Slow brain stem responses (SN10) to tone pips in normally hearing newborns and adults.

The recently discovered slow negative brain stem response at 10 ms (SN10) was investigated as a tool for assessment of hearing in 20 newborns and 20 adults. Tone pips of 500, 1 000 and 2 000 Hz and a click were presented at 60, 40 and 20 dB re normal hearing level. The SN10 response varied systematically as a function of frequency and intensity. SN10 was not observed for all stimuli, but percentages of detection improved as frequency and intensity increased. Newborns demonstrated significantly longer latencies than adults for all stimuli. The results suggest that SN10 is a reliable indicator of peripheral hearing for frequencies of 1 000 Hz and higher.