[Value assessment of MIRA (multichannel infant reflex audiometry). 1. On response detection from activity curves]

The activity curves (sucking, breathing, eye movements) of 18 babies were inspected for alterations which might indicate reactions of hearing. In 10 cases, 4 of them also confirmed by ABR findings, we found it possible to deduce the hearing threshold from alterations of the respective activities alone even without knowledge of the occurrence of the stimulus (blind experiment, addition of the stimulus time after identification of activity alterations). Greater discrepancies are discussed with respect to the experience of the investigator and to different methods of audiometry.