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At least 577 records · Page 32Linked to original sources
PubMed1996

Delaying and extending sleep during weekends: sleep recovery or circadian effect?

There is a well-known tendency to delay and prolong our sleep during weekends (Saturday and Sunday), with an advance and reduction of sleep during workdays (Monday to Friday). The objective of this work was to determine if the changes of sleep during weekends are produced by a partial sleep deprivation or a lack of entraining of circadian rhythms to an advanced phase, during workdays. The subjects were 52 undergraduate female students, mean age = 17.5 years, SD = 1.32. All students attended school following a regular schedule, from Monday to Friday. Two groups of students were studied: one attended school from 07:00 to 12:00 h (morning group, n = 30); the other attended school from 14:00 to 18:00 (afternoon group, n = 22). None of the students worked or was engaged in other activity with a fixed schedule. All kept a sleep-wake diary for 2 weeks, in which they recorded their bedtimes, wakeup times, and sleep-onset latencies. The morning group delayed 47.4 min [t(29) = 4.72, p < 0.0001] and prolonged their sleep 118.2 min [t(29) = 9.4, p < 0.0001] during weekends. Although the afternoon group had the opportunity to maintain a delayed phase and a long sleep time throughout the week, they delayed their bedtime by 24 min [t(21) = 2.99, p < 0.01] during weekends, without changing their sleep duration. The findings suggest that the prolonged sleep during weekends is due to reduction of sleep during workdays, whereas the delay of bedtime seems to be associated with a tendency of the human circadian system to maintain a delayed phase with respect to the solar daylight period.

Activities of Daily Living↗
PubMed1999

[Evaluation of sleep fragmentation by EEG spectrography in patients with obstructive sleep apnea syndrome].

Sleep fragmentation is considered to have a central role in the pathophysiology of sleep-disordered breathing. However, the evaluation of sleep fragmentation can be very troublesome work. We sought to evaluate sleep fragmentation in 10 patients with obstructive sleep apnea syndrome by utilizing fast-fourier transforms to render their sleep encephalograms as spectrograms (horizontal axis: time, vertical axis: frequency, color: power). Detailed 5-minute spectrograms revealed relatively uniform patterns of change in EEG spectra during and after apnea episodes. In non-REM sleep, delta activity during apnea was followed by alpha and beta activity during resumed breathing. In REM sleep, flat and low-power spectral patterns during apnea were followed by relatively weak alpha and beta activity during resumed breathing. In compressed, 1-hour views of the spectrograms, repeated apnea events appeared as vertical striped patterns of spectral change. These patterns were thought to be representative of sleep fragmentation. The spectrographic display of EEGs may be a very simple and easy method for the evaluation of sleep-fragmentation in sleep disordered breathing.

Adult↗
PubMed2000

Sleep deprivation and phasic activity of REM sleep: independence of middle-ear muscle activity from rapid eye movements.

In the recovery nights after total and partial sleep deprivation there is a reduction of rapid eye movements during REM sleep as compared to baseline nights; recent evidence provided by a selective SWS deprivation study also shows that the highest percentage of variance of this reduction is explained by SWS rebound. The present study assesses whether the reduction of rapid eye movements (REMs) during the recovery night after total sleep deprivation is paralleled by a decrease of middle-ear muscle activity (MEMA), another phasic muscle activity of REM sleep. Standard polysomnography, MEMA and REMs of nine subjects were recorded for three nights (one adaptation, one baseline, one recovery); baseline and recovery night were separated by a period of 40 hours of continuous wake. Results show that, in the recovery night, sleep deprivation was effective in determining an increase of SWS amount and of the sleep efficiency index, and a decrease of stage 1, stage 2, intra-sleep wake, and NREM latencies, without affecting REM duration and latency. However, MEMA frequency during REM sleep did not diminish during these nights as compared to baseline ones, while there was a clear effect of REM frequency reduction. Results indicate an independence of phasic events of REM sleep, suggesting that the inverse relation between recovery sleep after sleep deprivation and REM frequency is not paralleled by a concomitant variation in MEMA frequency.

Adult↗
PubMed2000

Heart rate variability during sleep stages in normals and in patients with sleep apnea.

Heart rate and heart rate variability are under the control of the autonomous nervous system. It can be assumed that during sleep internal influences dominate the autonomous nervous system. During the different sleep stages heart rate regulation differs in normal subjects. Obstructive sleep apnea is a disorder which has its origin in sleep and has strong modulating effects on the autonomous nervous system with prominent heart rate variations in consequence. In order to separate the influences of sleep stages and sleep apnea on heart rate variability we applied detrended fluctuation analysis in 12 healthy subjects and 20 patients with sleep apnea. We could show that the differences between sleep stages observed in healthy subjects were still present in subjects with sleep apnea despite their cyclical variation in heart rate. We conclude, that detrended fluctuation analysis is able to separate the influences of sleep stages and sleep apnea on heart rate variability.

Autonomic Nervous System↗
PubMed2005

Sleep and aging: prevalence of disturbed sleep and treatment considerations in older adults.

Although sleep patterns change with age, it is the change in the ability to sleep that precipitates sleep complaints in older adults. Waking not rested, waking too early, trouble falling asleep, daytime napping, nocturnal waking, and difficulty initiating or maintaining sleep are among the chief sleep complaints of older adults. The consequences of poor sleep include difficulty sustaining attention, slowed response time, difficulty with memory, and decreased performance. Both medical and psychiatric conditions as well as the medications used to treat them lead to sleep complaints in older adults. Circadian rhythm disturbances and primary sleep disorders may also result in sleep complaints. Appropriate treatment may be dictated by severity of symptoms and concurrent medications. Efficacious pharmacologic interventions are the nonbenzodiazepine hypnotics zolpidem, zaleplon, and eszop-iclone. Two new agents, ramelteon, which was recently approved by the U.S. Food and Drug Administration for use in adults with insomnia, and immediate release and modified release indiplon, which is currently under investigation, have been effective in clinical trials. Cognitive-behavioral therapy alone and in combination with medication have been effective in improving sleep in older adults. Sleep disturbance is not a natural consequence of aging, but rather a treatable condition.

Adolescent↗
PubMed2005

[Auto sleep staging and sleep quality estimation based on BP neural network].

To estimate the sleep quality, a 3-layer BP neural network was studied. The EEG complexity and the power spectrum of sleep-multigraph served as the input vector of the network . All-night sleep-stage scoring was performed. Then several parameters (sleep period, shallow sleep period, deep sleep period, REM period, ratio of the wakeful period and sleep one) were defined to estimate the sleep quality. The experiments revealed that the estimated sleep condition was the same as the subjects' impression. The data on six cases of all-night sleep show that this method is available to estimate the sleep quality.

Electroencephalography↗
PubMed1995

[Differentiation of arousal in sleep before and after CPAP therapy in patients with pronounced sleep apnea syndrome].

The sleep apnea syndrome is often associated with the syndromes of daytime exhaustion and involuntary daytime sleeping fits. The cause is assumed to be fragmentary sleep resulting from night-time arousal. The central nervous activation reactions caused by apnea or hypopnea, respectively, and not the movement arousal determine the sleep structure. We have examined 10 male patients in the age range 40-55 years (48 +/- 6 SD) before and during the first 3 nights of CPAP therapy. Cardiorespiratory polysomnography was performed in all four nights. Sleep way analyzed visually and differentiation was made between respiratory (RA) and movement arousal (MA). All 10 patients had a pronounced sleep apnea syndrome. Deep and dream sleep were reduced, significantly more respiratory arousals occurred than movement arousals. The SWS latency was shortened in the first therapy night, the deep and dream sleep proportions increased and the RA decreased significantly. No further significant changes in the sleep parameters occurred during the second and third nights. We found that the number of apnea/hypopnea was not equal to the number of RA. When less arousal was recognized it was suggestive of a deficit of the diversion function while more RA was indicative of additional respiratory events, e.g. pharyngeal obstructions and hyperventilations which were not recognized as apnea or hypopnea. In addition to its role in the differential diagnosis of sleeping disorders, in particular sleep apnea, arousal differentiation is also an important criterion for estimating the efficiency of CPAP therapy.

Adult↗
PubMed1996

The multiple sleep latency test: comparison of sleep onset criteria.

Determining sleep latency is one of the cornerstones of the interpretation of the multiple sleep latency test (MSLT). The purpose of this study was to compare various criteria used to determine sleep onset. We prospectively analyzed 100 consecutive MSLTs that were performed according to a standardized protocol. We scored each test using three separate sets of criteria for sleep onset: 1) one epoch of stage 1 sleep, 2) two consecutive epochs of stage 1 sleep, and 3) three consecutive epochs of stage 1 sleep. Each method yielded a mean sleep latency and a categorical classification of the record as normal if > 10 minutes, moderate if > or = 5 and < or = 10 minutes, and severe sleepiness if < 5 minutes. The ages of participants ranged from 4 to 78 years (mean 45.5). The averages of the mean sleep latencies across all three methods were: 6.2 minutes [standard deviation (SD) = 4.3] using one epoch, 7.2 minutes (SD = 4.7) using two epochs, and 7.5 minutes (SD = 4.9) using three epochs. Using the three categories of sleepiness, the implementation of the three-epoch criterion vs. the one-epoch criterion produced a change in category in 16 patients (16%). Five went from severe to moderate, 10 from moderate to normal, and 1 from severe to normal. As compared to using one epoch, using three produced an increase in mean sleep latency of at least 50% in 13 patients. The use of various criteria for sleep onset, especially criteria 1 and 3 above, produces differences in interpretation that are neither rare nor quantitatively negligible. Standardization of the methodology across centers would be desirable in clinical practice as well as for research protocols.

Adolescent↗
PubMed1985

Marked episodic elevation of cerebrospinal fluid pressure during nocturnal sleep in patients with sleep apnea hypersomnia syndrome.

The CSF pressure was measured continuously at the lumbar level during nocturnal sleep in 3 patients with sleep apnea hypersomnia syndrome. Nocturnal sleep was very unstable with frequent episodes of obstructive sleep apnea. When the patients were awake and relaxed in the supine position, their CSF pressure was stable and within the normal range. Episodic marked elevations of CSF pressure occurred frequently during sleep, and each elevation was preceded and accompanied by an episode of sleep apnea or hypopnea. Significant correlations were found between the duration of apneic episodes and increase of CSF pressure, and between decrease of SaO2 or TcPO2 and increase of CSF pressure. The duration of sleep apnea was longer, increase of CSF pressure was greater, and decreases of SaO2 and TcPO2 were more marked during REM sleep than during NREM sleep. It is suggested that the frequent marked episodic elevations of CSF pressure are caused by an increase in the intracranial vascular volume occurring mainly in response to transient hypercapnia and hypoxia, which are induced by pulmonary hypoventilation during the episodes of sleep apnea.

Adult↗
PubMed2001

Extended nights, sleep loss, and recovery sleep in adolescents.

In summary, this study of sleep in adolescents on an atypical schedule of 18-hour nights showed marked but not unanticipated differences in sleep as function of prior sleep deprivation. Unanticipated was the evidence of "recovery" sleep in adolescents who not only were not sleep deprived, but who had been on a sleep "optimizing" schedule and had been awake for only 10 hours. Extended sleep beginning about 4 hours in advance of entrained sleep onset phase was not associated with a return of SWS, a finding coinciding with predictions from studies in adults. Finally, this study provides an indication that the homeostatic sleep/wake process becomes less robust or sleep responsive during adolescent development, a phenomenon that may influence the delay of sleep common in adolescents.

Adolescent↗
PubMed1989

"Recovery" function of sleep: effects of purified human interleukin-1 on the sleep and febrile response of cats.

From cats prepared for chronic pollygraphic recording of sleep patterns, records were obtained for 8 hr, after (1) intracerebroventricular (i.c.v.) injection of artificial cerebrospinal fluid (aCSF), day 1; (2) i.c.v. injection of interleukin-1 (Il-1), day 2; and (3) injection of aCSF, day 3. Three doses of Il-1 were tested. The dose of 40 nmol totally inhibited sleep, whereas the dose of 10 nmol slightly prolonged sleep. The dose of 20 nmol of Il-1 elicited sleep and a body temperature increase. Total sleep (TS) time was significantly increased, due mainly to the significant increase in non-REM (NREM) sleep as compared to control day 1. REM sleep was also increased, but this increase did not reach statistical significance. Wakefulness (W) was significantly reduced. At this time cats were febrile. On day 3, a further significant increase in TS occurred. NREM was significantly increased compared with day 1, whereas the increase in REM sleep was significant compared to both day 1 and day 2. At this time body temperature was normal. The increase in REM sleep on days 2 and 3 resulted entirely from the significant increase in the number of REM periods. The results show that Il-1 at a dose of 20 nmol has sleep-promoting effects on NREM and REM sleep concomitant with pyrogenic effects. These two responses differed in their time courses and were not correlated (correlation coefficients were all nonsignificant).

Animals↗
PubMed2003

Quality of life in nonorganic and organic sleep disorders: II. Correlation with objective and subjective quality of sleep and awakening.

OBJECTIVE: The purpose of this study of 100 patients suffering from sleep-disorders was to determine correlations between their subjective health-related quality of life (HRQoL) and objective variables in sleep initiation and maintenance, sleep architecture, objective quality of awakening, psychophysiological parameters and subjective quality of sleep and awakening. METHODS: Objective measurements were obtained from overnight diagnostic polysomnography. Subjective HRQoL was determined from the Quality of Life Index (QLI, Mezzich and Cohen) completed prior to the adaptation night. Other measurements included subjective and objective quality of sleep and awakening (psychometry) the evening before and morning after polysomnographic investigations. RESULTS: 63% of the patients were suffering from nonorganic and 37% from organic sleep disorders (SDs). Within the first group, nonorganic insomnia predominated; within the second, sleep apnea. Subjective HRQoL correlated well with subjective sleep and awakening quality, especially in nonorganic SDs. There were only a few correlations of objective measurements with subjective HRQoL: in the total group of SD patients HRQoL correlated with sleep stage S2, and in nonorganic SDs with attention scores and psychophysiological measurements (mainly the pulse rate in the evening and morning). CONCLUSION: Our findings suggest only a weak relationship between objective sleep variables and subjective HRQoL in both organic and nonorganic SDs. However, we found various significant correlations of HRQoL with subjective measurements of sleep, especially in nonorganic SDs.

Adult↗
PubMed1978

Rapid eye movement sleep cycle, clock time and sleep onset.

The phase of the REM sleep rhythm was studied in 10 normal subjects each of whom was sleep studied for 4 consecutive nights. For analysis, each night of sleep was aligned according to clock time and each minute was scored as REM or non-REM. With these data, REM probability was found as a function of clock time. Fractional harmonic analysis indicates a 90 min periodicity. The REM probability curve shows peaks occurring at 1:30 a.m., 3:15 a.m., 4:30 a.m., 5:45 a.m. and 7:00 a.m. Statistical measures comparing the time of REM sleep across subjects suggests that subjects tend to have REM sleep at the same time of the night as each other. The influence of elapsed time after sleep onset on REM sleep is also reestablished. Results indicate that the time of REM sleep is determined by both clock time and time of sleep onset, suggesting two clocks, one sleep dependent and the other related to the basic rest activity cycle (BRAC), which are responsible for driving REM sleep. Furthermore, the similarity of REM times across subjects indicates the possible existence of an extra-personae REM driving force linked to clock time and possibly the BRAC.

Adult↗
PubMed2005

Improving day and night sleep problems in infants by changing day time sleep rhythm: a single group before and after study.

This study explores the duration and timing of day time waking periods required for sleep disturbed infants to improve day and night sleep. Seventy-nine sleep disturbed outpatients with day and night sleep problems were investigated before and two weeks after a brief sleep intervention. Data were collected by interviewing parents on their infants' day and night sleep patterns. Besides instructing the parents on night sleep regulation, they were advised to regulate day sleep. After the intervention, duration of day and night sleep increased and frequency of night waking decreased. The mean duration of the first waking period in the morning did not change, but the range decreased. The mean duration of the last waking period in the evening increased. The frequency of short and irregular day naps and the need for assistance in falling asleep decreased after the intervention. It is recommended that the last waking before night sleep is lengthened to reduce day and night sleep problems.

Analysis of Variance↗
PubMed1997

Dynamics of EEG background activity level during quiet sleep in multiple nocturnal sleep episodes in infants.

The study reported in this paper investigated the dynamics of EEG background activity during quiet sleep (QS) in the first year of life. These dynamics have been previously shown to follow an intra-sleep trend within a single sleep episode, and the aim of this study was to show whether they were similar in two successive nocturnal sleep episodes interrupted by a waking episode, or whether they exhibited a progressive trend across the two episodes. The polygraphic recordings of two groups of 6 infants aged from 9 to 15 weeks old and from 25 to 47 weeks old, whose nocturnal sleep organisation was spontaneously interrupted, were selected. Three indicators of the time course of the parameter value, obtained from automatic analysis and reflecting the degree of synchronisation of the EEG activity recorded by the centro-occipital lead, were computed for the first two QS periods of two successive sleep episodes: the parameter range (difference between the EEG parameter value at the QS onset and that at the trough); the trough latency (time interval between QS onset and trough); and rate of synchronisation (range/trough latency). All 3 indicators differed between the first and the second QS period of both sleep episodes independently of age. The rate of synchronisation (but not the parameter range and the trough latency) was higher in the first sleep episode than in the second one, showing an over-night decreasing trend. Those results show that, when nocturnal sleep in infants is split into two episodes separated by an intervening waking, also the second sleep episode displays an internal organisation of its EEG dynamics. Moreover, an across-night trend in the rate of synchronisation can be observed from an early age, a finding which suggests, again, the early emergence of homeostatic regulation of sleep.

Age Factors↗
PubMed2000

Sleep influence on seizures and epilepsy effects on sleep in partial frontal and temporal lobe epilepsies.

OBJECTIVES: A reciprocal effect is observed between sleep and epilepsy. Sleep effect on epilepsy is protective and facilitating. Reciprocally epilepsy alters sleep organization and microarchitecture. This interelationship is well established for some epilepsies but remains undefined for cryptogenic and symptomatic frontal and temporal lobe epilepsies. In order to research sleep influence on seizures and epilepsy effects on sleep we carried out two studies in patients with cryptogenic/symptomatic frontal or temporal lobe epilepsies. METHODS: The occurrence of seizures in relation to the state of alertness was analyzed in patients with (1) mesial temporal and frontal lobe epilepsy, and (2) in patients with mesio-lateral temporal and mesial temporal lobe epilepsy in several conditions. Sleep analysis (organization and microarchitecture) was realized. RESULTS: We found: (1) a precise relationship between sleep and seizures in frontal lobe epilepsy (FLE); (2) a precise relationship between wakefulness and seizures in temporal lobe epilepsy (TLE); (3) sleep organization was normal in FLE and altered in TLE; (4) alterations of sleep microarchitecture in FLE and TLE. CONCLUSIONS: Seizure occurrence was mainly in relation to sleep for FLE and to wakefulness for TLE. Sleep organization appeared more altered for TLE than FLE. These results allow practical applications to localize and study FLE and TLE.

Brain↗
PubMed2000

Sleep patterns and sleep disruptions in school-age children.

This study assessed the sleep patterns, sleep disruptions, and sleepiness of school-age children. Sleep patterns of 140 children (72 boys and 68 girls; 2nd-, 4th-, and 6th-grade students) were evaluated with activity monitors (actigraphs). In addition, the children and their parents completed complementary sleep questionnaires and daily reports. The findings reflected significant age differences, indicating that older children have more delayed sleep onset times and increased reported daytime sleepiness. Girls were found to spend more time in sleep and to have an increased percentage of motionless sleep. Fragmented sleep was found in 18% of the children. No age differences were found in any of the sleep quality measures. Scores on objective sleep measures were associated with subjective reports of sleepiness. Family stress, parental age, and parental education were related to the child's sleep-wake measures.

Age Factors↗
PubMed2003

The effect of cabergoline on sleep, periodic leg movements in sleep, and early morning motor function in patients with Parkinson's disease.

To investigate the effect of the dopamine D2 and D1 receptor agonist cabergoline on sleep, periodic leg movements (PLMs) in sleep, and early morning motor performance in patients with Parkinson's disease (PD). It was hypothesized that cabergoline had long-lasting beneficial effects on sleep and PLMs in sleep in patients with PD, after a single evening intake. A total of 15 patients with idiopathic PD underwent two nights of polysomnography and motor tests (UPDRS, tapping test) before and after 6-8 weeks of treatment with cabergoline (dosage: 3-6 mg/day). Additionally, patients completed a subjective sleep visual analog scale (VAS) before and during cabergoline treatment. Compared to baseline values, treatment with cabergoline did not change sleep efficiency or the amount of stage 1 and stage 2 sleep. The number of awakenings (22.4+/-10.1 vs 32.5+/-13.3, p<0.05) and stage shifts (119+/-42 vs 148+/-46, p<0.05) were increased during treatment with cabergoline, and PLMs in sleep were reduced (PLM index 34.9+/-44.9 vs 6.7+/-4.2 per hour, p<0.05). Cabergoline significantly improved early morning motor function, and in spite of increased phase shifts and awakenings, patients felt significantly more refreshed in the morning during cabergoline therapy. Cabergoline slightly fragmented sleep, without altering its total amount. The functional significance of this finding is uncertain. The subjective quality of sleep improved, and periodic limb movements in sleep decreased.

Activities of Daily Living↗