Purpose
to determine the minimum response and the latency of V wave in the Frequency-specific auditory brainstem responses (FS-ABR) in normal hearing neonates at the frequencies: 0.5, 1, 2 and 4 kHz by air and bone conduction and to determine normative values.
Methods
normal hearing neonates were assessed with FS-ABR at 0.5, 1, 2 and 4 kHz, air and bone conduction. Twelve ears were assessed in each frequency, totalizing 18 neonates. Results analysis considered the latency and the presence of wave V until 20 dB nHL in air and bone conduction, for four intensities.
Results
it was observed an increase of wave V latency with the decrease of intensity, and greater latencies at lower frequencies in both air and bone conduction. Nevertheless, there was no difference between the latencies at 0.5 and 1 kHz with strong intensity stimuli in both conditions, contrasting to literature findings. Considering air conduction, wave V was present at 0,5 kHz at 30 dB nHL in all ears and at 1 kHz 11 ears (91,66%) presented it at 20 dB nHL. All subjects (100%) presented responses to the other frequencies at 20 dBn HL. Considering bone conduction, all subjects presented wave V at 20 dB nHL in all frequencies.
Conclusion
the found values can be used in clinical practice in order to guide the differential diagnosis of hearing loss, complementing the evaluation as for hearing neonates.
Audiometry; Evoked Response; Infant; Newborn; Hearing
