Showing papers on "Non-rapid eye movement sleep published in 1989"

Why We Sleep: The Functions of Sleep in Humans and Other Mammals

Abstract: Sleep deprivation physiological effects of sleep deprivation body restitution and sleep waking awareness, subsequent sleep and cerebral restitution core and optical sleep sleep in other mammals REM sleep.

Sleep on the Night Shift: 24-Hour EEG Monitoring of Spontaneous Sleep/Wake Behavior

Abstract: The present study sought to objectively describe the spontaneous sleep/wakefulness pattern of shift workers during a 24-hour period. Portable Medilog tape-recorders were used for ambulatory EEG monitoring of 25 male papermill workers (25-55 years) during days with night and afternoon work. The results showed that sleep after night work was two hours shorter than after afternoon work. The sleep reduction affected mainly Stage 2 and REM sleep while slow wave sleep was unchanged. In connection with night work 28% of the workers took a nap in the afternoon. These naps contained a large proportion of slow wave sleep and were, apparently, caused by the sleep deficit after the short main sleep period. The EEG recordings also revealed that 20% of the participants had sleep episodes during night work. These naps were as long as the afternoon naps, were experienced as "dozing offs" rather than naps, occurred at the time of the trough of the circadian wakefulness rhythm, and were concomitant with extreme subjective sleepiness and low rated work load. It was concluded that not only the sleep of shift workers was disturbed, but also the wakefulness--to the extent that sleepiness during night work sometimes reached a level where reasonable wakefulness could not be maintained. The latter observation is probably of special importance in work situations demanding a great responsibility for human lives or for great economic values.

Electroencephalographic sleep in panic disorder. A focus on sleep-related panic attacks.

Abstract: • Sleep electroencephalograms were studied in 13 patients with panic disorder, six of whom experienced panic from sleep, and seven controls. Sleep was disturbed in the patients, as manifested by increased sleep latency, decreased sleep time, and decreased sleep efficiency. Rapid eye movement (REM) latencies were not reduced in the patient group. All six of the panic awakenings were preceded by non-REM sleep, which could be further characterized as a transition from stage II toward delta sleep. The overall degree of sleep disturbance (ie, sleep latency, sleep efficiency) did not appear to be influenced by the occurrence of sleep panic. There was also an association of increased REM latency with nights of sleep panic.

Sleep and fibrositis syndrome.

Abstract: Chronic diffuse myalgia, localized areas of tenderness, fatigue, and unrefreshing sleep are related to a physiologic arousal disorder within sleep, that is, the alpha EEG NREM sleep anomaly. This sleep physiologic disorder, nonrestorative sleep, and symptoms of fibrositis syndrome are shown to occur with psychologic, environmental, and physiologic distress conditions. Pathogenic mechanisms that link nonrestorative sleep physiology to pain and fatigue may involve metabolic dysfunction of the brain with sleep-related alteration in immunologic and neurotransmitter functions (serotonin, substance P, endorphins). These sleep-related mechanisms have important implications for the understanding and treatment of fibrositis/fibromyalgia syndrome.

Sleep initiation and initial sleep intensity: interactions of homeostatic and circadian mechanisms.

Abstract: Sleep initiation and sleep intensity in humans show a dissimilar time course. The propensity of sleep initiation (PSI), as measured by the multiple sleep latency test, remains at a relatively constant level throughout the habitual period of waking or exhibits a midafternoon peak. When waking is extended into the sleep period, PSI rises rapidly within a few hours. In contrast, sleep intensity, as measured by electroencephalographic slow-wave activity during naps, shows a gradual increase during the period of habitual waking. In the two-process model of sleep regulation, it corresponds to the rising limb of the homeostatic Process S. We propose that PSI is determined by the difference between Process S and the threshold H defining sleep onset, which is modulated by the circadian process C. In contrast to a previous version of the model, the parameters of H (amplitude, phase, skewness) differ from those of threshold L, which defines sleep termination. The present model is able to simulate the time course of PSI under baseline conditions as well as following recovery sleep after extended sleep deprivation. The simulations suggest that during the regular period of waking, a circadian process counteracts the increasing sleep propensity induced by a homeostatic process. Data obtained in the rat indicate that during the circadian period of predominant waking, a circadian process prevents a major intrusion of sleep.

Magnetic resonance findings in REM sleep behavior disorder

Abstract: Rapid eye movement (REM) sleep behavior disorder is characterized by bizarre acts during nocturnal sleep that may lead to physical injuries. Dream content suggests that motor overactivity is an attempted dream enactment and polygraphic studies reveal REM stage without atonia, an alteration of REM sleep generation that facilitates excessive motor activity. In 6 patients with REM sleep behavior disorder. MRI of the brain showed multifocal signal intensity lesions suggestive of lacunar infarcts in periventricular regions (5 patients) and in dorsal pontomesencephalic areas (3 patients). REM sleep behavior disorder may be the result of injury to the midrostral tegmentum nuclei, the tegmentoreticular tracts, or both. This condition is easily controlled with clonazepam.

Collapsibility of the human upper airway during normal sleep

Abstract: Upper airway resistance (UAR) increases in normal subjects during the transition from wakefulness to sleep. To examine the influence of sleep on upper airway collapsibility, inspiratory UAR (epiglottis to nares) and genioglossus electromyogram (EMG) were measured in six healthy men before and during inspiratory resistive loading. UAR increased significantly (P less than 0.05) from wakefulness to non-rapid-eye-movement (NREM) sleep [3.1 +/- 0.4 to 11.7 +/- 3.5 (SE) cmH2O.1-1.s]. Resistive load application during wakefulness produced small increments in UAR. However, during NREM sleep, UAR increased dramatically with loading in four subjects although two subjects demonstrated little change. This increment in UAR from wakefulness to sleep correlated closely with the rise in UAR during loading while asleep (e.g., load 12: r = 0.90, P less than 0.05), indicating consistent upper airway behavior during sleep. On the other hand, no measurement of upper airway behavior during wakefulness was predictive of events during sleep. Although the influence of sleep on the EMG was difficult to assess, peak inspiratory genioglossus EMG clearly increased (P less than 0.05) after load application during NREM sleep. Finally, minute ventilation fell significantly from wakefulness values during NREM sleep, with the largest decrement in sleeping minute ventilation occurring in those subjects having the greatest awake-to-sleep increment in UAR (r = -0.88, P less than 0.05). We conclude that there is marked variability among normal men in upper airway collapsibility during sleep.

The Cholinergic Rapid Eye Movement Sleep Induction Test With RS-86: State or Trait Marker of Depression?

Abstract: • Rapid eye movement (REM) sleep disinhibition at the beginning of the night is one of the most frequently described biologic abnormalities in depression. As REM sleep in animals and humans seems to be facilitated by cholinergic neuronal activity, it has been postulated that REM sleep disinhibition in depression is a consequence of cholinergic neuronal overactivity. The current study with the newly available cholinergic agonist RS-86, which is orally active, has a half-life of six to eight hours, and exhibits only minor peripheral side effects, supports this assumption. The application of this compound before sleep led to a significantly faster induction of REM sleep at the beginning of the night in patients with major depressive disorders compared with healthy subjects and patients with other nondepressive psychiatric diseases, such as eating disorders. Whereas 14 of 16 depressed patients displayed sleep-onset REM periods after the administration of RS-86, this happened only in three of the 16 healthy controls and in one of the 20 patients with other diagnoses. The increased susceptibility of REM sleep to cholinergic stimulation was limited to the state of depression and was not observed in a group of remitted depressed patients.

Bright morning light advances the human circadian system without affecting NREM sleep homeostasis

Abstract: Eight male subjects were exposed to either bright light or dim light between 0600 and 0900 h for 3 consecutive days each. Relative to the dim light condition, the bright light treatment advanced the evening rise in plasma melatonin and the time of sleep termination (sleep onset was held constant) for an average approximately 1 h. The magnitude of the advance of the plasma melatonin rise was dependent on its phase in dim light. The reduction in sleep duration was at the expense of rapid-eye-movement (REM) sleep. Spectral analysis of the sleep electroencephalogram (EEG) revealed that the advance of the circadian pacemaker did not affect EEG power densities between 0.25 and 15.0 Hz during either non-REM or REM sleep. The data show that shifting the human circadian pacemaker by 1 h does not affect non-REM sleep homeostasis. These findings are in accordance with the predictions of the two-process model of sleep regulation.

Sleep deprivation in the rat: IX. Recovery.

Abstract: Eight rats were subjected to total sleep deprivation, paradoxical sleep deprivation, or high amplitude sleep deprivation until they showed major deprivation-induced changes. Then they were allowed to sleep ad lib. Three rats that had shown the largest temperature declines died within two to six recovery days. During the first 15 days of ad lib sleep, surviving rats showed complete or almost complete reversal of the following deprivation-induced changes: debilitated appearance, lesions on the paws and tail, high energy expenditure, large decreases in peritoneal temperature, high plasma epinephrine and norepinephrine levels, and low thyroxine levels. The most prominent features of recovery sleep in all rats were immediate and large rebounds of paradoxical sleep to far above baseline levels, followed by lesser temporally extended rebounds. Rebounds of high amplitude non-rapid eye movement (NREM) sleep occurred only in some rats and were smaller and less immediate.

Sleep EEG spectral analysis in a diurnal rodent: Eutamias sibiricus

Abstract: 1. Sleep was studied in the diurnal rodent Eutamias sibiricus, chronically implanted with EEG and EMG electrodes. Analysis of the distribution of wakefulness, nonrapid eye movement (NREM) sleep, and rapid eye movement (REM) sleep over the 24 h period (LD 12:12) showed that total sleep time was 27.5% of recording time during the 12 h light period and 74.4% during the 12 h dark period. Spectral analysis of the sleep EEG revealed a progressive decay in delta power density in NREM sleep during darkness. Power density of the higher frequencies increased at the end of darkness. Power density of the higher frequencies decreased and that of the lower frequencies increased during light. 2. Analysis of the distribution of vigilance states under three different photoperiods (LD 18:6; 12:12; 6:18) revealed that changes in daylength mainly resulted in a redistribution of sleep and wakefulness over light and darkness. Under long days the percentage of sleep during light was enhanced. The time course of delta power density in NREM sleep was characterized by a long rising part and a short falling part under long days, while a reversed picture emerged under short days. As a consequence, the power density during days. As a consequence, the power density during light was relatively high under long days. 3. After 24 h sleep deprivation by forced activity, no significant changes in the percentages of wakefulness and NREM were observed, whereas REM sleep was slightly enhanced. EEG power density, however, was significantly increased by ca. 50% in the 1.25-10.0 Hz range in the first 3 h of recovery sleep. This increase gradually decayed over the recovery night. 4. The same 24 h sleep deprivation technique led to a ca. 25% increase in oxygen consumption during recovery nights. While the results of the EEG spectral analysis are compatible with the hypothesis that delta power density reflects the 'intensity' of NREM sleep as enhanced by prior wakefulness and reduced by prior sleep, such enhanced sleep depth after sleep deprivation is not associated with reduced energy expenditure as might be anticipated by some energy conservation hypotheses on sleep function.

Clomipramine and EEG sleep in depression

Abstract: Recent studies with clomipramine (CMI) have demonstrated that a pulse-loading approach is associated with a rapid improvement in symptomatology in the absence of continuous treatment. In the present study, sleep changes were evaluated to ascertain the rapidity of clomipramine's effect on electroencephalographic sleep, especially rapid eye movement (REM) and delta wave sleep measures. Clomipramine produced rapid changes in sleep with reduced sleep continuity and almost complete suppression of REM sleep as well as a redistribution of slow wave sleep. Delta waves during sleep were also found to be shifted to the earlier part of the night and increased in intensity. Spectral analysis revealed an increase in power in the delta frequency range that was correlated with clinical responsiveness. These studies point toward a role for clomipramine in the rapid treatment of depression and confirm that sleep physiology may be a good predictor of antidepressant action.

Decreased slow-wave and paradoxical sleep in a rat chronic pain model.

Abstract: Diurnal sleep-wake patterns in the normal and the adjuvant arthritic rat were measured during the first 3 h of both light and dark periods. During the hours of maximal sleep in the normal rat, arthritic rats showed a significant increase in wakefulness (Wake), a shift to non-rapid-eye-movement (NREM) stages with lower amplitudes (LS and HS1), and a large reduction of NREM sleep with the highest-amplitude (HS2) and paradoxical sleep. Arthritic rats also showed marked sleep fragmentation manifested by more episodes of Wake, LS, and HS1 and shorter episodes of HS2 during both the light and the dark periods. Thus, arthritic rats cannot sustain long periods of sleep. In contrast to control rats, arthritic rats lacked a diurnal variation in Wake, total sleep, and electroencephalographic (EEG) delta activity. They also showed a decrease in overall EEG amplitude. In addition, there was a positive correlation between the severity of arthritis and the percentages of NREM sleep with low (LS) and moderate (HS1) amplitude. Thus, the decline in EEG amplitude could indicate a deficit of EEG generating mechanisms or some aspect of disease severity, such as pain.

Effects of continuous positive airway pressure on phasic events of REM sleep in patients with obstructive sleep apnea.

Abstract: In patients with obstructive sleep apnea and associated rapid-eye-movement (REM) sleep deprivation and disruption, the first night of nasal continuous positive airway pressure (CPAP) is often associated with increases in REM sleep time and REM density (REM rebound). The amount of REM rebound, however, varies considerably. We sought to characterize the magnitude of REM rebound and to determine what factors determine individual differences in REM rebound with initial CPAP treatment. Twenty-six patients with sleep apnea had a baseline nocturnal polysomnogram and a second night with a trial of CPAP. REM sleep time increased by 69% with CPAP, REM density increased by 73%, and REM activity by 169%. REM density was highest in the second REM period. Improvement in respiratory disturbance index with CPAP correlated significantly with increased minutes of REM sleep with CPAP. Of polysomnographic measures on the baseline night, change in minutes of REM sleep with CPAP correlated best with minimum oxygen saturation and to a lesser degree with respiratory disturbance index, and minutes of Stage 1 sleep. One possible explanation for the effect of hypoxemia on subsequent REM rebound is that some physiological functions of REM sleep may fail when oxygen saturation falls below a certain level.