The influence of age and high-frequency hearing loss on sensitivity to temporal fine structure at low frequencies (L)

Cochlear implant (CI) users suffer from elevated speech-reception thresholds and may rely on lip reading. Traditional measures of spatial release from masking quantify speech-reception-threshold improvement with azimuthal separation of target speaker and interferers and with the listener facing the target speaker. Substantial benefits of orienting the head away from the target speaker were predicted by a model of spatial release from masking. Audio-only and audio-visual speech-reception thresholds in normal-hearing (NH) listeners and bilateral and unilateral CI users confirmed model predictions of this head-orientation benefit. The benefit ranged 2–5 dB for a modest 30° orientation that did not affect the lip-reading benefit. NH listeners' and CI users' lip-reading benefit measured 3 and 5 dB, respectively. A head-orientation benefit of ∼2 dB was also both predicted and observed in NH listeners in realistic simulations of a restaurant listening environment. Exploiting the benefit of head orientation is thus a robust hearing tactic that would benefit both NH listeners and CI users in noisy listening conditions.

Section: Group Differencessupporting

confidence: 70%

Head orientation benefit to speech intelligibility in noise for cochlear implant users and in realistic listening conditions

Grange

Culling

2016

“…In the current study ITD500 did not correlate significantly with PTA LF or with audiometric threshold at 500 Hz (r ¼À0.05, p > 0.05). Whilst King et al (2014) found a moderate correlation between TFS-ITD detection and absolute threshold at the same carrier frequency, most others have not (LacherFougère and Demany, 2005;Hopkins and Moore, 2011;Strelcyk and Dau, 2009;Moore et al, 2012a). Whereas Neher et al (2011Neher et al ( , 2012 and Hopkins and Moore (2011) tested ITD detection in quiet, the current study tested ITD detection in noise.…”

Section: B Psychoacoustic Tasksmentioning

confidence: 93%

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

King

Hopkins

Plack

et al. 2017

Self Cite

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.

“…Also, sensitivity to ITDs tends to become poorer with increasing age, even when audiometric thresholds are normal or near-normal (Hopkins and Moore, 2011;Moore et al, 2012a;Moore et al, 2012b). This is important, since most users of hearing aids are older people.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of a method for enhancing interaural level differences at low frequencies

Moore¹,

Kolarik²,

Stone³

et al. 2016

Self Cite

A method (called binaural enhancement) for enhancing interaural level differences at low frequencies, based on estimates of interaural time differences, was developed and evaluated. Five conditions were compared, all using simulated hearing-aid processing: (1) Linear amplification with frequency-response shaping; (2) binaural enhancement combined with linear amplification and frequency-response shaping; (3) slow-acting four-channel amplitude compression with independent compression at the two ears (AGC4CH); (4) binaural enhancement combined with four-channel compression (BE-AGC4CH); and (5) four-channel compression but with the compression gains synchronized across ears. Ten hearing-impaired listeners were tested, and gains and compression ratios for each listener were set to match targets prescribed by the CAM2 fitting method. Stimuli were presented via headphones, using virtualization methods to simulate listening in a moderately reverberant room. The intelligibility of speech at ±60° azimuth in the presence of competing speech on the opposite side of the head at ±60° azimuth was not affected by the binaural enhancement processing. Sound localization was significantly better for condition BE-AGC4CH than for condition AGC4CH for a sentence, but not for broadband noise, lowpass noise, or lowpass amplitude-modulated noise. The results suggest that the binaural enhancement processing can improve localization for sounds with distinct envelope fluctuations.