Effects of zolpidem on cyclic alternating pattern, an objective marker of sleep instability, in Japanese patients with psychophysiological insomnia: a randomized crossover comparative study with placebo.

OBJECTIVE: A placebo-controlled randomized crossover study to investigate the effects of zolpidem on sleep stability in Japanese insomniac patients was performed using the cyclic alternating pattern (CAP) rate, a polysomnographic marker that reflects sleep instability. METHODS: Seventeen patients (5 M and 12 F, mean age: 40.4+/-13.6 years) who met the International Classification of Sleep Disorders (ICSD) criteria for psychophysiological insomnia were evaluated. During the first period, patients were administered the placebo on the first night, followed by either zolpidem or the placebo on the second night (treatment night). The second crossover period was conducted after a minimum 3-day observation. Improvement in the overnight CAP rate was the primary endpoint. Secondary endpoints included the CAP variables, conventional sleep variables, EEG arousals, subjective evaluation of sleep quality (measured by means of a visual analogue scale and the St. Mary's Hospital Sleep Questionnaire), and drug safety. RESULTS: Zolpidem significantly decreased the overnight CAP rate values (57.6 vs. 39.0%, p=0.009) and improved "sleep depth" (p=0.044) and "sleep quality" (p=0.023) subjective questionnaire scores. Zolpidem also significantly improved VAS (p=0.036). The amount of time spent in sleep stages 3+4 was significantly increased by zolpidem without affecting the amounts of stage 2 and rapid eye movement (REM) sleep. Significant negative correlations were found when the sleep quality score was matched to the CAP rate (p=0.022). No serious adverse events occurred during the study. DISCUSSION: In Japanese patients with psychophysiological insomnia, zolpidem increased sleep stability by significantly improving the overnight CAP rate. Zolpidem also improved sleep depth and sleep quality, both subjectively and objectively.

The effects of flumazenil on sleepiness, task performance and nocturnal sleep after anesthesia with midazolam.

The purpose of the present study was to clarify the changes in psychophysiological functions after anesthesia with midazolam (intravenous (i.v.) benzodiazepine anesthetic) and to examine the ability of flumazenil (benzodiazepine antagonist) to prevent the adverse effects of anesthesia with midazolam. Clinical dose of midazolam (0.1 mg/kg i.v.) was administered to seven healthy volunteers and either flumazenil (0.3 mg i.v.) or saline was injected at the end of the anesthesia. After anesthesia with midazolam, subjective sleepiness and euphoria increased significantly, but these changes were not observed when flumazenil was administered. In addition, sleep latency was prolonged and sleep efficiency decreased significantly after midazolam anesthesia with and without flumazenil. Slow wave sleep decreased significantly only by co-administration of flumazenil.

Re-entrainment of the circadian rhythms of plasma melatonin in an 11-h eastward bound flight.

We investigated the re-entrainment of melatonin rhythm in an 11-h eastward-bound flight. Eight male subjects participated in the present study. Blood sampling was carried out once before the flight and twice after the flight. During the daytime the subjects were exposed to natural zeitgeber outdoors on the day except the blood sampling. Seven of eight subjects showed antidromic re-entrainment, and the other subject showed orthodromic re-entrainment. The intensity of natural day light in New York amounted to 20 000 lx. As for the direction of the re-entrainment in New York the antidromic re-entrainment is naturally dominant.

Sleep architectures of obstructive sleep apnea syndrome in the young child.

The sleep architectures of obstructive sleep apnea syndrome (OSAS) in the young child (child-OSAS, n = 17; mean age: 5.9+/-2.7 years; male:female 14:3) were compared with that of OSAS in the adult (n = 19; mean age: 44.7+/-10.7 years; male:female 18:1) and that of primary snoring in the child (n = 5; mean age: 7.0+/-2.4 years; male:female 5:0). Child-OSAS and OSAS in the adult had the same severity in oxygen desaturation. Child-OSAS showed lower Apnea-Hypopnea Index compared with OSAS in the adult. Sleep continuity in child-OSAS was not impaired compared with OSAS in the adult. Sleep fragmentation in child-OSAS was not so remarkable. The quantity of slow wave sleep in child-OSAS was similar to that of primary snoring in the child. Both profiles of sleep architectures showed nearly the same pattern.

Effect of 3 mg melatonin on jet lag syndrome in an 8-h eastward flight.

In order to assess the effect of melatonin on jet lag a field study was undertaken. The process of re-entrainment of circadian melatonin rhythm was investigated in six subjects. Except during 24-h blood sampling, the subjects were exposed to natural zeitgeber (time giver) outdoors and given 3 mg melatonin at 23:00 h. The subjects were exposed to bright sunlight from 3000 to 12000 lx. All of them showed orthodromic re-entrainment with taking melatonin, while two out of the six did not show orthodromic re-entrainment without taking melatonin. Melatonin accelerated the rate of the re-entrainment of the circadian melatonin rhythm. Melatonin was useful to jet travel from Tokyo to Los Angeles.

Changes in subjective sleepiness, subjective fatigue and nocturnal sleep after anaesthesia with propofol.

The purpose of this study was to clarify the changes in psycho-physiological functions after anaesthesia with propofol (PF). The subjects were seven healthy male volunteers and the duration of the anaesthesia was 1 h (14:00-15:00 h). The plasma concentration of PF immediately decreased after the anaesthesia. The subjective sleepiness and VAS (visual liner analogue scale) scores (i.e. effort to do something) increased significantly at 20 min after the anaesthesia. However, these changes were improved at 80 min after the anaesthesia. The sleep latency at the nocturnal sleep 8 h after the anaesthesia was prolonged significantly, but the other parameters including the distributions of stage 3 + 4 and the rapid eye movement 'REM' stage were not changed.

Re-entrainment of circadian rhythm of plasma melatonin on an 8-h eastward flight.

To estimate the process of re-entrainment we measured the melatonin rhythm on an eastward flight. After the baseline study, 24-hour blood sampling of six male subjects was done on the first and fifth days. During the daytime the subjects were exposed to natural zeitgeber outdoors every day except the blood sampling day. They were analyzed with an illuminometer when under the bright light condition. Four of the six subjects showed orthodromic re-entrainment, another subject showed antidromic re-entrainment, and the other subject kept the baseline pattern of plasma melatonin. The rate of re-entrainment in orthodromic re-entrainment was about 55 min per day. Measuring the circadian rhythm of plasma melatonin has clarified the interindividual re-entrainment difference.

Clinical features of circadian rhythm sleep disorders in outpatients.

The clinical data of 86 cases of primary circadian rhythm sleep disorder (primary CRSD) were retrospectively examined and compared to 40 cases of secondary circadian rhythm sleep disorder (secondary CRSD), who had presented with some kind of psychiatric or medical disorder, and had exhibited sleep-wake rhythm disorders that were judged to be secondary CRSD based on sleep logs. The comparison of cases found that: (i) the mean age at first presentation to the clinic was significantly younger for primary CRSD compared to secondary CRSD; (ii) more secondary CRSD cases were unemployed than were Primary CRSD cases; (iii) more cases in the secondary CRSD group had a clear trigger for sleep-wake rhythm disorder onset than cases in the primary CRSD group; and (iv) the types of sleep-wake rhythm disorders in the primary CRSD group consisted of delayed sleep phase syndrome (DSPS), 72 (83.7%), non-24 pattern, 11 (12.8%), and irregular, 3 (3.5%). In the secondary CRSD group there were 25 (62.5%) cases of DSPS pattern, 1 (2.5%) of non-24 pattern and 14 (35.0%) with irregular pattern. The 56 (65.1%) cases with primary CRSD showed good response to vitamin B12 and bright light therapy; however, 28 (70.0%) cases with secondary CRSD did not respond to such therapies.

[Arousal disorders].

Arousal disorders, which belong to parasomnias in ICSD, have some disfunction in the process from sleep to awakenings. And the undesirable behaviors, such as wandering and screaming, are observed in the middle of awakening. Arousal disorders contain 1) confusional arousal, 2) sleepwalking, and 3) sleep terrors. Their common characteristics are the following items. 1) these symptoms frequently can be observable in infants, 2) these symptoms appear after awakenings especially from slow wave sleep, 3) the organic change has not been proven, 4) patients lose memory about the episode in the next morning, 5) natural improvement of symptoms can be expected after puberty. Confusional arousal is considered as a partial episode of sleepwalking and sleep terrors.