Abstract
Stability and reversibility of each component of middle latency response (MLR) were studied at the stimulus intensities just above the behavioral hearing thresholds. MLR was recorded at the intensity of 30dB, 20dB, 10dB, and 0dB above the hearing thresholds, and 5 test-retest trials were carried out at every stimulus level in 8 normal hearing human subjects.
The results were as follows;
1) The early components of MLR, namely, Po, Na, Pa components were fairly stable at 20dB above the hearing thresholds
2) However complete reversibility of their components could not be obtained even at 30dB above the hearing thresholds.
3) When MLR is used as one of the neurological examinations and the patterns of MLR components are discussed, the intensity of acoustic stimuli should not be lower than 30dB above the behavioral hearing thresholds. However, it is reasonable to mention that the response threshold should be approximately 20dB above the hearing level when MLR is used for audiological examination.
