Shifts and awakenings: valuable indicators of the quality of sleep: do these parameters react differently to hypnotics?

In order to test the assumption that the sleep stability increases as the number of shifts and awakenings decreases, all-night sleep recordings (registered at home) were reanalyzed. The registrations belong to 10 young good sleepers, 10 adult good sleepers, 10 insomnia patients without treatment, 10 treated with a benzodiazepine and 10 treated with a nonbenzodiazepine hypnotic, 10 patients with proven narcolepsy, and 10 with obstructive sleep apnea syndrome (OSAS). For each of the categories NREM-1-2, NREM 3-4, and REM sleep, indices were defined as the number of shifts and awakenings that occurred per hour. Our results show that the indices of awakenings for the good as well for the bad sleepers were similar, whereas the indices of awakenings were very group dependent. We interpreted these results as showing that awakenings are valuable indicators for studying the quality of sleep, whereas shifts are not.