Showing papers in "Sleep in 1984"

Effect of sleep position on sleep apnea severity.

Abstract: Thirty male patients evaluated sequentially for sleep apnea syndrome by all-night clinical polysomnography were compared for apnea plus hypopnea index (A + HI) during the time in the side versus time in the back sleep posture. For 24 subjects of this sample, who occupied both major body positions during the evaluation night, the apnea index was found to be twice as high during the time spent sleeping on their backs as it was when they slept in the side position. This difference is reliable and inversely related to obesity. Five patients meeting diagnostic criteria for sleep apnea on an all-night basis fell within normal limits while in the side sleep position. This suggests sleep position adjustment may be a viable treatment for some nonobese sleep apnea patients.

Sleep fragmentation and daytime sleepiness.

Abstract: It has been noted that clinical populations complaining of excessive daytime sleepiness (EDS) frequently have disrupted or fragmented nocturnal sleep. The relation between sleep fragmentation and daytime sleepiness has not been systematically studied. This study was designed to use correlational techniques evaluating the relation between these variables in patients complaining of EDS, patients complaining of insomnia, and asymptomatic controls. The four groups studied included patients complaining of EDS with sleep apnea (n = 15) or with periodic leg movements (n = 15), patients complaining of insomnia (n = 15), and healthy volunteers with no sleep complaint (n = 10). One night of polysomnography followed by a Multiple Sleep Latency Test was obtained for each subject. Each recording was evaluated using standard criteria and also by a four-level arousal scoring system. Across all subjects, the total number of arousals correlated significantly with sleepiness index (r = 0.48, p less than 0.001). Closer analysis of the data shows that, depending upon the sleep complaint, different types of arousals are predictive of degree of daytime sleepiness. It is concluded that the number and type of nocturnal arousals play an important role in subsequent daytime sleepiness.

Mandibular osteotomy and hyoid bone advancement for obstructive sleep apnea: a case report.

Abstract: A 24-year-old man with obstructive sleep apnea syndrome and secondary daytime somnolence and nocturnal arrhythmias underwent palatopharyngoplasty. When he did not improve significantly, he underwent a new surgical procedure combining hyoid bone and mandibular horizontal sliding osteotomy.

Daytime alertness in relation to mood, performance, and nocturnal sleep in chronic insomniacs and noncomplaining sleepers.

Abstract: Nocturnal sleep was recorded prior to daytime testing that included the Multiple Sleep Latency Test, profile of mood states, card sorting, and Stanford Sleepiness Scale in 138 volunteers with the complaint of chronic insomnia and 89 noncomplaining sleepers ("normals"). In both groups daytime sleep tendency had no significant linear correlation either with any Minnesota Multiphasic Personality Inventory scale or with tension/anxiety and other moods assessed in the morning. In normals, speed of card sorting but not subjective sleepiness tended to correlate with sleep tendency. Given that physiological sleepiness is the most predictable consequence of sleep deprivation in normals, it is particularly interesting that 14% of the insomniac group are chronic insomniacs with no measurable daytime sleep tendency. Despite this lack of sleep tendency during the day, their nocturnal sleep was just as poor as insomniacs with greater daytime sleep tendency. The lack of daytime sleepiness seen in this subgroup may reflect a basic pathophysiological aspect of their insomnia.

EEG sleep of normal healthy children. Part I: Findings using standard measurement methods

Abstract: Despite the increasing application of all-night electroencephalographic (EEG) sleep studies to children for clinical as well as for research purposes, readily available normal EEG sleep standards for the period of childhood have remained sparse and, at present, reflect data on only approximately 100 children 6 to 16 years of age. As part of a large scale study examining various aspects of EEG sleep among children, findings derived using standard recording and scoring methods are reported for a new sample of nearly 100 normal, healthy children and are compared with existing standards. Data obtained add substantially to the existing database and generally confirm findings of previous normative reports on children in this age range.

Properties of human sleep-wake cycles: parameters of internally synchronized free-running rhythms.

Abstract: Sleep-wake alternations are governed by circadian regularities. In order to evaluate these regularities without interference from social constraints or behavioral influences, we conducted experiments under constant conditions, excluding all external time references. The experiments were conducted for approximately 1 month to ensure that the rhythms were at a steady state. A homogeneous sample of 27 human subjects with free-running and internally synchronized rhythms was analyzed with regard to numerous sleep-wake parameters. There was no temporal trend during the entire period or in individual wake or sleep episodes. The onset of sleep was consistently and by far the most variable reference phase within the sleep-wake cycle. The results of negative serial correlations within the sleep-wake rhythm were relevant. Essentially, every distortion in the duration of a cycle is followed, with high probability, by a deviation in the duration of the following cycles in the opposite direction; i.e., any chance variation in the duration of a cycle is corrected with the next, and to a smaller amount with the next but one, cycle. Hence, an intrinsic stabilizing mechanism of the underlying pacemaker is in effect. Secondarily, there are negative serial correlations among adjacent wake and sleep episodes. Every deviation of an episode from the long-term mean results in an opposite deviation of the following episode. In other words, a wake episode determines the duration of the following sleep, and a sleep episode determines the duration of the following wake. All these negative serial correlations are highly significant interindividually. Another relevant result concerns the difference between females and males. The mean sleep-wake cycle is significantly shorter in females than in males, on the average by 28 min. Even more significant is the sex difference in the fraction of sleep. On the average, the wake episode is shorter by 1 h 49 min and the sleep episode is longer by 1 h 21 min in females than in males; i.e., the fraction of sleep is larger for 18% in females than males. There are indications that the established sex difference concerns, within the human multioscillator system, only that oscillator which is predominantly responsible for sleep-wake rhythm, but not the other oscillator, which is predominantly responsible, for instance, for deep body temperature. On the other hand, no parameter describing variabilities for the period or the separate episodes shows a sex difference, either in amount or in the temporal sequence of the variations as expressed in the serial correlations.

Twenty-four hour rhythms of norepinephrine and serotonin in nucleus suprachiasmaticus, raphe nuclei, and locus coeruleus in the rat.

Abstract: Twenty-four hour rhythms, at 4 h intervals, of norepinephrine (NE) and serotonin (5-HT) contents were investigated in the rat brain regions where sleep-wakefulness regulation is believed to occur: Nucleus suprachiasmaticus (SC), n. raphe dorsalis (RD) and medialis (RM), and locus coeruleus. Cosinor method of Halberg was applied to evaluate sinusoidal rhythmicity of the measured values. In the SC only NE showed a significant rhythm with a peak value at the beginning of the light period, which suggests that a NE mechanism may be involved in oscillating biological rhythms in rats. In the RD and RM, 5-HT and 5-hydroxyindoleacetic acid increased significantly during the light period. Moreover, 5-HT rhythm in the RD was maintained even under constant dark conditions, which suggests that 5-HT rhythm in the RD may be endogenous.

Treatment of Obstructive Sleep Apnea Syndrome with Nasal Continuous Positive Airway Pressure

Abstract: To help define the place of nasal continuous positive airway pressure (n-CPAP) treatment in a general sleep apnea population we studied 12 of 13 consecutively diagnosed patients with obstructive sleep apnea syndrome (OSAS). The immediate effects of n-CPAP were tested during a nighttime sleep study divided into two approximately equal parts (control and n-CPAP). Nasal CPAP of 5-10 cm H2O decreased apnea index (apneas per hour of sleep) (control 35.1, n-CPAP 5.7; p less than 0.001) and significantly improved oxyhemoglobin saturation (SaO2). The effect was independent of body weight and the presence of cardiorespiratory complications. However, in three patients with lung disease and markedly elevated PaCO2, significant sleep-related hypoxemia persisted at the relatively low pressures required to open the upper airway. Long-term home-based n-CPAP was offered to 11 patients. (One patient was considered unsuitable because of persisting profound sleep-related hypoxemia). Seven patients consented and were followed for periods ranging from 1 to 18 months. All patients reported dramatic reversal of daytime hypersomnolence; three complained of minor nasal stuffiness but compliance was good and only one stopped using the mask (after 12 months). Apnea index decreased following home use of n-CPAP (before 35.9, after 18.1; p less than 0.01) but overall respiratory instability (apnea + hypopnea) and SaO2 were not significantly improved. It is concluded that n-CPAP is a highly effective means of preventing upper airway occlusion in OSAS and, except for some patients with coexisting lung disease, it totally reverses the accompanying gas exchange disturbance. Long-term home-based n-CPAP therapy is acceptable to a majority of patients, is free of serious side effects, and appears to result in a partial reversal of the underlying breathing disorder.

Daytime sleepiness and antihistamines.

Abstract: A daytime nap procedure was used to evaluate the daytime sleepiness associated with antihistamines, as well as to assess their hypnotic potential. Healthy, normal subjects received diphenhydramine (150 mg), terfenadine (120 mg), and placebo and went to bed at 900, 1100, 2000, and 2200 h with the instruction to try to fall asleep. The remained in bed for 60 min while standard sleep recordings were made. Across all conditions latency to stage 1 sleep increased significantly from nap 1 to nap 4 and the amount of sleep (all nonstage 1 sleep) decreased significantly. Over the four naps the mean latency to stage 1 sleep with diphenhydramine was significantly shorter than terfenadine and placebo, which did not differ. On the other hand, there were no differences among the drug conditions in the amount of nonstage 1 sleep. In sum, diphenhydramine at this dose produces sleepiness but shows little potential as a hypnotic, and accumulated sleep across the day makes people progressively more alert.

Distribution of rem latencies and other sleep phenomena in depression as explained by a single ultradian rhythm disturbance

Abstract: The McCarley-Hobson model, describing the alternation of NREM and REM sleep in the cat, was applied to human electroencephalographic data. The influence of initial conditions on oscillatory behavior was especially emphasized. It appears that the distribution of REM latency in depression, the abnormal accumulation of REM sleep, the variability of NREM-REM cycle duration, the frequent stage shifts, and frequent awakenings can be explained in this model by means of a decrease in the initial value of a single variable, which may be regarded as representing the strength of REM inhibition. The observation of slow wave sleep deficiency in depression may well be another reflection of this parameter.

Phasic Activity of the Basolateral Amygdala, Cingulate Gyrus, and Hippocampus During REM Sleep in the Cat

Abstract: We analyzed the electrical activity of the basolateral amygdala (BLA), anterior and posterior regions of the cingulate gyrus (A-CG and P-CG), the dorsal hippocampus (DH), the anterior ventral thalamic nucleus (AVTN), and the sensory motor cortex during the rapid eye movements and ponto-geniculo-occipital (PGO) activity of REM sleep in cats in chronic preparation. Polygraphic recordings and computational perievent averages using the phasic contractions of the lateral rectus muscle (LR) of the eyeball as the triggering signal of the analysis were performed. We observed biphasic potentials (200-300 ms) of variable amplitude, related to the phasic phenomena of REM sleep, in the BLA, A-CG, P-CG, DH, and AVTN. The latencies of the potentials of these regions were always greater than those of the geniculate PGO activities. We propose that the recorded limbic potentials resulted from propagation of PGO activity and that this phenomenon may reflect the limbic structure of the hallucinatory, vegetative, and emotional components of REM sleep.

Periodic movements during sleep, sleep fragmentation, and sleep-wake complaints.

Abstract: To better understand the relation of sleep complaint to sleep continuity and periodic movements during sleep (PMS), two groups of patients were studied retrospectively. One group of 51 patients, 26 men and 25 women, with a mean age of 56.4 years, complained of insomnia. The other group of 29 patients, 20 men and nine women, with a mean age of 55.8 years, complained of excessive daytime sleepiness. Sleepy patients differed significantly from insomnia patients in that they fell asleep faster and slept longer. They showed more frequent arousals (shifts to stage 1 sleep and number of awakenings) than insomnia patients who had longer arousals (mean duration of awakenings). Insomnia patients had more series of PMS, but sleepy patients had more PMS bursts per series.

Acute administration of triazolam for the daytime sleep of rotating shift workers.

Abstract: Ten rotating shift workers, who changed shifts every 1 to 4 weeks, slept in the laboratory during the first four daytime sleep periods of two consecutive tours of night shift. Prior to the first two sleep periods of one tour, the subjects were given 0.5 mg triazolam. Placebo was administered prior to sleep periods one and two of the other night shift tour. Neither drug nor placebo was given before the third and fourth sleep period of either tour of night shift. Conditions were counterbalanced among subjects. Polysomnography demonstrated that triazolam significantly increased total sleep time and sleep efficiency relative to placebo, primarily by promoting sleep maintenance. No adaptation to daytime sleep was seen during the four consecutive sleep periods without triazolam (placebo, then no drug). Triazolam did not appear to promote adaptation to daytime sleep on the 2 days following triazolam administration.

Effects of methoxamine and alpha-adrenoceptor antagonists, prazosin and yohimbine, on the sleep-wake cycle of the rat.

Abstract: A study was carried out on the effects of methoxamine, prazosin, and yohimbine on the sleep-wake cycle in rats prepared for chronic sleep recordings. Methoxamine (4-8 mg/kg), an alpha 1-adrenoceptor agonist, induced a dose-related increase in wakefulness (W) and a decrease in slow-wave sleep (SWS) and REM sleep (REMS). Prazosin (0.125-1 mg/kg), which selectively blocks alpha 1-adrenoceptors, modified only slightly the amount of time spent in W and SWS, and consistently decreased REMS values. Prazosin (0.5 mg/kg) reversed the effects of methoxamine, decreasing W and increasing sleep. Yohimbine (3 mg/kg), which blocks alpha 2-adrenoceptors, augmented W and diminished sleep. Methoxamine (4 mg/kg) in animals pretreated with yohimbine (3 mg/kg) induced a further decrease of SWS and REMS and an increase of W. Thus, pharmacological activation of alpha 1- or blocking of alpha 2-adrenoceptors appears to decrease sleep and increase W. Further, blocking of alpha 1-adrenoceptors decreases REMS. Rapid eye movement sleep depression by the alpha 1-agonist or the alpha 1-antagonist is tentatively ascribed to a critical change in noradrenergic transmission in the brain.

Nocturnal REM latency and sleep disturbance in narcolepsy.

Abstract: A retrospective study of 92 narcoleptics was undertaken to investigate the significance of prolonged nocturnal REM latencies observed in approximately one in every five narcoleptics undergoing single all-night clinical polysomnograms in our laboratory. Clinical and laboratory findings were examined as a function of REM latency. Our findings emphasize a high incidence of other sleep disorders, particularly sleep-related periodic leg movements, in narcoleptics. Furthermore, sleep disturbance secondary to other sleep disorders, especially during the period of NREM sleep preceding the first REM episode, accounts in large part for prolonged REM latencies observed in some narcoleptics. This study also provides one of the most extensive compilations of clinical and laboratory findings in a large population of narcoleptics.

Effects of 72 hour sleep deprivation on urinary cortisol and indices of metabolism.

Abstract: Cortisol, urea, glucose, electrolytes, and other compounds were measured in five consecutive 24 h urine collections during a 72 h sleep deprivation study in six young men. Urine was collected during a 24 h predeprivation day, 3 days of sleep deprivation, and a recovery day. Whereas urinary cortisol decreased only slightly, marked changes in other urinary constituents were observed. During sleep deprivation, urinary urea rose markedly, glucose decreased, and urinary electrolytes decreased. These data indicate that sleep deprivation under ad lib food and water conditions can cause disturbances in normal metabolism.

Sleep deprivation and the physiological response to exercise under steady-state conditions in untrained subjects.

Abstract: Seven physically untrained subjects underwent 72 h total sleep deprivation, followed a baseline day. Daily, at 0400 and 1600 h, subjects pedalled on a bicycle ergometer under individually set work loads of 40, 60, and 80% VO2max. This was not a study oriented towards endurance but towards capacity, requiring steady-state measurement. From assessments of heart rate, VO2 and VCO2 were calculated: VO2max, gross mechanical efficiency, VO2 at a heart rate of 150, and respiratory quotient. To assess possible training effects, a control group underwent identical procedures except that they slept at night and had the morning measure delayed until 0830 h. A series of statistical models were applied to the data, which centered on quantifying the inherent underlying variability, to estimate the level any main effect had to reach to become significant. the analysis showed that the noise level was small enough for any real effect of importance to have been detected, with a reasonably large probability. No statistically significant effects were found for any of the parameters with respect to conditions, days, and time. The main significant outcome was with mechanical efficiency, which displayed greater variability during sleep deprivation. Both groups displayed similar trends in training effects. It was concluded that the physiological ability to do work of the type and duration used here was not adversely affected by 72 h of sleep loss.

The detection of behavioral state cycles and classification of temporal structure in behavioral states.

Abstract: Previous methods for the analysis of temporal structure in sleep and other state time series have described cycles, rhythms, and semi-Markov chains. Methods, however, have been subjective and arbitrary. We propose an objective system of classification for these series, based on definitions of temporal structure which are consistent with those long used in the analysis of quantitative series. An ordered sequence of statistical tests is described which classifies observed behavioral state time series into four primary categories. The system is illustrated with examples from normal infant sleep. The results show that some infant sleep series are cycles, as previously reported, some are semi-Markov chains, and some are neither. The proposed objective methods promise consistency, clarity, and a richer understanding of behaviors such as sleep.

Evidence for a directional correspondence between eye movements and dream imagery in REM sleep.

Abstract: We examined the relationship between eye movement direction in REM sleep recorded by electrooculograph (EOG) and gaze direction in dream imagery. In a double-blind protocol, carefully screened and trained subjects were awakened subsequent to direct coupled EOG activity that was either predominantly horizontal or vertical. Following a target eye movement that fulfilled predetermined amplitude and directional criteria, a brief period of ocular quiescence was allowed to transpire before the subject was awakened. The dream narratives and EOG activity occurring prior to the REM awakenings were each reduced to a series of quantitatively scaled ratings. Analyses of variance demonstrated that when the confidence level of the experimenters' prediction is taken into account, statistically significant relationships exist between the number and direction of shifts of gaze in the dream report and scaled measurements of the corresponding EOG. When given dream narratives and the corresponding EOG recordings in sets of four, judges were unable to match them correctly better than by chance. However, in the above matching, judges significantly paired the dream narratives with EOG recordings that were in the same axis of gaze.

The Effect of Sleep Before or After Learning on Memory

Abstract: Early studies in which it was found that learning followed by sleep was better remembered than learning followed by wakefulness were interpreted as giving support for the Interference Theory of Forgetting. More recent studies have shown better retention over the first half of the night's sleep (slow-wave sleep) than over the second half (REM sleep), and conclusions have been drawn that a Decay Theory of Forgetting is more strongly supported. Those studies, however, confounded the type of sleep following learning with sleep prior to learning. When prior sleep was controlled in the present study, there was no support for a first half-night sleep benefit, and, contrary to Decay Theory, there was a second half-night benefit for high imagery material. The strong detrimental effect of sleep prior to learning was inconsistent with the Interference Theory of Forgetting and suggested, instead, the importance of the consolidation process for long-term memory.

Abnormal cerebrovascular responses to CO2 in sleep apnea patients.

Abstract: The responses of common carotid blood flow (CCF), pressure (BP), and resistance (R) to variations in respiratory gases were compared during waking periods in 10 sleep apnea patients (SA) and 10 healthy controls (N) of similar age. Respiratory gases were altered by 3-min CO2 rebreathing (RB), 3-min hyperventilation (HV), and 4-min hypoxia (HYP) procedures. CCF was measured continuously by a 5-MHz pulsed Doppler duplex scanner and R was calculated using brachial BP. During RB, which increased end-tidal PCO2 (PACO2) by 15 mm Hg, SA had a lower CCF and greater BP response and therefore a significantly different (positive) change in R compared with N. The ventilatory responses to CO2 were not significantly different. With HV the PACO2 fell by 13 mm Hg in both groups and CCF fell more markedly in SA than N with the same change in BP; therefore, R was increased significantly more in SA. The HYP results did not demonstrate a difference between groups. These results suggest that abnormal cerebrovascular responses to PACO2, initiated either by unusual vasoactive properties of cerebral resistance vessels or peculiar venous outlow patterns, may initiate or potentiate periodic breathing in SA by prolonging lung-to-brain circulation time.

Nifedipine blocks sleep induction by flurazepam in the rat.

Abstract: Previous studies have implicated the benzodiazepine receptor in the sleep-inducing effects of these widely used hypnotics, but the effector mechanism of this process is poorly understood. There is also in vitro evidence that benzodiazepines enhance calcium entry into synaptosomal preparations, leaving open the possibility that altered calcium flux may be involved in their actions. In order to explore this hypothesis, we administered intraventricular nifedipine, a calcium blocking agent. It was found that pretreatment with a dose of nifedipine which by itself does not affect sleep will prevent sleep induction by flurazepam in rats. Effects on anticonvulsant properties of flurazepam or anxiolytic effects of diazepam were not apparent. This suggests that changes in calcium channel function may be involved in the hypnotic action of benzodiazepines.

Sectioning the hyoid bone as a therapeutic approach for obstructive sleep apnea.

Abstract: After research studies, including systematic lateral x-rays, of normal controls and obstructive sleep apnea syndrome (OSAS) patients, we decided to perform a medial resection of the hyoid bone in OSAS patients. The procedure is similar to that performed for ductus thyreoglossus. To date, three patients have undergone the operation under anesthesia. The two cases have been followed for several months (the third underwent surgery only recently) and have improved, indicating that this procedure can be beneficial for OSAS.

NREM sleep continuity and the sense of having slept in normal sleepers.

Abstract: We assessed the effects of the length of sleep prior to awakening on the sense of having been asleep in 11 normal, healthy, young adults. They were awakened a total of 194 times out of stage 2 sleep, 153 times out of REM sleep, and 13 times out of slow-wave sleep over 54 nights in the laboratory. At each awakening, subjects were asked if they had been awake or asleep prior to the arousal. Continuous sleep time prior to the awakening was calculated in minutes to the first visually scorable alpha intrusion exceeding 10 s on either the central or occipital electroencephalogram (EEG) tracings. The sense of having been asleep prior to a NREM sleep awakening is dependent on the length of continuous, prior sleep time. However, the sense of having been asleep when aroused out of REM sleep shows no relationship to the length of continuous, prior sleep time.

Quantitative description of sleep stage electrophysiology using digital period analytic techniques.

Abstract: The purpose of the current study was to assess the overlap in variance of two procedures for the quantification of sleep electrophysiology: conventional stage scoring and computer quantification of tonic activity. Data were collected on 24 nights from eight subjects and were scored according to a modified set of Rechtschaffen and Kales criteria and submitted to a period-analytic computer analysis. Following this, discriminant function analyses were performed on the data for each night to predict the visual stage scores from the computer-generated data. The results indicate a very high degree of predictive accuracy (91.05%) supporting the contention that the computer-quantified data set includes the variance normally captured by stage scoring. The implications of computer quantification of sleep electrophysiology are discussed.

Electroencephalogram during sleep in the cat: age effects on slow-wave activity.

Abstract: In humans there is a substantial decline in NREM electroencephalographic (EEG) slow-wave activity with advancing age. The present findings show that similar age-related EEG changes occur in the cat. Slow-wave (0.5-4.0 Hz) EEG activity during NREM sleep was compared in six young adult (2-4 years) and six aged (10-12 years) cats of either sex. Computer measures of slow-wave incidence and amplitude disclosed significant age- and gender-related differences. Although old male and female animals were of comparable age, only males showed significant EEG alterations. These consisted of an attenuation of slow-wave amplitude over posterolateral cortex and reductions in both the incidence and amplitude of slow-wave activity over sensorimotor cortex.

Effect of physical fitness and body composition on sleep and sleep-related hormone concentrations.

Abstract: The study assessed the effect of physical fitness and body composition on sleep and the nighttime secretion of the hormones, human growth hormone (hGH), prolactin, and cortisol. Two groups of 17 subjects, one of fit athletes and the other of unfit nonathletes, were selected so that the groups were matched for weight, height, lean body mass (LBM), and fat levels. Subjects slept in a sleep laboratory for 3 nonconsecutive nights: 1 adaptation night and 2 experimental nights. On 1 experimental night blood samples were collected; on the other, baseline sleep was assessed and the catheter was not inserted. Weight and height were measured and LBM assessed by 24 h urinary creatinine. The effect of physical fitness was tested by a comparison of the two groups; body composition was assessed by correlation analyses. Physical fitness did not have a significant effect on either sleep or hormone levels, although in the latter case the results were marginal. In contrast, body composition was related to both sleep and hGH. Percentage LBM was negatively correlated with slow-wave sleep and positively correlated with hGH levels. These results were significant for all subjects combined and for the fit group, although not the unfit group alone.

Sleep interruption and exercise.

Abstract: Five men and five women participated in a study comparing the effects of sleep interruption with and without the imposition of physical activity. Subjects were awakened following the second REM period and returned to sleep 1 h later. In the IS condition they sat up and read during this period; in the ISE condition they exercised for 50 min at 60% VO2max. Relative to undisturbed sleep (US), IS resulted in a substantially shortened third non-REM (NREM) period, increased eye movement (EM) duration and density in the third REM period, and increased slow-wave sleep (SWS) in the fourth NREM period. The loss of delta sleep in the shortened NREM period was compensated for by an increase in delta sleep in the fourth NREM period (r = -0.90). However, total SWS obtained after interruption was unchanged from US. The ISE condition induced increases in cardiac output and temperature during sleep. No consistent changes in SWS were observed relative to IS, but the duration of the third REM period was reduced as well as EM duration and density within that REM period. Since REM sleep propensity is typically highest during the metabolic nadir of early morning sleep, the suppression of tonic and phasic components of REM sleep after ISE was concluded to result from the exercise-induced increase of metabolism and body temperature during sleep.

Relationship between physical, psychological, social, and environmental variables and subjective sleep quality

Abstract: In a survey study of patients of a general practitioner the relationship between sleep quality and a heterogeneous set of other variables was examined. The data file was divided randomly, and a two-staged multiple regression analysis was performed on each half. The two resulting regression equations were cross-validated on the data of the other data file. The variables mood, age, and use of medicine proved to have the most significant relationship to sleep quality.

Sleep-related electrodermal activity patterns in impotent patients

Abstract: The etiology of erectile failure is not always clear despite the fact that recordings of nocturnal penile tumescence (NPT) are used to detect patients with a significant organic component to their complaint. We recorded electrodermal activity in addition to NPT in 60 impotent patients. Normally more electrodermal activity occurs in stage 2 than in stage REM sleep. Despite a similar total amount of electrodermal activity, organically impotent patients tended to have less electrodermal activity in stage 2 and more in stage REM sleep than those with normal NPT. This difference was due to a subgroup of 15 organically impotent patients with less electrodermal activity in stage 2 than in stage REM sleep. Because of this difference in the pattern of electrodermal activity in relation to sleep stages, the results suggest a central nervous system change is related to impaired erectile capability and abnormal NPT in these cases.