The sensitivity of the ce-chirp auditory brainstem response in estimating hearing thresholds in different audiometric configurations

Abstract

Background CE-Chirp is a new broadband stimulus that permits the energy from the stimulus to reach the whole regions of the cochlea at approximately the same time. Aim Comparison of auditory brainstem response (ABR) thresholds obtained by using click stimulus, broadband CE-Chirp and 500 Hz, 1, 2, and 4 kHz narrow band CE-Chirp stimuli to those obtained by behavioral hearing thresholds in adults with normal hearing and with varying configurations of sensorineural hearing loss (SNHL). Patients and Methods Ten adult patients with normal-hearing thresholds, whose age ranged from 19 to 50 years, with a mean age of 30.4±9.1 years constituted a control group (group 1). Thirty adult patients with different configurations of SNHL constituted group 2, whose age ranged from 18 to 65 years, with a mean age of 32.5±9.8 years. All cases and controls were subjected to pure-tone audiometry, click, CE-Chirp and four narrow band CE-Chirp (at 500, 1000, 2000, and 4000 Hz) evoked ABRs. Results ABR thresholds to chirps have a relationship closer to behavioral hearing thresholds than ABR thresholds to clicks in individuals with normal-hearing thresholds and SNHL. Wave V mean latencies at threshold in response to click stimuli were earlier than those obtained using CE-Chirp in both groups. Wave V mean amplitudes at threshold with CE-Chirp were significantly larger than those with click in both groups. Wave V amplitude increased and latency decreased as the stimulus frequency increased in both groups. Conclusion There are evidences to suggest that ABR recording in response to CE-Chirps provide an efficient tool for estimating hearing thresholds in normal-hearing thresholds and individuals suffering from SNHL in comparison to click stimuli. The use of CE-Chirp had the potential to provide high sensitivity and accuracy for frequency-specific thresholds estimation in young children and difficult to test adults.