The Effects of Sensorineural Hearing Impairment on Asynchronous Glimpsing of Speech

Abstract

In a previous study with normal-hearing listeners, we evaluated consonant identification masked by two or more spectrally contiguous bands of noise, with asynchronous square-wave modulation applied to neighboring bands. Speech recognition thresholds were 5.1–8.5 dB better when neighboring bands were presented to different ears (dichotic) than when all bands were presented to one ear (monaural), depending on the spectral width of the frequency bands. This dichotic advantage was interpreted as reflecting masking release from peripheral spread of masking from neighboring frequency bands. The present study evaluated this effect in listeners with sensorineural hearing loss, a population more susceptible to spread of masking. Speech perception (vowel-consonant-vowel stimuli, as in /aBa/) was measured in the presence of fluctuating noise that was either modulated synchronously across frequency or asynchronously. Hearing-impaired listeners (n = 9) and normal-hearing controls were tested at either the same intensity (n = 7) or same sensation level (n = 8). Hearing-impaired listeners had mild-to-moderate hearing loss and symmetrical, flat audiometric thresholds. While all groups of listeners performed better in the dichotic than monaural condition, this effect was smaller for the hearing-impaired (3.5 dB) and equivalent-sensation-level controls (3.3 dB) than controls tested at the same intensity (11.0 dB). The present study is consistent with the idea that dichotic presentation can improve speech-in-noise listening for hearing-impaired listeners, and may be enhanced when combined with amplification.

Contributions of lexical tone to Mandarin sentence recognition in hearing-impaired listeners under noisy conditions

“…On the other hand, hearing-impaired listeners have been shown to have broadened frequency resolution (Wang et al, 2015) and impaired temporal fine structure processing (Hopkins and Moore, 2009). As a result, they may not have been able to take advantage of the fluctuations in amplitude in the TTB maskers in order to glimpse speech information that could improve speech recognition (Ozmeral et al, 2016;Hu et al, 2018). Our results indicated that the hearing-impaired listeners performed even worse in the TTB than in the SSN conditions for both natural-tone and flat-tone sentences.…”

“…We attempt to address the issue of contributions of lexical tone to Mandarin sentence recognition in hearing-impaired listeners without using any hearing devices. In addition, hearing impaired listeners often show more susceptibility to fluctuating noise than to steady-state noise (e.g., Bernstein and Grant, 2009;Ozmeral et al, 2016;Hu et al, 2018). Thus, two types of noise [i.e., speech-shaped noise (SSN) and two-talker babble (TTB)] are used in the present study to examine the different masking effects when tone information is removed in the target sentences.…”