommend screening for symptoms of sleep-disordered breathing (SDB). We aimed to assess the role of self-reported daytime sleepiness in detection of patients with SDB and AF. MethodsA total of 442 consecutive ambulatory patients with AF who were considered candidates for rhythm control and underwent polysomnography comprised the study population. The utility of daytime sleepiness (quantified by the Epworth Sleepiness Scale [ESS]) to predict any (apnea-hypopnea index [AHI] ≥ 5), moderate-to-severe (AHI ≥ 15), and severe (AHI ≥ 30) SDB on polysomnography was tested. ResultsMean age was 60 ± 11 years and 69% patients were men. SDB was present in two-thirds of the population with 33% having moderate-to-severe SDB. Daytime sleepiness was low (median ESS = 8/24) and the ESS poorly predicted SDB, regardless of the degree of SDB tested (area under the curve: 0.48-0.56). Excessive daytime sleepiness (ESS ≥ 11) was present in 11.9% of the SDB population and had a negative predictive value of 43.1% and a positive predictive value of 67.5% to detect moderate-to-severe SDB. Male gender (odds ratio [OR]: 2.3, 95% confidence interval [CI]: 1.4-3.8, P = 0.001), obesity (OR: 3.5, 95% CI: 2.3-5.5, P < 0.001), diabetes (OR: 2.3, 95% CI: 1.2-4.4, P = 0.08), and stroke (OR: 4.6, 95% CI: 1.7-12.3, P = 0.002) were independently associated with an increased likelihood of moderate-to-severe SDB. ConclusionsIn an ambulatory AF population, SDB was common but most patients reported low daytime sleepiness levels. Clinical features, rather than daytime sleepiness, were predictive of patients with moderate-to-severe SDB. Lack of excessive daytime sleepiness should not preclude patients from being investigated for the potential presence of concomitant SDB.

ASSOCIATION BETWEEN OLFACTORY IDENTIFICATION ABILITY AND COGNITIVE FUNCTION IN NON-DEMENTED ELDERLY

Olfactory function declines gradually as aging and is impaired in people with neurodegenerative disorder. The deficit of odor identification has been used to predict mild cognitive impairment (MCI), Alzheimer's disease (AD), and conversion from MCI to AD. However, limited studies have related olfactory function to cognitive domains in community-dwelling elders. This cross-sectional study (2015-2017) is part of a cohort study “Taiwan Initiative for Geriatric Epidemiological Research”, and 605 community-dwelling elders (aged 65+) were recruited from elderly health checkup program at National Taiwan University Hospital between 2011 and 2013. The target population included 415 elders who completed the 4-year follow-up and without cognitive impairment. The cross-culture modified version of 15-item Sniffin’ Sticks Odor Identification Test (SS-OIT) was used to evaluate the ability of identifying odorants. The Montreal Cognitive Assessment-Taiwanese version (MoCA-T) and a battery of neuropsychological tests were administered to assess the global and domain-specific (logical memory, executive function, verbal fluency, and attention) cognition. Multivariable linear and logistic regression models were utilized to assess the association between the olfactory identification ability and cognitive function adjusting for important covariates (e.g., age, sex, years of education, apolipoprotein E ε4 carrier, and instrumental activities of daily living). Better olfactory identification ability (i.e., increased SS-OIT score) was associated with better performance of global cognition [β=0.22, 95% confidence interval (CI)=0.1−0.35; T3 vs. T1+T2: adjusted odds ratio (aOR)=3.93, 95% CI=1.29-11.95], logical memory (β=0.07, 95% CI=0.03−0.1; T3 vs. T1+T2: aOR=1.69, 95% CI=1.03-2.79), verbal fluency (β=0.07, 95% CI=0.04−0.1; aOR=2.4, 95% CI=1.43-4.02), and attention (aOR=1.96, 95% CI=1.13-3.41). After stratified analyses, the associations above remain significant in men (logical memory, aOR=3.6; verbal fluency, aOR=3.26), the older population (age ≥ 75, logical memory, aOR=2.69; verbal fluency, aOR=2.24; attention, aOR=2.36), elders with lower daytime sleepiness (verbal fluency, aOR=1.96; attention, aOR=2.04), and those with less functional decline (logical memory, aOR=1.71; verbal fluency, aOR=2.19; attention, aOR=2.34). Our results revealed a positive association of odor identification with global and domain-specific (logical memory, verbal fluency, and attention) cognition in non-demented elders. These findings provide more understanding of olfactory identification in relation to cognitive domains to identify AD in the pre-clinical phase.

Nighttime sleep disorders in patients with daytime sleepiness in Parkinson s disease

Daytime sleepiness is one of the clinically significant non-motor manifestations of Parkinson's disease (PD). One of its insufficiently studied aspects is a relationship between daytime sleepiness and nighttime sleep disorders.Objective:to clarify the clinical characteristics of PD in patients with different types of daytime sleepiness and to estimate of the ratio of daytime sleepiness to clinical and polysomnographic characteristics of nighttime sleep in patients with advanced stages of PD.Patients and methods. The investigation included 110 patients (56 men and 54 women) (mean age, 63.78+0.6 years) with PD (Hoehn and Yahr stage 2.6+0.2; disease duration, 6.3+3.2 years) without dementia. All the patients received therapy with levodopa at a mean daily dose of 667.8 mg; 98 of them had the drug in combination with dopamine receptor agonists at a stable dose. The unified PD rating scale, the PD sleep scale (PDSS), and the Epworth sleepiness scale (ESS) were applied. Nocturnal polysomnography (PSG) and the multiple sleep latency test (MSLT) were performed.Results and discussion. There was daytime sleepiness in 44% of the patients: permanent sleepiness in 15%, sudden daytime sleep attacks (along with low daytime sleepiness (ESS) in 14%, and permanent drowsiness concurrent with sleep attacks in 15%. The PSG findings showed a decrease in sleep efficiency, an increase in the duration of the first stage of sleep, a reduction in the duration of the second and third sleep stages, an extension of rapid eye movement (REM) sleep latency, and frequent awakenings (sleep fragmentation). PSG also demonstrated REM sleep behavior disorders (RBD) in half of the examinees.Patients with sleep attacks differed from those with permanent drowsiness without sleep attacks with more severe sleep disorders (PDSS) and shorter sleep latency (MSLT). Patients with the RBD phenomenon had shorter sleep latency (MTLS) than those without this parasomnia. Patients with moderate or severe sleepiness (ESS scores of &gt;10) differed from those with milder drowsiness (ESS scores of 410) and a lower representation of the third sleep stage.Conclusion.There is evidence for the association of daytime sleepiness in PD with reduced efficiency, changes in the nighttime sleep pattern, and RBD.

Efficacy of auto-trilevel positive airway ventilation in hypercapnic patients with overlap syndrome

To observe the efficacy of auto-trilevel positive airway pressure (Auto-trilevel PAP) ventilation in overlap syndrome (OS) patients with hypercapnia. From October 2012 to May 2014, 21 OS patients with a PaCO2> 45 mmHg (1 mmHg = 0.133 kPa) and coexisting stable chronic obstructive pulmonary diseases (COPD) and moderate-to-severe OSAS were recruited. Three different positive airway pressure (PAP) modes of ventilators (SOMNOvent auto-S, Weinmann Inc, Germany) were employed for 8 hours per night with each mode at each night and two nights' interval without any treatment among different modes. Under mode one, the expiratory positive airway pressure (EPAP) issued by bilevel positive airway pressure (BiPAP) was titrated as the minimal positive pressure for a disappearance of snoring. The same inspiratory positive airway pressure (IPAP) titrated by end tidal CO2 levels under mode 1 was used under modes 2 and 3 as well. However, the EPAP issued by BiPAP under mode 2 was 3 cmH2O (1 cmH2O = 0.098 kPa) higher than that under mode 1. Under mode 3 with autotrilevel PAP, the beginning of EPAP was set the same as that under mode 1 while the end of EPAP (EEPAP) was automatically adjusted based on upper airway patency condition. Comparisons were made for parameters before and after treatment as well as among different ventilation modes. The following parameters were compared such as nocturnal apnea hypopnea index (AHI), minimal SpO2 (miniSpO2), arousal index, sleep efficiency, morning PaCO2 and Epworth sleepiness score (ESS). Compared with the parameters pre-therapy, modes 1-3 showed a significant decrease in nocturnal AHI (6.3 ± 1.3), (3.1 ± 1.0), (3.6 ± 0.6) vs (38.6 ± 11.3) events/h), arousal index ((7.0 ± 1.1), (5.1 ± 0.9), (4.2 ± 1.7) vs (27.5 ± 5.4) events/h), morning PaCO2 (42.4 ± 3.8), (47.9 ± 2.6) and (43.2 ± 3.3) vs (57.3 ± 4.3) mmHg and daytime ESS (7.2 ± 1.3, 7.4 ± 1.3 and 5.3 ± 1.5 vs 11.4 ± 2.7), but a significant increase in nocturnal miniSpO2 (82.3 ± 5.4), (89.6 ± 3.9) and (90.3 ± 3.2) vs (62.4 ± 11.3) mmHg and sleep efficiency caused (71.3 ± 5.2)%, (79.4 ± 4.3)% and (83.2 ± 4.4)% vs (59.8 ± 6.3)% (all P < 0.01). Comparison of 3 modes demonstrated that, with the same IPAP, mode 3 resulted in the lowest arousal index, daytime ESS and the highest sleep efficiency. Comparison of modes 1 and 2 revealed a statistically lower AHI but higher miniSpO2 and morning PaCO2 under mode 2 (all P < 0.01). Compared with mode 1, mode 3 showed a lower AHI, higher miniSpO2 (all P < 0.01), but there was no significant difference in PaCO2 at the end of therapy. Compared with mode 2, mode 3 showed a significant lower PaCO2 (P < 0.01), but there was no significant difference in AHI and miniSpO2. Auto-trilevel PAP ventilation is superior to fixed BiPAP ventilation in the treatment of hypercapnic OS since this novel PAP mode can achieve a higher efficacy in simultaneous removal of residual apnea hypopnea events and correction of hypercapnia and yield a higher sleep quality and lower daytime sleepiness.

Efficacy of auto-trilevel positive airway ventilation on patients with both obesity hypoventilation and moderate to severe obstructive sleep apnea syndromes

Introduction To observe the efficacy of auto-trilevel positive airway pressure (Auto-trilevel PAP) ventilation on patients with both obesity hypoventilation syndrome (OHS) and moderate to severe obstructive sleep apnea syndromes (OSAS) by comparison of fixed bilevel positive airway pressure (BiPAP) ventilation. Materials and methods 17 patients with both OHS and moderate to severe OSAS were recruited. Three different positive airway pressure (PAP) modes issued by the ventilators (SOMNOvent auto-S, Weinmann Inc, Germany were used for 8h per night with each mode at each night and two nights' interval without any treatment among different modes. In mode one, the EPAP issued by BiPAP was titrated as the minimal positive pressure for disappearance of snoring. The same inspiratory positive airway pressure (IPAP) titrated by PaCO2 in mode 1 was used in modes 2 and 3 as well. However, the EPAP issued by BiPAP in mode 2 was 3cm H 2 O higher than that in mode 1. In mode 3 with autotrilevel PAP, the beginning of EPAP was set the same as that in mode 1 while the end of EPAP (EEPAP) was automatically adjusted to elevate based on upper airway patency condition. Comparisons were made for parameters before and after treatment as well as among different ventilation modes. The following parameters were compared such as nocturnal apnea hypopnea index (AHI), minimal SpO 2 (miniSpO 2 ), arousal index, sleep efficiency, morning PaCO 2 and daytime ESS. Results Compared with the parameters before ventilation therapies, there was a significant decrease in nocturnal AHI, arousal index, morning PaCO 2 and daytime ESS, but a significant increase in nocturnal miniSpO 2 and sleep efficiency caused by all three modes of ventilation (all P 2 and morning PaCO 2 in mode 2 (all P P 2 ( P 2 . Conclusion Auto-trilevel PAP ventilation is superior over fixed BiPAP ventilaiton for treatment of OHS with coexisting moderate to severe OSAS, since this novel PAP mode can achieve a higher efficacy in simultaneous removal of residual apnea hypopnea events and correction of hypercapnia as well as in achieving a higher sleep quality and lower daytime sleepiness. Acknowledgement Thanks to the Weinmann Inc, Germany which provided our research with Auto-trilevel PAP ventilators for clinical study.

Circadian Preference and Sleep-Wake Regularity: Associations With Self-Report Sleep Parameters in Daytime-Working Adults

The aim of this study was to explore how interindividual differences in circadian type (morningness) and sleep timing regularity might be related to subjective sleep quality and quantity. Self-report circadian phase preference, sleep timing, sleep quality, and sleep duration were assessed in a sample of 62 day-working adults (33.9% male, age 23–48 yrs). The Pittsburgh Sleep Quality Index (PSQI) measured subjective sleep quality and the Sleep Timing Questionnaire (STQ) assessed habitual sleep latency and minutes awake after sleep onset. The duration, timing, and stability of sleep were assessed using the STQ separately for work-week nights (Sunday–Thursday) and for weekend nights (Friday and Saturday). Morningness-eveningness was assessed using the Composite Scale of Morningness (CSM). Daytime sleepiness was measured using the Epworth Sleepiness Scale (ESS). A morning-type orientation was associated with longer weekly sleep duration, better subjective sleep quality, and shorter sleep-onset latency. Stable weekday rise-time correlated with better self-reported sleep quality and shorter sleep-onset latency. A more regular weekend bedtime was associated with a shorter sleep latency. A more stable weekend rise-time was related to longer weekday sleep duration and lower daytime sleepiness. Increased overall regularity in rise-time was associated with better subjective sleep quality, shorter sleep-onset latency, and higher weekday sleep efficiency. Finally, a morning orientation was related to increased regularity in both bedtimes and rise-times. In conclusion, in daytime workers, a morning-type orientation and more stable sleep timing are associated with better subjective sleep quality. (Author correspondence: asoehner@berkeley.edu)

S26-3 Clinical application of PSG to REM sleep behavior disorder and periodic leg movements during sleep

Periodic leg movements during sleep (PLMS) is frequently observed in rapid eye movement (REM) sleep behavior disorder (RBD) especially during REM sleep period. We made a series of studies for investigating the clinical significance and the underlying mechanism of PLMS in RBD. Consecutive 54 patients with idiopathic RBD without PLMS (iRBD w/o PLMS, 65.9±6.9 yrs), 27 patients with iRBD with PLMS (iRBD-PLMS, 67.7±7.1 yrs), and 31 patients with idiopathic PLMS (iPLMS, 63.5±5.9 yrs) were enrolled. Scores of Epworth Sleepiness Scale (ESS) were compared among the three patients groups. PLMS index, mean duration of PLMS, and inter-PLMS interval were calculated during both NREM sleep period and REM sleep period respectively, and compared among the three patient groups. Correlation analysis between ratio of PLMS related arousal index to PLMS index (PLMAI/PLMI) and proportion of REM sleep without atonia to total REM sleep (RWA/REM) were performed in the iRBD-PLMS group. The associated factor for the presence of PLMS during REM sleep period was also investigated in the subject iRBD group. In 15 out of iRBD-PLMS patients, effectiveness of the treatment with pramipexole, a dopamine agonst, was also evaluated. The iRBD-PLMS group showed significantly lower ESS score than the iPLMS w/o PLMS group did. PLMAI/PLMI was negatively correlated with RWA/REM. The iRBD-PLMS group showed significantly higher PLMS index, longer duration of PLMS, and shorter inter-PLMS interval than the iPLMS group did. RWA/REM appeared as a significantly associated factor for the presence of PLMS during REM sleep period among the iRBD patients. However, pramipexole treatment did not show a statistical decrease in the amount of PLMS. Conclusions: RWA could be associated with attenuation of arousal response to PLMS possibly leading to lower daytime sleepiness in iRBD. Our result impresses that PLMS during this sleep period could become an disease process marker of iRBD.

Occurrence of ‘microsleeps’ during daytime sleep onset in normal subjects

The main aim of this study was to explore whether the multiple sleep latency test (MSLT) could be made more sensitive to low daytime sleepiness in normal, healthy subjects by adopting a shorter period of sleep (microsleep) as a sleep onset criterion. Subjects underwent MSLTs under two conditions: after normal (baseline) nightime sleep, and after nighttime sleep extension (creating a ‘floor effect’ of minimal daytime sleepiness). MSLT sleep onset thresholds of 5 s (microsleeps), 30 s (the norm) and 90 s of sustained sleep gave 3 separate sleep latency scores for 240 MSLT trials derived from 10 subjects. With low daytime sleepiness, whether this be in the morning after baseline sleep or throughout the day after sleep extension, the 5 s sleep onset criterion was a more sensitive measure of sleepiness than the established 30 s criterion. This was the case both for sleep onset latency and for the frequency of sleep onsets. Spectral analyses of the EEG indicated that successive microsleep episodes generally became more substantial, and, depending on the level of sleepiness, culminated in more overt signs of sleep. There was little difference between the 30 s and 90 s criteria for sleep onset latency scores, although there was a small but significant difference between them in the frequency of sleep onsets. As daytime sleepiness increased, particularly in the afternoon and under baseline, the 5 s criterion reached a ceiling, with the 30 s criterion becoming more sensitive.

Sleep and wakefulness in normal preadolescent children.

Eighteen healthy children, 9 boys and 9 girls, between 8 and 12 years of age were examined with polygraphic sleep records, multiple sleep latency tests (MSLTs), and measurements of reaction times. Sleep was recorded at home on Oxford Medilog 9 channel cassette tape recorders (Oxford Medical Systems, Abingdon, U.K.) and sleep staging was performed from the screen of the display unit. Two consecutive nights were recorded. MSLT was done in the laboratory. The subjects were given 30 min to fall asleep on four occasions during the day after the last recorded night of sleep. Reaction times were measured repeatedly between each MSLT trial. More slow wave sleep was found in this study compared to others. Also, the first night effect was slight. It is proposed that this is due to the fact that the recordings were performed at home. The initial sleep cycle was incomplete in almost all subjects. A sleep stage with traits of both rapid eye movement (REM) and non-REM could be seen in this cycle, probably representing an abortive REM period. MSLT confirmed the low daytime sleepiness in healthy preadolescent children. A sleep latency of 10 min or less on two or more sleep trials, or a daily mean sleep latency of less than 20 min, is rarely seen in this age group. The reaction times were within normal limits for the age of the subjects. Nighttime sleep values, daytime sleep latencies, and reaction times were not correlated in these normal-sleeping children.