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At least 667 records · Page 37Linked to original sources
PubMed2002

Homeostatic control of slow-wave and spindle frequency activity during human sleep: effect of differential sleep pressure and brain topography.

The impact of a 40 h sleep deprivation versus a 40 h multiple nap paradigm on topographic and temporal aspects of electroencephalographic (EEG) activity during the subsequent recovery sleep was investigated in 10 young volunteers in a controlled 'constant posture' protocol. The accumulation of sleep pressure with extended wakefulness could be significantly attenuated by intermittent naps. The differential sleep pressure conditions induced frequency- and topographic-specific changes in the EEG slow wave range (0.5-5 Hz) and in the low (LSFA, 12.25-13.25 Hz) and high spindle frequency activity range (HSFA, 13.75-16.5 Hz) during non-REM sleep. The observed increase of EEG slow-wave activity (SWA) after high sleep pressure was significantly more pronounced in the fronto-central (Fz, Cz) than in the parieto-occipital (Pz, Oz) derivations. Low sleep pressure after the nap paradigm decreased SWA with an occipital predominance. Spindle frequency activity showed a dissimilar homeostatic regulation: HSFA was significantly decreased after high sleep pressure and increased after low sleep pressure, exclusively in the centro-parietal brain region (Cz, Pz). LSFA was significantly enhanced after both manipulations. The data indicate that EEG activity, in particular frontal SWA and centro-parietal HSFA, are under a clear sleep-wake-dependent homeostatic control and imply a reciprocal relationship in the homeostatic regulation of SWA and HSFA, which however shows different spatio-temporal aspects.

Adult↗
PubMed2006

The sleep-enhancing effect of valerian inhalation and sleep-shortening effect of lemon inhalation.

We examined the effects of odorant inhalation on the sleep-wake states in rats. Odorants used in the experiment were clove, jasmine, lavender, lemon, peppermint, pine, rose, sandalwood, valerian, and ylang-ylang. Valerian and rose inhalation significantly prolonged the pentobarbital-induced sleeping time, whereas lemon inhalation significantly shortened it. The effect of valerian inhalation was markedly noticeable. In the anosmic rats, a significant effect of odorants on the pentobarbital sleep time was not seen. Electroencephalographic studies on natural sleep revealed that rose inhalation did not exert any significant effect on sleep, but a significant shortening in sleep latency and a significant prolonging in total sleep time were observed with valerian inhalation, whereas a significant prolonging in sleep latency was observed with lemon inhalation. Such effects of valerian and lemon inhalation were not admitted in anosmic rats. gamma-Aminobutyric acid (GABA) transaminase assay indicates that valerian inhalation decreases the activity of the enzyme and enhances GABA activity. Although valerian has been reported to exert a good effect for sleep as a medicine for internal use, the present study is the first medical report suggesting that the inhalation of valerian may enhance the sleep. On the other hand, the present results may suggest the possibility that lemon inhalation may cause a worsening of insomnia symptoms.

Animals↗
PubMed1993

Attention, stress and negative emotion in persistent sleep-onset and sleep-maintenance insomnia.

This study investigated the relation of negative emotions, attention and stress to sleep parameters in insomniacs. It also assessed whether sleep-onset insomniacs differ from sleep-maintenance/mixed insomniacs in the relations of these variables to sleep parameters. Fourteen sleep-onset insomniacs, 13 sleep-maintenance or mixed insomniacs and 13 normal sleepers were recruited using two sequential questionnaires. The groups differed significantly on diagnostically relevant sleep parameters, assessed over 1 week by sleep diary. After completing standard anxiety, anger and depression inventories, subjects participated in two laboratory procedures during which electrophysiological responses were recorded: orienting response habituation and emotional stress elicitation. The 28 significant correlations of sleep parameters with emotion, habituation and stress measures averaged r = 0.415. In multiple regression analyses, emotion, attention and stress variables accounted for an average of 41% of the variance in sleep parameters (mean R = 0.64). Discriminant function analysis using these variables correctly classified 66% of the subjects into the three groups. It was concluded that negative emotions, stress responsiveness and attentional factors interact to influence insomnia.

Adolescent↗
PubMed1999

Circadian timed wakefulness at dawn opposes compensatory sleep responses after sleep deprivation in Octodon degus.

The circadian timing system in mammals is thought to promote wakefulness and oppose sleep drive that accumulates across the activity phase in diurnal and nocturnal species. Whether the circadian system actively opposes compensatory sleep responses in mammals with episodes of alertness consolidated at dawn and dusk is unknown. In the present study, an interaction between circadian timed arousal at dawn and compensatory sleep responses after sleep deprivation (SD) was examined in Octodon degus, a hystricomorph rodent with crepuscular episodes of wakefulness. Recovery sleep was compared after 6 hours and 12 hours of SD ending at either CT 21 or 12, just before the dawn, and just after the dusk crepuscular episodes of consolidated wakefulness, respectively. Total sleep time and NREM sleep after SD increased proportionally to the amount of sleep loss; however, compensatory sleep responses after SD were attenuated at CT 23, a circadian time when a crepuscular event of wakefulness occurs in this species. EEG slow-wave activity (SWA) and body temperature levels in the first two hours after 6 and 12 hours of SD ending at CT 12 were similar. However, both were significantly higher than after 12 hours of SD ending at CT 21, suggesting factors other than the amount of prior wake duration can influence SWA levels. This study provides evidence that the circadian arousal system opposes compensatory sleep responses at dawn by actively promoting wakefulness in this species.

Animals↗
PubMed1981

Comparisons of home sleep recordings and polysomnograms in older adults with sleep disorders.

A major problem with studying the prevalence of sleep disorders is the high cost. We tested a portable home recording system which can decrease the cost of screening sleep recordings. Twenty-four senior volunteers and 12 patients referred to our sleep disorders clinic were studied for two nights. On one night, recordings were done in the laboratory with a traditional polysomnogram and the portable home recorder. On another night, portable home recorders were used in the subjects' homes. Of 36 subjects, 42% had sleep apnea and 39% had nocturnal myoclonus. Intermethod correlations were highly significant for sleep apnea index, nocturnal myoclonus index, total sleep period (TSP), total sleep time (TST), and wake time after sleep onset (WASO). The portable home recorder detected sleep apnea on 100% of nights during which sleep apnea was diagnosed by polysomnogram. The labor-saving and cost-saving benefits of home recordings as well as the increased comfort, privacy, and convenience will make the portable home recording the preferred method for many research and clinical applications.

Aged↗
PubMed1985

Periodic movements in sleep and sleep-wake complaint.

Periodic movements during sleep (PMS) are frequent, involuntary movements, usually of the lower extremities, that disrupt sleep. Twelve patients (nine men and three women, mean age 53.9 years) with a complaint of persistent insomnia (DIMS) were compared with 11 patients (eight men and three women, mean age 53.0 years) complaining of excessive daytime sleepiness (DOES). DIMS patients had more PMS (both absolute and relative), a longer delay to sleep onset and to REM onset, more wakefulness after sleep onset, and less total sleep time. Although the fragmentation of physiological sleep was more severe in the DIMS patients, those individuals with DOES reported cognitive intrusions during their sleep. While DOES patients may be regarded as "sleeping through" the brief arousals associated with leg activity during sleep, there appears to be sufficient cognitive awareness of the nocturnal interruption to precipitate a complaint of daytime sleepiness. Insomnia patients, however, appear to experience longer and more frequent awakenings, which are proportional to increased fragmentation of sleep.

Electromyography↗
PubMed1986

Daytime sleep characteristics and their relationships with night sleep in the narcoleptic patient.

Thirty-six narcoleptic patients with overwhelming sleep episodes, cataplexy, and sleep onset REM (SOREM) episodes were recorded for 34 continuous hours in the laboratory starting at 2200 h and ending at 0800 h a day and a half later. There were 94 SOREM and 60 sleep onset NREM (SONREM) episodes. While SONREM episodes were evenly distributed across daytime, SOREM episodes peaked between 0800 and 1000, 1200 and 1400, and 1600 and 1800 h. The ratio of SOREM to SONREM episodes was at its highest level between 1200 and 1400 h. Correlation coefficients between night 1 and night 2 for total sleep time (TST) and percentages of sleep stages were all positive and significant, whereas between daytime and each night, they were significant for percentages of stages 1, 2, and REM. Sleep-stage distribution across the last 24 h of continuous recording indicated that although TST levels were higher than that typical of normal subjects, REM sleep and slow wave sleep followed the same circadian distribution as that observed in normal subjects. The results are interpreted as evidence that the daytime sleep of narcoleptic patients is modified, similar to their night sleep, and that SOREM episodes are influenced by a time-of-day effect which culminates between 1200 and 1400 h.

Adolescent↗
PubMed2006

Sleep disturbances detected by a sleep apnea monitor in craniofacial surgical patients.

Sleep apnea in craniofacial surgery was investigated. Between January 1999 and December 2003, 18 patients were measured at an at least 6-month interval before and after surgery. Eight patients underwent palatoplasty for cleft palate, and the other 10 patients underwent orthognathic surgery, syndromic craniosynostosis, and postpharyngeal flap surgery. All patients included in the study demonstrated clinical signs of obstructive sleep apnea, such as snoring and cessation of breathing during sleep. An apnomonitor was used for presurgical and postsurgical sleep apnea status by measuring: 1) position during sleep; 2) percutaneous oxygen saturation; 3) respiratory analysis, such as the type of apnea-hypopnea, frequency of the events, and duration of apnea-hypopnea; 4) heart rate; and 5) snore analysis, such as trains, time, mean, and minimal and maximal amplifications. The apnea-hypopnea index (AHI) was significantly improved after surgery, especially in cases other than palatoplasty (7.4 +/- 8.73/h and 1.6 +/- 0.43/h, before and after surgery, respectively; P < 0.05 excluding palatoplasty). The percentage of snoring to total sleep was also improved significantly (22.4 +/- 19.74% and 9.0 +/- 8.54%, before and after surgery, respectively; P < 0.01 in all patients). Therefore, changes in sleep apnea parameters were elucidated in craniofacial surgery. Palatoplasty did not necessarily worsen the sleep apnea status, although there were snoring and anatomic abnormalities. Detachment of the pharyngeal flaps improved sleep apnea, and bimaxillary advancement was effective in normalizing sleep apnea.

Adolescent↗
PubMed1993

Sleep habits and sleep disturbances among the elderly--an epidemiological survey.

OBJECTIVES: To analyse simultaneously sleep habits and sleep disturbances in an elderly population and numerous factors possibly affecting sleep at the same time. DESIGN: A cross-sectional epidemiological survey by means of questionnaires. SETTING: The capital city of Iceland, Reykjavík and surrounding suburbs. PARTICIPANTS: A randomly selected, but stratified sample with 100 men and 100 women in each 5-year age group of the ages 65-84 years--800 individuals altogether. MAIN OUTCOME MEASURE: Sleep habits and sleep disturbances. RESULTS: The mean duration of sleep was 7.25 h (SD 74 min). Mean sleep onset time was 00.13 hours and was not related to age and gender but was delayed at weekends. Daytime napping was reported by 50% of the men and 31% of the women (P < 0.001). Difficulty maintaining sleep (DMS) was the most commonly reported insomnia complaint (men 37% and women 30%). Sleep charts revealed that men woke up an average of 1.2 times per night but women 0.8 times per night (P < 0.01). Difficulty initiating sleep was reported by 9.6% and early morning awakening (EMA) by 16.7%. Pain was a strong factor contributing to EMA. There was also an increase in EMA complaints among the elderly with obstructive pulmonary diseases and systemic hypertension. The prevelance of insomnia was only partly related to age and gender. Multiple regression analyses, however, showed different interrelationships between insomnia and other symptoms and findings for men versus women. CONCLUSION: DMS is the most commonly reported insomnia complaint among the elderly (men 37% and women 30%). The prevalence of insomnia did not increase with age in our study group.

Age Factors↗
PubMed2004

Regional pattern of metabolic activation is reflected in the sleep EEG after sleep deprivation combined with unilateral whisker stimulation in mice.

Regional differences in EEG slow wave activity (SWA) during sleep after sleep deprivation (SD) may be a consequence of differential metabolic activation of cortical areas. We investigated the relationship between the regional EEG dynamics and 2-deoxyglucose (DG) uptake after SD in mice. Six hours' SD were combined with natural unilateral whisker stimulation in an enriched environment to selectively activate the barrel cortex and motor areas. As expected, an interhemispheric asymmetry of 2-DG uptake was found in the barrel cortex immediately after SD. To test whether sleep contributes to recovery of the asymmetry, the stimulation was followed by either undisturbed sleep or by an additional SD. The asymmetry vanished after recovery sleep but also after the additional period of wakefulness without stimulation. In addition, relative 2-DG uptake in the primary motor cortex and retrosplenial area was significantly higher immediately after the SD than after the additional sleep or wakefulness, whereas no other region differed between the groups. Whisker stimulation elicited a greater increase in EEG SWA during non rapid eye movement sleep in the stimulated hemisphere than in the control hemisphere; this increase lasted for 10 h. Within a hemisphere, the initial increase in SWA was higher in the frontal than in the parietal derivation. We conclude that the regional SWA differences during sleep are use-dependent and may be related to the regional pattern of metabolism during the previous waking episode. However, the regional metabolic recovery is not dependent on sleep, and is not directly reflected in changes in SWA during sleep.

Animals↗
PubMed1996

Long-term extension to sleep--are we really chronically sleep deprived?

During 26 consecutive nights, electroencephalographic recordings and/or actigraphs were used to monitor the nighttime sleep of 10 asymptomatic healthy sleepers (mean age = 23.6 years). The schedule comprised: 7 nights of baseline sleep, 14 nights of extended sleep (up to 10 hr/night), and 5 nights of recovery sleep. During extended sleep, subjects slept significantly longer (approximately 1 hr), but sleep latency and interim wakefulness deteriorated. Extended sleep produced no improvements to self-rated mood or subjective sleepiness. Vigilance tests showed a small but significant reduction in reaction time following extended compared with both baseline and recovery nights. Ability to detect target tones did not change significantly. Multiple Sleep Latency Test scores during extended sleep showed small (about 1 min) reductions. These findings give little support to the view of chronic sleep deprivation in the average 7.5-hr sleeper.

Adolescent↗
PubMed2005

Heart rate variability during sedentary work and sleep in normal and sleep-deprived states.

The possibility of using heart rate variability (HRV) as an indicator of sleepiness was investigated by analysing heart rate (HR) activity and electroencephalography (EEG) recordings from 10 individuals who performed a monotonous attention task for 120 min in both sleep-deprived and rested states. In both conditions, measurements were collected during 60 min of sleep immediately following a 120 min of non-sleep (awake phase). Although HR decreased significantly in both the rested and the sleep-deprived states during the awake phase, HR significantly changed sooner when subjects were sleep-deprived than when they were rested. No significant changes in HRV were found during the awake phase; however, HRV correlated significantly with alpha and theta power densities when rested but not when sleep-deprived. During the sleep phase, the total HRV and very low and low frequency HRV components significantly decreased approximately 40 min after sleeping in the sleep-deprived condition. These HRV components were also significantly and negatively correlated with delta power densities. HRV does not seem to be a viable indicator of sleepiness; however, HRV may be useful for determining sleep stages.

Adult↗
PubMed1986

Normal sleep, disturbed sleep, transient and persistent insomnia.

There are three fundamental principles for understanding sleep; the sleeping brain is not a resting brain, the sleeping brain functions in a different manner from the waking brain and the activity and work of the sleeping brain are purposeful. The sleeping brain does fail and this failure is manifest in a variety of clinical symptoms; all sleep complaints should be taken seriously and investigated. Transient insomnia is uniformly associated with objective sleep disturbances which have been documented following phase shifts of the major sleep period such as that caused by transmeridian travel. However, the degree to which the individual responds to these factors is variable. There is a consensus that sleep medications are indicated for transient and short-term insomnia. Benzodiazepine hypnotics are commonly used to induce and maintain sleep, and improve daytime alertness.

Anti-Anxiety Agents↗
PubMed1977

Sleep apnoea syndrome: states of sleep and autonomic dysfunction.

Eleven patients with upper airway apnoea during sleep (one with SHY-Drager syndrome) were monitored polygraphically for wakefulness, sleep, and cardiovascular variables. Systemic hypertension and most of the severe arrhythmias recorded during sleep were secondary to repetitive obstructive apnonea and were mediated through the autonomic nervous system. Sleep related elevations of pulmonary arterial pressure were not influenced by atropine or impaired autonomic functions. Upper airway sleep apnoea is sleep related; the type of sleep (REM or NREM) is critical in the appearance of abnormalities. The distinction between two patient subgroups (total sleep dependent and NREM sleep dependent) has haemodynamic, and possibly long-term, implications. Sleep apnoea syndrome should be looked for in pateints with the Shy-Drager syndrome.

Adult↗
PubMed1995

Wrist actigraphic assessment of sleep in 116 community based subjects suspected of obstructive sleep apnoea syndrome.

BACKGROUND: The combined use of wrist actigraphic assessment and self assessment of sleep in the screening of obstructive sleep apnoea syndrome was evaluated in a community based sample. METHODS: One hundred and sixteen community based subjects clinically suspected of having obstructive sleep apnoea (syndrome) were evaluated by means of simultaneous ambulatory recording of respiration (oronasal flow thermistry), motor activity (wrist actigraphy), and subjective sleep (sleep log) during one night of sleep. RESULTS: The subjects were distributed according to their apnoea index (AI); AI < 1 (non-apnoeic snorers) 44%; AI 1- < 5 39%; and AI > or = 5 17%. High apnoea index values were associated with self reported disturbed sleep initiation and more fragmented and increased levels of motor activity and decreased duration of immobility periods, particularly in those with an apnoea index of > or = 5. Across subjects the duration of immobility periods was the only predictor of the apnoea index, explaining 11% of its variance. Use of the multiple regression equation to discriminate retrospectively between those with an apnoea index of < 1 and > or = 5 resulted in sensitivity and specificity values of 75% and 43%, and 5% and 100%, respectively. CONCLUSIONS: The combined use of a sleep log and actigraphic assessment of sleep failed to identify reliably those subjects who suffered from obstructive sleep apnoea (syndrome) in a sample of community based subjects reporting habitual snoring combined with excessive daytime sleepiness and/or nocturnal respiratory arrests.

Cross-Sectional Studies↗
PubMed2004

Antioxidant defense responses to sleep loss and sleep recovery.

Sleep deprivation in humans is widely believed to impair health, and sleep is thought to have powerful restorative properties. The specific physical and biochemical factors and processes mediating these outcomes, however, are poorly elucidated. Sleep deprivation in the animal model produces a condition that eventually becomes highly lethal, lacks specific localization, and is reversible with sleep, implying mediation by a biochemical abnormality. Metabolic and immunological consequences of sleep deprivation point to a high potential for antioxidant imbalance. The objective, therefore, was to study glutathione content in the liver, heart, and lung, because glutathione is considered a major free radical scavenger that reflects the degree to which a tissue has been oxidatively challenged. We also investigated major enzymatic antioxidants, including catalase and glutathione peroxidase, as well as indexes of glutathione recycling. Catalase activity and glutathione content, which normally are tightly regulated, were both decreased in liver by 23-36% by 5 and 10 days of sleep deprivation. Such levels are associated with impaired health in other animal models of oxidative stress-associated disease. The decreases were accompanied by markers of generalized cell injury and absence of responses by the other enzymatic antioxidants under study. Enzymatic activities in the heart indicated an increased rate of oxidative pentose phosphate pathway activity during sleep deprivation. Recovery sleep normalized antioxidant content in liver and enhanced enzymatic antioxidant activities in both the liver and the heart. The present results link uncompensated oxidative stress to health effects induced by sleep deprivation and provide evidence that restoration of antioxidant balance is a property of recovery sleep.

Alanine Transaminase↗
PubMed1985

Circadian rhythms of sleep and wakefulness in mice: analysis using long-term automated recording of sleep.

Circadian rhythms of wheel-running activity and polygraphically defined wakefulness, rapid-eye-movement (REM) sleep and non-REM (NREM) sleep were continuously observed in ten mice (Mus musculus) under both alternating light-dark (LD 12:12) and continuous darkness (DD) conditions. Sleep-wake state was determined automatically using a computer-based method that allowed continuous recordings of from 60 to 280 days in duration. The sleep-wake state percentages (of the circadian cycle) thus obtained were in substantial agreement with other estimates for this or similar strains and showed no significant difference between LD 12:12 (wake 54.3%, NREM sleep 38.1%, REM sleep 7.6%) and DD (wake 53.1%, NREM sleep 39.9%, REM sleep 7.0%) conditions. All 10 mice exhibited clear circadian rhythms in each of the three states and wheel-running activity under both lighting conditions for the entire duration of observation. Probability functions, computed using stationary sections of data from all 10 mice, showed distinct waveforms for all three states and wheel running. These waveforms were remarkably similar under entrained and free-running conditions. This documentation of sustained circadian rhythmicity in sleep-wake state throughout observations of unprecedented length contradicts the currently common assertion that circadian control of sleep state is weaker than that of activity.

Animals↗
PubMed1989

Effect of sleep and circadian cycle on sleep period energy expenditure.

Energy expenditure is lower during sleep than relaxed wakefulness. However, there is disagreement as to the particular metabolic changes that produce the difference. The present study assessed the contribution of sleep, circadian cycle, and the specific dynamic action effect of the evening meal to the sleep period fall in metabolic rate. Five subjects were tested for a total of nine nights under three conditions in a repeated-measures design. Subjects were confined to bed throughout their usual sleep period but were instructed to go to sleep 0, 3, or 6 h after their usual time for lights out. O2 consumption was measured in all conditions for the 0.5 h before and after each of the times for lights out and then throughout the sleep period after lights out. The results demonstrated that changes in energy expenditure during the sleep period are a function of both sleep and circadian cycle. In this study, the contribution of the two components was approximately equal. However, the effect of sleep was rapid asymptoting within 15 min of sleep onset, whereas that of circadian cycle was constant over the assessment period.

Adult↗