Narrowband noise masking disproportionately impairs hearing-impaired listeners’ amplitude modulation detection

Evidence

Comparison between AM detection thresholds in quiet and noise demonstrated that the mild HI listeners were heavily impacted by the NB noise. This finding is in line with the idea that the NB noise targets temporal coding fidelity within a single auditory filter, especially because 4 out of 6 HI listeners did not have EFRs at the ‑8 dB modulation depth. Also the NH listeners showed a large variability in how the NB noise impacted their performance with a trend (p = 0.09) towards degraded AM detection performance in NB noise for those listeners with steeper EFR slopes. Even though the NB condition was designed to target within auditory filter aspects of temporal coding fidelity, it is possible that another mechanism could also explain these results. For example, because the temporal envelope of the NB noise waveform is much more fluctuating than the BB noise envelope, it is possible that the quality of a modulation coding mechanism in the brainstem and not the numbers of auditory-nerve fibers responsible for a robust coding of temporal envelopes could also explain the NB results. — Dijk, Pim van, Physiology, Psychoacoustics and…, 5906

Categorization

• QUESTION: The alternative brainstem modulation-coding explanation for the NB result is flagged but not resolved here — worth checking whether later EFR or central measures disambiguate it.