[Auditory middle latency response: a study of optimal measuring conditions and determination of normal values]

The purposes of the present study were to select the optimal conditions for middle latency response (MLR) measuring with a statistical model of orthogonal test, and to determine the normal values of MLR. It showed that stimuli click and logon of different frequencies could be used to evoke MLR. The filter-setting was a significant factor in effecting the measurement of MLR. 30-50Hz or 30-100Hz was the most optimal filter-band. The effects of stimulus polarities on MLR bore no significant difference statistically. In clinical practice, stimulus repetition rate of 11/s was most desirable. We determined that mean thresholds of MLR were approximately 10dBnHL and latencies of wave Po, Na and Pa were approximately 10, 20 and 30ms respectively. The amplitudes of MLR varied greatly.