Proposed supplements and amendments to 'A Manual of Standardized Terminology, Techniques and Scoring System for Sleep Stages of Human Subjects', the Rechtschaffen & Kales (1968) standard

The respiratory response to inspiratory resistive loading during rapid eye movement sleep in humans

We investigated the respiratory response to an added inspiratory resistive load (IRL) during rapid eye movement (REM) sleep in humans and compared this with those in non-REM (NREM) sleep and wakefulness. Results were obtained from 7 out of 15 healthy subjects (n = 7; 32 +/- 9 years, mean +/- s.d.). Linearised IRLs (4 and 12 cmH(2)O l(-1) s(-1)) were applied for five breaths during NREM sleep (4-10 trials per subject; total 101), REM sleep (2-5 trials; total 46) and wakefulness (2-3 trials; total 40). Respiratory variables were compared, between unloaded breathing (UL: mean of 5 breaths preceding IRL) and the 1st (B1) and 5th (B5) loaded breaths in each state. During wakefulness, 12 cmH(2)O l(-1) s(-1) IRL produced an immediate respiratory compensation with prolongation of inspiratory time (T(I); UL: 2.0 +/- 0.6; B1: 2.6 +/- 0.7 s) and an increase in tidal volume (V(T); UL: 0.49 +/- 0.12; B1: 0.52 +/- 0.12 l). During REM sleep, T(I) was prolonged (UL: 2.0 +/- 0.3; B1: 2.2 +/- 0.5 s), although V(T) fell (UL: 0.27 +/- 0.15; B1: 0.22 +/- 0.10 l). For both wakefulness and REM sleep the TI response was significantly greater than seen in NREM sleep (UL: 1.9 +/- 0.3; B1: 1.9 +/- 0.3 s.). For VT, only the wakefulness response was significantly different from NREM sleep (UL: 0.31 +/- 0.14; B1: 0.21 +/- 0.10 l). The B5 responses were not significantly different between states for any of the variables. REM sleep is associated with partial respiratory load compensation suggesting that exacerbation of sleep disordered breathing in REM (compared to NREM) sleep is unlikely to be secondary to an inability to overcome increases in upper airway resistance.

Effects of an experimentally induced rhinovirus cold on sleep, performance, and daytime alertness

STUDY OBJECTIVES

There is accumulating evidence that the common cold produces impairments in psychomotor vigilance. This has led some investigators to hypothesize that such illnesses may also have disruptive effects on sleep. While several self-report studies suggest that viral illness may influence sleep parameters, no studies have assessed polysomnographically recorded sleep following viral infections.

DESIGN

Parallel control group comparison.

SETTING

Sleep laboratory in a large urban medical center.

PARTICIPANTS

Twenty-one men and women with susceptibility to the rhinovirus type 23.

INTERVENTIONS

Nasal inoculation with rhinovirus type 23.

MEASUREMENTS

Polysomnographically recorded sleep for five nights (2300-0700 h) post-viral inoculation. Twice daily (1030 and 1430 h) performance assessment during each experimental day using auditory vigilance and divided attention tasks. A multiple sleep latency test (MSLT) was performed daily for the duration of the study.

RESULTS

In symptomatic individuals, total sleep time decreased an average of 23 min, consolidated sleep decreased an average of 36 min, and sleep efficiency was reduced by an average of 5% during the active viral period (experimental days/nights 3-5) compared with the incubation period. Psychomotor performance was impaired. These changes were significantly greater than those observed in asymptomatic individuals.

CONCLUSIONS

The common cold can have detrimental effects on sleep and psychomotor performance in symptomatic individuals during the initial active phase of the illness.

Activity of midbrain reticular formation and neocortex during the progression of human non-rapid eye movement sleep

To clarify the neural correlates and brain activity during the progression of human non-rapid eye movement (NREM) sleep, we examined the absolute regional cerebral blood flow (rCBF) during light and deep NREM sleep and during wakefulness in normal humans using positron emission tomography with H(2)(15)O. Relative changes in rCBF during light and deep NREM sleep in comparison to the rCBF during wakefulness were also analyzed. During light NREM sleep, the rCBF in the midbrain, in contrast to that in the pons and thalamic nuclei, did not decrease when compared to that during wakefulness, whereas rCBF decreased in the left medial frontal gyrus, left inferior frontal gyrus, and left inferior parietal gyrus of the neocortex. During deep NREM sleep, the rCBF in the midbrain tegmentum decreased, and there was a marked and bilateral decrease in the rCBF in all neocortical regions except for the perirolandic areas and the occipital lobe. There have been three groups of brain structures, each representing one type of deactivation during the progression of NREM sleep. The activity of the midbrain reticular formation is maintained during light NREM sleep and therefore represents a key distinguishing characteristic between light and deep NREM sleep. Selective deactivation of heteromodal association cortices, including those related to language, occurs with increasingly deep NREM sleep, which supports the recent theory that sleep is not a global, but it is a local process of the brain.

Ageing and the circadian and homeostatic regulation of human sleep during forced desynchrony of rest, melatonin and temperature rhythms

1. The circadian timing system has been implicated in age-related changes in sleep structure, timing and consolidation in humans. 2. We investigated the circadian regulation of sleep in 13 older men and women and 11 young men by forced desynchrony of polysomnographically recorded sleep episodes (total, 482; 9 h 20 min each) and the circadian rhythms of plasma melatonin and core body temperature. 3. Stage 4 sleep was reduced in older people. Overall levels of rapid eye movement (REM) sleep were not significantly affected by age. The latencies to REM sleep were shorter in older people when sleep coincided with the melatonin rhythm. REM sleep was increased in the first quarter of the sleep episode and the increase of REM sleep in the course of sleep was diminished in older people. 4. Sleep propensity co-varied with the circadian rhythms of body temperature and plasma melatonin in both age groups. Sleep latencies were longest just before the onset of melatonin secretion and short sleep latencies were observed close to the temperature nadir. In older people sleep latencies were longer close to the crest of the melatonin rhythm. 5. In older people sleep duration was reduced at all circadian phases and sleep consolidation deteriorated more rapidly during the course of sleep, especially when the second half of the sleep episode occurred after the crest of the melatonin rhythm. 6. The data demonstrate age-related decrements in sleep consolidation and increased susceptibility to circadian phase misalignment in older people. These changes, and the associated internal phase advance of the propensity to awaken from sleep, appear to be related to the interaction between a reduction in the homeostatic drive for sleep and a reduced strength of the circadian signal promoting sleep in the early morning.

Arousal from sleep shortens sympathetic burst latency in humans

1. Bursts of sympathetic activity in muscle nerves are phase-locked to the cardiac cycle by the sinoaortic baroreflexes. Acoustic arousal from non-rapid eye movement (NREM) sleep reduces the normally invariant interval between the R-wave of the electrocardiogram (ECG) and the peak of the corresponding sympathetic burst; however, the effects of other forms of sleep disruption (i.e. spontaneous arousals and apnoea-induced arousals) on this temporal relationship are unknown. 2. We simultaneously recorded muscle sympathetic nerve activity in the peroneal nerve (intraneural electrodes) and the ECG (surface electrodes) in seven healthy humans and three patients with sleep apnoea syndrome during NREM sleep. 3. In seven subjects, burst latencies were shortened subsequent to spontaneous K complexes (1.297 +/- 0.024 s, mean +/- s. e.m.) and spontaneous arousals (1.268 +/- 0.044 s) compared with latencies during periods of stable NREM sleep (1.369 +/- 0.023 s). In six subjects who demonstrated spontaneous apnoeas during sleep, apnoea per se did not alter burst latency relative to sleep with stable electroencephalogram (EEG) and breathing (1.313 +/- 0.038 vs. 1.342 +/- 0.026 s); however, following apnoea-induced EEG perturbations, burst latencies were reduced (1.214 +/- 0.034 s). 4. Arousal-induced reduction in sympathetic burst latency may reflect a temporary diminution of baroreflex buffering of sympathetic outflow. If so, the magnitude of arterial pressure perturbations during sleep (e.g. those caused by sleep disordered breathing and periodic leg movements) may be augmented by arousal.

The effect of rapid eye movement (REM) sleep on upper airway mechanics in normal human subjects

1. It has been proposed that the upper airway is more compliant during rapid eye movement (REM) sleep than during non-rapid eye movement (NREM) sleep. The purpose of this study was to test this hypothesis in a group of subjects without sleep-disordered breathing. 2. On the first night, the effect of sleep stage on the relationship of retropalatal cross-sectional area (CSA; visualized with a fibre-optic scope) to pharyngeal pressure (PPH) measured at the soft palate during eupnoeic breathing was studied. Breaths during REM sleep were divided into phasic (associated with eye movements) and tonic (not associated with eye movements). There was a significant decrease in pharyngeal CSA during NREM sleep compared with wakefulness. There was no further decrease observed during either tonic or phasic REM sleep. Pharyngeal compliance, defined as the slope of the regression CSA versus PPH, was significantly increased during NREM sleep compared with wakefulness and REM sleep, with the compliance during both tonic and phasic REM sleep being similar to that observed in wakefulness. 3. On the second night, the effect of sleep stage on pressure-flow relationships of the upper airway was investigated. There was a trend towards the upper airway resistance being highest in NREM sleep compared with wakefulness and REM sleep. 4. We conclude that the upper airway is stiffer and less compliant during REM sleep than during NREM sleep. We postulate that this difference is secondary to differences in upper airway vascular perfusion between REM and NREM sleep.

Structure of nocturnal sleep in patients with cerebral insult

The aim of the present work was to study the structure of nocturnal sleep in patients who had sustained brain insults, and to relates sleep structure to the stage of disease and the location of the focal lesion. Studies were performed on 18 patients with ischemic insult, 8 affected in the right hemisphere, 6 affected in the left hemisphere, and 4 with brainstem lesions; controls consisted of 5 healthy subjects. Diagnoses were in all cases confirmed by computer tomography. Clinical and neurological studies were performed, along with recording of polygraph traces of nocturnal sleep (electroencephalograms, electrooculograms, electromyograms). Sleep parameters were analyzed using a program developed at the Sleep Studies Center, I. M. Sechenov Moscow Medical Academy; along with standard parameters, this program included analysis of the segmental structure of sleep. Sleep quality-the level of normality or disturbance to its structure-was assessed using a sleep index (SI). Patients showed profound disorganization of nocturnal sleep structure, with disruption of the mechanisms organizing sleep as a whole and generating and maintaining the individual stages. The greatest sleep disturbances were seen in ischemic insult in the right hemisphere and in patients with lesions in medial deep structures.

Instantaneous change in transient shift of sleep stage in response to passing truck noise

The transient effects of passing truck noise on sleep stage shift were examined in fifteen male students aged 19-21 years old for 7 to 11 non-consecutive nights. Shift percentage for proceeding from Stage 2 to shallower stages (Stage 1, waking or movement time) as well as that from Stages 3 to 2, Stage 1, waking or movement time were determined. Change in Stage REM by noise was examined for shift to other stages. The percentage for shallower stages from Stage 2 significantly increased by exposure to 45, 50, 55 and 60 dBA noise compared to the non-exposed control, though this was not observed in Stage REM. The percentage of shift to shallower stages from Stage 3 significantly increased at 50, 55 and 60 dBA noise compared to the control. The minimum effective sound level for the percentage of shift to shallower stages from Stage 2 by the passing truck noise was less than 45 dBA, while that for the percentage of change in Stage REM was greater than 60 dBA and that for the percentage of shift to shallower stages from Stage 3 by the noise was between 45 and 50 dBA. Responses to noise exposure in Stage REM was less sensitive than in Stage 3.

A normative study of the maintenance of wakefulness test (MWT)

The maintenance of wakefulness test (MWT) is a daytime polysomnographic procedure which quantifies wake tendency by measuring the ability to remain awake during soporific circumstances. We present normative data based on 64 healthy subjects (27 males and 37 females) who adhered to uniform MWT procedural conditions including polysomnographic montage, illuminance level, seating position, room temperature, meal timing, and subject instructions. When allowed a maximum trial duration of 40 min, subjects' mean sleep latency to the first epoch of sustained sleep was 35.2 +/- 7.9 min. The lower normal limit, defined as two standard deviations below the mean, was 19.4 min. Calculation of data on the basis of a maximum trial duration of 20 min and sleep latency to the first appearance of brief sleep (a microsleep episode or one epoch of any stage of sleep) yielded a mean sleep latency of 18.1 +/- 3.6 min and a lower normal limit of 10.9 min. Sleep latency scores were significantly higher than those previously reported in patients with disorders of excessive somnolence. Therefore, the MWT appears to be a useful procedure in differentiating groups with normal daytime wake tendency from those with impaired wake tendency and in identifying individuals with pathologic inability to remain awake under soporific circumstances.

The sleep of long-haul truck drivers

BACKGROUND

Fatigue and sleep deprivation are important safety issues for long-haul truck drivers.

METHODS

We conducted round-the-clock electrophysiologic and performance monitoring of four groups of 20 male truck drivers who were carrying revenue-producing loads. We compared four driving schedules, two in the United States (five 10-hour trips of day driving beginning about the same time each day or of night driving beginning about 2 hours earlier each day) and two in Canada (four 13-hour trips of late-night-to-morning driving beginning at about the same time each evening or of afternoon-to-night driving beginning 1 hour later each day).

RESULTS

Drivers averaged 5.18 hours in bed per. day and 4.78 hours of electrophysiologically verified sleep per day over the five-day study (range, 3.83 hours of sleep for those on the steady 13-hour night schedule to 5.38 hours of sleep for those on the steady 10-hour day schedule). These values compared with a mean (+/-SD) self-reported ideal amount of sleep of 7.1+/-1 hours a day. For 35 drivers (44 percent), naps augmented the sleep obtained by an average of 0.45+/-0.31 hour. No crashes or other vehicle mishaps occurred. Two drivers had undiagnosed sleep apnea, as detected by polysomnography. Two other drivers had one episode each of stage 1 sleep while driving, as detected by electroencephalography. Forty-five drivers (56 percent) had at least 1 six-minute interval of drowsiness while driving, as judged by analysis of video recordings of their faces; 1067 of the 1989 six-minute segments (54 percent) showing drowsy drivers involved just eight drivers.

CONCLUSIONS

Long-haul truck drivers in this study obtained less sleep than is required for alertness on the job. The greatest vulnerability to sleep or sleep-like states is in the late night and early morning.

Regional cerebral blood flow changes as a function of delta and spindle activity during slow wave sleep in humans

In the present study, we investigated changes in regional cerebral blood flow (rCBF) in humans during the progression from relaxed wakefulness through slow wave sleep (SWS). These changes were examined as a function of spindle (12-15 Hz) and delta (1.5-4.0 Hz) electroencephalographic (EEG) activity of SWS. rCBF was studied with positron emission tomography (PET) using the H215O bolus method. A maximum of six 60 sec scans were performed per subject during periods of wakefulness and stages 1-4 of SWS, as determined by on-line EEG monitoring. Spectral analysis was performed off-line on the EEG epochs corresponding to the scans for computation of activity in specific frequency bands. The relationship between EEG frequency band activity and normalized rCBF was determined by means of a voxel-by-voxel analysis of covariance. delta activity covaried negatively with rCBF most markedly in the thalamus and also in the brainstem reticular formation, cerebellum, anterior cingulate, and orbitofrontal cortex. After the effect of delta was removed, a significant negative covariation between spindle activity and the residual rCBF was evident in the medial thalamus. These negative covariations may reflect the disfacilitation and active inhibition of thalamocortical relay neurons in association with delta and spindles, as well as the neural substrates underlying the progressive attenuation of sensory awareness, motor responsiveness, and arousal that occur during SWS. delta activity covaried positively with rCBF in the visual and auditory cortex, possibly reflecting processes of dream-like mentation purported to occur during SWS.

Pharyngeal wall vibration detection using an artificial neural network

An artificial-neural-network-based detector of pharyngeal wall vibration (PWV) is presented. PWV signals the imminent occurrence of obstructive sleep apnoea (OSA) in adults who suffer from OSA syndrome. Automated detection of PWV is very important in enhancing continuous positive airway pressure (CPAP) therapy by allowing automatic adjustment of the applied airway pressure by a procedure called automatic positive airway pressure (APAP) therapy. A network with 15 inputs, one output, and two hidden layers, each with two Adaline-nodes, is used as part of a PWV detection scheme. The network is initially trained using nasal mask pressure data from five positively diagnosed OSA patients. The performance of the ANN-based detector is evaluated using data from five different OSA patients. The results show that on the average it correctly detects the presence of PWV events at a rate of approximately 92% and correctly distinguishes normal breaths approximately 98% of the time. Further, the ANN-based detector accuracy is not affected by the pressure level required for therapy.

Functional neuroanatomy of human slow wave sleep

The distribution of regional cerebral blood flow (rCBF) was estimated during sleep and wakefulness by using H215O positron emission tomography (PET) and statistical parametric mapping. A group analysis on 11 good sleepers (8 with steady slow wave sleep, SWS) showed a significant negative correlation between the occurrence of SWS and rCBF in dorsal pons and mesencephalon, thalami, basal ganglia, basal forebrain/hypothalamus, orbitofrontal cortex, anterior cingulate cortex, precuneus, and, on the right side, in a region that follows the medial aspect of the temporal lobe. Given the known decrease in global cerebral blood flow levels during SWS, these negative correlations suggest that rCBF is decreased significantly more in these cerebral areas than in the rest of the brain. The marked rCBF decreases in the pons, mesencephalon, thalamic nuclei, and basal forebrain reflect their close implication in the generation of SWS rhythms. The influence of these rhythms on the telencephalon usually are thought to be global and homogeneous. In contrast, our results show that rCBF is decreased more in some cortical areas (especially in orbitofrontal cortex) than in the rest of the cortex. We hypothesize that cellular processes taking place during SWS might be modulated differently in these regions. Given the functions of the ventromedial frontal areas, we surmise that SWS might be particularly critical for the adaptation of behavior to environmental pressures. This hypothesis is supported indirectly by results of sleep deprivation experiments.

Relationship between self-rating and polygraphic sleep parameters - analysis of compiled data from 12 young Japanese adults -

An examination of the relationship of the self-rating sleep score to polygraphic sleep parameters was conducted. The self-rating sleep questionnaire, OSA, includes five sleep quality factors: sleepiness (Fl), sleep maintenance without interruption (F2), worry about daily life or poor emotional condition (F3), integrated or perceived sleep feeling (F4) and sleep initiation or induction (F5). Polygraphic sleep parameters including each sleep stage in minutes were used. If intercorrelation coefficients exceeded 0.8, only one of the related parameters was selected for multivariate analysis. Twelve male students slept a total of 88 nights, among which the first night was not included, in an experimental room. When absolute values of Spearman's rank correlation coefficient of not less than 0.4 were tentatively selected, the following pairs were extracted: F2 score and S1 (-0.423) or S3+S4 (0.409), F5 score and sleep latency (-0.439). Deeper sleep was closely associated with sleep maintenance without interruption. Agreement between self-rating and a polygraphic sleep parameter was recognized between the F5 score and sleep latency. Each OSA factor score was predicted by other polygraphic sleep parameters using multiple regression analysis. MT significantly contributed to the Fl, F3 and F4 scores. The number of stage shifts per night significantly contributed to the Fl and F3 scores, and the number of sleep spindles significantly contributed to the F5 score. Though prediction of sleep quality by polygraphic sleep parameters is limited, the association between concrete subjective and objective sleep parameters was clarified as mentioned above, and their practical meaning was partially elucidated.

Prevalence of sleep-disordered breathing in ages 40-64 years: a population-based survey

Previous research has offered widely varying prevalence estimates for sleep apnea in the population, leaving uncertain which breathing patterns are abnormal. To explore the distribution of sleep apnea in the population and its co-morbidities, random telephone dialing was used between 1990 and 1994 to recruit subjects for a prevalence survey of sleep-disordered breathing in San Diego adults. Events from which blood oxygen desaturations > or = 4% resulted were monitored with home recording instruments, usually for three consecutive nights. Among 190 women ages 40-64 years, a median of 4.3 desaturation events per hour of sleep were observed. A higher median of 6.7 events per hour was observed among 165 men. Frequencies were much higher among members of minority groups, leading to a standard estimate that 16.3% of U.S. Hispanics and racial minorities have > or = 20 events/hour as compared to 4.9% of non-Hispanic Whites ages 40-64. Obesity indicated by body-mass index was the most important demographic predictor of sleep-disordered breathing, followed by age, male gender, and ethnicity. Quality of well-being was not significantly impaired in subjects with more respiratory events; however, there was some increase in blood pressure and wake-within-sleep associated with sleep-disordered breathing. This survey indicates that sleep-disordered breathing is more common, especially among minorities, than had been previously believed, but less co-morbidity may be associated.

Hypersomnia in association with dysthymia in comparison with idiopathic hypersomnia and normal controls

Polysomnographic studies in hypersomniac patients with mood disorders are rare. Previous studies investigated patients with a severe mood disorder, but our study was done in patients with dysthymia, who complained of sleepiness. Mean sleep latency test (MSLT) and continuous polysomnographic recording (CPR) were done in 12 dysthymic patients, in comparison with 12 idiopathic hypersomnia patients, and 12 normal controls. In dysthymic patients mean sleep latency on the MSLT (13 +/- 1) was normal, and when CPR was done during 24 hours, no hypersomnia was found (553 +/- 24). Dysthymic patients showed an abnormal macrostructure of sleep (characterised by an excess of sleep stage I and a decrease of stages 3 and 4), which could be related to their complaint of hypersomnia.

Hypnotic self administration and dose escalation

The dependence liability of benzodiazepines in the context of their use as hypnotics (i.e. by insomnia patients as pre-sleep medications) is unresolved. A recent study found that insomniacs self administer capsules at bedtime at a high rate, with triazolam (0.25 mg) taken as often as placebo. This study sought to determine if differential self administration would develop when multiple capsules are available nightly. Eighteen men and women, age 21-45 years, with insomnia complaints (nine with objective sleep disturbance and nine without) were studied, 1 week with placebo and 1 week with triazolam (0.25 mg). The two conditions were administered double-blind and presented in a counter-balanced order with a week between conditions. In each condition, after 3 consecutive sampling nights of the available single capsule for that condition, subjects could self administer 0-3 capsules before bed on the 4 subsequent nights. Triazolam was self administered as many nights as placebo, but the number of placebo capsules self administered was twice that of triazolam capsules. The objective insomniacs self administered more capsules than the subjective insomniacs and neither group differentially choose triazolam over placebo. The number of triazolam capsules taken nightly was stable and the number of placebo capsules variable. It is concluded that insomniacs show no short-term escalation of triazolam dose, but do choose an increased and variable number of placebos, a pattern which is interpreted as being insomnia relief-seeking behavior.

The effects of acute and chronic exercise on sleep. A meta-analytic review

Studies attempting to ascertain the effects of acute and chronic exercise on measures of sleep have yielded conflicting results and interpretations. Methodological differences among studies may explain this lack of consensus; however, small sample sizes and subsequently low statistical power may also have contributed. In an attempt to resolve these issues, this review used meta-analytical techniques to: (a) re-examine the effects of exercise on sleep; and (b) examine possible moderators of these effects. Studies meeting the selection criteria were included in the analysis. Analyses of moderating factors were performed for stage 4 sleep and rapid eye movement (REM) sleep. The results indicated that acute and chronic exercise increased slow wave sleep (SWS) and total sleep time but decreased sleep onset latency and REM sleep. Moderating variables influencing the magnitude and direction of these effects were related to characteristics of the individual (e.g. sex, age, fitness level) and the exercise (e.g. time of day exercise was completed, type of exercise, exercise duration). Mechanisms which have been suggested to explain the relationship between exercise and sleep are discussed and directions for further research are provided.

Methods of testing for sleepiness [corrected]

Normal nonrandom fluctuation in daily human performance have been documented for years. Published research reports have shown patterns of workers' errors in reading gas meters, operators' delays in answering calls, drivers' drowsiness, sleepy locomotive engineers' automatic breaking, vehicle crashes, deaths resulting from disease, brief periods of sleep, and sleep latency in structured naps. The authors summarized these data sets and fitted them with a two-peak-per-day cosine curve derived from the population growth function used in chaos theory. Median parameters extracted from the curve fits predicted a sharp peak of sleepiness at 2:30 AM and a secondary peak at 2:30 PM. The shape of the curve was modified by a nonlinear sleep-deprivation factor. The model appeared to be biological rather than behavioral or social because it applied well to disease-related deaths. The authors also review measurement of sleepiness through electroencephalographic monitoring, self-reports, pupillography, and the Multiple Sleep Latency and the Maintenance of Wakefulness Tests.

Effects of chronic treatment with methadone and naltrexone on sleep in addicts

Previous studies have described sleep disturbance secondary to chronic opiate use and abuse. Drug-dependency insomnia is of interest because chronic sleep disturbances can promote depressive symptoms which could lead to a drug relapse. For the first time we compared the polysomnographic parameters of 10 methadone-substituted outpatients and 10 naltrexone-treated outpatients. Methadone (mu-opioid agonist) produced a marked fragmentation of the sleep architecture with frequent awakenings and a decrease in EEG arousals. In comparison with methadone and controls, the naltrexone (mu-opioid antagonist) group showed the shortest sleep latency and the longest total sleep time. These data indicate that mu-agonists and mu-antagonists have different effects on sleep. The implications, especially the involvement of opioid-dopamine interactions on sleep and movements during sleep, are discussed.

Effects of transderman nicotine on mood and sleep in nonsmoking major depressed patients

The role of nicotine as an indirect cholinergic agent in sleep has been studied in normal subjects. There are no studies of its effects on sleep in depressed patients. Nicotine transdermal patches (17.5 mg), were studied in eight depressed patients (DSM-III-R) and eight normal volunteers. Subjects wore placebo and nicotine patches for 24 h. Depressed patients showed increased REM sleep without changes in other sleep variables. They also showed a short term improvement of mood. Normal volunteers had sleep fragmentation, and reduction of REM sleep time. No major side effects were reported in either group.

Effects of daytime administration of zolpidem versus triazolam on memory

To determine whether zolpidem (an imidazopyridine hypnotic) produces amnestic effects which are similar to those produced by triazolam (a benzodiazepine hypnotic), 70 subjects were administered either triazolam (0.125, 0.25, or 0.5 mg), zolpidem (5, 10, or 15 mg) or placebo, then tested on Simulated Escape, Restricted Reminding, and Paired-Associates memory tests at 1.5 hours post-dosing (i.e., near the time of estimated peak blood concentration for both drugs) and again at 6 hours post-dosing. Triazolam 0.5 mg produced the greatest memory impairment at both test times, and also produced the greatest degree of sedation during intervening daytime naps in a non-sleep-conducive environment. Other doses of triazolam and zolpidem produced less memory impairment, but also failed to significantly enhance sleep. The results are consistent with the view that the amnestic and hypnotic effects of these sleep-inducing medications are functionally coupled.

Inhibition of REM sleep by ipsapirone, a 5HT1A agonist, in normal volunteers

In order to test the hypothesis that serotonergic mechanisms inhibit REM sleep via a 5HT1A receptor, we administered placebo and ipsapirone (10 and 20 mg by mouth 15 min before bedtime) to ten normal volunteers in a double blind fashion. Ipsapirone is a relatively selective 5HT1A receptor agonist. As predicted, ipsapirone prolonged REM latency and Mean Latency to Eye Movements (M-LEM), a measure of time between onset of REM sleep and the first eye movement of the REM period, and REM% at both doses compared with placebo. It also reduced sleep efficiency and total REM sleep time at the highest dose. These results support the hypothesis that systemic stimulation of 5HT1A receptors prolong REM latency and inhibit REM sleep.

Effect of a single dose (10 mg) of zolpidem on visual and spectral analysis of sleep in young poor sleepers

Four non-consecutive nights of sleep were recorded in eight young volunteers complaining of chronic poor sleep. The subjects received a placebo or a 10 mg zolpidem dose prior to bedtime according to a Latin square double-blind design. All-night spectral analyses of the Cz-Pz lead were associated to the standard polysomnography. According to the visual scoring performed with the Rechtschaffen and Kales criteria, zolpidem significantly increased the stage 4 amount and reduced waking. Compared to placebo no difference in sleep stages was observed when the scoring was based on the power in the 0.7 to 4-Hz band. In zolpidem nights power was significantly reduced in the 4 to 8-Hz band during NREM (stages 2, 3 and 4) and was increased in the 2 to 4-Hz band during REM sleep. A significant reduction of fast activities over 12 Hz was observed during the first 3 h of sleep. Concerning slow wave activity, the only change noted was a significant slowing of its build-up rate at the beginning of cycle 1.

Sedative, memory, and performance effects of hypnotics

The sedative, amnestic, and performance disruptive effects of benzodiazepine (Bz) receptor selective and non-selective hypnotics were studied in 23 healthy, normal subjects, aged 26.8 +/- 1.0 years. Triazolam (0.25 and 0.50 mg), zolpidem (10 and 20 mg) and placebo were administered, double-blind, at bedtime in a repeated measures design. During an awakening 90 min later (at approximate peak concentration of each drug) a 30-min performance battery which included memory, vigilance, and psychomotor tasks was completed. Each drug and dose impaired memory (both immediate and delayed), vigilance, and psychomotor performance relative to placebo. Among active drugs impairment was greatest with zolpidem 20 mg, next triazolam 0.50 mg, then zolpidem 10 mg, and finally triazolam 0.25 mg. Next morning delayed recall was also impaired by all drugs and doses (i.e. anterograde amnesia). The amnestic and performance-disruptive effects paralleled the relative hypnotic effects of the drugs and doses. No receptor selectivity in these pharmacodynamic effects was observed.

Sleep EEG of patients with obsessive-compulsive disorder

Twenty-two patients suffering from an obsessive and compulsive disorder (OCD) according to DSM-III-R were investigated by polysomnographic sleep EEG recordings under drug-free conditions and compared to age- and sex-matched healthy controls. Sleep efficiency was significantly lower and wake % SPT was significantly increased in the patient group compared to healthy subjects. Sleep architecture did not differ among the two samples. Especially REM sleep measures, in particular, REM latency did not differ among the groups. No positive correlation was found between sleep variables and rating inventories for obsession and compulsions (Y-BOCS), depression (Hamilton) and anxiety (CAS). A secondary depression did not influence sleep EEG variables. The results of this study contradict the assumption that OCD patients show REM sleep and slow wave sleep abnormalities similar to those shown by patients with primary depression.

Flumazenil exerts intrinsic activity on sleep EEG and nocturnal hormone secretion in normal controls

The physiological function of benzodiazepine (BDZ) receptors includes regulation of sleep and neuroendocrine activity. Most of the pharmacological effects of BDZ are blocked by flumazenil. However, recent neurological and behavioral studies suggest that flumazenil has its own central intrinsic activity. This issue was addressed in a study of the sleep EEG and the nocturnal secretion of growth hormone and cortisol in ten normal male controls, who were given flumazenil either alone or in combination with the BDZ agonist midazolam, placebo and midazolam alone. Flumazenil prompted an increase in sleep onset latency, a decrease in slow wave sleep and an increase in wakefulness. Plasma cortisol concentrations after flumazenil administration were lower than after midazolam. Both flumazenil and midazolam decreased nocturnal growth hormone secretion. After simultaneous application of both BDZ receptor ligands the growth hormone blunting was amplified. Our study demonstrates that at the level of the sleep EEG and neuroendocrine activity flumazenil is capable of exerting both agonistic and inverse agonistic or antagonistic effects.

Beneficial effect of inhaled CO2 in a patient with non-obstructive sleep apnoea

A 63-year-old man with severe non-obstructive sleep apnoea (apnoea index 28; apnoea duration 45-60s; O2 saturation between 72% and 98%), who did not respond to common modes of treatment, was successfully treated with CO2. A tent was perfused with compressed air (6 1/min) and increasing amounts of CO2. A concentration of 3% CO2 (180 ml/min) was sufficient to raise the PaCO2 above apnoea threshold and to suppress apnoeas completely. As a result, O2 saturation remained normal throughout the whole night and the symptoms of sleep apnoea disappeared. We hypothesize that the PCO2 ventilatory drive was intact in our patient and that hypocapnia was the major factor causing the non-obstructive sleep apnoea syndrome. Administration of CO2 with a constant flow system could be a safe and easy alternative for patients with non-obstructive sleep apnoea syndrome who present with hypocapnia and an intact respiratory feedback control system.

Evaluation of human consciousness level by means of "Automated Fluctuation Analysis" of high frequency electroencephalogram fitted by double Lorentzians

Since Berger's discovery of the electroencephalogram (EEG), its analysis has been generally restricted to the visual range (upmost 100Hz) and has ignored higher frequency components. One reason should be that there are no reliable methods to distinguish the brain potentials from muscle activity. We have introduced fluctuation analysis, which is popular method especially in the field of basic physiology to clinical electrophysiology. In our previous study, it was declared that power spectral density (PSD) of human high frequency EEG was composed of double Lorentzians and vanished into white level within 1kHz. Then the purpose of this study is to elucidate the "Automated Fluctuation Analysis," which enables us to evaluate these higher frequency components and its physiological meaning especially focused on conscious level from wakefulness to sleep stage 1. Seventy-four scalp recording EEGs in twenty normal subjects were studied. In short, "Automated Fluctuation Analysis" is made of three steps: amplification of EEG signal, A/D conversion and Fast Fourier Transform by signal processor and extraction of Lorentzian parameters. PSD of high frequency EEG was displayed on log-log graph and the algorithm fit to the following Lorentzian formula were mathematically based on Brown & Dennis. S(f) = S1/[1+(f/fc1)2]+S2/[1+(f/fc2)2], where S(f) is PSD (mu V2/Hz) at each frequency (f;Hz), S1 and S2 are the plateau level or zero-frequency power of the initial and second Lorentz, and fc1 and fc2 are the corner or half-power frequency of the initial and second Lorentz, respectively. As results, during wakefulness the PSD of high frequency EEG activity was composed of double Lorentzian fluctuations and the power distribution of S1 value in topographical display was frontal dominant. This pattern of S1 value disappeared and S2 value became lower during sleepiness and the second Lorentz disappeared during sleep.

Diabetes mellitus and male sexual function: a controlled study

There is an extensive clinical literature on the erectile disorders of diabetic men but a paucity of controlled studies that have taken into account the effects of age, concurrent illnesses and medication on sexual function. This investigation was carried out on 40 diabetic men free from other illness or drugs that could affect sexual capacity and 40 age-matched healthy control subjects. Each subject and his female partner underwent semistructured interviews and the men had comprehensive medical evaluations and polygraphic assessment of sleep and nocturnal penile tumescence in the sleep laboratory during three nights. In comparison to control subjects, diabetic patients reported significant decreases in sexual desire, subjective arousal, erectile capacity, coital frequency and sexual satisfaction. The diabetic group also had significant decrements in duration of rapid eye movement sleep and in frequency, duration and degree of nocturnal penile tumescent episodes. There were no differences between Type 1 (insulin-dependent) and Type 2 (non-insulin dependent) diabetic patients in prevalence of sexual problems or in nocturnal tumescent measures. Significant relations were observed between lack of metabolic control, diabetic complications and impaired nocturnal tumescence. Sexually non-dysfunctional diabetic men had significant nocturnal penile tumescence abnormalities. Diabetic men without coital failures may have a subclinical impairment in erectile function which, although of not significant magnitude to interfere with penetration, is reflected in nocturnal penile tumescent measures. This result raises a note of caution in the interpretation of the nocturnal penile tumescence test for the differential diagnosis of diabetic erectile impotence.

Effect of bedtime ethanol on total inspiratory resistance and respiratory drive in normal nonsnoring men

We have previously reported that bedtime ethanol (2.0 ml/kg of 100 proof vodka) increases upper airway closing pressure in males who habitually snored but were otherwise healthy. We also observed that some of these snorers developed obstructive apneas. To explore this phenomenon in more detail, we measured the inspiratory resistance (RI) and respiratory drive after bedtime ethanol in 10 nonobese men (ages 23 to 33) with no history of snoring. Subjects went to bed wearing a tightly fitting valved mask over the nose and mouth that allowed measurement of inspiratory and expiratory flow, pressure in the mask, and endtidal CO2. We measured RI by calculating the pressure difference between the mouth and a balloon positioned in the midesophagus. Respiratory drive was quantified by the inspiratory occlusion pressure (P0.1), the ventilatory response to hyperoxic hypercapnia (delta VE/delta PETCO2), and the ventilatory response to isocapnic hypoxia (delta VE/delta SaO2). Measurements were made during waking and during stage 2 NREM sleep on two nights: (1) when the subjects drank 1.5 ml/kg of 100 proof vodka in orange juice over a 30-min period 15-45 min before lights out and (2) when the orange juice contained less than 0.1 ml of vodka floating on the top. Eight of the nine men in whom we had technically adequate measurements showed a rise in RI during NREM sleep above the waking level on both control and ethanol nights and the sleeping RI was greater on the ethanol than on the control night.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in sleep polygraphic variables and clinical state in depressed patients during treatment with citalopram

Drug-induced improvement of depression may be mediated by changes in sleep physiology. The aim of this study was to relate changes in sleep polygraphic variables to clinical state during treatment with citalopram, a highly specific serotonin uptake inhibitor. Sixteen patients took part. The study was single-blind and uncontrolled. A 1-week wash-out period was followed by 1 week of placebo administration, a medication period of 5 weeks, and a 1-week placebo period. For the entire group a significant decrease of rapid eye movement sleep (REMS) and a significant lengthening of REMS latency were observed initially as well as at the end of treatment. No changes in sleep continuity were found, but non-REMS stage 2 (percentage) was significantly increased. On the basis of clinical change, as expressed by the scores of the Hamilton Rating Scale for Depression, at the end of the citalopram treatment the patient group was split in two halves: eight less and eight more improved patients. The groups did not differ with respect to any sleep polygraphic variable.

Cognitive function in type 1 (insulin-dependent) diabetic patients after nocturnal hypoglycaemia

Eight Type 1 (insulin-dependent) diabetic patients with no diabetic complications were studied on two consecutive and one subsequent overnight occasions. The aim was to evaluate the influence of nocturnal hypoglycaemia on neuropsychological and reaction time tests the following morning. Hypoglycaemia was induced by i.v. insulin infusion, blood glucose nadir was 1.5 +/- 0.3 mmol/l. Duration of hypoglycaemia (blood glucose less than 3 mmol/l) was 101 +/- 38 min. Whole night sleep statistics for all patients showed no statistical differences between the normoglycaemic and hypoglycaemic nights, however, there was a tendency of prolongation of the second sleep cycle in the nights with hypoglycaemia. Each patient was used as his own control and periods with blood glucose concentration less than 3 mmol/l were compared to exactly the same periods in nights with blood glucose level over 5 mmol/l. During hypoglycaemia the amount of deep sleep was reduced and replaced by superficial sleep and arousals of short duration. Further, the reduction in deep sleep was replaced later at night. Neuropsychological test scores and reaction time measurements in the morning showed no differences between the normoglycaemic and hypoglycaemic nights.

IN CONCLUSION

despite sleep disturbances, nocturnal hypoglycaemia did not impair cognitive function the following morning in Type 1 (insulin-dependent) diabetic patients.

Rebound insomnia and hypnotic self administration

Twenty-one (three groups of seven), men and women, 25-50 years of age were studied to determine whether or not rebound insomnia would increase the likelihood of self administering a benzodiazepine (triazolam 0.25 mg) hypnotic. The groups compared were patients with insomnia and disturbed sleep, insomnia and normal sleep, and healthy normals. Rebound insomnia, by both subjective and polysomnographic assessment, was induced. The experience of rebound insomnia did not increase the likelihood of self administering a benzodiazepine hypnotic in any of the groups. There were clear group differences in pill self administration with normals rarely and insomnia patients frequently, but not differentially (placebo versus active drug) self administering pills.

Influence of continuous positive airway pressure on sleep apnea-related desaturation in sleep apnea patients

To investigate the influence of nasal continuous positive airway pressure (CPAP) on apnea-related desaturation, we compared the sleep apnea-related desaturations obtained during a polysomnographic study before and during nasal CPAP in 15 sleep apnea patients. An individual desaturation curve was determined with a regression analysis by plotting the lowest SaO2 value reached during each apnea against its duration; these data were collected throughout the night. At baseline, we only considered the apneas with a preapneic SaO2 value greater than 90% and a minimal SaO2 value above or equal to 60%. For the CPAP study, the preapneic SaO2 value also had to be within 2% the baseline value for the apneas to be retained. Due to the restriction criteria imposed to characterize apnea-related SaO2 falls, residual apneas still had to be recorded with CPAP. These data were analyzed separately for obstructive apnea for non-rapid eye movement (REM) and REM sleep stages. A desaturation curve was obtained from 10 sec to a variable upper limit that corresponded to the longest apnea duration commonly reached during both baseline and CPAP for a given apnea-type and sleep stage. The individual apnea-related SaO2 fall was characterized by measuring a desaturation area corresponding to the area under the curve. It was expressed in % SaO2/sec of apnea. CPAP reduced the number of apneas per hour of sleep from 37.5 +/- 6.5 (mean +/- SEM) to 14.3 +/- 3.7 (p = 0.001), and improved the whole night SaO2 level as estimated by a cumulative SaO2 curve. The mean apnea duration was reduced from 22.9 +/- 1.5 sec at baseline to 16.8 +/- 0.5 sec during CPAP therapy (p = 0.005). The preapneic SaO2 value was 94.8 +/- 0.3% at baseline and 95.5 +/- 0.2% during CPAP (p = 0.5). The desaturation area decreased from 267 +/- 48% SaO2/sec at baseline to 152 +/- 41% SaO2/sec during CPAP (p less than 0.001). We conclude that CPAP improves the apnea-related desaturation independently of the shortening of apneas and of any difference in the preapneic SaO2 value.

Injurious sleep behavior disorders (parasomnias) affecting patients on intensive care units

There are no previous reports on parasomnias (sleep behavior disorders) affecting patients on intensive care units (ICUs). During 8 years of clinical practice, we evaluated over 200 adults with complaints of injurious, sleep-related behaviors, 20 of whom had ICU admissions while their parasomnias had been active and generally undiagnosed/untreated. Mean age during ICU confinement was 62.8 (+/- SD 13.1) years; 85.0% (17/20) were males. Patients underwent comprehensive clinical examinations along with extensive polysomnographic and audiovisual monitoring (electrooculogram, 9 channel EEG with paper speeds of 15 and 30 mm/sec, electromyogram [submental and 4 limbs], EKG, airflow). The polysomnographic studies were diagnostic for the REM sleep behavior disorder (vigorous dream-enactment during rapid eye movement [REM] sleep) in 85.0% (17/20) of patients, and for night terrors/sleepwalking in 15.0% (3/20). Three groups of parasomnia-ICU relationships were identified: i) Parasomnias originating in ICUs, stroke-induced (n = 3); ii) Admission to ICUs resulting from parasomnia-induced injuries: C2 odontoid process fracture and C3 spinous process fracture with severe concussion (n = 2); iii) Parasomnias in patients admitted to ICUs for various other medical problems (n = 15). Physicians should be thus alerted about the possibility of injurious, but usually treatable, parasomnias in ICU patients.

Effect of zolpidem on sleep and sleep EEG spectra in healthy young men

A single 10 mg dose of zolpidem, an imidazopyridine hypnotic, was administered to young, healthy male volunteers prior to bedtime. The drug reduced REM sleep but did not significantly affect other sleep stages and subjective sleep parameters. All-night spectral analysis of the EEG revealed that power density in nonREM sleep was reduced in the low-frequency range (1.25-2.5 Hz; 5.25-10.0 Hz) and increased in the spindle frequency range (12.25-13.0 Hz). Significant changes in the EEG spectrum were present in the first 4 h of sleep. The pattern of the spectral changes was similar to those induced by other hypnotics that bind to the GABAA/benzodiazepine receptor complex. There were no residual effects of zolpidem on psychomotor performance in the morning, on the self-rated state in the morning and at noon, and on sleep and EEG parameters in the subsequent drug-free night.

Flow-volume curves in obstructive sleep apnea and snoring

The diagnostic value of flow-volume curves for sleep apnea was studied in 32 patients with obstructive sleep apnea, 40 simple snorers, and 30 healthy nonsnorers. A sawtooth appearance of the flow-volume curve was seen in 22 of the sleep apnea patients (69%), 14 of the simple snorers (35%), and 10 of the nonsnorers (33%). The ratio of midexpiratory flow (FEF 50) to midinspiratory flow (FIF 50) was greater than 1 in 6 of the sleep apnea patients (19%), 3 of the simple snorers (8%), and 2 of the nonsnorers (7%). Thus, only the sawtooth sign was more frequently found in sleep apnea patients than in controls (p less than 0.01). Sleep apnea patients with a sawtooth appearance of the flow-volume curve had a higher apnea index (38.7 +/- 22 vs. 21.5 +/- 12.1; p less than 0.01) and lower nocturnal minimum oxygen saturation (68.1% +/- 16.8 vs. 81.3% +/- 9.97; p less than 0.01) than those without. In symptomatic snorers, sensitivity of the sawtooth sign for sleep apnea was 72% and specificity 61%, for a FEF50/FIF50 ratio above 1 sensitivity was 17% and specificity 83%. In asymptomatic patients, sensitivity of either sign was extremely poor (33%) and specificity was 67% for the sawtooth sign and 85% for FEF50/FIF50 greater than 1. We conclude that abnormal flow-volume curves are of limited value for predicting sleep apnea.

Breathing patterns and HbSaO2 changes during nocturnal sleep in patients with Duchenne muscular dystrophy

A night-time polygraphic sleep recording with continuous HbSaO2 monitoring was performed in 11 chair-bound Duchenne muscular dystrophy patients with severe restrictive lung disease but with blood gas values within normal limits when awake. No abnormalities of sleep pattern were detected. Nocturnal sleep did not have significant adverse effects on respiration. However, in 6 patients, infrequent central apnoeas or hypopnoeas occurred which were associated with falls in HbSaO2 greater than those that have been reported to be in normal subjects. The magnitude of HbSaO2 falls appeared to be significantly correlated with functional residual capacity values. Overall, the findings revealed a relatively preserved, although unstable, blood O2 balance during nocturnal NREM and REM sleep in patients with Duchenne muscular dystrophy, even in an advanced stage of their illness.

Effects of 1 week administration of two benzodiazepines on the sleep and early daytime performance of normal subjects

This study analyzed the effects of 1 week administration of alprazolam (AL; 0.25 mg), lorazepam (LO; 1 mg) and placebo (PL) on sleep as well as their residual effects on attention upon awakening. Under a crossed, double-blind design, six healthy male volunteer subjects between 19 and 30 years of age were studied. After two habituation sessions and a control session, each substance was given orally, twice a day for 7 days, with a 1-week washout period between administrations. At the end of each administration period, sleep studies were conducted from 2300 to 0700 hours. Evaluation of attention was carried out by means of a simple visuomotor reaction time (RT) task, and a time estimation (TE) task, that started at 0700 hours, lasting 1 h. Neither drug significantly affected any sleep variable. Both benzodiazepines tended to increase RT, but only LO did so significantly at the beginning of the attention test. No significant changes in predictive and failure responses during the RT task were produced by either drug. Also, no significant changes were observed in the TE. Even though only LO produced a significant increase of RT at the selected doses and with 1 week administration, it is suggested that both benzodiazepines could have residual effects on attention.

Administration of triazolam prior to recovery sleep: effects on sleep architecture, subsequent alertness and performance

The effects of triazolam (0.125, 0.25, and 0.5 mg) versus placebo on recovery sleep staging, subsequent alertness and psychomotor performance were evaluated in humans. Forty-five healthy male subjects were deprived of sleep for 24 h, then administered a single dose of triazolam or placebo using a double-blind procedure. Subjects then attempted to obtain recovery sleep under non-sleep-conducive conditions (sitting upright in a well-lit, crowded chamber) for the next 6 h, followed by 18 more hours of sleep deprivation. During all sleep deprivation periods subjects were tested bihourly on a performance assessment battery which included symbol digit modalities tests (SDMT), four-letter search (FLS), logical reasoning (LR), time estimation (TE), visual vigilance (VV), and short term memory (STM) tasks. Sleepiness levels were measured objectively with multiple sleep latency tests (MSLT) and subjectively with the Stanford Sleepiness Scale (SSS). Compared to placebo, all doses of triazolam resulted in increased amounts of stage 3-4 sleep, and the 0.5 mg dose significantly reduced awakenings (Ps less than 0.05). Although subjects receiving triazolam averaged 21-42 min more total sleep time (TST) than subjects receiving placebo, differences in TST were not statistically significant. Apparent triazolam-mediated benefits to sleep quality resulted in no obvious improvements in performance or alertness levels during subsequent sleep deprivation. It was concluded that the increases in stage 3-4 sleep amounts were most likely due to triazolam-mediated increases arousal thresholds, and the triazolam mediated changes in sleep parameters obtained in the present study were not indicative of substantial changes in the recuperative value of sleep.

Are periodic movements in sleep a basal ganglia dysfunction?

Muscle activity during sleep is a new area of interest in sleep research. No precise brain structures are known to be involved in sleep movement. The etiology of periodic movements during sleep is unknown. The present study was dedicated to evaluate involvement of basal ganglia in periodic movements of the legs during sleep (PMS) in Parkinson's diseased patients. Sleep was monitored in 3 patients suffering from Parkinson's disease and PMS (PMS/PD) and in 3 patients suffering from restless legs syndrome and PMS (PMS/non PD). Following treatment, the six patients were monitored again during sleep. It was found that only the PMS/PD group of patients had improved significantly with appropriate treatment. Improved motor function in PD patients is associated with decreased PMS, regardless of wether the patients are treated with dopaminergic or anticholinergic agents. This is consistent with our previous data. It may be suggested that the striopallidal system is involved in periodic sleep movements of Parkinson's diseased patients.

L-tryptophan administered to chronic sleep-onset insomniacs: late-appearing reduction of sleep latency

The effects of 3 g L-tryptophan on sleep, performance, arousal threshold, and brain electrical activity during sleep were assessed in 20 male, chronic sleep-onset insomniacs (mean age 20.3 +/- 2.4 years). Following a sleep laboratory screening night, all subjects received placebo for 3 consecutive nights (single-blind), ten subjects received L-tryptophan, and ten received placebo for 6 nights (double-blind). All subjects received placebo on 2 withdrawal nights (single-blind). There was no effect of L-tryptophan on sleep latency during the first 3 nights of administration. On nights 4-6 of administration, sleep latency was significantly reduced. Unlike benzodiazepine hypnotics, L-tryptophan did not alter sleep stages, impair performance, elevate arousal threshold, or alter brain electrical activity during sleep.

Fitness facilitates sleep

Eight army recruits were studied at the start, middle, and end of their initial 18-week training programme. At each point the subjects were studied for four consecutive nights in the sleep laboratory. Their sleep was characterized by the means of the recordings on the last two nights. Within 2 days of the sleep recordings (but never on the same day) each subject spent 2 non-consecutive days in the exercise laboratory. On the 1st day a maximum oxygen consumption (VO2 max) measurement was performed on a treadmill and on the 2nd day a 24-min progressive exercise bicycle ergometer test was carried out with simultaneous venous sampling (for lactic acid measurements) and oxygen consumption recordings from which the lactate turn point (LTP) was calculated. LTP was used as a measure of fitness. Approximately 1 week after the above measures lean muscle mass as calculated by total body potassium estimation was obtained for each subject. Slow wave sleep (SWS) as a percentage of total sleep time increased significantly between the start and the measurements at 9 and 18 weeks, being 21.9%, 29.9%, and 28.5% respectively. Anaerobic threshold increased significantly (P less than 0.05) over the first 9 weeks and continued to increase to the end of the training period (P less than 0.001) using VO2 when lactate level was 2 mmol/l as a percentage of VO2 max. With increase in fitness, sleep onset latency and wake time during sleep decreased and sleep efficiency improved. The results suggest that as fitness increases sleep quality improves.

Nocturnal penile tumescent evaluation of erectile function in insulin-dependent diabetic men

This study compared nocturnal penile erections in four age-matched groups of young subjects: diabetic patients with and without erectile problems, psychogenically impotent men and healthy control subjects. All men were assessed under similar conditions during three nights, each for a total of 156 study nights. Diabetic impotent men exhibited a significantly decreased number of erectile episodes (p less than 0.05) and episodes of maximum tumescence per night (p less than 0.01). They also spent significantly less time in tumescence (p less than 0.005) and in simultaneous rapid eye movement sleep and tumescence (p less than 0.005). Diabetic men without sexual problems, psychogenically impotent men, and normal control subjects did not differ. Diabetic men in both groups spent less sleep time in rapid eye movement sleep and had longer latencies to onset of rapid eye movement. The decreased time in erection noted in impotent diabetic patients was no longer significant when adjusted for differences in duration of rapid eye movement sleep. In comparison to healthy control subjects and psychogenically impotent men, non-impotent diabetic men did show significantly diminished circumferential increases during erections, similar in degree to impotent diabetic patients (p less than 0.05).

EEG and sleep in aged hospitalized patients with senile dementia: 24-h recordings

Polygraphic recordings of wake and sleep were performed on 10 partly bed-ridden, severely deteriorated patients with senile dementia. Compared with healthy elderly persons these subjects showed less SWS (slow wave sleep, characterized by high amplitude, slow EEG waves), less REM sleep (rapid eye movement sleep, usually accompanied by dream activity) and poorly organized stage 2 sleep (no sleep spindles, i.e. phasic EEG activity with a frequency of 12-14 Hz). Six of the 10 patients had no dominant alpha rhythm during wakefulness; this seemed to be related to their more deteriorated clinical state, to still less SWS and REM sleep and more time spent in stage 2. The basic NREM-REM cycle of sleep, i.e. the regular alternation between non-REM- and REM-periods, could still be distinguished, however, and showed similar average temporal characteristics as in healthy old and younger people. Similarly, although sleep was severely fragmented in most patients and many sleep episodes occurred during the day, the day-night alternation of wakefulness and sleep was maintained in the sample as a whole.

REM sleep episodes during the maintenance of wakefulness test in patients with sleep apnea syndrome and patients with narcolepsy

Twelve patients with sleep apnea, 12 narcoleptic patients, and 10 controls were given 20-min opportunities to remain awake while sitting comfortably. Test sessions were administered at 10:00, 12:00, 14:00, 16:00, and 18:00. Apneic and narcoleptic subjects were less capable of maintaining wakefulness than controls. Patients with sleep apnea had an average of 1.4 daytime rapid eye movement (REM) episodes with the peak incidence at 14:00. Narcoleptics also had sleep onset REM periods (mean of 2.7), whereas none of the controls had REM episodes during the daytime testing. Narcoleptic and control groups differed in the probability of REM occurring at each session. There were time-of-day differences in the probability of REM occurring between patient groups. The amount of stage REM the night preceding testing was unrelated to the occurrence of REM episodes during the day in either patient group. In addition, there were notable differences in the frequency of sleep onset REM periods when patients were sitting as opposed to being supine during nap studies. Sleep latency and frequency of REM episodes on the maintenance of wakefulness test were independent of the subject's age. The maintenance of wakefulness test proved unsatisfactory as a diagnostic procedure, but appeared useful as an adjunct procedure in the evaluation of treatment efficacy of hypersomnia.

Acute effects of viloxazine HCl and flurazepam when given alone and in combination on sleep EEG: a double-blind interaction study with normals

Viloxazine, an aryl-oxypropanolamine type of beta-adreno-receptor antagonist, has been used in the treatment of depression. In a double-blind drug interaction study with flurazepam, a commonly used benzodiazepine hypnotic, viloxazine administered alone decreased the amount of time spent in REM sleep, increased the amount of time in the "light" stages of sleep, and increased the number of transitions to awake. However, no interactive effects of the combined administration of viloxazine and flurazepam could be detected.

REM ocular activity in Parkinsonian patients chronically treated with levodopa

REM ocular activity of levodopa treated Parkinsonian patients was compared to REM ocular activity of normal young adults. REM densities were significantly higher in patients than in normal controls. This difference was most prominent after 10 min of REM sleep. Previous findings that levodopa treated patients reported usually vivid and detailed dreams suggest that increase in REM ocular activity is underlying the new dreaming experiences.