[A study on measurement of auditory reaction time].

In order to determine auditory reaction time, different test methods for central conducting modes (simple reaction, choice reaction, simultaneous reaction and time lag reaction) were carried out on normal subjects. As test sounds, pure tone, white noise and Japanese vowels were employed. The following results were obtained. 1) The results were simple reaction time 186 ms, choice reaction time 283 ms, simultaneous reaction time 288 ms and time lag reaction time 370 ms (delay time 50 ms), 361 ms (delay time 100 ms), 298 ms (delay time 200 ms) and 273 ms (delay time 400 ms). 2) Simple reaction time by stimulus sound pressure level of over 40 dB sensation level was almost a certain value, the determination of reaction time of about 40 dB sensation level was considered to be suitable. 3) In each sound and each examination method, no significant differences between reaction times according to left and right ears were found. 4) According to examination method, the tendency of significant shortening was found only in white noise. This was considered to be due to broad frequency component of white noise or its tonality, accordingly if it was used as test sound, it needed to be loudness balanced with other test sound. 5) In simultaneous reaction and time lag reaction, such acoustic psychological problems as binaural fusion, interaural attentional switching mechanism and warning effect of preceding sound needed to be considered. 6) In the subjects having normal auditory function, it might be estimated that identification time may be about 100 ms and discrimination time may be about 70-80 ms. 7) Auditory reaction time includes the time required in central information conducting process as direct real time, and conveniency of its examination items were superior to the other methods. Also, the analyses of identification time and discrimination time were considered to be applicable for the diagnosis of quantitative auditory function of the central auditory handicapped persons in future.