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Concept: Somnolence


Insufficient sleep is common among high school students and has been associated with an increased risk for motor vehicle crashes (1), sports injuries (2), and occupational injuries (3). To evaluate the association between self-reported sleep duration on an average school night and several injury-related risk behaviors (infrequent bicycle helmet use, infrequent seatbelt use, riding with a driver who had been drinking, drinking and driving, and texting while driving) among U.S. high school students, CDC analyzed data from 50,370 high school students (grades 9-12) who participated in the national Youth Risk Behavior Surveys (YRBSs) in 2007, 2009, 2011, or 2013. The likelihood of each of the five risk behaviors was significantly higher for students who reported sleeping ≤7 hours on an average school night; infrequent seatbelt use, riding with a drinking driver, and drinking and driving were also more likely for students who reported sleeping ≥10 hours compared with 9 hours on an average school night. Although insufficient sleep directly contributes to injury risk, some of the increased risk associated with insufficient sleep might be caused by engaging in injury-related risk behaviors. Intervention efforts aimed at these behaviors might help reduce injuries resulting from sleepiness, as well as provide opportunities for increasing awareness of the importance of sleep.

Concepts: Sleep, Injuries, High school, Somnolence, Driver's license, Automobile, Helmet, Remove Intoxicated Drivers


A 61-year-old man was referred to our hospital for evaluation of sleep apnea. He snored loudly and had apnea during sleep. During the day, he was sleepy, and when lying down, he could quickly fall asleep. He had a score of 15 on the Epworth Sleepiness Scale, which ranges from 0 to 24, with a score of more than 10 suggestive of excessive daytime somnolence. On physical examination, there were no abnormalities other than obesity (100 kg [220 lb]; body-mass index [the weight in kilograms divided by the square of the height in meters], 31). Overnight polygraphy revealed a score . . .

Concepts: Mass, Sleep, Sleep disorder, Sleep apnea, Sleep medicine, Epworth Sleepiness Scale, Somnolence, Kilogram


The biology underlying excessive daytime sleepiness (hypersomnolence) is incompletely understood. After excluding known causes of sleepiness in 32 hypersomnolent patients, we showed that, in the presence of 10 μM γ-aminobutyric acid (GABA), cerebrospinal fluid (CSF) from these subjects stimulated GABA(A) receptor function in vitro by 84.0 ± 40.7% (SD) relative to the 35.8 ± 7.5% (SD) stimulation obtained with CSF from control subjects (Student’s t test, t = 6.47, P < 0.0001); CSF alone had no effect on GABA(A) signaling. The bioactive CSF component had a mass of 500 to 3000 daltons and was neutralized by trypsin. Enhancement was greater for α2 subunit- versus α1 subunit-containing GABA(A) receptors and negligible for α4 subunit-containing ones. CSF samples from hypersomnolent patients also modestly enhanced benzodiazepine (BZD)-insensitive GABA(A) receptors and did not competitively displace BZDs from human brain tissue. Flumazenil-a drug that is generally believed to antagonize the sedative-hypnotic actions of BZDs only at the classical BZD-binding domain in GABA(A) receptors and to lack intrinsic activity-nevertheless reversed enhancement of GABA(A) signaling by hypersomnolent CSF in vitro. Furthermore, flumazenil normalized vigilance in seven hypersomnolent patients. We conclude that a naturally occurring substance in CSF augments inhibitory GABA signaling, thus revealing a new pathophysiology associated with excessive daytime sleepiness.

Concepts: Brain, Receptor, Cerebrospinal fluid, Somnolence, Benzodiazepine, Excessive daytime sleepiness, Hypersomnia, GABAA receptor


A 66-year-old man with hypertension presented with complaints of excessive daytime sleepiness (Epworth Sleepiness Score 14/24), dyspnea upon exertion, and episodes of noninjurious dream-enacting behavior. He reported tongue biting when sleeping in the right lateral decubitus position. Medications included atenolol 12.5 mg, lovastatin 20 mg, doxazosin 2 mg, amlodipine 5 mg, isosorbide mononitrate 60 mg, and aspirin 81 mg. He denied headaches, visual changes, dysarthria, dysphagia, or localized weakness. He denied use of alcohol, tobacco, or drugs.

Concepts: Hypertension, Ibuprofen, Aspirin, Sleep apnea, Epworth Sleepiness Scale, Somnolence, Excessive daytime sleepiness, Isosorbide mononitrate


Fatigue is one of the most common and disabling symptoms in Parkinson’s disease (PD). Since fatigue was first described as a common feature of PD 20 years ago, little progress has been made in understanding its causes or treatment. Importantly, PD patients attending the 2013 World Parkinson Congress voted fatigue as the leading symptom in need of further research. In response, the Parkinson Disease Foundation and ProjectSpark assembled an international team of experts to create recommendations for clinical research to advance this field. The working group identified several areas in which shared standards would improve research quality and foster progress including terminology, diagnostic criteria, and measurement. Terminology needs to (1) clearly distinguish fatigue from related phenomena (eg, sleepiness, apathy, depression); (2) differentiate subjective fatigue complaints from objective performance fatigability; and (3) specify domains affected by fatigue and causal factors. We propose diagnostic criteria for PD-related fatigue to guide participant selection for clinical trials and add rigor to mechanistic studies. Recommendations are made for measurement of subjective fatigue complaints, performance fatigability, and neurophysiologic changes. We also suggest areas in which future research is needed to address methodological issues and validate or optimize current practices. Many limitations in current PD-related fatigue research may be addressed by improving methodological standards, many of which are already being successfully applied in clinical fatigue research in other medical conditions (eg, cancer, multiple sclerosis). © 2016 International Parkinson and Movement Disorder Society.

Concepts: Alzheimer's disease, Clinical trial, Disease, Symptom, Parkinson's disease, Somnolence, Movement disorder, James Parkinson


Objective Insufficient time for recovery between workdays may cause fatigue and disturbed sleep. This study evaluated the impact of an intervention that reduced weekly working hours by 25% on sleep, sleepiness and perceived stress for employees within the public sector. Method Participating workplaces (N=33) were randomized into intervention and control groups. Participants (N=580, 76% women) worked full-time at baseline. The intervention group (N=354) reduced worktime to 75% with preserved salary during 18 months. Data were collected at baseline and after 9 and 18 months follow-up. Sleep quality, sleep duration, sleepiness, perceived stress,and worries, and stress at bedtime were measured with diary during one week per data collection. Result A multilevel mixed model showed that compared with the control group, at the 18-month follow-up, the intervention group had improved sleep quality and sleep duration (+23 minutes) and displayed reduced levels of sleepiness, perceived stress and worries, and stress at bedtime on workdays (P<0.002). The same effects were shown for days off (P<0.006), except for sleep length. Effect sizes were small (Cohen's f2<0.08). Adding gender, age, having children living at home, and baseline values of sleep quality and worries and stress at bedtime as additional between-group factors did not influence the results. Conclusion A 25% reduction of weekly work hours with retained salary resulted in beneficial effects on sleep, sleepiness and perceived stress both on workdays and days off. These effects were maintained over an 18-month period. This randomized intervention thus indicates that reduced worktime may improve recovery and perceived stress.

Concepts: Controlling for a variable, Scientific control, Scientific method, Sleep, Stress, Fatigue, Somnolence, Result


Chronic sleep loss and associated sleepiness and daytime impairments in adolescence are a serious threat to the academic success, health, and safety of our nation’s youth and an important public health issue. Understanding the extent and potential short- and long-term repercussions of sleep restriction, as well as the unhealthy sleep practices and environmental factors that contribute to sleep loss in adolescents, is key in setting public policies to mitigate these effects and in counseling patients and families in the clinical setting. This report reviews the current literature on sleep patterns in adolescents, factors contributing to chronic sleep loss (ie, electronic media use, caffeine consumption), and health-related consequences, such as depression, increased obesity risk, and higher rates of drowsy driving accidents. The report also discusses the potential role of later school start times as a means of reducing adolescent sleepiness.

Concepts: Health care, Medicine, Public health, Health, Sleep, Sleep deprivation, Adolescence, Somnolence


Shift work is common in today’s society, and is associated with negative health outcomes, and accidents and incidents. These detrimental effects can be primarily attributed to sleeping and working at an adverse circadian time. The aim of this study was to examine whether a split sleep schedule is as effective as a consolidated day shift or night shift schedule for maintaining performance and sustaining sleep. Fifty-three healthy male volunteers (mean ± SD age = 26.51 ± 4.07 years) underwent a randomized three condition study design. A split sleep condition involving two 5-h sleeping opportunities in 24 h [time in bed (TIB) 0300 h-0800 h and 1500 h-2000 h] was compared to a 10-h consolidated nighttime sleep (TIB 2200 h-0800 h) and 10-h consolidated daytime sleep (TIB 1000 h-2000 h). All participants underwent a baseline period of 10 h of nocturnal time in bed (TIB) followed by a 5-d simulated workweek spent in one of the three conditions. Polysomnography, psychomotor vigilance task, digit-symbol substitution task and subjective state were assessed. During the 5-d simulated workweek, participants in the nighttime sleep condition slept the most (total sleep time per day (TST) 8.4 h ± 13.4 min), followed by the split sleep condition (TST 7.16 h ± 14.2 min) and the daytime sleep condition (TST 6.4 h ± 15.3 min). Subjective sleepiness was highest in the daytime sleep condition and lowest in the nighttime sleep condition. No significant differences in performance were observed between the conditions. Compared to a nighttime consolidated sleep opportunity or split sleep, placement of a consolidated sleep opportunity during the day yielded truncated sleep and increased sleepiness. Further research in real-world situations is warranted to fully assess the efficacy of alternative split sleep schedules for improving safety and productivity.

Concepts: Effectiveness, Sleep, Sleep disorder, Polysomnography, Circadian rhythm, Somnolence, Shift work, Bed


Insomnia identity refers to the conviction that one has insomnia, and this sleep complaint can be measured independently of sleep. Conventional wisdom predicts that sleep complaints are synchronous with poor sleep, but crossing the presence or absence of poor sleep with the presence or absence of insomnia identity reveals incongruity with expected patterns. This review of existing research on insomnia identity processes and influence finds that about one-fourth of the population are uncoupled sleepers, meaning there is an uncoupling of sleep and sleep appraisal, and daytime impairment accrues more strongly to those who endorse an insomnia identity. Research supports the conclusion that there is a cost to pathologizing sleep. Individuals claiming an insomnia identity, regardless of sleep status, are at greater risk for a range of sequelae including self-stigma, depression, suicidal ideation, anxiety, hypertension, and fatigue. A broad research agenda is proposed with hypotheses about the sources, clinical mechanisms, and clinical management of insomnia identity.

Concepts: Sleep deprivation, Bipolar disorder, Somnolence, Depression, Suicide, Complaint, The Conclusion, Legal terms


Chronic insufficient sleep is a growing concern among adolescents and is associated with a host of adverse health consequences. Early school start times may be an environmental contributor to this problem. The purpose of this study was to examine the impact of a delay in school start time on sleep patterns, sleepiness, mood, and health-related outcomes.

Concepts: Time, Sleep, Bipolar disorder, Circadian rhythm, Somnolence