The effect of tone-vocoding on spatial release from masking for old, hearing-impaired listeners

Abstract

Old, hearing-impaired listeners generally benefit little from lateral separation of multiple talkers when listening to one of them. This study aimed to determine how spatial release from masking (SRM) in such listeners is affected when the interaural time differences (ITDs) in the temporal fine structure (TFS) are manipulated by tone-vocoding (TVC) at the ears by a master hearing aid system. Word recall was compared, with and without TVC, when target and masker sentences from a closed set were played simultaneously from the front loudspeaker (co-located) and when the maskers were played 45° to the left and right of the listener (separated). For 20 hearing-impaired listeners aged 64 to 86, SRM was 3.7 dB smaller with TVC than without TVC. This difference in SRM correlated with mean audiometric thresholds below 1.5 kHz, even when monaural TFS sensitivity (discrimination of frequency-shifts in identically filtered complexes) was partialed out, suggesting that low-frequency audiometric thresholds may be a good indicator of candidacy for hearing aids that preserve ITDs. The TVC difference in SRM was not correlated with age, pure-tone ITD thresholds, nor fundamental frequency difference limens, and only with monaural TFS sensitivity before control for low-frequency audiometric thresholds.

Impaired Binaural Hearing in Adults: A Selected Review of the Literature

“…Figure 8B shows the deviation from the predictions for the listeners with impaired hearing. In addition, as has been found by others (Jerger et al, 1984;Neher et al, 2011Neher et al, , 2017Bernstein and Trahiotis, 2016, 2018King et al, 2017), low-frequency PTA was a significant predictor both of ITD sensitivity and of BRM.…”

Retracted Article: Temporal fine structure: relations to cognition and aided speech recognition

“…No significant correlations were found between binaural TFS sensitivity and speech recognition in that study (King et al 2017). However, Neher et al (2012) observed a significant association between binaural TFS sensitivity and performance in a test of spatial speech recognition using the same sentence corpus as both King et al (2017) and Strelcyk and Dau (2009). Both King et al (2017) and Neher et al (2012) used a masker of two female talkers.…”

“…However, Neher et al (2012) observed a significant association between binaural TFS sensitivity and performance in a test of spatial speech recognition using the same sentence corpus as both King et al (2017) and Strelcyk and Dau (2009). Both King et al (2017) and Neher et al (2012) used a masker of two female talkers. In contrast, L} ocsei et al (2016) found no evidence of a relation between binaural TFS and matrix sentence recognition in different types of noise, both co-located and separated from the target.…”

“…Strelcyk and Dau (2009) found that both binaural and monaural TFS correlated significantly with speech recognition in two-talker background, or in noise lateralised to one ear, but not with speech presented in amplitude-modulated noise. King et al (2017) also reported mixed results, finding that monaural TFS sensitivity was significantly correlated with natural speech but only when the target and masker were spatially separated. No significant correlations were found between binaural TFS sensitivity and speech recognition in that study (King et al 2017).…”

“…King et al (2017) also reported mixed results, finding that monaural TFS sensitivity was significantly correlated with natural speech but only when the target and masker were spatially separated. No significant correlations were found between binaural TFS sensitivity and speech recognition in that study (King et al 2017). However, Neher et al (2012) observed a significant association between binaural TFS sensitivity and performance in a test of spatial speech recognition using the same sentence corpus as both King et al (2017) and Strelcyk and Dau (2009).…”