On the fundamental research of the acoustic pupillen reflex for the objective audiometry. Application of Iriscorder

The purpose of this study was a recording of acoustic pupillen reflex by Iroscorder. Acoustic reflex of 10 normal hearing subjects was examined by Iriscoder. Based on this examination, the optimum intensity of illumination for acoustic pupillen reflex, appearance rate of pupillen reflex and its reflex were discussed. Prior to the experiment, three kinds of light intensity such as 0, 60, and 400 Lux were tested to determine the optimum intensity of illumination. The following results were obtained. 400 Lux light presumed the most available for our experiment because in 400 Lux light, pupillen were observed keeping physiologically composed condition, less varied in pupillen area in the stage of no stimuli and when they were stimulated with sound, the pupillen areas obviously varied.By this method, acoustic pupillen reflex was induced in 8 cases 80%) by 20 dB tone stimuli, the other 2 subjects at over 40dB. The reflex includes the mydriasis patterns as it was reported previously. The pupillen reflex pattern in our study was divided into 4 types, but these patterns were influenced by the condition of the subject and degree of sound pressure. The peak latency of acoustic pupillen reflex was shortened according to the increasing sound pressure.