Showing papers on "Slow-wave sleep published in 2003"

The Cumulative Cost of Additional Wakefulness: Dose-Response Effects on Neurobehavioral Functions and Sleep Physiology From Chronic Sleep Restriction and Total Sleep Deprivation

Abstract: OBJECTIVES: To inform the debate over whether human sleep can be chronically reduced without consequences, we conducted a dose-response chronic sleep restriction experiment in which waking neurobehavioral and sleep physiological functions were monitored and compared to those for total sleep deprivation. DESIGN: The chronic sleep restriction experiment involved randomization to one of three sleep doses (4 h, 6 h, or 8 h time in bed per night), which were maintained for 14 consecutive days. The total sleep deprivation experiment involved 3 nights without sleep (0 h time in bed). Each study also involved 3 baseline (pre-deprivation) days and 3 recovery days. SETTING: Both experiments were conducted under standardized laboratory conditions with continuous behavioral, physiological and medical monitoring. PARTICIPANTS: A total of n = 48 healthy adults (ages 21-38) participated in the experiments. INTERVENTIONS: Noctumal sleep periods were restricted to 8 h, 6 h or 4 h per day for 14 days, or to 0 h for 3 days. All other sleep was prohibited. RESULTS: Chronic restriction of sleep periods to 4 h or 6 h per night over 14 consecutive days resulted in significant cumulative, dose-dependent deficits in cognitive performance on all tasks. Subjective sleepiness ratings showed an acute response to sleep restriction but only small further increases on subsequent days, and did not significantly differentiate the 6 h and 4 h conditions. Polysomnographic variables and delta power in the non-REM sleep EEG-a putative marker of sleep homeostasis--displayed an acute response to sleep restriction with negligible further changes across the 14 restricted nights. Comparison of chronic sleep restriction to total sleep deprivation showed that the latter resulted in disproportionately large waking neurobehavioral and sleep delta power responses relative to how much sleep was lost. A statistical model revealed that, regardless of the mode of sleep deprivation, lapses in behavioral alertness were near-linearly related to the cumulative duration of wakefulness in excess of 15.84 h (s.e. 0.73 h). CONCLUSIONS: Since chronic restriction of sleep to 6 h or less per night produced cognitive performance deficits equivalent to up to 2 nights of total sleep deprivation, it appears that even relatively moderate sleep restriction can seriously impair waking neurobehavioral functions in healthy adults. Sleepiness ratings suggest that subjects were largely unaware of these increasing cognitive deficits, which may explain why the impact of chronic sleep restriction on waking cognitive functions is often assumed to be benign. Physiological sleep responses to chronic restriction did not mirror waking neurobehavioral responses, but cumulative wakefulness in excess of a 15.84 h predicted performance lapses across all four experimental conditions. This suggests that sleep debt is perhaps best understood as resulting in additional wakefulness that has a neurobiological "cost" which accumulates over time.

Shift work and disturbed sleep/wakefulness.

Abstract: Of the many health-related effects of shift work, disturbed sleep is the most common. This review describes the main observed effects of the three principal shifts (night, morning and afternoon) on patterns of sleep and wakefulness. The mechanism of sleep disruption in relation to circadian rhythms and the specific impact of aspects of shift organization (speed and direction of rotation) are discussed. The most troublesome acute symptoms are difficulty getting to sleep, shortened sleep and somnolence during working hours that continues into successive days off. These are only partially amenable to amelioration by manipulating shift patterns. However, there is no clear indication that chronic sleep problems result from long-term shift work.

Comparison of detrended fluctuation analysis and spectral analysis for heart rate variability in sleep and sleep apnea

Abstract: Sleep has been regarded as a testing situation for the autonomic nervous system, because its activity is modulated by sleep stages. Sleep-related breathing disorders also influence the autonomic nervous system and can cause heart rate changes known as cyclical variation. We investigated the effect of sleep stages and sleep apnea on autonomic activity by analyzing heart rate variability (HRV). Since spectral analysis is suited for the identification of cyclical variations and detrended fluctuation analysis can analyze the scaling behavior and detect long-range correlations, we compared the results of both complementary techniques in 14 healthy subjects, 33 patients with moderate, and 31 patients with severe sleep apnea. The spectral parameters VLF, LF, HF, and LF/HF confirmed increasing parasympathetic activity from wakefulness and REM over light sleep to deep sleep, which is reduced in patients with sleep apnea. Discriminance analysis was used on a person and sleep stage basis to determine the best method for the separation of sleep stages and sleep apnea severity. Using spectral parameters 69.7% of the apnea severity assignments and 54.6% of the sleep stage assignments were correct, while using scaling analysis these numbers increased to 74.4% and 85.0%, respectively. We conclude that changes in HRV are better quantified by scaling analysis than by spectral analysis.

A role of melanin-concentrating hormone producing neurons in the central regulation of paradoxical sleep.

Abstract: Peptidergic neurons containing the melanin-concentrating hormone (MCH) and the hypocretins (or orexins) are intermingled in the zona incerta, perifornical nucleus and lateral hypothalamic area. Both types of neurons have been implicated in the integrated regulation of energy homeostasis and body weight. Hypocretin neurons have also been involved in sleep-wake regulation and narcolepsy. We therefore sought to determine whether hypocretin and MCH neurons express Fos in association with enhanced paradoxical sleep (PS or REM sleep) during the rebound following PS deprivation. Next, we compared the effect of MCH and NaCl intracerebroventricular (ICV) administrations on sleep stage quantities to further determine whether MCH neurons play an active role in PS regulation. Here we show that the MCH but not the hypocretin neurons are strongly active during PS, evidenced through combined hypocretin, MCH, and Fos immunostainings in three groups of rats (PS Control, PS Deprived and PS Recovery rats). Further, we show that ICV administration of MCH induces a dose-dependant increase in PS (up to 200%) and slow wave sleep (up to 70%) quantities. These results indicate that MCH is a powerful hypnogenic factor. MCH neurons might play a key role in the state of PS via their widespread projections in the central nervous system.

Objective and subjective sleep quality in premenopausal, perimenopausal, and postmenopausal women in the Wisconsin Sleep Cohort Study.

Abstract: Study Objective: Assess objectively measured sleep quality in premenopausal, perimenopausal, and postmenopausal women. Design: Observational epidemiology study. Setting: Community-based. Participants: Probability sample of 589 premenopausal, perimenopausal, and postmenopausal women recruited from state employee records. Interventions: None. Measurements and Results: Menopausal status was determined by menstrual history, surgical history, and use of hormone replacement therapy. Sleep quality was objectively measured by full in-laboratory polysomnography and by self-reported sleep problems. Linear and logistic regression were used to estimate associations adjusted for potential confounding factors. Objective: Sleep quality was not worse in perimenopausal or postmenopausal women, compared with premenopausal women. To the contrary, postmenopausal woman had more deep sleep (16% vs 13% stages 3/4, P<0.001) and significantly longer total sleep time (388 minutes vs 374 minutes, P=0.05). Menopausal status was moderately related to self-reported dissatisfaction with sleep but was not consistently associated with symptoms of insomnia or sleepiness. Conclusions: Menopause is not associated with diminished sleep quality measured by polysomnography. Although perimenopausal and postmenopausal women, relative to premenopausal women, were less satisfied with their sleep, menopause was not a strong predictor of specific sleep-disorder symptoms. Symptoms and signs of sleep abnormalities in midlife women should not be attributed primarily to menopause before ruling out underlying sleep disorders. Citation: Young T; Rabago D; Zgierska A et al. Objective and subjective sleep quality in premenopausal, perimenopausal, and postmenopausal women in the Wisconsin Sleep Cohort Study.

Sleepwalking and Sleep Terrors in Prepubertal Children: What Triggers Them?

Abstract: Objectives. To evaluate the clinical presentation and polysomnography of prepubertal children with repetitive sleep terrors and sleepwalking, to compare them with a control group, and to evaluate the treatment of associated sleep disorders. Methods. Patients with complaint of sleep terrors with or without sleepwalking were studied retrospectively. A control group was also recruited. Each subject received a standardized evaluation, which included the following: 1) Pediatric Sleep Questionnaire; 2) interview regarding child’s medical and sociofamilial history, orthodontic history, schooling, psychological difficulties, medication intake, and family history of medical and sleep disorders; 3) general pediatric physical examination and neurologic, otolaryngological, and craniofacial examination by a specialist; 4) obtaining medical history on variables relevant to early life sleep disorders; 5) polysomnography, which included electroencephalogram (EEG; C3/A2, Fp1/T1, T1/O1, O1/C3, C4/A1, Fp2/T2, T2/O2, O2/C4), chin and leg electromyelogram, right and left electro-oculogram, and electrocardiogram (modified V2 lead); respiration was monitored with a nasal cannula/pressure transducer system, mouth thermistor, chest and abdominal bands, pulse oximeter, and neck microphone; respiratory effort was monitored with calibrated esophageal manometry; variables were collected on a computerized sleep system; and 6) available family members with a positive history of sleep terrors and sleepwalking received clinical evaluations similar to those used for index cases; they also underwent ambulatory monitoring with an Edentrace system, which monitors heart rate, body position, oro-nasal flow, chest impedance, breathing noises (neck microphone), and pulse oximetry. Movements are deduced from artifact, and leg movements may be recorded on one channel if the equipment is preset for such recording. Subjects used logs to record “lights out” time, “lights on” time, nocturnal awakenings, and other events that occurred during the night. All original and follow-up recordings were rescored by 2 of 4 randomly selected specialists who were blind to subject identity. Mann-Whitney U test was used for group comparison. Nonparametric χ 2 test was used to compare percentages of symptoms in symptomatic children versus control children. Results. Eighty-four children (5 with sleep terrors and 79 with both sleep terrors and sleepwalking) and 36 normal control children formed the studied population. All subjects were Tanner stage 1 (prepubertal). None of the control children had any parasomnias. Fifty-one (61%) of 84 children with parasomnia had a diagnosis of an additional sleep disorder: 49 with sleep-disordered breathing (SDB) and 2 with restless leg syndrome (RLS). Twenty-nine of the children with both parasomnia and SDB had a positive family history of parasomnias, and 24 of the 29 also had a positive family history of SDB. Of the 51 children with associated sleep disorders, 45 were treated. Forty-three of 49 children with SDB were treated with tonsillectomy, adenoidectomy, and/or turbinate revision, and 2 of 2 children with RLS were treated with Pramipexole, a dopamine agonist, at bedtime. Treatment of the precipitating sleep disorder eliminated parasomnias in all 45 children. In all 43 children who received surgery, polysomnography performed 3 to 4 months later indicated the disappearance of SDB. The recordings also showed an absence of confusional arousals. The number of EEG arousals significantly decreased from a mean of 9 ± 2.6 EEG arousals ≥3 seconds/hour during total sleep time to 3 ± 1.5. The number of EEG arousals ≥3 seconds during the first sleep cycle of slow wave sleep (stage 3–4 non–rapid eye movement sleep) decreased from 4 ± 1.4 to 1 ± 0.2. In all surgically treated cases, parents also reported subsequent absence of the parasomnia. The 2 symptomatic children who were treated with Pramipexole had a complete absence of confusional arousals on the follow-up recording and reported no parasomnia since treatment. The periodic limb movement syndrome arousal index (number of EEG arousals associated with periodic limb movement/hour) decreased from 11 and 16 to 0 and 0.2, respectively. Parasomnia persisted in the 6 children who were untreated for SDB. Surgeons had refused to perform surgery on these children because of lack of data on the relationship between parasomnia and SDB-related tonsil and adenoid enlargement. Conclusion. Children with chronic parasomnias may often also present SDB or, to a lesser extent, RLS. Furthermore, the disappearance of the parasomnias after the treatment of the SDB or RLS periodic limb movement syndrome suggests that the latter may trigger the former. The high frequency of SDB in family members of children with parasomnia provided additional evidence that SDB may manifest as parasomnias in children. Children with parasomnias are not systematically monitored during sleep, although past studies have suggested that patients with sleep terrors or sleepwalking have an elevated level of brief EEG arousals. When children receive polysomnographies, discrete patterns (eg, nasal flow limitation, abnormal respiratory effort, bursts of high θ or slow α EEG frequencies) should be sought; apneas are rarely found in children. Children’s respiration during sleep should be monitored with nasal cannula/pressure transducer system and/or esophageal manometry, which are more sensitive than the thermistors or thermocouples currently used in many laboratories. The clear, prompt improvement of severe parasomnia in children who are treated for SDB, as defined here, provides important evidence that subtle SDB can have substantial health-related significance. Also noteworthy is the report of familial presence of parasomnia. Studies of twin cohorts and families with sleep terror and sleepwalking suggest genetic involvement of parasomnias. RLS and SDB have been shown to have familial recurrence. RLS has been shown to have genetic involvement. It remains to be investigated whether a genetic factor directly influences sleep terror and sleepwalking or instead influences other disorders that fragment sleep and lead to confusional arousals. Additional studies are needed to investigate the association between SDB and non–rapid eye movement parasomnias in the general population.

Impaired nighttime sleep in healthy old versus young adults is associated with elevated plasma interleukin-6 and cortisol levels: physiologic and therapeutic implications

Abstract: IL-6 and TNF alpha secretion is increased by sleep loss or restriction. IL-6 secretion progressively increases with age, yet its association with decreased quality and quantity of sleep in old adults is unknown. This study examined the alteration of 24-h secretory pattern of IL-6, TNF alpha, and cortisol in 15 young and 13 old normal sleepers who were recorded in the sleep laboratory for four consecutive nights. Serial 24-h plasma measures of IL-6, TNF alpha, and cortisol were obtained during the fourth day, and daytime sleepiness was assessed with the multiple sleep latency test. Old adults, compared with young subjects, slept poorly at night (wake time and percentage stage 1 sleep were increased, whereas their percentage slow wave sleep and percentage sleep time were decreased, P < 0.05). Accordingly, their daytime sleep latency was longer than in young adults (P < 0.05). The mean 24-h IL-6 and cortisol levels were significantly higher in old than young adults (P < 0.05). In both groups, IL-6 and cortisol plasma concentrations were positively associated with total wake time, with a stronger association of IL-6 and cortisol with total wake time in the older individuals (P < 0.05); their combined effect was additive. IL-6 had a negative association with rapid eye movement (REM) sleep only in the young (P < 0.05), but cortisol was associated negatively with REM sleep both in the young and old, with a stronger effect in the young. We conclude that in healthy adults, age-related alterations in nocturnal wake time and daytime sleepiness are associated with elevations of both plasma IL-6 and cortisol concentrations, but REM sleep decline with age is primarily associated with cortisol increases.

The effects of pramipexole in REM sleep behavior disorder

Abstract: The authors evaluated the effects of pramipexole, a dopaminergic D2-D3 receptor agonist, on eight patients with idiopathic REM sleep behavior disorder. Five patients reported a sustained reduction in the frequency or intensity of sleep motor behaviors, which was confirmed by video recording, although no change was observed for the percentage of phasic EMG activity during REM sleep. Surprisingly, a decrease in the percentage of time spent with REM sleep muscle atonia was observed with treatment. The treatment did not modify the indexes of periodic leg movements.

The effects of sodium oxybate on clinical symptoms and sleep patterns in patients with fibromyalgia.

Abstract: OBJECTIVE: Fibromyalgia (FM) is associated with the sleep phenomenon of alpha intrusion, and with low growth hormone secretion. Sodium oxybate has been shown to increase both slow-wave sleep and growth hormone levels. This double blind, randomized, placebo controlled crossover trial was conducted to evaluate the effects of sodium oxybate on the subjective symptoms of pain, fatigue, and sleep quality and the objective polysomnographic (PSG) sleep variables of alpha intrusion, slow-wave (stage 3/4) sleep, and sleep efficiency in patients with FM. METHODS: Patients received either 6.0 g/day sodium oxybate or placebo for 1 month, with an intervening 2 week washout period. Efficacy measures included PSG evaluations, tender point index (TPI), and subjective measurements from daily diary entries. Safety measures included clinical laboratory values, vital signs, and adverse events. RESULTS: Twenty-four female patients were included in the study; 18 completed the trial. TPI was decreased from baseline by 8.5, compared with an increase of 0.4 for placebo (p = 0.0079). Six of the 7 pain/fatigue scores (overall pain, pain at rest, pain during movement, end of day fatigue, overall fatigue, and morning fatigue) were relieved by 29% to 33% with sodium oxybate, compared with 6% to 10% relief with placebo (p

Low sleep quality and daytime sleepiness in obese patients without obstructive sleep apnoea syndrome

Abstract: . Resta O, Foschino-Barbaro MP, Bonfitto P,Giliberti T, Depalo A, Pannacciulli N, De Pergola G(Respiratory Pathophysiology, University of Bari,School of Medicine, Bari, Italy; University of Foggia,School of Medicine, Foggia, Italy; and InternalMedicine, Endocrinology, and Metabolic Diseases,University of Bari, Bari, Italy). Low sleep quality anddaytime sleepiness in obese patients withoutobstructive sleep apnoea syndrome. J Intern Med2003; 253: 536–543.Objectives. To evaluate sleep quality, sleep-relatedsymptoms, and degree of excessive daytimesleepiness (EDS) in severe obesity, independently ofobstructive sleep apnoea syndrome (OSAS).Design. A cross-sectional study.Setting. Primary-care setting.Subjects, main outcome measures. Anthropometricparameters, respiratory function data and sleeprelated symptoms were evaluated in 78 severelyobese patients (aged 16–75 years) without OSASand in 40 healthy sex- and age-matched normalweight subjects, who underwent a full-nightpolysomnography.Results. Obese patients and control subjects hadsimilar sleep latency and rapid eye movement (REM)latency, but they showed lower percentage of REM(P < 0.01) and sleep efficiency (P < 0.05) thancontrols. All sleep-related symptoms (observed orreported apnoea, awakenings, choking andunrefreshing sleep) were significantly morefrequent in obese patients than in control subjects.Loud snoring was present in 46.7% of the obesepatients and in 8.1% of the control individuals(P < 0.01). Excess daytime sleepiness was reportedby 34.7% of the obese patients and by 2.7% of thenormal weight subjects (P < 0.01). The EpworthSleepiness Scale (ESS) was higher in the obese groupthan in the control group (P < 0.01), whereasarousals were not different between the two groups.Conclusions. This study clearly shows that severeobesity, even in the absence of OSAS, is associatedwith sleep-related disorders and EDS. All thesealterations may be partly responsible for a lowerquality of life, a higher prevalence of medicalcomplications, an increased risk of occupationalinjury, and both social and family problemscharacterizing obese patients, independently of thepresence of OSAS.Keywords: excessive daytime sleepiness, severeobesity, sleep quality, sleep-related symptoms.

Effect of oral appliance therapy on upper airway collapsibility in obstructive sleep apnea.

Abstract: Oral appliance therapy is emerging as an alternative to continuous positive airway pressure for the treatment of obstructive sleep apnea (OSA). However, its precise mechanisms of action are yet to be defined. We examined the effect of a mandibular advancement splint (MAS) on upper airway collapsibility during sleep in OSA. Ten patients with proven OSA had a custom-made MAS incrementally adjusted during an acclimatization period until the maximum comfortable limit of mandibular advancement was reached. Polysomnography with the splint was then performed. After a 1-week washout period, upper airway closing pressures during sleep (with and without MAS) were determined. Significant improvements with MAS therapy were seen in the apnea/hypopnea index (25.0 3.1 vs. 13.2 4.5/ hour, p 0.03) and upper airway closing pressure in Stage 2 sleep (–1.6 0.4 vs. –3.9 0.6 cm H2O, p 0.01) and in slow wave sleep (–2.5 0.7 vs. –4.7 0.6 cm H2O, p 0.02) compared with no therapy. These preliminary data indicate that MAS therapy is associated with improved upper airway collapsibility during sleep. The mediators of this effect remain to be determined.

Sleep and Dreaming: The case against memory consolidation in REM sleep

Abstract: We present evidence disputing the hypothesis that memories are processed or consolidated in REM sleep. A review of REM deprivation (REMD) studies in animals shows these reports to be about equally divided in showing that REMD does, or does not, disrupt learning/memory. The studies supporting a relationship between REM sleep and memory have been strongly criticized for the confounding effects of very stressful REM deprivation techniques. The three major classes of antidepressant drugs, monoamine oxidase inhibitors (MAOIs), tricyclic antidepressants (TCAs), and selective serotonin reuptake inhibitors (SSRIs), profoundly suppress REM sleep. The MAOIs virtually abolish REM sleep, and the TCAs and SSRIs have been shown to produce immediate (40-85%) and sustained (30-50%) reductions in REM sleep. Despite marked suppression of REM sleep, these classes of antidepressants on the whole do not disrupt learning/memory. There have been a few reports of patients who have survived bilateral lesions of the pons with few lingering complications. Although these lesions essentially abolished REM sleep, the patients reportedly led normal lives. Recent functional imaging studies in humans have revealed patterns of brain activity in REM sleep that are consistent with dream processes but not with memory consolidation. We propose that the primary function of REM sleep is to provide periodic endogenous stimulation to the brain which serves to maintain requisite levels of central nervous system (CNS) activity throughout sleep. REM is the mechanism used by the brain to promote recovery from sleep. We believe that the cumulative evidence indicates that REM sleep serves no role in the processing or consolidation of memory.

Correlation of subjective and objective sleep measurements at different stages of the treatment of depression

Abstract: Studies of the correlation of subjective and objective sleep measures in depressed patients have produced mixed results so far. Further, they were carried out in sleep laboratories and tended to obtain one-off assessments, thus not taking into account the effect of treatment. We investigated forty (40) patients over the course of 8-week treatment of depression with either paroxetine or nefazodone. We used home polysomnography at baseline, nights 3 and 10, and week 8 of treatment, with extensive assessments of subjective sleep, the morning after each sleep recording. The patients were able to judge accurately their total sleep time and sleep onset latency, both before and during treatment. However, they were inaccurate in estimating the number of times they woke up during the night. Sleep satisfaction correlated negatively with Stage 1 sleep at baseline. Sleep quality was represented by a combination of subjective parameters measuring the ease of initiation and maintenance of sleep, and it appeared to derive from slow wave sleep and sleep continuity as seen in polysomnography. The partial discrepancy between subjective and objective measures suggests that a cognitive element is combined with the biological element to produce the sleep problems reported by depressed patients.

EEG Slow (∼1 Hz) Waves Are Associated With Nonstationarity of Thalamo-Cortical Sensory Processing in the Sleeping Human

Abstract: Intracellular studies reveal that, during slow wave sleep (SWS), the entire cortical network can swing rhythmically between extremely different microstates, ranging from wakefulness-like network activation to functional disconnection in the space of a few hundred milliseconds. This alternation of states also involves the thalamic neurons and is reflected in the EEG by a slow (<1 Hz) oscillation. These rhythmic changes, occurring in the thalamo-cortical circuits during SWS, may have relevant, phasic effects on the transmission and processing of sensory information. However, brain reactivity to sensory stimuli, during SWS, has traditionally been studied by means of sequential averaging, a procedure that necessarily masks any short-term fluctuation of responsiveness. The aim of this study was to provide a dynamic evaluation of brain reactivity to sensory stimuli in naturally sleeping humans. To this aim, single-trial somatosensory evoked potentials (SEPs) were grouped and averaged as a function of the phase of the ongoing sleep slow (<1 Hz) oscillation. This procedure revealed a dynamic profile of responsiveness, which was conditioned by the phase of the spontaneous sleep EEG. Overall, the amplitude of the evoked potential changed sistematically, increasing and approaching wakefulness levels along the negative slope of the EEG oscillation and decaying below SWS average levels along the positive drift. These marked and fast changes of stimulus-correlated electrical activity involved both short (N20) and long latency (P60 and P100) components of SEPs. In addition, the observed short-term response variability appeared to be centrally generated and specifically related to the evolution of the spontaneous oscillatory pattern. The present findings demonstrate that thalamo-cortical processing of sensory information is not stationary in the very short period (approximately 500 ms) during natural SWS.

Sleep and endocrinology

Abstract: . Steiger A (Max Planck Institute of Psychiatry, Munich, Germany). Sleep and endocrinology (Minisymposium). J Intern Med 2003; 254: 13–22. A bidirectional interaction between sleep electroencephalogram and endocrine activity is well established in various species including humans. Various hormones (peptides and steroids) participate in sleep regulation. A keyrole was shown for the reciprocal interaction between sleep-promoting growth hormone-releasing hormone (GHRH) and sleep-impairing corticotropin-releasing hormone (CRH). Changes in the GHRH : CRH ratio result in changes of sleep-endocrine activity. It is thought that the change of this ratio in favour of CRH contributes to aberrances of sleep during ageing and depression (shallow sleep, blunted GH and elevated cortisol). Besides GHRH, ghrelin and galanin enhance slow wave sleep. Somatostatin is another sleep-impairing factor. Neuropeptide Y acts as a CRH antagonist and induces sleep onset. There are hints that CRH promotes rapid eye movement sleep (REMS). In animals prolactin enhances REMS. In humans vasocactive intestinal polypeptide (VIP) appears to play a role in the temporal organization of sleep as, after VIP, the non-REMS–REMS cycle decelerated. Cortisol appears to enhance REMS. Finally, gonadal hormones participate in sleep regulation. Oestrogen replacement therapy and CRH-1 receptor antagonism in depression are beneficial clinical applications of sleep-endocrine research.

Experience-dependent slow-wave sleep development

Abstract: Sleep enhances plasticity in neocortex, and thereby improves sensory learning1. Here we show that sleep itself undergoes changes as a consequence of waking experience during a late critical period in cats and mice. Dark-rearing produced a robust and reversible decrement of slow-wave electrical activity during sleep that was restricted to visual cortex and impaired by gene-targeted reduction of NMDA receptor function.

The ontogeny of mammalian sleep: a reappraisal of alternative hypotheses.

Abstract: Newborn mammals spend as much as 90% or more of their time in a sleep state characterized by frequent twitches, rapid eye movements (REMs), and irregular respiratory cycles. These motor and respiratory patterns resemble the phasic motor/respiratory components of adult REM sleep, and as a consequence, this sleep state is traditionally viewed as an immature form of REM sleep. An alternative view is that a significant portion of what has been called REM sleep in these species is a form of spontaneous activity typical of the immature nervous system. In this review, we compare and contrast these two opposing views about the ontogenetic origins of REM sleep, and review the evidence most often cited to support the idea that REM sleep is present in newborn altricial mammals. Critical review of this evidence indicates that REM sleep may not be present at birth in these species; rather, it appears that all mammals early in development exhibit spontaneous, dissociated activity that progressively becomes organized into the distinct states of REM and non-rapid eye movement sleep.

The effect of combined therapy (ultrasound and interferential current) on pain and sleep in fibromyalgia

Abstract: Multidisciplinary treatment has proven to be the best therapeutic option to fibromyalgia (FM) and physiotherapy has an important role in this approach Considering the controversial results of electrotherapy in this condition, the aim of this study was to assess the effects of combined therapy with pulsed ultrasound and interferential current (CTPI) on pain and sleep in FM Seventeen patients fulfilling FM criteria were divided into two groups, CTPI and SHAM, and submitted to pain and sleep evaluations Pain was evaluated by body map (BM) of the painful areas; quantification of pain intensity by visual analog scale (VAS); tender point (TP) count and tenderness threshold (TT) Sleep was assessed by inventory and polysomnography (PSG) After 12 sessions of CTPI or SHAM procedure, patients were evaluated by the same initial protocol After treatment, CTPI group showed, before and after sleep, subjective improvement of pain in terms of number (BM) and intensity (VAS) of painful areas (P<0001, both); as well as objective improvement, with decrease in TP count and increase in TT (P<0001, both) Subjective sleep improvements observed after CTPI treatment included decrease in morning fatigue and in non-refreshing sleep complaint (P<0001, both) Objectively, PSG in this group showed decrease in sleep latency (P<0001) and in the percentage of stage 1 (P<0001), increase in the percentage of slow wave sleep (P<0001) and in sleep cycle count (P<0001) Decrease in arousal index (P<0001), number of sleep stage changes (P<005) and wake time after sleep onset (P<005), were also observed and no difference regarding pain or sleep parameters were verified after SHAM procedure This study shows that CTPI can be an effective therapeutic approach for pain and sleep manifestations in FM

Slow wave sleep drives inhibition of pituitary-adrenal secretion in humans.

Abstract: During the first half of nocturnal sleep, the secretory response of the pituitary-adrenal axis to either CRH or vasopressin (VP) administration is reduced. Two experiments were performed aiming (i) to investigate the impact of sleep on the response to a combined CRH/VP administration and (ii) to specify the onset of sleep associated pituitary-adrenal suppression and its relation to specific sleep stages. In experiment I, we compared the effect of simultaneous administration of VP (0.5 IU i.v., within 6 min) and CRH (50 micrograms bolus i.v., in the third min of VP infusion) on the secretion of ACTH, cortisol and GH in healthy men during the first nocturnal epoch of slow wave sleep (SWS) and during nocturnal wakefulness. The increase of ACTH and cortisol concentrations after combined VP/CRH administration was distinctly higher during wakefulness than sleep (P < 0.01). In experiment II, CRH (30 micrograms/h, after an initial bolus of 30 micrograms) was continuously infused in 7 healthy men on 2 nights. On one of the nights, the men were allowed to sleep (between 23.00 h and 05.00 h) after a 3-h period of wakefulness, on the other night they stayed awake throughout the experiment. In both conditions, CRH enhanced ACTH/cortisol plasma levels. Compared with concentrations during continuous wakefulness, sleep and in particular SWS was associated with a suppression of ACTH/cortisol levels (P < 0.05). The findings further support an inhibitory influence of early nocturnal sleep on pituitary-adrenal activity. The effect appears to be strongest during SWS and is probably mediated via hypothalamic secretion of a release inhibiting factor of ACTH.

Insomnia, metabolic rate and sleep restoration.

Abstract: Studies have shown occasional evidence of increased physiological activity in patients with primary insomnia. We hypothesized that metabolic rate, as measured by overall oxygen use (VO2), might be a more general index of increased physiological activity. An initial experiment found elevated VO2 both at night and during the day in patients with primary insomnia as compared with matched normal sleepers. A second experiment found significant but more modest increases in VO2 in patients with Sleep State Misperception Insomnia [who complain of poor sleep but who had normal sleep by electroencephalographic (EEG) criteria]. In a third experiment, normal young adults were given caffeine 400 mg three times per day (TID) for 1 week as a means of increasing VO2 and possibly producing other symptoms of insomnia. Participants developed many symptoms consistent with those seen in patients with primary insomnia (poor sleep, increased latency on the Multiple Sleep Latency Test, increasing fatigue despite physiological activation, and increased anxiety on the Minnesota Multiphasic Personality Inventory (MMPI)). In a final experiment, physiological arousal was again produced by caffeine to determine if sleep with elevated arousal would be less restorative. All subjects (Ss) slept for 3.5 h after being given 400 mg of caffeine. During 41 h of sleep deprivation that followed, there was no significant condition difference for the Multiple Sleep Latency Test or mood measures. The results provided only weak support for the idea that sleep is less restorative after physiological arousal.