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PubMed1976

[Sleep and respiration in the syndrome "apnea during sleep" in the child].

A sleep apnea syndrome has been diagnosed in eight children (age range 5-14). Before undertaking therapeutic trials, sleep and respiration were extensively studied. Sleep and respiration were again analyzed 3 months after tonsillectomy and adenoidectomy (6 cases) or tracheostomy with insertion of valve (2 cases). Sleep induced apneic apisodes in these children who had normal respiration during wakefulness. Three types of apnea (central, upper airway, and mixed) were recorded in each case. The minimum number of apneas recorded during a single night was 75; the maximum was 816. Polygraphic monitoring demonstrated greatly disturbed sleep. Sleep changes were quantitative as well as qualitative. REM sleep percent was decreased, but stages 3 and 4 NREM sleep were also impaired. A relationship between stages 3-4 NREM sleep and respiration was noted: stages 3-4 sleep disappeared when apneic episodes were numerous; no apnea was recorded during stage 4 sleep. Follow-up nocturnal recordings of two tracheostomized children with valve open, then closed, confirmed this "stage 4/no apnea" relationship. Apneas were also noted to induce marked sinus arrhythmia during sleep.

Adolescent↗
PubMed1980

Nocturnal sleep in severely mentally retarded children: abnormal EEG patterns in sleep cycle.

Sleep EEG patterns in 43 mentally retarded children (from 4 months to 80 years of age) were studied throughout nocturnal sleep and the following results were obtained. (1) Twenty-two cases evidenced normal sleep patterns that could be classified into 6 stages. (2) The 21 other cases showed some abnormal sleep EEG patterns as follows: (a) absence of sleep spindles (n = 18) which included cases of high voltage fast activity (n = 2) and cases of low voltage activity throughout nocturnal sleep (n = 3); (b) indistinguishable delta and theta activities (n = 1), extreme spindle-like pattern (n = 1), absence of REM sleep (n = 1). (3) The severely mentally retarded children under 18 months had definitely decreased spindle activity in comparison to the values obtained by other authors from normal children. (4) The majority of the abnormal sleep EEG patterns occurred during light sleep. (5) A significant decrease in DQ was found in children with abnormal sleep patterns throughout NREM sleep as compared with those in whom abnormal EEGs occurred only during stages 1 and 2. (6) It was concluded that the EEG recorded in nocturnal sleep may serve as a useful indicator of abnormality in mentally retarded children.

Cerebral Cortex↗
PubMed1985

Spontaneous termination of ad libitum sleep episodes with special reference to REM sleep.

The spontaneous terminations of 72 ad libitum sleep episodes, recorded from 9 young adults, were analysed with respect to their proximity to REM sleep periods. Sleep episodes occurred throughout the 24 h day as a result of the experimental design, in which subjects were confined to bed for 60 continuous hours. For the group, sleep terminations occurred from REM sleep significantly more often than would be expected by chance (40% of the time). However, substantial individual differences in 'style' of sleep termination were observed, with 4 subjects contributing 82% of all terminations from REM sleep. Such individual differences were noted also in the tendency to exhibit brief interruptions of ongoing REM episodes. Both terminations of sleep from REM and brief interruptions of REM showed a general tendency to occur prior to about halfway through a REM sleep episode. The tendency to awaken differentially from REM sleep is interpreted on the basis of REM sleep providing the optimal physiological conditions for the transition from sleep to waking.

Adolescent↗
PubMed1992

Sleep deprivation in narcoleptic subjects: effect on sleep stages and EEG power density.

Sleep of 8 narcoleptic and 8 control subjects was recorded under baseline (i.e., prior wakefulness 16 h) and after 24 h without sleep. During both baseline and recovery total sleep time and stage 2 non-REM sleep were significantly decreased in narcoleptic subjects. Slow wave activity (i.e., EEG power density in the range of 0.75-4.5 Hz) decayed exponentially during baseline and after sleep deprivation in both narcoleptic and control subjects. During both baseline and recovery EEG power density in delta and sigma frequencies in non-REM sleep was enhanced in narcoleptic subjects relative to controls. In REM sleep differences in the same direction were present in delta and beta frequencies. After sleep deprivation EEG power density in non-REM sleep was elevated in delta and some higher frequencies in both patients and controls, but the response to sleep deprivation was stronger in narcoleptic subjects. These data show that in narcoleptic subjects regulatory processes underlying non-REM sleep homeostasis are operative and indicate that the response to sleep deprivation is stronger than in control subjects.

Adolescent↗
PubMed1984

Increased brain serotonin metabolism during rebound sleep in sleep-deprived rats.

Adult male Wistar rats were almost totally deprived of sleep by handling for 24 hr. 5-Hydroxyindolacetic acid concentrations in the dorsal raphe nucleus area and thalamus increased by 140-180%, immediately after sleep deprivation and when the rats had a 3- or 30-min rebound sleep. The higher levels of 5-hydroxyindolacetic acid were still observed after the rats were awakening from a 4-hr sleep. The concentrations of 5-hydroxytryptamine (serotonin) decreased after sleep deprivation and increased during and after sleep, but the differences were not significant. Tryptophan accumulated in the dorsal raphe area and thalamus after sleep deprivation, and an elevated level did not return to baseline concentrations until the rats were awakening. Tryptophan hydroxylase activity did not change in the dorsal raphe area during and after sleep deprivation. These results suggest that the release and synthesis of 5-hydroxytryptamine in the dorsal raphe area and thalamus increased when the rats had a sleep pressure or a rebound sleep after total sleep deprivation. An increased transport of tryptophan into the brain may be closely involved in sleep-inducing mechanisms.

Animals↗
PubMed1982

Sleep fragmentation in the elderly: relationship to daytime sleep tendency.

Sleep in the elderly is known to be disturbed, and many elderly persons also complain of daytime sleepiness. The present study assessed sleep and waking behavior in 12 male (aged 63 to 86) and 12 female (ages 63 to 82) subjects. Sleep stages, respiration, and movement were recorded at night, and daytime sleep tendency was measured using the Multiple Sleep Latency Test during a single 24-hour period. Daytime sleepiness did not correlate with total sleep time or any sleep stage, but was significantly correlated with measures of sleep fragmentation. The latter included transient arousals, a measure of less than 15-sec awakenings, and sleep-related respiration disturbance. These findings suggest that fragmented nocturnal sleep is a significant cause of reduced daytime well-being in elderly individuals. The continuity of both sleep and wakefulness appears to be disrupted with age. Experimental strategies for achieving a rational sleep hygiene are discussed.

Aged↗
PubMed2004

Sleep deprivation induced by the modified multiple platform technique: quantification of sleep loss and recovery.

Vigilance status was continually monitored in socially stable groups of rats exposed to the modified multiple platform (MMP) technique for sleep deprivation. For comparison, sleep parameters were also monitored in socially isolated rats deprived of sleep by the single platform (SP) method. In all cases, sleep was continuously recorded during baseline, during 96 h of sleep deprivation and during 4 days of recovery. Both multiple- and single-platform techniques completely abolished paradoxical sleep (PS) during the deprivation period, but also resulted in significant decreases in slow wave sleep (SWS) (-31% and -37%, respectively). Unexpectedly, animals on large platforms, which are normally intended as controls, also showed significant reductions in PS and SWS, and these effects were more pronounced in rats deprived in groups than in animals deprived in isolation. Another control preparation, rats placed on wire-mesh grids in the deprivation tank, also showed PS reduction (-39%) but no loss of SWS during the 4 test days. Paradoxical sleep rebound was observed in the first 24 h in all groups, except for grid controls. Overall, no significant differences were found between single- and multiple-platform procedures during the 4 days of deprivation. However, sleep rebound was more pronounced in MMP-deprived rats than in SP-deprived rats. Sleep loss in both control groups may reflect residual effect of stress that remain in the platform technique. These findings indicate that the MMP technique is effective in inducing PS deprivation (PSD). However, the fact that SWS is also affected may have implications for conclusions on paradoxical sleep function based upon paradoxical sleep deprivation.

Animals↗
PubMed2006

The effects of sleep stages and time of night on NREM sleep ERPs.

Event-related potential (ERP) is one of the best techniques for studying information processing during sleep because it does not require behavioral responses or consciousness awareness. Several ERP components have been identified during non-rapid eye movement (NREM) sleep, but the associated underlying processes of these waveforms remain unclear. The present study examines the effect of sleep stage and time of night on the NREM ERPs to further understand these processes. An oddball paradigm was conducted in 11 healthy subjects to elicit ERPs throughout the night. Polysomnographic recordings were also applied to identify sleep stages. The results showed that P220, N350, and P900 decreased during the second half of the night, when the NREM sleep drive is partially satiated. This finding is consistent with the notion that the NREM ERPs reflect an inhibitory process associated with sleep drive. P220 and P900 were also found to increase as subjects entering deep sleep. However, the N350 was not affected by the deepening of sleep and peaked earlier during stage 1 sleep. Although these components are all related to the process for sleep preservation, the N350 may be more associated with sleep-wake transition and the P220 and P900 with the process of deepening of sleep.

Acoustic Stimulation↗
PubMed2006

Topographic differences in mean computational sleep depth between healthy controls and obstructive sleep apnoea patients.

In this work, topographic differences in computational sleep depth between healthy controls and obstructive sleep apnoea syndrome (OSAS) patients have been examined. Sleep depth estimation was based on continuous monitoring of the mean frequency of the EEG. During the experiments, all-night sleep EEG recordings of carefully age and gender matched sets of 16 healthy controls and 16 OSAS patients were compared on six electrode locations (Fp1-M2, Fp2-M1, C3-M2, C4-M1, O1-M2, and O2-M1). To optimise the diagnostic ability of the method, we examined the influence of 45 sets of adjustable analysis parameters on the ability of the method to show differences in computational sleep depth between the diagnostic groups. The results show clearly that although the visual scores for a set of epochs are the same for both clinical groups, computational sleep depth measure still shows deeper local sleep for healthy controls, both during NREM and REM sleep. Although the best achievable performance in different sleep stages is reached in different EEG derivations and with different parameter values, computation of sleep depth with 1-s output resolution in non-overlapping segments of 2s (400 samples) with maximum analysis band frequency of 20.5 Hz and 51-point moving median smoothing on Fp2-M1 or O1-M2 leads to near-optimal performance in deep sleep or wakefulness/light sleep, respectively.

Adult↗
PubMedDate not supplied

The perception of sleep as a function of the level of daytime sleepiness among patients with obstructive sleep apnea.

Subjective estimates of sleep onset among patients with a variety of sleep disorders have been shown to be inaccurate. This inability in perceiving sleep onset is potentially dangerous for this population, in particular, for individuals who are required to drive long distances or operate heavy machinery as part of their daily activities. This study evaluated the perception of sleep among 237 consecutive patients diagnosed with obstructive sleep apnea. Patients completed an overnight sleep-laboratory evaluation followed by an objective evaluation of sleep propensity. The latter was done using the Multiple Sleep Latency Test (MSLT). Patients with an accurate perception of having slept on the MSLT were found to have shorter sleep latencies when compared with those with an inaccurate perception of their sleep. The results of this study suggest that the rapidity with which sleep is manifested is an important contributor to the accurate perception of sleep.

Adult↗
PubMed2001

Sleep dysfunction in Rett syndrome: lack of age related decrease in sleep duration.

The sleep patterns of a cohort of 83 Rett syndrome females were characterized using a sleep diary for 7 consecutive days and nights and compared with normative sleep data. The mean total sleep time of the cohort was 10.75 h, daytime sleep 0.77 h, sleep efficiency 89.7%, and sleep latency 0.52 h. When subjects were categorized according to age and Rett syndrome classification, there was no significant difference in their sleep characteristics. There was a significant difference in the percentage predicted total sleep time (P<0.001) and Z scores for total sleep time (P<0.001), when subjects were categorized according to age and compared with normal children. The Rett syndrome subjects in this study did not show the age related decrease in total and daytime sleep time seen in normal children. The immature sleep pattern demonstrated in this cohort, may be a consequence of arrested brain development.

Adolescent↗
PubMed2003

Dynamics of heart rate and sleep stages in normals and patients with sleep apnea.

Sleep is not just the absence of wakefulness but a regulated process with an important restorative function. Based on electroencephalographic recordings and characteristic patterns and waveforms we can distinguish wakefulness and five sleep stages grouped into light sleep, deep sleep, and rapid-eye-movement (REM) sleep. In order to explore the functions of sleep and sleep stages, we investigated the dynamics of sleep stages over the night and of heart-rate variability during the different sleep stages. Sleep stages and intermediate wake states have different distributions of their duration and this allows us to create a model for the temporal sequence of sleep stages and wake states. Heart rate is easily accessed with a high precision by the recording and analysis of the electrocardiogram (ECG). Heart-rate regulation is part of the autonomous nervous system and sympathetic tone is strongly influenced by the sleep stages.

Heart Rate↗
PubMed2002

Sleep quality and responses to insufficient sleep in women on different work shifts.

1. The aim of this study was to examine degrees of cognitive behavioural effects of fatigue, mood changes and somatic responses to sleep loss in women with and without sufficient sleep, and to explore possible links between effects of sleep loss and specific sleep disturbances in selected groups. 2. A total 156 women working in a casualty department on different work shifts responded to a questionnaire which measured sleep quality, strain and symptoms related to working conditions, as well as effects of sleep loss. 3. About 40% of the women had perceived insufficient sleep during the last 6 months. They perceived significantly worse sleep quality and a higher degree of strain according to working conditions than the others. Palpitation and dysphoria as effects of sleep loss were independently predicted by sleep quality. Dysphoria was also predicted by difficulty in falling asleep. Cognitive behavioural effects of fatigue was predicted by disturbed sleep. Palpitation effects led to a 10-fold increase in the probability of cognitive behavioural effects of fatigue. The effects were most prominent among women suffering from gastrointestinal problems of long duration and chronic pain. 4. Responses to reduced sleep quality in women constitute a form of stress, with sympathetic activation, increased susceptibility to infection, moderate cognitive impairment, mood changes and somatic distress.

Adult↗
PubMed1987

Lithium carbonate: effects on sleep patterns of normal and depressed subjects and its use in sleep-wake pathology.

The effects of lithium carbonate on sleep patterns have been investigated both acutely in normal and depressed subjects and chronically in depressed subjects. In normal subjects receiving lithium for two weeks total sleep time did not vary, REM sleep decreased and REM sleep latency increased. In depressed subjects, either on short therm therapy or on long term therapy stages 3 and 4 increased, REM sleep decreased, REM latency increased and REM activity/time spent asleep (an index of REM intensity per minute of sleep) decreased. Plasma lithium levels were negatively correlated with REM sleep percentage and positively correlated with REM sleep latency. Besides, it has been shown in one paper that short term therapy with lithium caused small but significant delays in the sleep-wake circadian rhythm. These effects are of interest in view of polygraphic sleep abnormalities found in affective disorders and possible circadian disturbances accounting for these abnormalities. Indeed lithium might act in correcting spezial sleep abnormalities and/or circadian disturbances. In addition to its predominant use for the prophylaxis of recurrent mania and depression, lithium carbonate has been proposed and tried in the prophylactic treatment of abnormally prolonged sleep episodes featuring the Kleine-Levin syndrome.

Circadian Rhythm↗
PubMed1991

Sleeping with and without norepinephrine: effects of metoclopramide and D,L-threo-3,4-dihydroxyphenylserine on sleep in dopamine beta-hydroxylase deficiency.

Sleep characteristics are presented for two female patients (aged 21 and 31 years) with central and peripheral dopamine beta-hydroxylase (DBH) deficiency. This deficiency results in the absence of norepinephrine, epinephrine, and their metabolites in plasma, urine, and cerebrospinal fluid, while concentrations of dopamine are increased. The sleep pattern of these patients was studied when they were untreated, after blockade of central dopamine receptors with metoclopramide, and after restoring norepinephrine production with D,L-threo-3,4-dihydroxyphenylserine (DOPS). When the patients were untreated sleep duration was normal, with tendencies of a decreased amount of rapid eye movement (REM) sleep, presence of alpha-delta sleep, and an increased amount of slow-wave sleep. The amount of REM sleep varied between 18 and 21% of sleep period time. Administration of metoclopramide resulted in a slight reduction of REM sleep to 16-17%, whereas wakefulness after sleep onset increased. During treatment with DOPS, an increase in the amount of REM sleep was observed in both patients to an average amount of 27%. These data indicate that in patients with DBH deficiency norepinephrine is not essential for the development of a normal sleep/wake pattern but may have a facilitatory role in the generation of REM sleep.

Adult↗
PubMed1991

Sleep extension in humans: sleep stages, EEG power spectra and body temperature.

In eight male subjects the electroencephalogram (EEG) and core body temperature (Tcore) were recorded during long sleep episodes from 0000 to 1,500 hr. EEGs were visually scored and subjected to spectral analysis by fast Fourier transform. Slow-wave sleep [SWS, i.e. stages 3 + 4 of non-rapid eye movement (NREM) sleep and slow wave activity (SWA, mean EEG power density in the range of 0.75-4.5 Hz)] in NREM sleep attained highest values in the first 3 hr of sleep and lowest values in the morning hours when rapid eye movement (REM) sleep was at its maximum. Wakefulness was significantly enhanced in the last 3 hr of the recording period. Occasional NREM episodes containing SWS were observed in the late morning and early afternoon. However, no significant increase in SWS or SWA in the last 3 hr of the sleep episode over any of the preceding 3-hr intervals was present and SWA in this interval was significantly below the values observed at the beginning of sleep. The duration of NREM episodes varied significantly over the sleep episode. Analysis of the dynamics of SWA within NREM episodes revealed that SWA gradually rose during the episode. Consequently, SWA averaged per episode was positively correlated with episode duration. Tcore dropped in the initial part of sleep, rose during the morning hours and reached values in the afternoon that were higher than at the beginning of sleep. Thus the time course of Tcore dissociated from the time course of SWA. This indicates that SWA in NREM sleep is not directly related to the variation in core body temperature.

Adult↗
PubMed1998

The Taskforce 2000 survey on medical education in sleep and sleep disorders.

Previous research has shown evidence of a widening gap between scientific research and clinical teaching in sleep and sleep disorders. To address the deficiencies in current medical education in sleep, the Taskforce 2000 was established by the American Sleep Disorders Association. The present study was undertaken to assess the teaching activities, needs and interests of the membership of the two largest professional sleep societies (American Sleep Disorders Association and Sleep Research Society). Survey instruments included a brief, 5-item postcard survey, which was mailed to all members, followed by an in-depth, 34-item questionnaire, which was completed by 158 respondents from the intitial postcard survey (N = 808). Results indicated that the majority of respondents (65.2%) are currently involved in teaching sleep to medical students or postgraduate trainees, although the average amount of teaching time was only 2.1 hours for undergraduate and 4.8 hours for graduate education in sleep. Teaching of sleep laboratory procedures and clinical evaluation of sleep-disordered patients is limited at either an undergraduate or postgraduate level. The major deficiencies noted were the lack of time in the medical curriculum and the need for better resources and teaching facilities. A large majority of respondents indicated their willingness to be involved in sleep education for physicians, and rated this a high priority for the professional organization.

Curriculum↗
PubMed2001

Sleep in the laboratory and sleep at home II: comparisons of middle-aged insomnia sufferers and normal sleepers.

STUDY OBJECTIVES: The study compared adaptation responses and sleep pattern differences shown by normal sleepers and insomnia sufferers during lab (LPSG) and home (HPSG) polysomnography. DESIGN: A counter-balanced, matched-group design was used. Participants underwent 3 consecutive nocturnal LPSG's and 3 consecutive nocturnal PSG's in their homes (HPSG's). SETTING: The sleep disorders laboratories at affiliated VA and university medical centers. PARTICIPANTS: Thirty-five (18 women) middle-aged (40 to 59 years) noncomplaining normal sleepers and an age-matched sample of 33 (17 women) individuals who met structured interview criteria for persistent primary insomnia were the study participants. MEASUREMENTS AND RESULTS: A series of multivariate and univariate analyses were conducted with 9 common sleep parameters to address study objectives. Bed partner influences were controlled by conducting separate sets of analyses for those with and without routine home bed partners. The interaction of participant type (normal vs. insomnia), sleep setting, and PSG sequence (HPSG 1st vs. LPSG 1st) affected first night values of sleep efficiency and stage 2 sleep among those without routine bed partners, and REM latency and sleep efficiency among those with routine bed partners. Analyses which controlled for first night and sequencing effects showed a significant participant type x sleep setting interaction among those with bed partners. These latter analyses suggested that LPSG's may underestimate the home sleep time of insomnia sufferers and overestimate the sleep continuity of normal sleepers, at least among those who routinely sleep with a bed partner. CONCLUSIONS: The nocturnal recording site may influence adaptation effects and sleep pattern differences noted between insomnia sufferers and normal sleepers.

Adaptation, Physiological↗