Effect of age on sleep onset time in rotating shift workers

BACKGROUND: To determine the relationship between sleep onset time and age in rotating shift workers. METHODS: Sleep diaries were used to record the sleeping onset time in rotating shift workers. Work shifts were rotated on a weekly basis and fell into three periods: morning (06:00-14:00 h), evening (14:00-22:00 h), and night (22:00-06:00 h). Work shifts were rotated in the following order: night, evening, and morning. One working week consisted of 5 days. The mean age of the male shift workers was 40.3 years. RESULTS: A significantly earlier sleep onset time was observed in older workers working morning and evening shifts (r=-0.42 and r=-0.66, respectively), but not when working night shifts (r=-0.10). Regardless of age, night-shift workers usually go to sleep after their shift ends at 06:00 h. After the evening shift ends at 22:00 h, older workers tend to go to sleep earlier than younger workers. CONCLUSIONS: Sleep onset time becomes earlier with age in morning- and evening-shift workers. The morning shift starts very early, at 06:00 h, so workers must go to sleep very early to obtain an adequate amount of sleep. Older workers may go to sleep earlier because of physiological (circadian) and/or social factors associated with shift work.     

Sleep homeostasis in rats assessed by a long-term intermittent paradoxical sleep deprivation protocol

Numerous studies have evaluated the sleep homeostasis of rats after short- or long-periods of sleep deprivation, but none has assessed the effects of prolonged sleep restriction on the rat's sleep pattern. The purpose of the present study, therefore, was to evaluate the sleep homeostasis of rats under a protocol of chronic sleep restriction. Male Wistar rats were implanted with electrodes for EEG and EMG recordings. Using the single platform method, the animals were submitted to 18 h of sleep restriction, beginning at 16:00 h (lights on at 07:00 h), followed by a 6 h sleep window (from 10:00 h to 16:00 h) for 21 days. Immediately after this period, rats were allowed to sleep freely for 4 days (recovery period). The sleep–wake cycle was recorded throughout the entire experiment and the results showed that during the 6 h sleep window there was an increase on the percentage of sleep time, reflected by augmented time in high amplitude slow wave sleep and in paradoxical sleep, when compared to baseline sleep, whereas bouts of awakening longer than 1.5 min were greatly reduced, with the animals exhibiting a monophasic-type sleep pattern. During the deprivation period, paradoxical sleep was abolished. High amplitude slow wave sleep was also greatly affected by the protocol. Nonetheless, one day of recovery was sufficient to restore the normal sleep pattern. These findings indicate that this protocol was capable to induce many changes in the rat's sleep patterns, suggesting that during the 6 h sleep window there is a sleep adaptive homeostatic process.     

Partial sleep deprivation therapy combined with sertraline affects subjective sleep quality in major depressive disorder

BACKGROUND AND PURPOSE: Earlier studies have shown an association between mood disorders and sleep regulation. Total or partial sleep deprivation was demonstrated to have rapid antidepressive effects in depression. Depressive symptoms recur after one night of recovery sleep, but relapse is less when patients are receiving medication. In this study, we examined the subjective sleep quality changes with the antidepressive therapy using partial sleep deprivation plus sertraline and sertraline monotherapy in patients with major depressive disorder. PATIENTS AND METHODS: Thirteen patients received six partial sleep deprivation therapies in addition to sertraline; the sleep schedule on deprivation nights started at 11:00 p.m. and ended at 3:00 a.m. Eleven patients were treated with sertraline monotherapy as a control group. Six nights of partial sleep deprivation were completed in the first two weeks. Subjective sleep quality was evaluated with the Pittsburgh Sleep Quality Index (PSQI); depression and the accompanying anxiety were also assessed at baseline and at the end of the fourth week. RESULTS: The late partial sleep deprivation (LPSD) group showed less increase in estimated sleep duration and less significant improvement in subjective sleep quality than the control group. Although decreased sleep latency and increased sleep efficiency are associated with the sleep deprivation, contrary results were found in our study. CONCLUSIONS: In conclusion, changes in subjective sleep quality could occur relative to the combined partial sleep deprivation therapy and to pharmacotherapy and must be differentiated from the rapid effects of sleep deprivation therapy and objective polysomnographic measures.     

Oculomotor impairment after 1 night of total sleep deprivation: a dissociation between measures of speed and accuracy.

OBJECTIVES: The present study examined the effects of 40 h of sleep deprivation and of time-of-day on saccadic and smooth pursuit oculomotor performance. METHODS: Nine normal subjects slept for 3 consecutive nights in the laboratory (one adaptation, one baseline, one recovery). Baseline and recovery were separated by a period of 40 h of continuous wakefulness, during which subjects were tested every 2 h. Oculomotor performance assessed at the following hours: 10:00, 12:00, 14:00, 16:00, 18:00, 20:00, 22:00, of both the days preceding and following the sleep deprivation night, as well as at 24:00, 02:00, 04:00, 06:00 and 08:00 h during the deprivation period. RESULTS: Saccade latency increased and peak velocity decreased significantly during the post-deprivation day; saccadic accuracy was unaffected. As regards smooth pursuit performance, phase (a measure of accuracy) was not affected by sleep loss, while velocity gain significantly decreased during the day that followed the sleep deprivation night. Significant time-of-day effects on the considered oculomotor variables except saccadic accuracy were also found, indicating an overall performance impairment during the night. CONCLUSIONS: It is concluded that 40 h of sleep deprivation significantly impaired diurnal performance in pursuit and saccadic tasks. This performance worsening is limited to the measures of speed, while accuracy is not affected by sleep loss. A significant operational relevance of these results is suggested, since saccadic velocity has recently been found to be negatively correlated with simulator vehicle crash rates.     

Objective measurement of sleepiness in summer vacation long-distance drivers

The study investigated whether sleepiness at the wheel is a problem in non-commercial drivers going on summer vacation. All drivers, who stopped at a rest area on a large European freway while one of the interviewers was available, were systematically approached and asked to respond to a questionnaire. All subjects who had driven at least 400 km (240 miles), whose age was between 20 and 46 years of age, and who agreed to participate were asked to undergo a longer investigation that included a short sleep/wake diary describing overall sleep habits during the year, a sleep/wake log covering the days just prior to departure, an analog visual scale indicating sleepiness at time of interview, and a polygraphically monitored two nap sleep test (TNST). A control group was recruited that consisted of subjects of the same age range, normal sleep habits, and normal nocturnal sleep time before administration of the TNST. One hundred and four drivers (2 women) participated between 08:00 and 20:00 h. The total group was subdivided into 6 subgroups based upon the time of day of their investigation (08:00–10:00 h, 10:01–12:00 h, etc.). The control group included 50 men with 50–55% of control subjects, relative to the total number of index-cases, in each subgroup. Eighty-eight percent (n =92) of studied drivers had experienced acute sleep deprivation within one day prior to departure due to the planned long driving. The TNST demonstrated that, overall, drivers had a significantly shorter sleep latency in nap 1 and nap 2 than controls, had a significantly longer sleep duration in nap 1 and nap 2, and there was a significant correlation between the sleep debt prior to departure and the sleep stage reached during the TNST. It is concluded that the TNST is a test which allows the objective study of sleepiness in drivers without the burden of the multiple sleep latency test. Many drivers are excessively sleepy when making long summer vacation journeys.     

Timing of light exposure and activity in adults with delayed sleep-wake phase disorder

ObjectiveTo characterize the patterns of light exposure and physical activity level and assess their relationship with sleep quality and depressive symptoms in adults with delayed sleep-wake phase disorder (DSWPD).Methods42 DSWPD (22 female, mean age 34.5 y) and 26 (±4 years) age-and-sex-matched controls (12 female, mean age 33.4 y) underwent seven days of light and activity monitoring.ResultsIndividuals with DSWPD had significantly delayed bed times and wake times, but similar sleep duration compared to controls. Subjective sleep quality (Pittsburgh Sleep Quality Index (PSQI)) was poorer in DSWPDs compared to controls. Those with DSWPD had significantly more activity and light exposure late at night (2:00–4:00) and significantly less activity and light exposure in the morning (8:00–11:00). Total 24 h levels of light and activity were not significantly different between DSWPD and controls. However, the DSWPD group had significantly more light exposure than controls 22 h after waking, during their sleep period. Later light exposure correlated with higher depression scores [Beck Depression Index (BDI)] and poorer sleep quality (PSQI).ConclusionsThe light exposure patterns observed in DSWPD likely contribute to and perpetuate the chronically delayed sleep and wake phase in these patients. In addition, increased light exposure during the sleep period may also contribute to the poor sleep quality and mood disorders that are common in these individuals.     

Dynamics of EEG spindle frequency activity during extended sleep in humans: relationship to slow-wave activity and time of day

The dynamics of EEG spindle frequency activity (SFA; spectral power density in the 12.25–15.0 Hz range) and its relationship to slow-wave activity (SWA; 0.75–4.5 Hz) were investigated in long sleep episodes (>12 h). Young healthy men went to bed at either 19:00 h (early sleep; prior waking 36 h, n=9) or 24:00 h (late sleep; prior waking 17 h, n=8). In both nights, SWA in non-rapid-eye-movement sleep (NREMS) decreased over the first three to four 1.5-h intervals and remained at a low level in the subsequent five to six 1.5-h intervals. In contrast, the changes of SFA were more variable and differed between the lower (12.25–13.0 Hz), middle (13.25–14.0 Hz) and higher frequency bin (14.25–15.0 Hz). A pronounced influence of time of day was present in the lower and higher SFA bin, when the dynamics were analyzed with respect to clock time. In both the early and late sleep condition, power density in the lower bin was highest between 2:00 and 5:00 h in the morning and decreased thereafter. In the higher bin, power density was low in the early morning hours and increased as sleep was extended into the daytime hours. The results provide further evidence for a frequency-specific circadian modulation of SFA which becomes more evident at a time when SWA is low.     

Disturbances in hypothalamo pituitary adrenal and thyroid axis identify different sleep EEG patterns in major depressed patients

This study was aimed at investigating the relationships between sleep EEG abnormalities and hypothalamo pituitary adrenal (HPA) and hypothalamo pituitary thyroid (HPT) disturbances in major depressive disorder. Post dexamethasone (DXM) cortisol levels and the dual TSH response to 08:00 h and 23:00 h TRH administration were determined after a 2 weeks wash-out period in a group of 113 DSM-IV major depressed patients (72 females aged 44.3+/-13.0 and 41 males aged 45.7+/-11) who were consecutively admitted to undergo sleep EEG recordings. Post-DXM cortisolemia, 08:00 and 23:00 post-TRH TSH values, time spent in rapid eye movement sleep (REMS), in slow wave sleep (SWS), and in stage 2 as well as time awake after sleep onset were introduced in a principal component (PC) analysis. The four 3 PC scores explaining up to 74% of the data set were further calculated for each patients and used in a cluster analysis. A three-cluster solution was retained. Controlling for the effects of age and gender, patients belonging to these three clusters could clearly be differentiated on the basis of their neuroendocrine responses and on their sleep EEG profiles. Compared to the two other clusters, cluster I (n=26) patients showed the most severe sleep continuity disturbances. Post-DXM cortisol escape and sleep architecture disturbances (consisting of a shortening of REMS latency and a decreased SWS) identified patients belonging to cluster II (n=39). Patients in cluster III (n=48) had the lowest TSH response to TRH and the less marked sleep EEG alteration. Clinical or demographic variables were unable to differentiate the three clusters. Our results suggest that different biological dysfunctions could each underlie particular neuroendocrine and sleep EEG disturbances in major depression.     

Effects of zopiclone on sleep, daytime somnolence and nocturnal and daytime performance in healthy volunteers

Ten healthy volunteers, aged 20 to 39, underwent 2 adaptation nights and 3 sessions of 2 consecutive experimental nights and days at 1 week intervals. In the 3 sessions, subjects received under double blind conditions either Zopiclone 3.75 mg or 7.5 mg or placebo, according to a latin-square design. On nights 1 and 2 of each session, subjects were continuously polygraphically monitored, except for a 45 min provoked wake episode 135 min after sleep onset on night 2. Sleep continuity and architecture were evaluated during night 1, degree of daytime somnolence during day 1 and residual effects during night 2 (0 h 00) and day 2 (8 h 00 and 12 h 00). Sleep continuity was not modified, except for a reduction of the number of night awakenings. NREM sleep stage 1 was reduced and stage 2 was increased (in duration but not in percentage) with Zopiclone 3.75 and 7.5 mg. NREM sleep stages 3 and 4 were increased with Zopiclone 3.75 mg only. REM sleep was reduced (in percentage only) with Zopiclone 3.75 and 7.5 mg. Daytime somnolence varied according to the time but not with the 3 different conditions. One performance test only (choice reaction time test) showed a significant impairment at 0 h 00 with Zopiclone 7.5 mg. From a subjective point of view, sleep quality was improved and night time awakening was reduced with Zopiclone 7.5 mg.     

Diurnal variations in alpha power density and subjective sleepiness while performing repeated vigilance tasks.

OBJECTIVE: Diurnal variations in EEG activity and subjectively rated sleepiness while performing repeated vigilance tasks were examined. METHODS: Nine diurnally active healthy males underwent repeated vigilance tasks at 08:00, 11:00, 14:00, 17:00 and 20:00 h. An electroencephalogram (EEG) was taken while the subjects performed the tasks with their eyes open. The alpha power spectra (8.6-13.3 Hz) of EEG was integrated. Subjectively rated sleepiness, reaction time and oral temperature were also measured. RESULTS: Significant diurnal variations were found for alpha power, subjectively rated sleepiness and oral temperature. The alpha power was significantly smaller at 08:00 than at 11:00, 14:00, 17:00 and 20:00 h. The subjectively rated sleepiness was significantly larger at 08:00 than at 11:00, 17:00 and 20:00 h. The diurnal variation in alpha power did not correspond to that in subjectively rated sleepiness. On the other hand, repeated vigilance tasks increased the alpha power, subjectively rated sleepiness and reaction time at each time of day. The increase in alpha power was significantly greater at 14:00 than at 08:00 and 20:00 h. CONCLUSIONS: The diurnal variation was found in alpha power while performing vigilance tasks. Furthermore, the increase in alpha power with repetition of the task depended on the time of day.     

Repeated nocturnal sleep latencies in narcoleptic, sleepy and alert subjects.

OBJECTIVES: The purpose of this study was to assess nocturnal sleep latencies among narcoleptics. METHODS: Thirteen narcoleptics and matched sleepy and alert controls participated in this study. Subjects were awakened three times on each of two experimental nights. The latencies to sleep and rapid eye movement sleep were evaluated at the beginning of the night and following each experimental awakening. RESULTS: The alert group (AG) had a significantly longer mean nocturnal sleep latency than the narcoleptic (NG) and sleepy groups (SG). The sleep latencies at 23:00 and 01:10 h were significantly longer than the latencies at 03:10 and 05:10 h. The interaction between group and time of night demonstrated longer latencies at 23:00 and 03:10 h for the AG when compared to the SG and the NG. At 01:10 and 05:10 h all groups had comparable latencies. The number of subjects in the NG who had multiple sleep onset REM periods (SOREMPs) was significantly higher than in either the AG or the SG. CONCLUSIONS: Narcoleptics were found to have a heightened propensity to fall asleep and increased number of SOREMPs during nocturnal sleep opportunities. These characteristics are consistent with the daytime polysomnographic findings known in this patient population.     

Intravenous administration of the neuropeptide galanin has fast antidepressant efficacy and affects the sleep EEG

OBJECTIVE: Recently, we demonstrated that the intravenous administration of the neuropeptide galanin acts on the sleep EEG of healthy young subjects similar to sleep deprivation. As this effect could imply an antidepressive potency we studied the effect of intravenous galanin administration on psychopathology and sleep EEG in patients with depression. METHODS: Galanin was administered to 10 patients with depression, who were on a stable dose of trimipramine. A placebo controlled double blind randomized design was used. Intravenous boli of galanin in a dose of 4 x 50 microg or placebo were administered hourly between 09:00 and 12:00 h. Galanin or placebo, respectively were administered on 2 days each. The sequence of the galanin or placebo days was randomized, allowing for various crossovers. The Hamilton depression rating scale score (HAMD) was performed 30 min before the first and 30 min after the last injection. The mean of the HAMD change between 08:30 and 12:30 h was chosen as primary efficacy variable. Sleep EEGs were recorded once post placebo treatment and once post verum treatment. In this case, recordings started at 23:00 h and ended at 07:00 h the next morning. RESULTS: The HAMD-difference between 08:30 and 12:30 h was significantly greater at the days of galanin-treatment compared to placebo-treatment. MANOVA revealed a significant change in sleep-EEG parameters (p < 0.05), mainly due to an increase in REM-latency (p < 0.06). CONCLUSION: The data provide preliminary evidence for an acute antidepressive efficacy of galanin, probably by a mechanism related to that of therapeutic sleep deprivation.     

Ghrelin enhances the nocturnal secretion of cortisol and growth hormone in young females without influencing sleep

Ghrelin was shown to increase slow wave sleep (SWS) and the secretion of growth hormone (GH) and cortisol in young males. In terms of sleep, such information for females, however, is lacking. Therefore, polysomnographies were recorded (23:00-07:00 h) and nocturnal (20:00-07:00 h) secretion profiles of GH and cortisol were determined in 10 healthy females (24.9+/-2.4 years, body mass index: 21.2+/-1.1) twice, receiving four boluses of 50 microg ghrelin or placebo at 22:00, 23:00, 00:00, and 01:00 h, in this single-blind, randomized, cross-over study. No significant differences of conventionally or quantitatively analyzed sleep were observed between ghrelin and placebo condition. First administration of ghrelin caused a marked mean increase of GH by 53.3 to 64.4+/-14.2 ng/ml (placebo: 5.9+/-1.5 ng/ml) and cortisol by 54.2 to 96.4+/-15.3 ng/ml (placebo: 27.5+/-4.7 ng/ml). The following ghrelin injections were associated with smaller increases of GH and cortisol. In the ghrelin condition, GH plasma levels remained significantly (P<0.05) higher from 22:20 to 02:00 h and cortisol plasma levels from 22:20 to 02:20 h. In contrast to findings in young men, ghrelin did not affect sleep in young women, indicating a sexual dimorphism. In accordance with the findings in young men, ghrelin stimulated secretion of GH and cortisol.     

Fluctuations of rectal and tympanic temperatures with changes of ambient temperature during night sleep

Abstract Many studies have demonstrated a decline in core temperature during slow wave sleep (SWS) in animals and humans. However, there are few studies that have investigated core temperature fluctuation during rapid eye movement sleep (REM) at different ambient temperatures. This study examined the effects on core temperature of continuous hot or cold exposure during sleep. Ten male subjects were exposed to hot and cold stress from 00 h to 1:00 h, when SWS is most predominant, and from 5:00 h to 7:00 h, when REM is predominant. Rectal temperature (Tr) and tympanic temperature (Tt) were monitored for 3 days, and polysomnographies (PSG) were recorded from 23:00 h to 7:00 h. The experiments lasted 3 weeks for each subject, over 2 consecutive nights each week (including an adaptation night and an experimental night). On the experimental night, subjects were exposed to hot (29°C) or cold (21°C) ambience. The core temperature fluctuation under the hot or cold ambience were compared with under the thermoneutral ambience. Under hot ambience, Tr declined significantly in the first 2 hours of sleep, but Tt did not change. In the last 2 hours, both Tr and Tt were significantly elevated. Under cold ambience, both Tr and Tt declined significantly in the first 2 hours. However, in the last 2 hours, neither Tr nor Tt showed any change. The result that Tr and Tt rose in hot ambience during the last 2 hours when REM is predominant suggests that body temperature during REM is influenced by ambient temperature.     

Sleep loss activates cellular markers of inflammation: Sex differences

Sleep disturbance is associated with inflammation and related disorders including cardiovascular disease, arthritis, and diabetes mellitus. Given sex differences in the prevalence of inflammatory disorders with stronger associations in females, this study was undertaken to test the effects of sleep loss on cellular mechanisms that contribute to proinflammatory cytokine activity. In 26 healthy adults (11 females; 15 males), monocyte intracellular proinflammatory cytokine production was repeatedly assessed at 08:00, 12:00, 16:00, 20:00, and 23:00 h during a baseline period and after partial sleep deprivation (awake from 23:00 to 3.00 h). In the morning after a night of sleep loss, monocyte production of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) differentially changed between the two sexes. Whereas both females and males showed a marked increase in the lipopolysaccharide (LPS) — stimulated production of IL-6 and TNF-α in the morning immediately after PSD, production of these cytokines during the early- and late evening was increased in the females as compared to decreases in the males. Sleep loss induces a functional alteration of monocyte proinflammatory cytokine responses with females showing greater cellular immune activation as compared to changes in males. These results have implications for understanding the role of sleep disturbance in the differential risk profile for inflammatory disorders between the sexes.     

The effects of a 20 min nap in the mid-afternoon on mood, performance and EEG activity.

OBJECTIVE: The aim of the study is to examine the effects of a 20 min nap in the mid-afternoon on mood, performance and EEG activities. METHODS: Seven young adults who had normal sleep-wake habits without habitual daytime napping participated in the study. They underwent Nap and No-nap conditions at intervals of 1 week. After a nocturnal sleep recording (00:00-08:00 h), their EEG recordings during relaxed wakefulness, and their mood, performance and self-ratings of performance level were measured every 20 min from 10:00 to 18:00 h. For the nap condition, they went to bed at 14:00 h and were awakened when 20 min had elapsed from the onset of sleep stage 1. For the No-nap condition, they took a rest without sleep by sitting on a semi-reclining chair. RESULTS: All of the subjects were awakened from sleep stage 2 during the nap. The 20 min nap improved the subjective sleepiness, performance level and self-confidence of their task performance. The nap also suppressed EEG alpha activity during eyes-open wakefulness. CONCLUSIONS: The results suggest that a short 20 min nap in the mid-afternoon had positive effects upon the maintenance of the daytime vigilance level.     

Association between subjective well-being and sleep among the elderly in Japan

OBJECTIVE: The purpose of this study was to examine the association between sleep and subjective quality of life in an elderly Japanese population. METHODS: Elderly people aged 70 years or more (n=1,769) were selected randomly from all areas of Japan. They were visited and interviewed in November 2003. Subjective well-being of the subjects was assessed using the Philadelphia Geriatric Center (PGC) Morale Scale. A logistic regression analysis was performed using sleep-related factors as explanatory variables. RESULTS: A positive linear association was observed between subjective sleep sufficiency and the mean PGC Morale Scale score. The crude and adjusted odds ratios for sleep disorders such as difficulty initiating sleep, excessive daytime sleepiness, and restless legs syndrome were significantly low. The mean score was highest for a sleep duration of 7-8h and became lower at sleep durations of <6 and 9h (inverted U-shaped association). However, the adjusted odds ratio for sleep duration did not show a significant reduction. CONCLUSIONS: In order to improve the subjective well-being of the elderly, better subjective sleep sufficiency and alleviation of sleep disorders are necessary. Different mechanisms may reduce subjective well-being in individuals who sleep less than 6h or who sleep 9h or more.     

Changes in circadian rhythm for mRNA expression of melatonin 1A and 1B receptors in the hypothalamus under a neuropathic pain‐like state

Several clinical reports on neuropathic pain of various etiologies have shown that it significantly interferes with sleep. Inadequate sleep due to neuropathic pain may contribute to the stressful negative consequences of living with pain. It is generally recognized that melatonin (MT) system in the hypothalmus is crusial for circadian rhythm and sleep‐wake transition. However, little, if any, is known about whether neuropathic pain could affect the MT system associated with sleep disturbance. In this study, we investigated the possible changes in circadian rhythm for the expression of MT receptors, especially MT1A and MT1B receptors, in the hypothalamus of mice with sciatic nerve ligation. The samples for real‐time RT‐PCR assay were prepared at 8:00, 14:00, 20:00, and 2:00 on day 7 after sciatic nerve ligation or sham operation. The mRNA expression of MT1A and MT1B receptors at 2:00 in sciatic nerve‐ligated mice, which exhibited thermal hyperalgesia along with an increase in wakefulness and a decrease in nonrapid eye movement sleep, was significantly greater than those in sham‐operated mice, whereas the levels of both MT1A and MT1B receptors at 8:00 in sciatic nerve‐ligated mice were significantly lower than those in sham‐operated mice. These findings suggest that neuropathic pain‐like stimuli lead to sleep disturbance in parallel with changes in circadian rhythm for mRNA expression of MT 1A and 1B receptors in the hypothalamus of mice. Synapse 68:153–158, 2014. © 2014 Wiley Periodicals, Inc.     

Slow wave sleep rebound and REM rebound following the first night of treatment with CPAP for sleep apnea: correlation with subjective improvement in sleep quality

Objective: The purpose of this study was to correlate changes in PSG parameters between the diagnostic polysomnogram (dPSG) and the first night of treatment with continuous positive airway pressure (CPAP) (cpapPSG) to subjective improvement in sleep quality.Background: In patients with obstructive sleep apnea syndrome (OSAS), therapy with CPAP results in reduction of sleep latency, stage 1 sleep, arousal index (Al) and respiratory disturbance index (RDI), and increase in stage 2 sleep, REM sleep and REM density. No data exists on the differences in polysomnographic (PSG) parameters in patients who have subjective improvement in sleep quality and those who do not.Methods: We retrospectively reviewed PSG studies of 44 patients with OSAS who presented to the Sleep Disorders Center at Duke University Medical Center. Patient's qualitative assessment of sleep was noted using a Likert-type scale administered the morning after the dPSG and cpapPSG. PSG indices of patients noting subjective improvement were compared to those with no improvement.Results: Patients noting a subjective improvement in sleep quality showed a decrease in the percentages of stage 1 sleep (P<0.001) and an increase in percentages of stages 3 and 4 sleep (slow wave sleep rebound; P<0.007) and stage REM sleep (REM rebound; P<0.008).     

Nocturnal proinflammatory cytokine-associated sleep disturbances in abstinent African American alcoholics

Animal studies reveal that cytokines play a key role in the regulation of sleep. Alcoholic patients show profound alterations of sleep and a defect in the homeostatic recovery of sleep following sleep loss. In this study, we investigated whether nocturnal plasma levels of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF) were associated with disordered sleep in alcohol dependence by testing the temporal relationships between these inflammatory cytokines and sleep, before and after sleep deprivation. All-night polysomnography and serial blood sampling at 23:00, 03:00, and 06:30 h were conducted across baseline, partial sleep deprivation, and recovery nights in abstinent African American alcoholics (n=16) and matched controls (n=15). Coupled with prolonged sleep latency and increased rapid eye movement sleep, alcoholics showed nocturnal elevations of IL-6 and TNF as compared to controls after adjustment for alcohol consumption and body mass index. Following sleep deprivation, alcoholics showed greater nocturnal levels of IL-6 and greater nocturnal increases of TNF as compared to controls. Pre-sleep IL-6 levels at 23:00 h correlated with prolonged sleep latency after adjustment for potential confounders whereas IL-6 levels at 03:00 h correlated with rapid eye movement sleep in the second half of the night. Taken together, these findings indicate that circulating levels of proinflammatory cytokines may have a negative influence on sleep initiation. These findings have implications for determining why sleep is disordered in alcoholics and may aid in the development of novel treatments to optimize sleep in this population.