A comparative study of measurements of SN-10 and the 40/sec middle latency responses in newborns.

Auditory SN-10 responses and summed middle latency responses (40/sec MLR) were obtained from 36 full-term newborns. Wave V latencies from 20-70 dB nHL were in agreement with previous studies. Although the amplitudes of the SN-10 and the 40/sec MLR paradigms were not significantly different, we were able to detect the lowest thresholds with an SN-10 response for unfiltered clicks. The mean threshold for the click evoked SN-10 potential was 5 dB better than the mean threshold for the click evoked 40/sec MLR and 10 dB better than the mean threshold for the 500 Hz toneburst 40/sec MLR. We conclude that both the SN-10 and 40/sec MLR techniques can be useful in the assessment of the hearing of newborns, but that only the 40/sec MLR may be useful in obtaining responses to a 500 Hz toneburst.