Enhanced Place Specificity of the Parallel Auditory Brainstem Response: A Modeling Study

Abstract

While each place on the cochlea is most sensitive to a specific frequency, it will generally respond to a sufficiently high-level stimulus over a wide range of frequencies. This spread of excitation can introduce errors in clinical threshold estimation during a diagnostic auditory brainstem response (ABR) exam. Off-frequency cochlear excitation can be mitigated through the addition of masking noise to the test stimuli, but introducing a masker increases the already long test times of the typical ABR exam. Our lab has recently developed the parallel ABR (pABR) paradigm to speed up test times by utilizing randomized stimulus timing to estimate the thresholds for multiple frequencies simultaneously. There is reason to believe parallel presentation of multiple frequencies provides masking effects and improves place specificity while decreasing test times. Here, we use two computational models of the auditory periphery to characterize the predicted effect of parallel presentation on place specificity in the auditory nerve. We additionally examine the effect of stimulus rate and level. Both models show the pABR is at least as place specific as standard methods, with an improvement in place specificity for parallel presentation (vs. serial) at high levels, especially at high stimulus rates. When simulating hearing impairment in one of the models, place specificity was also improved near threshold. Rather than a tradeoff, this improved place specificity would represent a secondary benefit to the pABR's faster test times.

Enhanced Place Specificity of the Parallel Auditory Brainstem Response: An Electrophysiological Study

“…Our finding of improved place specificity for the 500 Hz responses supports the findings of our previous study which used computational models to investigate place specificity of the pABR (Stoll & Maddox, 2023). However, the modeling study suggested improvements would be present for almost all stimulus frequencies (depending on the stimulus rate and level), which is not supported by the present study.…”

“…Here, we were able to examine place specificity of the pABR in human subjects, supporting our findings from a previous modeling study examining the same question (Stoll & Maddox, 2023). While we were only able to compare serial and parallel presentation for two stimulus frequencies, all parallel stimulus frequencies were able to be compared.…”

“…We further hypothesized the simultaneous presentation could improve place specificity of responses with no additional masking noise, as each stimulus may serve as both test stimulus and masker since the toneburst trains are uncorrelated (Figure 1). We previously used computational modeling to predict that the pABR produces responses which are more place specific than standard methods (Stoll & Maddox, 2023). We used two models of the auditory periphery to simulate responses across a range of stimulus rates and levels for both parallel (all toneburst trains summed and presented together) and serial (a toneburst train of one frequency presented in isolation) stimuli.…”

“…1). We previously used computational modeling to examine pABR response spread and found that parallel presentation produces responses which are more place specific than standard methods [14]. We used two models of the auditory periphery to simulate responses across a range of stimulus rates and levels for both parallel (all toneburst trains summed and presented together) and serial (a toneburst train of one frequency presented in isolation) stimuli.…”

Fundamental frequency predominantly drives talker differences in auditory brainstem responses to continuous speech

“…Computational modeling has been previously used to simulate ABRs and explore stimulus differences (e.g., Dau, 2003;Stoll and Maddox, 2023;Temboury-Gutierrez et al, 2024). Average ABRs (areas show ± SE) measured in previous work (left, n = 11) and the current study (right, n = 15) are larger and earlier for male-than female-narrated speech.…”