LS CE-Chirp vs. Click in the neuroaudiological diagnosis by ABR.

Introduction: The chirp stimulus was developed seeking to counterbalance the delay of the sound wave on its journey through the cochlea, allowing the hair cells to depolarize at the same time. The result is a simultaneous stimulation providing better neural synchrony and, consequently, the recording of responses with greater amplitudes.

Objective: To compare the absolute latency of waves I, III and V, the interpeak intervals I-III, III-V and I-V, amplitude values of wave V and its association with the amplitude of wave I, and the interaural difference V-V in the auditory brainstem response (ABR) using Click and LS CE-Chirp stimuli to determine whether the responses evoked by LS CE-Chirp could be applied to neuroaudiological diagnosis.

Methods: Cross-sectional study with 30 normal-hearing individuals. The parameters used were: intensity of 85dBnHL, alternating polarity; 17.1 stimuli/s and 100-3000Hz filters.

Results: The absolute latencies of waves I, III and V observed with LS CE-Chirp and click did not show significant differences. Significantly higher amplitudes of wave V were observed with the LS CE-Chirp. The interaural difference between the wave V latencies between stimuli showed no significant difference.

Conclusion: The LS CE-Chirp stimulus was shown to be as efficient as the click to capture ABR at high levels of stimulation, with the advantage of producing greater-amplitude V waves.