Evaluation of excessive daytime sleepiness.
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Excessive Daytime Sleepiness (EDS) is a difficult clinical problem, which is often indicative of a serious underlying physiologic condition. EDS is associated with automobile accidents, work-related injury, and increased use of the health care system, but it appears to be under-appreciated despite its common occurrence. There are many causes of EDS, ranging from insufficient sleep or inadequate sleep hygiene to drug effects and serious medical conditions. Assessment of EDS should begin with a detailed clinical history, and may also include self-rated instruments and ultimately physiologic tests to measure propensity to fall asleep or stay awake. Ultimately, evaluation in the sleep laboratory is often required in order to arrive at an accurate diagnosis and an appropriate therapeutic recommendation. (+info)
Sleep, sleepiness and school start times: a preliminary study.
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BACKGROUND: High school students are reported to be excessively sleepy, resulting in decreased academic performance, increased psycho-social problems and increased risk of morbidity and mortality from accidents. Early school start times have been noted to contribute to this problem. This report attempts to confirm the relationship of early school start times with decreased sleep and increased sleepiness. METHODS: We examined sophomore and junior students in 2 local high schools with different start times and measured the amount of time slept and sleepiness. RESULTS: We found that students at the early start school reported reduced sleep time and more sleepiness than their counterparts at the later starting school. CONCLUSION: Early school start times are associated with student reports of less sleep and increased sleepiness. Further studies in larger groups are recommended in view of the potential significant impact of sleep deprivation in this age group. (+info)
Daytime sleepiness during Ramadan intermittent fasting: polysomnographic and quantitative waking EEG study.
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During the lunar month of Ramadan, Muslims abstain from eating, drinking and smoking from sunrise to sunset. We reported previously that Ramadan provokes a shortening in nocturnal total sleep time by 40 min, an increase in sleep latency, and a decrease in slow-wave sleep (SWS) and rapid eye movement (REM) sleep duration during Ramadan. During the same study, the effects of Ramadan intermittent fasting on daytime sleepiness were also investigated in eight healthy young male subjects using a quantitative waking electroencephalograph (EEG) analysis following the multiple sleep latency test (MSLT) procedure. This procedure was combined with subjective alertness and mood ratings and was conducted during four successive experimental sessions: (1) baseline (BL) 15 days before Ramadan, (2) beginning of Ramadan (R11) on the 11th day of Ramadan, (3) end of Ramadan (R25) on the 25th day of Ramadan, (4) recovery 2 weeks after Ramadan (AR). During each session, four 20-min nap opportunities (MSLTs) were given at 10:00, 12:00, 14:00 and 16:00 h and were preceded by rectal temperature readings. Nocturnal sleep was recorded before each daytime session. Subjective daytime alertness did not change in R25 but decreased in R11 at 12:00 h, and subjective mood decreased at 16:00 h, both in R11 and R25. During the MSLT, mean sleep latency decreased by an average of 2 min in R11 (especially at 10:00 and 16:00 h) and 6 min in R25 (especially at 10:00 and 12:00 h) compared with BL. There was an increase in the daily mean of waking EEG absolute power in the theta (5.5-8.5 Hz) frequency band. Significant correlations were found between sleep latency during the MSLT and the waking EEG absolute power of the fast alpha (10.5-12.5 Hz), sigma (11.5-15.5 Hz) and beta (12.5-30 Hz) frequency bands. Sleep latency was also related to rectal temperature. In conclusion, Ramadan diurnal fasting induced an increase in subjective and objective daytime sleepiness associated with changes in diurnal rectal temperature. (+info)
Sleep-wake rhythm in an irregular shift system.
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Sleep in shift work has been studied extensively in regular shift systems but to a lesser degree in irregular shifts. Our main aim was to examine the sleep-wake rhythm in shift combinations ending with the night or the morning shift in two irregular shift systems. Three weeks' sleep/work shift diary data, collected from 126 randomly selected train drivers and 104 traffic controllers, were used in statistical analyses including a linear mixed model and a generalized linear model for repeated measurements. The results showed that the sleep-wake rhythm was significantly affected by the shift combinations. The main sleep period before the first night shift shortened by about 2 h when the morning shift immediately preceded the night shift as compared with the combination containing at least 36 h of free time before the night shift (reference combination). The main sleep period before the night shift was most curtailed between two night shifts, on average by 2.9 and 3.5 h among the drivers and the controllers, respectively, as compared with the reference combination. Afternoon napping increased when the morning or the day shift immediately preceded the night shift, the odds being 4.35-4.84 in comparison with the reference combination. The main sleep period before the morning shift became 0.5 h shorter when the evening shift preceded the morning shift in comparison with the sleep period after a free day. The risk for dozing off during the shift was associated only with the shift length, increasing by 17 and 35% for each working hour in the morning and the night shift, respectively. The results demonstrate advantageous and disadvantageous shift combinations in relation to sleep and make it possible to improve the ergonomy of irregular shift systems. (+info)
The effect of sleep loss on next day effort.
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The study had two primary objectives. The first was to determine whether sleep loss results in a preference for tasks demanding minimal effort. The second was to evaluate the quality of performance when participants, under conditions of sleep loss, have control over task demands. In experiment 1, using a repeated-measures design, 50 undergraduate college students were evaluated, following one night of no sleep loss and one night of sleep loss. The Math Effort Task (MET) presented addition problems via computer. Participants were able to select additions at one of five levels of difficulty. Less-demanding problems were selected and more additions were solved correctly when the participants were subject to sleep loss. In experiment 2, 58 undergraduate college students were randomly assigned to a no sleep deprivation or a sleep deprivation condition. Sleep-deprived participants selected less-demanding problems on the MET. Percentage correct on the MET was equivalent for both the non-sleep-deprived and sleep-deprived groups. On a task selection question, the sleep-deprived participants also selected significantly less-demanding non-academic tasks. Increased sleepiness, fatigue, and reaction time were associated with the selection of less difficult tasks. Both groups of participants reported equivalent effort expenditures; sleep-deprived participants did not perceive a reduction in effort. These studies demonstrate that sleep loss results in the choice of low-effort behavior that helps maintain accurate responding. (+info)
Hypersomnia and low CSF hypocretin-1 (orexin-A) concentration in a patient with multiple sclerosis showing bilateral hypothalamic lesions.
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A 45-year-old Japanese woman with multiple sclerosis (MS) manifested hypersomnia in a relapse of MS. Magnetic resonance imaging revealed new bilateral hypothalamic lesions, and the hypocretin-1 level in the cerebrospinal fluid (CSF) was significantly low. Methylprednisolone pulse treatment successfully resolved the hypersomnia and the left hypothalamic lesion, and it normalized the hypocretin-1 level in the CSF. These findings suggest that the hypothalamic hypocretin (orexin) system may be crucial to maintaining the arousal level and that lesions in the system can cause hypersomnia in MS. (+info)
Event-related potentials during forced awakening: a tool for the study of acute sleep inertia.
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Sleep propensity and sleep inertia were assessed in 43 patients with excessive daytime sleepiness (EDS) and 21 sleep-deprived controls, using a forced awakening test under continuous electroencephalographic (EEG) recording. Event-related potentials (ERPs) were first obtained in waking, while participants performed a target detection auditory task. Subjects were then allowed to take a nap with lights off and sleep latency was calculated. After 3 min of continuous sleep, frequent and rare tones were suddenly presented again (and ERPs recorded) in a forced awakening condition, which was repeated a second time if patients fell asleep. ERPs in pre-nap wakefulness did not differ in patients and controls. On forced awakening, almost half (48%) of EDS patients retained morphologically normal ERPs, but showed a significant delay of P300 relative to waking. In the other half of the patients (and none of the controls), the N200/P300 complex to targets was replaced on forced awakening by high-amplitude negative waves ('sleep negativities'). Single subject analysis showed that 65% of patients had abnormal responses during forced awakening (significant P3 delay or sleep negativities), while only three of them (7%) had abnormal ERPs on wakefulness. The presence of sleep negativities was associated with shorter sleep latencies and increased target detection errors on forced awakening. Sleep negativities were more prevalent in narcolepsy and idiopathic hypersomnia than in EDS associated to psychiatric disorders. By combining sleep latency and ERP measures, the forced awakening test provided a robust and relatively rapid tool (45-60 min) to evaluate both sleep propensity and sleep inertia within a single recording session. The test allows each subject to act as his/her own control, thus increasing sensitivity. In the present series, it proved to be much more discriminative than waking ERPs alone to demonstrate specific abnormalities in patients complaining of excessive daytime sleepiness. (+info)
Underlying sleep pathology may cause chronic high fatigue in shift-workers.
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About 20-25% of the population in primary healthcare settings complains of chronic fatigue but this symptom has been under-emphasized compared with sleepiness in clinical practice. Shift-workers are particularly vulnerable because of various fatigue-related personal and public morbidity and mortality. The goal of this cross-sectional study was to explore if fatigue severity could be used as an independent predictive tool to identify underlying sleep pathology. The 21 most-fatigued (study group) and 23 least-fatigued (control) miners were selected on the basis of the Fatigue Severity Scale (FSS), which was administered to 195 subjects in an underground mine in Timmins, a town in northern Ontario. The two groups were matched for age, gender, and body mass index (BMI). Mean FSS score for the most-fatigued subjects was 4.9 +/- 0.5 and the least-fatigued was 2.2 +/- 0.5 (P < 0.0001). The subjects from each group were studied polysomnographically to identify sleep disorders. The polysomnographic data in 15 of 21 (71.4%) of the most-fatigued subjects displayed significant sleep pathology compared with only three of 23 (13.0%) in the least-fatigued subjects. Based on Fisher's exact test, the difference between the two groups was highly significant (P < 0.0001). Also, in the total subject pool (n = 195), the correlation between subjective fatigue and sleepiness was not very strong (Pearson's r = 0.45), suggesting that these two symptoms can be independent phenomena. It is concluded that chronic high fatigue can be an independent manifestation of underlying sleep pathology, which warrants independent subjective and objective assessment. (+info)