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MacEwan, Sarah

University of British Columbia

The aim of this project was to provide normative behavioural threshold data for brief-tone and chirp stimuli, two stimuli that are used in auditory brainstem response (ABR) testing. I collected thresholds from 20 typical-hearing adults using fixed-frequency Bekesy audiometry with a 1-dB step-size. The test stimuli, 5-cycle exact Blackman-gated brief-tones and CE-chirps, were collected via both air-conduction (ER-3A inserts) and bone-conduction (B-71 oscillator) at a presentation rate of 10/s at every octave from 250 - 4000 Hz, with 6000 Hz also tested for air-conduction. I also collected brief-tones at 1000 Hz at a rate of 20/s for both air- and bone-conduction in the interest of comparing the effect of stimulation rate on threshold. Data analysis showed air-conduction chirp thresholds were a statistically significant 1.80 dB higher on average compared to brief-tone thresholds, and bone-conduction chirp thresholds were similarly significantly elevated by 2.56 dB. I found that air-conduction brief-tone thresholds did not significantly differ from the norms published by the BCEHP (Hatton, Van Maanen, & Stapells, 2022; Small & Stapells, 2017). Air conduction normative threshold results for brief-tones and chirps were significantly greater by 3.93-5.57 dB for frequencies 500 and 1000 Hz compared to previous literature (Fedke & Richter, 2007; Gøtsche-Rasmussen, Poulsen, & Elberling, 2012), although these results are generally below our a-priori definition for clinical significance of ≤5 dB. BC results were significantly lower by 7.21 – 19.67 dB compared to previous literature (Small & Stapells, 2003) for 500 through 2000 Hz, all of which fall above our definition of clinical significance. A closer look at my data revealed variable participant response patterns to the Bekesy audiometry procedure. Thus, there is a caveat to the results collected in this study, and further research is needed to explore the reliability of intra-participant response patterns in comparison to other automated and manual behavioural audiometric tests.

Text

2023-10-18

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/86193

Audiology and Speech Sciences

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/