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

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).

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.

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.

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.