Effects of stimulus rate and gender on the auditory middle latency response

The effects of stimulus rate and gender on the auditory middle latency response (AMLR) waveforms were examined in 20 young adult male and female subjects. Four different repetition rates were presented to subjects (1.1/sec, 4.1/sec, 7.7/ sec, and 11.3/sec). Stimulus repetition rate had a significant effect on Pa latency, Pa amplitude, and Pb amplitude. Pa and Pb amplitudes decreased with increasing the stimulus rate, and Pa latency significantly increased with increasing the stimulus rate. No significant differences were seen on Pb latency or site of recording. Gender had a significant effect on Pa latency and Pa amplitude. Pa latencies were longer in male subjects, and Pa amplitudes were larger in female subjects. Gender did not have a significant effect on the Pb waveform.