Sleep need in adolescents: a longitudinal approach.

A sample of 190 male and female "high school" students completed a sleep questionnaire for the first time when they were 10 to 14 years old. The survey was repeated five times at 2 year intervals. Ninety-three subjects answered the questionnaire each time. Subjective sleep need was assessed by the indicated wish for more sleep. The wish for more sleep was very pronounced, varying between 54.3% and 74.5% across the years. Individual consistency, however, was low since only 14.5% of the adolescents indicated the wish for more sleep in each survey, emphasizing the state dependency of this variable. Within each total sample, subjects with the wish for more sleep (MSL) and with sufficient sleep (SSL) were compared. Subjective sleep need was consistently validated by a syndrome of morning-tiredness. In the last two surveys, there was reduced time in bed (TIB) on weekdays in MSL subjects and longer TIB during vacation in surveys 2 through 5. Furthermore, MSL subjects more often showed irregular sleep habits. The previous sleep history of the MSL subjects in the last survey indicated that concomitants of the wish for more sleep were already experienced earlier in adolescence. The desired sleep duration of these subjects was 1.7 h longer than their current sleep on weekdays, an amount they had not obtained on weekdays since early adolescence. It is concluded that a substantial proportion of the adolescents seem to have had difficulties adapting to the general sleep time reduction occurring in adolescence.

Effect of benzodiazepine hypnotics on all-night sleep EEG spectra.

The effect of a single, oral bedtime dose of the benzodiazepine hypnotics flunitrazepam (FR; 2 mg), flurazepam (FR; 30 mg), and triazolam (TR; 0.5 mg) on the sleep stages and the sleep EEG was investigated in eight healthy, young subjects. In comparison to the placebo night, all drugs reduced the percentage of stage 1 and REM sleep, increased stage 2, and decreased the number of stage shifts. For FN and FR, some of these changes persisted in the postdrug night. All-night spectral analysis of the EEG showed a reduction of low-frequency activity (0.25-10.0 Hz) in stages 2, 3 + 4 and REM sleep, changes that persisted for all three drugs in the post-drug night. In the drug nights, activity in the spindle frequency range (11-14 Hz) was enhanced particularly in stage 2 and 3 + 4, activity in the high frequency range (17-25 Hz) particularly in REM sleep and stage 1. In the first third of the drug night, the depression of low-frequency activity in stage 2 was either absent (FR) or less prominent (FN, TR) than in the following part of the night. The results demonstrate that benzodiazepine hypnotics induce specific changes in the EEG spectra which reflect the immediate and residual drug effects more sensitively than conventional sleep scores.

A single dose of benzodiazepine hypnotics alters the sleep EEG in the subsequent drug-free night.

All-night spectral analysis of the sleep EEG was used to study the effect and after-effect of a single bedtime dose of flunitrazepam (2 mg), flurazepam (30 mg) or triazolam (0.5 mg) in healthy young males. In the night of drug treatment all 3 hypnotics reduced the EEG slow waves and enhanced the activity in the frequency range of sleep spindles. In the subsequent drug-free night, the latter changes were no longer present after triazolam, whereas the reduction of slow wave activity persisted after all compounds.

Day-time residual effects and motor activity after three benzodiazepine hypnotics.

The benzodiazepine hypnotics triazolam (T) (0.25, 0.5 and 1.0 mg), nitrazepam (N) (10 mg) and flunitrazepam (F) (2.0 mg) were investigated with respect to night-time effects and day-time residual effects, in healthy, young subjects. Drug or placebo was taken orally at home before bed-time. Tests for residual drug effects were administered in the laboratory throughout the following day. They included multiple sleep latency tests, the digit cancellation test, questionnaires, self-ratings and experimenter ratings. In addition, motor activity was recorded with a wrist-worn activity monitor during the drug-night, the day following drug intake, and the two subsequent nights. Residual effects consisted of reduced day-time motor activity (T 0.5, F 2.0), enhanced self-rated day-time sleepiness (T 1.0, F 2.0), increased experimenter-rated tiredness (T 0.5, F 2.0), and impaired performance in the digit cancellation test (F 2.0). Grogginess was a common symptom in the morning after flunitrazepam. All drugs reduced motor activity during sleep, and increased subjective depth and quietness of sleep. Increased motor activity in the second post-drug night was observed after triazolam 0.5 mg. The results indicate that a small dose of a short-acting benzodiazepine may be appropriate for promoting sleep without subsequent day-time residual sequelae.

Sleep deprivation: effect on sleep stages and EEG power density in man.

Sleep was analysed in 8 young adults subjects during two baseline nights and two recovery nights following 40.5 h sleep deprivation. Sleep stages were scored from the polygraph records according to conventional criteria. In addition, the EEG records of the entire nights were subjected to spectral analysis to compute the frequency distribution of the power density in the 0.25-25 Hz range for 0.5 Hz or 1.0 Hz bins. In the first recovery night, the power density in the delta band was significantly higher than baseline for total sleep time as well as for sleep stages 2, 3 and 4, 4 and REM. These changes were not restricted to the delta band, but extended to higher frequency bands. Minor, but significant, effects of sleep deprivation were seen in the power density distribution of the second recovery night. In the baseline nights, a progressive reduction of power density in the delta/theta range was present for successive non-REM-REM sleep cycles for total sleep time and stages 2, 3 and 4, and 4. The results show that effects of sleep deprivation as well as trends within the sleep periods are readily apparent from spectral analysis, but are inadequately reflected by conventional sleep scoring. When the power density values were integrated over the entire frequency range (0.75-25 Hz) for each non-REM-REM sleep cycle, an exponential decline from cycle 1 to cycle 3 was suggested. The present findings support the hypothesis that the EEG power density in the low frequency range is an indicator of a progressively declining process during sleep whose initial value is determined by the duration of prior waking.

[Behavior of total complement as a humoral parameter of nonspecific resistance in hormonal contraception and pregnancy].

PIP: Total complement levels were studied in 216 pregnant women, 170 women (aged 18-46 years) taking Non-Ovlon or Ovosiston, and 305 male and female blood donors. Complement titers in the pregnant group were significantly higher than those of controls; those of women using hormonal contraception were similar to those of the pregnant group. The question of steroid induction of immunological phenomena is discussed.^ieng