[Sleep and vigilance in students]. / Sommeil et vigilance des étudiants.

A cross-sectional survey was carried out among students with the higher education system in Paris in November, 1992, during a medical exam carried out during their first year of study. The objective was to better determine the characteristics of sleep, vigilance and prevalence of sleep problems. This survey concerned 3152 students, 52% of them girls. The average age was 20 years +/- 2.38% of students felt they don't sleep sufficiently. Twenty one percent of students maintained that they experience sleep difficulties. Ten percent of students said they are sleepy during the day. Four percent of students take medications for sleeping. 3% of students snore regularly. The practice of a sport, living environment, the duration of daily transportation, remunerated work, and the consumption of stimulants all impact on sleep and/or daytime vigilance.

Rapid shift in peak melatonin secretion associated with improved performance in short shift work schedule.

We studied the performance and adaptability of 40 nurses (median age 35 years), 20 on permanent day shift and 20 on permanent night shift with fast rotation of work and days off, matched for age, gender, and socio-familial responsibilities. For 15 days prior to the study, subjects maintained sleep logs and trained for performance tests. Questionnaires were administered to evaluate adaptability to shift work. During the experimental phase, sleep/wake patterns were monitored using sleep logs and activity/inactivity with wrist actigraphy. Performance levels were measured with the four choice reaction time and memory test for seven letters, eight times/day during the wake period, days on and off. On the last day of work and first day off, 6-sulfatoxy-melatonin levels were assayed from urine samples collected every 2 hours. Estimated total sleep time during the 15-day experimental period was not significantly different in the dayshift and nightshift nurses. Night nurses shifted regularly to daytime activities on days off and, as a group, were significantly sleep deprived on work days with napping on the job in 9 of the 20 night shift nurses (mean of 114+/-45 minutes per shift) and a significant performance decrement during the work period. Further analysis revealed two subgroups of night nurses: The majority (14 nurses) had a mean peak of 6-sulfatoxy-melatonin at 0718 hours on days off and no peak during night work while the other 6 night shift nurses presented a fast melatonin shift with two clear peaks on both work and days off. Comparison of performance scores revealed that all nurses performed similarly on days off. Daytime nurses and fast-shifting night nurses had similar scores on work days, while nonshifting night nurses had significantly lower scores at work. Despite similar gender, age, social conditions, and light exposure levels, a minority of the nurses studied possessed the physiological ability to adapt to a fast-shifting sleep-wake schedule of more than 8 hours and were able to perform appropriately in both conditions. This shift was associated with a change in the acrophase of 6-sulfatoxy-melatonin.

Light therapy as treatment of dyschronosis in brain impaired children.

Fourteen children aged 9 months-4 years with moderate to severe mental retardation and varying neurologic lesions were referred for severe and continuous nocturnal sleep disturbances and very abnormal day/night schedules. All children had previously been given hypnotic medications and behavioral treatments which had little or no effect on nocturnal sleep. The severity of the sleep disturbances significantly affected family life and was a major handicap to the children. All children were treated with light therapy (minimum 4000 lux). Five children responded to treatment and had normal sleep-wake cycles at the most recent post-treatment evaluation (2-5 years after the first treatment). Two of the patients' families were unable to follow the prescribed regimen. Treatment failed in 7 children. One of these seven children spontaneously improved 3 years later. In three of the failure children the neurologic problem progressively worsened, leading to death in one of them. Phototherapy is a treatment worth pursuing in children with very significant sleep/wake disruption which is unresponsive to behavioral or other treatments. It has few side-effects and may lead to normalization of the sleep-wake cycle. Recent improvement in the technology used to monitor the 24-h temperature rhythm over several days and the present commercial availability of "light boxes" should render these therapeutic trials easier than at the time of these initial investigations.

Effect of zolpidem during sleep on ventilation and cardiovascular variables in normal subjects.

A double-blind study comparing the effect of zolpidem 10 mg, and placebo, on sleep architecture, nocturnal ventilation, cardiovascular parameters (heart rate, systolic, diastolic and mean blood pressures) was carried out. Ten healthy middle-aged males took part in the study. No significant differences were found between zolpidem and placebo in relation to sleep architecture. Mean respiratory disturbance index (RDI) and SaO2 values (mean SaO2, time spent with SaO2 < 90%) were similar under both conditions. The diastolic and mean blood pressure readings taken from REM periods which occurred during the first third of the night were significantly higher with zolpidem. No changes in systolic blood pressure or heart rate were found with zolpidem in comparison to placebo.

The role of personality factors and suggestion in placebo effect during mental stress test.

The aims of this study were first of all to document a placebo effect on systolic blood pressure and heart rate during mental arithmetic induced stress and secondly to assess the role of suggestion in producing this effect. Two types of placebo were used, a simple placebo and a placebo with an implied therapeutic action. Both were compared with alprazolam. A placebo response was seen in just over half of the volunteers when the cardiovascular changes to mental arithmetic induced stress in healthy volunteers were measured. This response appeared to be unaffected by the suggested therapeutic effect. Dominant, independent subjects, identified using the Cattell 16 PF personality test were less likely to respond to placebo. Alprazolam (0.5 mg) did not prevent, to a significantly greater degree than placebo, the systolic blood pressure or heart rate increases provoked by the mental stress.

Compliance and side effects in sleep apnea patients treated with nasal continuous positive airway pressure.

Nasal continuous positive airway pressure (CPAP) is an effective therapy for sleep apnea. We treated 144 patients with nasal CPAP and observed them for periods of as long as 25 months. No pneumothoraces occurred in any patient. Compliance rates were between 65% (90/139) and 83% (90/108), depending on the patient population considered. Demographic factors unrelated to discontinuing using CPAP included age, sex, and the presence of a housemate. Better-educated patients were less able to tolerate the equipment. Dry throat and nose and sore eyes were the most common side effects, but only sore eyes related to the amount of pressure. Side effects were unrelated to the number of months on the treatment, and obesity was related to higher pressures. Our study provides optimistic intermediate-term follow-up observations of patients on nasal CPAP therapy for sleep apnea. Whether adverse consequences occur over longer periods of time remains to be seen.