Brain stem evoked response audiometry in neonates.

Brain stem evoked response audiometry (BERA) was performed in 50 normal full term newborn infants (25 male, 25 female) to generate normative data base for this age group. The stimuli of 30 dB, 40 dB and 80 dB nHL (normal hearing level) intensities were delivered to each subjects. 30 dB stimulus failed to produce clear wave patterns, whereas upto six vertex positive waves were recognised among which waves I, III and V were commonly present. The absolute latencies of waves I and V at 40 dB nJL were 2.54 +/- 0.21 msec and 7.56 +/- 0.26 msec and at 80 dB nHL these were 2.06 +/- 0.15 msec and 7.09 +/- 0.17 msec respectively. I-V interpeak latencies (IPL) were 5.02 +/- 0.13 msec at 40 dB and 5.03 +/- 0.13 at 80 dB nHL. The latencies of waves I and V were decreased with the increase of intensity of stimuli with the rate of 0.012 msec/dB, bit I-V IPL, i.e., central conduction time remained almost constant. There were no statistically significant differences in the brain stem auditory evoked responses between male and female subjects. Brain stem evoked response audiometry is objective and reliable for hearing screening in neonates.