Masking Release for Speech in Modulated Maskers: Electrophysiological and Behavioral Measures

Abstract

Objectives-The purpose of this study was to obtain an electrophysiological analog of masking release using speech-evoked cortical potentials in steady and modulated maskers, and to relate this masking release to behavioral measures for the same stimuli. The hypothesis was that the evoked potentials can be tracked to a lower stimulus level in a modulated masker than in a steady masker, and that the magnitude of this electrophysiological masking release is of the same order as that of the behavioral masking release for the same stimuli. Design-Cortical potentials evoked by an 80-ms /ba/ stimulus were measured in two steady maskers (30-and 65-dB SPL), and in a masker that modulated between these two levels at a rate of 25 Hz. In each masker, a level series was undertaken to determine electrophysiological threshold. Behavioral detection thresholds were determined in the same maskers using an adaptive tracking procedure. Masking release was defined as the difference between signal thresholds measured in the steady 65-dB SPL masker and the modulated masker. A total of 23 normalhearing adults participated. Results-Electrophysiological thresholds were uniformly elevated relative to behavioral thresholds by about 6.5 dB. However, the magnitude of masking release was about 13.5 dB for both measurement domains. Conclusions-Electrophysiological measures of masking release using speech-evoked cortical auditory evoked potentials correspond closely to behavioral estimates for the same stimuli. This suggests that objective measures based on electrophysiological techniques can be used to reliably gauge aspects of temporal processing ability.

The effect of noise on the amplitude and morphology of cortical auditory evoked potentials

“…This result was already expected and, therefore, the comparison of latencies between the two stimulus presentation conditions is irrelevant for the study of the forward masking phenomenon. The reduced amplitudes in the Delta-t 64 ms condition demonstrate that with the presentation of noise, the cortical responses are expressed at a lower magnitude, characterizing the forward masking phenomenon 4 , 16 ( Table 2 ).…”

“…16 The clinical application of the CAEPs is still not prevalent in the field of audiology; however, the test has shown to be relevant, including for the study of speech comprehension in the presence of noise. 4 , 21 , 22 …”

O benefício do mascaramento modulado nos potenciais evocados auditivos corticais com estímulo de fala

“…Essa diferença no limiar entre as duas condições de mascaramento pode ser tomada como uma medida representante da habilidade de resolução temporal dos indivíduos, estando relacionada à integridade do processamento temporal (8) .…”

“…Para medidas eletrofisiológicas, a diferença no limiar entre as duas condições de mascaramento é tomada como uma medida representante da habilidade de resolução temporal dos indivíduos (8) .…”

Age-Related Differences in Early Cortical Representations of Target Speech Masked by Either Steady-State Noise or Competing Speech

“…Indeed, there is evidence that the release from masking due to certain characteristics of the stimulus is comparable in magnitude between behavioural and electrophysiological domains. Tanner et al (2019) examined the CAEPs evoked by a /ba/ presented concurrently with either steady-state maskers of 30 and 60 SPL, or a masker that was modulating between the two levels, and examined the electrophysiological and behavioural threshold for detection under all three maskers. The authors found a release from masking of about 13.5 dB in magnitude in both the behavioural and electrophysiological domains.…”