[The problem of noise adaptation during sleep]

Within experimental series carried out till now habituation to noise during sleep was, as a rule, statistically insignificant, though most of the papers are reporting a decrease of awakening-reaction during the experiment. This discrepancy rises from the small number of experimental trials, so that statistical test fail. Summarizing the published data the decrease of reaction during test series is significant. Based on these data a function of habituation has been calculated demonstrating an increase of O-reactions (all reactions less than a change of one sleep stage) and a decrease of awakening-reactions caused by acoustical stimuli. The ascent of the curve of habituation becomes flatter and is about 0 within the 9th test night. As indicated by the calculated curve, it seems that a second process of habituation takes place but this further decrease of reactions could not be proven. The increase of 0-reactions as well as the decrease of awakening reactions is dependent on the content of information of the acoustical stimuli which decreases with the number of stimuli.