[Comparison of the waking EEG with the subjective impressions of the waking individual (author's transl)].

Sleep EEGs of 30 chronic insomnia patients are compared with the patients' subjective estimation of the duration of sleep and the number of waking periods during the night's recording. Overall, the patients overestimated the duration of sleep and, to a lesser degree, the time they awaken in the morning. The number and duration of waking periods in the night were regularly underestimated, and no correlation could be found between the estimated number of waking periods and those actually recorded on the EEG. The composition of sleep on falling asleep and on waking, when these are overestimated, showed an appreciable period of waking sleep at these times (21% and 41% respectively). The authors suggest that their results indicate that study of the transitional periods of sleep and waking may provide a better understanding of insomnia and lead to alternative therapeutic approaches. They also indicate that the shorter duration of sleep is only one aspect of insomnia and other factors are probably important.