Comparison of LS CE-Chirp and Click Stimuli in Auditory Brainstem Responses in High-Frequency Hearing Loss.

Objectives: The auditory brainstem response (ABR) is an evoked potential used to estimate the hearing thresholds and identify potential auditory pathologies. Although a click stimulus is generally used as an auditory stimulus in diagnostics, recent reports show that the Level-Specific CE-Chirp (LS CE-Chirp) stimulus can also be used for clinical diagnosis. In this study, we compared the auditory brainstem test outcomes of the LS CE-Chirp stimulus and the click stimulus in individuals with high-frequency hearing loss (HFHL).

Design: Patients with HFHL (n = 30) and individuals with normal hearing (n = 30) were included in the study. Audiometric pure-tone thresholds were determined for all subjects at 250 to 8000 Hz. For individuals with normal hearing, the pure-tone thresholds were required to be ≤20 dB HL for all frequencies. HFHL cases were selected from people with at least 5 years of hunting experience. All subjects were tested with ABR at 80 and 60 dB nHL. The ABR test was performed using click and LS CE-Chirp stimuli at a rate of 11.1/sec. ABR wave I, III, and V peak latencies and I to V interpeak latency values were compared within and among the groups.

Results: Longer latency values were obtained with the LS CE-Chirp stimulus at 80 dB nHL intensity and 11.1/sec stimulus frequency than with the click stimulus in the control group. No significant difference was detected between the LS CE-Chirp and click stimuli at the 80 dB nHL intensity level in the HFHL group ( p > 0.005). When the HFHL patients were classified according to the 4000 Hz threshold, the click stimulus was found to be more compatible with the behavioral 4000 Hz threshold.

Conclusions: The wave latency values obtained with the LS CE-Chirp stimulus in the HFHL group, unlike with the click stimulation, were less affected by the level of hearing loss in the HFHL group. For this difference to have a diagnostic value, further studies would be needed on patients with different pathologies and hearing loss configurations.