J Audiol Otol.  2021 Oct;25(4):199-208. 10.7874/jao.2021.00248.

Influence of Stimulus Polarity on the Auditory Brainstem Response From Level-Specific Chirp

• Dzulkarnain AAA
• Salamat S
• Shahrudin FA
• Jamal FN
• Zakaria MN

• KMID: 2521617
• DOI: http://doi.org/10.7874/jao.2021.00248

Abstract

Background and Objectives
No known studies have investigated the influence of stimulus polarity on the Auditory Brainstem Response (ABR) elicited from level-specific (LS) chirp. This study is important as it provides a better understanding of the stimulus polarity selection for ABR elicited from LS chirp stimulus. We explored the influence of stimulus polarity on the ABR from LS chirp compared to the ABR from click at 80 dBnHL in normal-hearing adults.
Subjects and Methods
Nineteen adults with normal hearing participated. The ABRs were acquired using click and LS chirp stimuli using three stimulus polarities (rarefaction, condensation, and alternating) at 80 dBnHL. The ABRs were tested only on the right ear at a stimulus rate of 33.33 Hz. The ABR test was stopped when the recording reached the residual noise level of 0.04 µV. The ABRs amplitudes, absolute latencies, inter-peak latencies (IPLs), and the recorded number of averages were statistically compared among ABRs at different stimulus polarities and stimuli combinations.
Results
Rarefaction polarity had the largest ABR amplitudes and SNRs compared with other stimulus polarities in both stimuli. There were marginal differences in the absolute latencies and IPLs among stimulus polarities. No significant difference in the number of averages required to reach the stopping criteria was found.
Conclusions
Stimulus polarities have a significant influence on the ABR to LS chirp. Rarefaction polarity is recommended for clinical use because of its larger ABR peak I, III, and V amplitudes than those of the other stimulus polarities.

Keyword

Level-specific chirp; Stimulus polarity; Auditory brainstem response; Auditory evoked potentials; Auditory pathway