[Periodic discharges of sleep spindles with placebo and zopiclone]

According to our experiences (parietal) sleep spindles often show a periodical appearance. Successive sleep spindles in series have a distance of about four seconds. In 95% the duration of such series of sleep spindles is not longer than 40 s, so that there appears no more than ten successive periodical sleep spindles. In the present study ten subjects aged between 57 and 77 years were given Placebo and 7.5 mg Zopiclone. Under the effect of verum we found a doubling of sleep spindle series. However, the distance between the periodical spindles and the length of the spindle series remained unchanged. The variance in the ability to generate sleep spindle series was very high across subjects. One subject for example produced only one sleep spindle series in the Placebo-night (three under verum) and another subject on the other hand 95 (under verum 130). The results of the present study well corresponding to the results of a former investigation comparing Placebo, Pentobarbital, Methaqualon, Carbromal, Flunitrazepam, Triazolam and Lormetazepam.