Evaluation of the Effects of Two Different Types of Chirp Stimuli on Auditory Brainstem Response in Young Adults.

Abstract

Background: The chirp stimulus is a type of stimulus designed to neutralize the lack of temporal synchronization in the cochlea caused by progressive wave delay. The CE-Chirp® stimulus is a modified form of the chirp stimulus that allows for better neural synchronization and the recording of larger amplitude responses.Purpose: This study compared wave V latencies and amplitudes of CE-Chirp and chirp stimuli in auditory evoked brainstem responses (ABRs).Research Design: This was a cross-sectional analytical research study.Study Sample: Data of 25 healthy individuals (15 female and 10 male individuals) between 20 and 26 years of age (22.84 ± 1.81 years) were included.Data Collection and Analysis: Pure-tone audiometry, tympanometry, chirp ABR, and CE-Chirp ABR tests were applied. Chirp (broadband [BB] chirp [BB-chirp] and narrowband [NB] chirp [NB-chirp]) and CE-Chirp ABRs were evaluated at 20, 40, 60, and 80 decibels for normal hearing level (dBnHL) at BB and NB frequencies (1,000, 2,000, and 4,000 Hz).Results: The BB frequency evaluation showed a significant difference between the BB-chirp stimulus and CE-Chirp stimulus in terms of latency (p = 0.01 at 20, 40, 60, and 80 dBnHL), but no significant difference in amplitude (p > 0.05 at 20, 40, 60, and 80 dBnHL). The comparison of the NB-chirp stimulus and CE-Chirp stimulus showed that CE-Chirp stimulus latencies were significantly shorter than chirp stimulus latencies when a high stimulus intensity was applied at NB frequencies.Conclusions: A comparison of chirp and CE-Chirp stimuli revealed a significant difference in latency at BB frequencies, but different results were observed at NB frequencies. Amplitude comparisons of stimuli revealed different findings at different frequencies and different stimulus intensities. Additional research is necessary to determine the latency and amplitude differences between chirp and CE-Chirp stimuli.