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At least 613 records · Page 34Linked to original sources
PubMed1994

Sleep and cortical temperature in the Djungarian hamster under baseline conditions and after sleep deprivation.

The Djungarian hamster (Phodopus sungorus) is a markedly photoperiodic rodent which exhibits daily torpor under short photoperiod. Normative data were obtained on vigilance states, electroencephalogram (EEG) power spectra (0.25-25.0 Hz), and cortical temperature (TCRT) under a 16:8 h light-dark schedule, in 7 Djungarian hamsters for 2 baseline days, 4 h sleep deprivation (SD) and 20 h recovery. During the baseline days total sleep time amounted to 59% of recording time, 67% in the light period and 43% in the dark period. The 4 h SD induced a small increase in the amount of non-rapid eye movement (NREM) sleep and a marked increase in EEG slow-wave activity (SWA; mean power density 0.75-4.0 Hz) within NREM sleep in the first hours of recovery. TCRT was lower in the light period than in the dark period. It decreased at transitions from either waking or rapid eye movement (REM) sleep to NREM sleep, and increased at the transition from NREM sleep to waking or REM sleep. After SD, TCRT was lower in all vigilance states. In conclusion, the sleep-wake pattern, EEG spectrum, and time course of TCRT in the Djungarian hamster are similar to other nocturnal rodents. Also in the Djungarian hamster the time course of SWA seems to reflect a homeostatically regulated process as was formulated in the two-process model of sleep regulation.

Animals↗
PubMed2002

To breathe, perchance to sleep: sleep-disordered breathing and chronic insomnia among trauma survivors.

Standard psychiatric classification (DSM-IV-TR) traditionally attributes post-traumatic sleep disturbance to a secondary or symptomatic feature of a primary psychiatric disorder. The DSM-IV-TR paradigm, however, has not been validated with objective sleep assessment technology, incorporated nosological constructs from the field of sleep disorders medicine, or adequately addressed the potential for post-traumatic stress disorder (PTSD) sleep problems to manifest as primary, physical disorders, requiring independent medical assessments and therapies. This paradigm may limit understanding of sleep problems in PTSD by promulgating such terms as "insomnia related to another mental disorder," a.k.a. "psychiatric insomnia." Emerging evidence invites a broader comorbidity perspective, based on recent findings that post-traumatic sleep disturbance frequently manifests with the combination of insomnia and a higher-than-expected prevalence of sleep-disordered breathing (SDB). In this model of complex sleep disturbance, the underlying sleep pathophysiology interacts with PTSD and related psychiatric distress; and this relationship appears very important as demonstrated by improvement in insomnia, nightmares, and post-traumatic stress with successful SDB treatment, independent of psychiatric interventions. Continuous positive airway pressure treatment in PTSD patients with SDB reduced electroencephalographic arousals and sleep fragmentation, which are usually attributed to central nervous system or psychophysiological processes. Related findings and clinical experience suggest that other types of chronic insomnia may also be related to SDB. We hypothesize that an arousal-based mechanism, perhaps initiated by post-traumatic stress and/or chronic insomnia, may promote the development of SDB in a trauma survivor and perhaps other patients with chronic insomnia. We discuss potential neurohormonal pathways and neuroanatomatical sites that may be involved in this proposed interaction between insomnia and SDB.

Adult↗
PubMed2004

Rat strain differences in sleep after acute mild stressors and short-term sleep loss.

Genetic and physiological diversity amongst rodent strains provide the potential for developing models that may give insight into factors that regulate sleep in response to environmental challenges. We examined home cage activity, behavioral performance in the open field and sleep after a number of mild stressors (cage change [CC], open field [OF]) and after 1 and 4h of sleep deprivation (1hSD and 4hSD) in rat strains (Fischer 344 [F344], Lewis [LEW], Wistar [WST] and Sprague-Dawley [Sp-D], n=16 per strain) that differ in behavior and sleep. F344 and WST rats had greater home cage locomotion than LEW and Sp-D rats, but F344 rats exhibited the least relative locomotion in OF. In 24h baseline recordings of sleep, strain rankings were LEW=WST=Sp-D>F344 in rapid eye movement sleep (REM), and LEW=Sp-D>F344 and LEW>WST in non-REM (NREM). Compared to baseline, total sleep was reduced in all four strains after CC, OF and 1hSD, but not after 4hSD, in the first hour after treatment. Afterwards, increases in REM and NREM were seen after all treatments with the amount and time course varying across treatments and strains. CC induced the weakest and 4hSD the largest effects on sleep, whereas OF and 1hSD had intermediate effects. Among strains, the more anxious F344 rats exhibited the greatest sleep increases during the light period after OF, 1hSD and 4hSD. The results are discussed with respect to the relationship between behavioral and sleep responses to stressors, and to potential mechanisms underlying the strain differences.

Analysis of Variance↗
PubMed2005

Sleep extension: getting as much extra sleep as possible.

Nearly all people, whether they consider themselves sleep deprived or not, can initially obtain extra sleep. However, as accumulating extra sleep reduces carryover sleep debt, a point is reached where it is no longer possible to obtain extra sleep. If there were a practical method to make a precise measurement of a person's daily sleep requirement, it may be possible to show that most individuals are carrying a very large sleep debt. Several observations and studies demonstrate that almost everyone is sleep deprived and carries some amount of sleep debt. How long such an indebtedness will persist without change if no extra sleep is obtained is not known.

Homeostasis↗
PubMed2006

Opioids, sleep architecture and sleep-disordered breathing.

Opioid use whether acute or chronic, illicit or therapeutic is prevalent in Western societies. Opioid receptors are located in the same nuclei that are active in sleep regulation and opioid peptides are suggested to be involved in the induction and maintenance of the sleep state. mu-Opioids are the most commonly used opioids and are recognized respiratory depressants that cause abnormal awake ventilatory responses to hypercapnia and hypoxia. Abnormal sleep architecture has been reported during the process of opioids induction, maintenance and withdrawal. During induction and maintenance of opioid use there is reduction of rapid eye movement (REM) sleep and slow wave sleep. More recently, central sleep apnoea (CSA) has been reported with chronic opioid use and 30% of stable methadone maintenance treatment patients have CSA. Given these facts, it is sobering to note the paucity of human data available regarding the effects of short and long-term opioid use on sleep architecture and respiration during sleep. In this manuscript, we review the current knowledge regarding the effects of mu-opioids on sleep and respiration during sleep and suggest research pathways to advance our knowledge and to explore the possible responsible mechanisms related to these effects.

Analgesics, Opioid↗
PubMed2000

Sleep rebound in animals deprived of paradoxical sleep by the modified multiple platform method.

The objective of the present study was to assess the sleep rebound of animals exposed to the modified multiple platform method (MMPM), in which cage-mate rats were placed onto narrow platforms (NP=6.5 cm in diameter), onto wide platforms (WP=14 cm in diameter) or onto a grid (GR). The last two groups were included as environmental controls for the deprivation method. Animals were implanted with bipolar electrodes in the cortex, hippocampus and neck muscle. Baseline sleep was recorded for 6 h, after which the animals were placed in one of the above-mentioned settings for 90 h and their sleep was again recorded. Comparison between baseline and post-GR recordings revealed no sleep differences in these animals. Placement of animals onto WP resulted in augmented sleep time (16%), time spent in PS (+99%), duration of PS episodes (+77%), sleep efficiency (+16%), and in reduced latency to PS (-84.8%). Finally, NP animals exhibited a dramatic increase in sleep time (+34.3%), time spent in PS (+184.7%), duration of PS episodes (+106%), and in sleep efficiency (+34.4%). Moreover, sleep latency (-52.2%) and time spent in SWS (-12.2%) were reduced. Based on the results of sleep rebound, the data indicated that placement of animals onto narrow platforms in the MMPM was an effective PS deprivation method and the grid should be considered as an adequate environmental control.

Animals↗
PubMed1986

Problems in the interpretation of nocturnal penile tumescence studies: disruption of sleep by occult sleep disorders.

A review of the sleep of 31 patients 45 years old or older undergoing nocturnal penile tumescence studies showed that 19 had a previously undiagnosed sleep disorder. Of the patients 9 had periodic leg movements in sleep, 9 had sleep apnea and 1 had both disorders. In 10 of these patients the sleep disorders affected nocturnal penile tumescence by disrupting sleep and causing brief periods of detumescence, movement artifacts and delays in the tumescing phase of nocturnal penile tumescence. These disruptions resulted in an apparently abnormal nocturnal penile tumescence that appeared as if the patient had difficulty in achieving or maintaining an erection. The nocturnal penile tumescence disruptions may have reflected only a disruption of the necessary conditions for normal nocturnal penile tumescence to occur, namely adequate sleep and rapid eye movement sleep. The results strongly suggest that failure to measure concurrent sleep parameters and screen for occult sleep disorders could result in the incorrect diagnosis of abnormal nocturnal penile tumescence.

Aged↗
PubMed1997

Selective and total sleep deprivation: effect on the sleep EEG in the rat.

Although sleep deprivation is known to exert an antidepressant effect in depressed patients, the involvement of sleep regulation is still unknown. Selective sleep deprivation experiments were performed in the rat to investigate the interactions between non-REM sleep (NREMS) and REM sleep (REMS) in an animal model. A12-h total sleep deprivation (TD) period ending at lights on was followed by one of the following protocols: (1) recovery sleep (TD12); (2) 4-h total sleep deprivation (TD16); (3) 4-h slow-wave deprivation (SWD); (4) 4-h REMS deprivation (RD). In the SWD protocol, the reduction of EEG slow-wave activity (SWA; power density in the 0.75-4.0 Hz band) was obtained by curtailing NREMS episodes to 20 s. During RD the number of interventions required to prevent REMS increased during the first 2 h and then remained constant. While RD caused only a minor reduction of NREMS, it increasingly suppressed SWA in NREMS. The rebound of SWA occurred later and was less prominent after RD than after SWD. Whereas an REMS rebound occurred after all three 4-h sleep deprivation protocols, a persistent increase in the dark period was present only after TD16. It is concluded that (a) SWA in NREMS is inhibited by an increased level of REMS propensity; (b) the hypothesis that REMS propensity increases only during NREMS is not supported; and (c) the results are compatible with the hypothesis that the suppression of NREMS intensity is the common denominator of different antidepressive sleep manipulations in depressive patients.

Animals↗
PubMed2004

Interrater reliability between scorers from eight European sleep laboratories in subjects with different sleep disorders.

Interrater variability of sleep stage scorings is a well-known phenomenon. The SIESTA project offered the opportunity to analyse interrater reliability (IRR) between experienced scorers from eight European sleep laboratories within a large sample of patients with different (sleep) disorders: depression, general anxiety disorder with and without non-organic insomnia, Parkinson's disease, period limb movements in sleep and sleep apnoea. The results were based on 196 recordings from 98 patients (73 males: 52.3 +/- 12.1 years and 25 females: 49.5 +/- 11.9 years) for which two independent expert scorings from two different laboratories were available. Cohen's kappa was used to evaluate the IRR on the basis of epochs and intraclass correlation was used to analyse the agreement on quantitative sleep parameters. The overall level of agreement when five different stages were distinguished was kappa = 0.6816 (76.8%), which in terms of kappa reflects a 'substantial' agreement (Landis and Koch, 1977). For different groups of patients kappa values varied from 0.6138 (Parkinson's disease) to 0.8176 (generalized anxiety disorder). With regard to (sleep) stages, the IRR was highest for rapid eye movement (REM), followed by Wake, slow-wave sleep (SWS), non-rapid eye movement 2 (NREM2) and NREM1. The results of regression analysis showed that age and sex only had a statistically significant effect on kappa when the (sleep) stages are considered separately. For NREM2 and SWS a statistically significant decrease of IRR with age has been observed and the IRR for SWS was lower for males than for females. These variations of IRR most probably reflect changes of the sleep electroencephalography (EEG) with age and gender.

Female↗
PubMed1995

Subjective estimates of sleep differ from polysomnographic measurements in obstructive sleep apnea patients.

It is well established that, as a group, insomnia patients overestimate sleep onset latency (SOL) and underestimate total sleep time (TST) when compared to objective polysomnographic (PSG) findings. Whether a similar phenomenon occurs with other sleep disorders is not fully established. We compared the PSG sleep of 84 patients with suspected sleep apnea (SA) to their subjective experience of sleep reported on a sleep diary the morning after PSG testing. Both patients with SA (SA+) and those without (SA-) tended to overestimate SOL, but the SA+ group (n = 50) made larger overestimations (p < 0.02). The SA+ and SA- groups also differed in their accuracy at estimating TST, with SA+ patients underestimating TST (p < 0.05). These findings support the premise that marked discrepancies between subjective and PSG-determined sleep may not be limited to insomnia, but present in other sleep disorders as well, and should be appreciated by practitioners when obtaining sleep histories.

Adult↗
PubMed2004

Expiratory changes in pressure: flow ratio during sleep in patients with sleep-disordered breathing.

OBJECTIVES: The size of the upper airway is smallest during sleep, at the end of expiration. This may favor upper-airway collapse in patients with obstructive sleep apnea. In the respiratory cycles preceding obstructive events during sleep, our hypothesis is that upper-airway resistance (UAR) increased earlier during expiration prior to changes occurring during inspiration. DESIGN: We analyzed the pharyngeal pressure-to-flow ratios in order to determine variations in UAR for both inspiration and expiration during stable respiration and the 4 consecutive breaths preceding upper-airway obstructive events in stage 2 sleep. To assess the variation of resistance throughout the within-breath period during stable respiration and the 4 breaths preceding obstructive events, results were expressed as the instantaneous resistance at fixed points 10%, 30%, 50%, 70%, and 90% of time values of inspiration and expiration. Global inspiratory and expiratory UARs during wakefulness and sleep in stable respiration were expressed by the median of instantaneous UAR values. SETTING: Tertiary-care academic medical center. PATIENTS: Eleven patients with moderate to severe sleep-disordered breathing. INTERVENTION: None. MEASUREMENTS AND RESULTS: During stable respiration, both inspiratory and expiratory resistance increased during sleep, compared to values while awake. The difference between inspiratory and expiratory UAR increased when sleep deepened. During the respiratory cycle, the increase in the end-expiratory UAR occurred earlier than during inspiration; during stable respiration, UAR was much aggravated during the last three breaths preceding an obstructive event. CONCLUSION: Increases in the expiratory UAR occurred earlier than during inspiration in the cycles preceding upper-airway collapse in patients with sleep apnea. This finding suggested an important role of the expiratory phase in promoting upper-airway collapse and is in accordance with the inspiratory pharyngeal instability occurring when lowering the expiratory pressure in patients with obstructive sleep apnea.

Adult↗
PubMed2006

Attention bias for sleep-related stimuli in primary insomnia and delayed sleep phase syndrome using the dot-probe task.

STUDY OBJECTIVES: Cognitive models of primary insomnia (PI) suggest attention bias as a maintaining process. This study used a hallmark measure of attention bias, the dot-probe task, to determine whether attention bias to sleep-related stimuli is present in individuals with PI. Control groups of good sleepers (GS) and individuals with delayed sleep phase syndrome (DSPS), a sleep disorder with no presumed cognitive pathway and, hence, no predicted association with attention bias, were included. DESIGN: A between-groups (PI, DSPS, GS) design was employed. Participants completed a dot-probe task with stimuli comprising sleep-related and neutral words, balanced for length and frequency of usage. It was predicted a priori that PI would show greater attention bias to sleep stimuli compared with GS and DSPS groups. No difference between GS and DSPS was predicted. PARTICIPANTS: Sixty-three individuals completed the study (PI = 21; DSPS = 22; GS = 20), with those in PI and DSPS classified by International Classification of Sleep Disorders criteria according to self-report sleep diaries and actigraphy. GS scored < 5 on the Pittsburgh Sleep Quality Index, reported being good sleepers, and met no criteria for a current or previous sleep disorder. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: As predicted, PI showed increased vigilance for sleep-related stimuli relative to GS and DSPS. No differences between GS and those with DSPS were found. The PI group showed shorter response latencies relative to the GS and DSPS groups. CONCLUSIONS: Results support an association between attention bias and PI. Further work must determine whether or not attention bias is a causal factor. Speeded responses in the PI group suggest heightened arousal, indicating that physiologic factors may play a related role.

Adolescent↗
PubMed1982

Sleep regulation after reduction of brain serotonin: effect of p-chlorophenylalanine combined with sleep deprivation in the rat.

Sleep was recorded in the rat after combined treatment with p-chlorophenylalanine (PCPA; 300 mg/kg) and 24-h sleep deprivation (SD) and then compared with sleep recorded after either treatment alone. PCPA alone reduced total sleep (TS), rapid eye movement sleep (REMS) per TS, as well as the power density of the EEG delta band (1.25-4.00 Hz) of non-REM sleep (NREMS). SD enhanced these sleep parameters and reduced the frequency of wake episodes. The combined treatment with PCPA and SD reduced TS and REMS/TS to a level similar to that induced by PCPA alone, and it increased delta activity to a level similar to that induced by SD alone. The frequency of wake episodes was reduced. It is concluded that essential aspects of sleep regulation are still functional during PCPA-induced insomnia. The sleep-inhibiting action of PCPA may be related to the hyperresponsiveness to stimuli rather than to the impairment of sleep regulation itself.

Animals↗
PubMed2004

Effect of cognitive behavioural therapy for insomnia on sleep architecture and sleep EEG power spectra in psychophysiological insomnia.

There is now an overwhelming preponderance of evidence that cognitive behavioural therapy for insomnia (CBT-I) is effective, as effective as sedative hypnotics during acute treatment (4-8 weeks), and is more effective in long term (following treatment). Although the efficacy of CBT-I in the treatment of chronic insomnia is well known, however there is little objective data on the effects of CBT-I on sleep architecture and sleep EEG power densities. The present study evaluated, first, subjective change in sleep quality and quantity, and secondly the modifications occurring in polysomnography and EEG power densities during sleep after 8 weeks of CBT-I. Nine free drug patients with psychophysiological insomnia, aged 33-62 years (mean age 47 +/- 9.7 years), seven female and two male participated in the study. Self-report questionnaires were administered 1 week before and 1 week after CBT-I, a sleep diary was completed each day 1 week before CBT-I, during CBT-I and 1 week after CBT-I. Subjects underwent two consecutive polysomnographic nights before and after CBT-I. Spectral analysis was performed the second night following 16 h of controlled wakefulness. After CBT-I, only scales assessing insomnia were significantly decreased, stages 2, REM sleep and SWS durations were significantly increased. Slow wave activity (SWA) was increased and the SWA decay shortened, beta and sigma activity were reduced. In conclusion CBT-I improves both subjective and objective sleep quality of sleep. CBT-I may enhance sleep pressure and improve homeostatic sleep regulation.

Adult↗
PubMed2004

Activation of c-fos in GABAergic neurones in the preoptic area during sleep and in response to sleep deprivation.

Neurones in the median preoptic nucleus (MnPN) and the ventrolateral preoptic area (vlPOA) express immunoreactivity for c-Fos protein following sustained sleep, and display elevated discharge rates during both non-REM and REM sleep compared to waking. We evaluated the hypothesis that MnPN and vlPOA sleep-active neurones are GABAergic by combining staining for c-Fos protein with staining for glutamic acid decarboxylase (GAD). In a group of six rats exhibiting spontaneous total sleep times averaging 82.2 +/- 5.1% of the 2 h immediately prior to death, >75% of MnPN neurones that were Fos-immunoreactive (IR) were also GAD-IR. Similar results were obtained in the vlPOA. In a group of 11 rats exhibiting spontaneous sleep times ranging from 20 to 92%, the number of Fos + GAD-IR neurones in MnPN and vlPOA was positively correlated with total sleep time. Compared to control animals, Fos + GAD-IR cell counts in the MnPN were significantly elevated in rats that were sleep deprived for 24 h and permitted 2 h of recovery sleep. These findings demonstrate that a majority of MnPN and vlPOA neurones that express Fos-IR during sustained spontaneous sleep are GABAergic. They also demonstrate that sleep deprivation is associated with increased activation of GABAergic neurones in the MnPN and vlPOA.

Animals↗
PubMed2006

Wavelength-dependent effects of evening light exposure on sleep architecture and sleep EEG power density in men.

Light strongly influences the circadian timing system in humans via non-image-forming photoreceptors in the retinal ganglion cells. Their spectral sensitivity is highest in the short-wavelength range of the visible light spectrum as demonstrated by melatonin suppression, circadian phase shifting, acute physiological responses, and subjective alertness. We tested the impact of short wavelength light (460 nm) on sleep EEG power spectra and sleep architecture. We hypothesized that its acute action on sleep is similar in magnitude to reported effects for polychromatic light at higher intensities and stronger than longer wavelength light (550 nm). The sleep EEGs of eight young men were analyzed after 2-h evening exposure to blue (460 nm) and green (550 nm) light of equal photon densities (2.8 x 10(13) photons x cm(-2) x s(-1)) and to dark (0 lux) under constant posture conditions. The time course of EEG slow-wave activity (SWA; 0.75-4.5 Hz) across sleep cycles after blue light at 460 nm was changed such that SWA was slightly reduced in the first and significantly increased during the third sleep cycle in parietal and occipital brain regions. Moreover, blue light significantly shortened rapid eye movement (REM) sleep duration during these two sleep cycles. Thus the light effects on the dynamics of SWA and REM sleep durations were blue shifted relative to the three-cone visual photopic system probably mediated by the circadian, non-image-forming visual system. Our results can be interpreted in terms of an induction of a circadian phase delay and/or repercussions of a stronger alerting effect after blue light, persisting into the sleep episode.

Adult↗
PubMed2001

[Efficient use of sleep pillows in patients suffering from non-organic sleep disorders--a pilot study].

OBJECTIVE: Sleep disorders may critically affect working performance and quality of life. Sleep pillows have been traditionally used to overcome such disorders. Scientifically based clinical trials to demonstrate the efficacy are missing. METHODS: 28 patients with problems falling asleep and/or staying asleep not related to psychiatric or organic diseases were investigated in an accredited sleep laboratory. The diagnosis was confirmed by polysomnography. After 2 and 4 weeks of treatment the polysomnography was repeated to document any influences by the sleep pillows. RESULTS: The polysomnographic records showed a monotonic trend to regain an age-related distribution of the non-REM sleep stages. The REM sleep phase increased nearly twofold; however, the norm values were not reached within the 4-week period of treatment. Sleep pillows of intensity 2 were superior to those of intensity 1; a further increase to intensity 3 did not create any additional effect. CONCLUSION: The results demonstrate an effective treatment of non-complicated sleep disorders with sleep pillows, which has been shown with objective measurements in a sleep laboratory.

Aromatherapy↗
PubMed1992

Lack of effect of external warming on sleep architecture in sleep apnea/hypopnea syndrome.

Sleep apnea/hypopnea syndrome (SAHS) is characterized by nocturnal apneas (A) and/or hypopneas (H) occurring in various sleep stages. However, these disordered breathing events (DBE) occur rarely in slow-wave sleep (SWS) and are most severe in rapid eye movement (REM) sleep when severe hypoxemia results. Several studies have shown that a rise in body temperature by external warming, induced according to a specific protocol, affects normal human sleep architecture by diminishing the time spent in REM and increasing the time spent in SWS. The purpose of this study was to determine if external warming is as effective in sleep apneic patients in decreasing REM and increasing SWS, hoping that DBE and hypoxemia may diminish. Seven newly diagnosed patients were studied two more nights, on one of which (selected randomly) the sleep study was preceded by sitting in a warm bathtub with temperature of 41 degrees C for 1/2 h, 2 1/2 h before the start of sleep study. The mean maximum rise in oral temperature with warm bath was 2.0 +/- 0.4 degrees C. Total bed time (min) and sleep efficiency, REM, and SWS (%) were, respectively, 320 +/- 17 (SD), 81 +/- 8, 19 +/- 7, and 1.2 +/- 1.1 for the control (C) and 339 +/- 33, 79 +/- 11, 19 +/- 5, and 2.4 +/- 1.6 for the bath (B) night. In both C and B, the lowest O2 saturation (%) occurred in REM sleep and was 78 +/- 7 and 77 +/- 9, respectively. Comparing respective paired values between C and B, no significance was found.(ABSTRACT TRUNCATED AT 250 WORDS)

Baths↗