Questionnaire relating to sleep paralysis.

A sleep survey was conducted on 8162 citizens. The cumulative experience rate of sleep paralysis was 39.6%. The initial occurrence of sleep paralysis peaked at age 16 years. In addition to being higher in young people than in older subjects, the incidence of sleep paralysis was also higher among women than among men, and was significantly higher among shift worker than non-shift worker, and among persons engaged in the nursing profession than those not engaged in the nursing profession. The experience rate of sleep paralysis demonstrated a strong correlation with the frequency of dreaming, the experience rate of nightmares, times and regularity of going to bed and waking up, and particularly with the degree of insomnia.

Melatonin therapy for REM sleep behavior disorder.

Rapid eye movement sleep behavior disorder (RBD) is a parasomnia with clinical symptoms that include punching, kicking, yelling and leaping out of bed in sleep. Polysomnographic (PSG) finding showed REM sleep without muscle atonia. Clonazepam is generally used for treating RBD symptoms but melatonin was reported to be effective so we reconfirmed the effect of melatonin on RBD patients in the present study. We used melatonin (3-9 mg/day) which could ameliorate problem sleep behaviors remarkably, as well as %tonic activity in PSG variables. In the present study, melatonin was reconfirmed to be effective in RBD symptoms, especially for patients with low melatonin secretion, while its mechanism was not clearly known in the present study.

Development and application of the 'Sleep Ukiha' automated sleep analysis system.

We attempted to develop an automated sleep analysis system that uses a personal computer as an aid to the entire sleep research process. Analysis is based on electroencephalogram, chin muscle electromyogram and electrooculography, while other physiological phenomena can be handled arbitrarily. Major characteristics of the system include: (i) simultaneous gathering of physiological phenomena from up to three patients; (ii) high-speed waveform analysis; (iii) user-friendly operating environment through the use of a graphical user interface; and (iv) versatile utilization of analytical data in research.

Time course of saliva and serum melatonin levels after ingestion of melatonin.

Salival and serum melatonin levels after melatonin ingestion were measured by gas chromatography-mass spectrometry. Ingestion of 3 mg melatonin caused a marked increase in serum melatonin (3561+/-1201 pg/mL) within 20 min, followed by a gradual decrease, but the level still remained higher than the basal level at 240 min after the ingestion. The saliva melatonin 60 min after the ingestion showed the highest level (1177+/-403 pg/mL) which was one-third of the plasma level. The saliva melatonin level was highly correlated with the serum level throughout the experimental period (r=0.82, P=0.0001). These data indicate that the measurement of saliva melatonin level may be a suitable indicator for the melatonin secretion into general circulation.

Vitamin B12 treatment for delayed sleep phase syndrome: a multi-center double-blind study.

The active form of vitamin B12 (methylcobalamin) has been reported to be effective on sleep-wake rhythm disorders. Previous studies, however, were performed under open trial, and the effect of vitamin B12 has not been properly evaluated. The aim of this double-blind study was to investigate the efficacy of methylcobalamin on delayed sleep phase syndrome (DSPS). Methylcobalamin (3 mg/day) or placebo was administered for 4 weeks. The subjects were 50 patients with DSPS aged 13-55 years (26.8 +/- 1.3), 27 of whom received the active drug while 23 received the placebo. No significant differences were observed between the 2 groups in subjective evaluations of mood or drowsiness during the daytime or in night sleep by sleep-log evaluation. These results indicate that 3 mg methylcobalamin administered over 4 weeks is not an effective treatment for DSPS.

Effects of hCRH on sleep and body temperature rhythms.

We investigated the effects of human corticotropin-releasing hormone (hCRH) on the sleep structure and body temperature rhythms of seven healthy young men. Polysomnographic recordings were obtained and body temperatures were monitored continuously for 48 h in each subject following the intravenous administration of saline or of 100 micrograms hCRH. The administration of hCRH was associated with a significant phase-advancement in body temperature rhythm vs the saline control. The administration of hCRH affected non-rapid eye movement (NREM) sleep by reducing significantly slow wave sleep (SWS) and sleep efficiency, whereas the percentage of sleep stages 1 and 2 were increased significantly. These changes in body temperature rhythms and sleep structure induced by hCRH resembled those observed in patients with endogenous depression, except for the findings during rapid eye movement (REM) sleep. We hypothesize that a hypersecretion of hCRH in patients with endogenous depression may help to explain the changes in body temperature rhythms and sleep structure often reported in such patients.

Effects of acetazolamide on the sleep apnea syndrome and its therapeutic mechanism.

Twenty male patients with sleep apnea syndrome were treated with acetazolamide (AZM), a carbonic anhydrase inhibitor. In 14 of the patient a significant decrease was found in the number of apnea, apnea index and % apnea time (percentage of time spent with apnea to the total sleep time) with improvement in sleep structure, clinical symptoms, such as insomnia, daytime excessive sleepiness and snoring. A significant decrease was also observed in arterial blood pH and HCO-3 in the 14 improved patients. On the other hand, no improvement occurred in the parameters of sleep apnea and sleep with AZM in the remaining six patients. Moreover, metabolic acidosis and an improvement in arterial blood gases did not occur with AZM in the six patients.

Treatment of sleep apnea with prosthetic mandibular advancement (PMA).

Nine males with sleep apnea DOES syndrome and three males with sleep apnea DIMS syndrome were treated with prosthetic mandibular advancement (PMA). The method uses a prosthesis, which is designed to advance the mandible 3-5 mm to prevent upper airway occlusion during sleep. The apnea index in the obstructive-type apnea and the percentage of time spent in obstructive apnea decreased significantly with PMA. Although the apnea index showed merely a tendency to decrease in central apnea (p < 0.1), the percentage of time spent in central apnea decreased significantly with PMA. A marked improvement in sleep structures was observed with PMA; a significant increase was seen in total sleep time, percent slow wave sleep (SWS) and percent rapid eye movement (REM) sleep, and the time spent in intra-sleep awakening decreased remarkably. PMA had excellent effects on snoring, and daytime hypersomnolence was reduced in almost all patients. Moreover, a survey on the therapeutic effects of PMA on sleep apnea syndrome and problems associated with wearing PMA was performed with a questionnaire for the sample of nine DOES patients and an additional 22 patients who were treated over a long time. The therapeutic effects could be maintained without any problems in about 2/3 of these patients. The therapeutic mechanisms of PMA in its reduction of both obstructive and central apnea are discussed.

Comparison of body temperature rhythms between healthy elderly and healthy young adults.

The fact that the elderly are usually aware of early sleep onset and early morning awakening shows that the phase of sleep-wake rhythms in the elderly is more advanced than that in young adults. Since it has been suggested that human sleep onset, morning awakening, sleep period and depth of sleep are highly influenced by body temperature rhythms, rectal temperature rhythms were analyzed in 7 healthy elderly and 7 healthy young adults under the condition with time cue. Although a significant 24-hour period was found in the rhythms for all subjects, the phase of the rhythms in the elderly was more advanced than in the young adults. Moreover, a significant inverse correlation was observed between age and acrophase time in the elderly.

Biorhythm of core temperature in depressive and non-depressive alcoholics.

Core temperature was longitudinally evaluated during the day- and nighttime in six non-depressive and in four depressive alcoholics who had been abstaining from alcoholic beverages. The least squares spectrum method was employed for detecting the periods and acrophase of the circadian rhythm of core temperature. Although normal periods were observed in all the patients throughout the study, an abnormal acrophase was found in many patients, especially in depressive alcoholics. On the 3rd and 4th days after alcohol withdrawal, all of the four depressive alcoholics showed a phase advance of the circadian rhythm, and three patients of the six non-depressive alcoholics exhibited an abnormal acrophase. On the 21st and 22nd days after alcohol withdrawal, a normal acrophase was observed in two patients of the four depressives and in four of the six non-depressives. The mean core temperature was higher in the depressives than in the non-depressives on the third and fourth days after alcohol withdrawal.

Effects of medroxyprogesterone acetate on sleep of healthy young male adults.

The effects of a single 100 mg dose of medroxyprogesterone acetate (MPA) on human sleep were investigated using healthy young male adults. After a baseline night recording, two consecutive MPA nights and the following two withdrawal nights were recorded. The total sleep time was reduced after the 2nd MPA night and the decrease was significant on the 1st withdrawal night. The time of intrasleep awakening increased after the 2nd MPA night. Stage 1 sleep increased significantly on the 2nd MPA and 1st withdrawal nights. Stage 4 sleep decreased and the sleep latency gradually increased after the MPA administration. REM sleep reduced slightly on the 1st withdrawal night. These results indicate that MPA has a mild arousal action on human sleep and that the action may be pronounced a few days after administration of MPA.

Effects of antibiotics, minocycline and ampicillin, on human sleep.

The effects of two kinds of antibiotics, minocycline (MNC) and ampicillin (AB-PC), on human sleep were investigated on 19 healthy male students to test for a relationship between human sleep and protein synthesis. These drugs and placebos were capsulated identically in appearance and were given to the subjects using the single blind method. MNC has been proven to prevent protein synthesis whereas AB-PC does not inhibit protein synthesis, and both antibiotics are commonly used in clinical practice. With the administration of a single dose of 200 mg of MNC, an apparent decrease in slow wave sleep (SWS) was revealed on the drug night and the effects lasted through the following two consecutive nights being given a placebo. REM sleep was not reduced on all the recording nights. On the other hand, both SWS and REM sleep were not reduced with the administration of a single dose of 500 mg of AB-PC. These results are different from those previously obtained from animal experiments since many kinds of protein synthesis inhibitors have been proven to suppress mainly REM sleep in animals. It might be supposed that the species difference may be responsible for this difference, and that some proteins or polypeptides induce human sleep, especially SWS.

Serum folic acid levels and antipyrine clearance rates in smokers and non-smokers.

Serum folic acid (FA) levels and antipyrine clearance rates were determined in 15 healthy male subjects who had not been administered any drug and alcohol for a month preceding the study. Eight of the 15 subjects smoked cigarettes daily while the remaining seven did not. The serum FA levels were measured by Lactobacillus casei bioassay. The antipyrine clearance rates were estimated in plasma or saliva obtained after oral administration of antipyrine for evaluating the activity of hepatic microsomal oxidase. The serum FA levels in the smokers were significantly lower than those in the non-smokers and the antipyrine clearance rates were significantly higher in the smokers compared with the non-smokers. The increase of the antipyrine clearance rates in the smokers was supposed to be caused by an increase in the activity of hepatic microsomal oxidase since it has been established that polycyclic aromatic hydrocarbons contained in cigarette smoke induce these enzymes. The association of the decrease in the serum FA levels and the increase of the antipyrine clearance rates was investigated.