The effects of selective consonant amplification on sentence recognition in noise by hearing-impaired listeners

Abstract

Weak consonants (e.g., stops) are more susceptible to noise than vowels, owing partially to their lower intensity. This raises the question whether hearing-impaired (HI) listeners are able to perceive (and utilize effectively) the high-frequency cues present in consonants. To answer this question, HI listeners were presented with clean (noise absent) weak consonants in otherwise noisecorrupted sentences. Results indicated that HI listeners received significant benefit in intelligibility (4 dB decrease in speech reception threshold) when they had access to clean consonant information. At extremely low signal-to-noise ratio (SNR) levels, however, HI listeners received only 64% of the benefit obtained by normal-hearing listeners. This lack of equitable benefit was investigated in Experiment 2 by testing the hypothesis that the high-frequency cues present in consonants were not audible to HI listeners. This was tested by selectively amplifying the noisy consonants while leaving the noisy sonorant sounds (e.g., vowels) unaltered. Listening tests indicated small ($10%), but statistically significant, improvements in intelligibility at low SNR conditions when the consonants were amplified in the high-frequency region. Selective consonant amplification provided reliable low-frequency acoustic landmarks that in turn facilitated a better lexical segmentation of the speech stream and contributed to the small improvement in intelligibility.

Sentence intelligibility during segmental interruption and masking by speech-modulated noise: Effects of age and hearing loss

“…Second, the similarly high performance in the consonant condition, where the local SNR during vowel segments was estimated at 0 dB SNR, may indicate the relative preservation of cues during the vowel and during transitional information at the consonant-vowel boundary that significantly contributes to intelligibility (e.g., Chen and Loizou, 2012;Lee and Kewley-Port, 2009). Previous studies have implemented testing similar to the consonant condition here using IEEE sentences in 20-talker babble for normal hearing listeners (Li and Loizou, 2008) and older listeners with normal and impaired hearing (Saripella et al, 2011). Across both studies, authors found that preservation of obstruent consonants significantly contributes to intelligibility, providing gains of 20-40 percentage points compared to overall scores for speech in continuous noise at À5 dB SNR.…”

Masking release for hearing-impaired listeners: The effect of increased audibility through reduction of amplitude variability

“…Although seemingly similar to EEQ processing, there are important differences between the two methods. First, many implementations of CV ratio enhancement (e.g, GordonSalant, 1986;Kennedy et al, 1998) require explicit segmentation of speech into consonant and vowel components, or attempt to approximate segmentation using approaches such as detection of voiced versus unvoiced segments (Skowronski and Harris, 2006;Saripella et al, 2011) or cross-frequency-band energy comparisons (Preves et al, 1991). The relative energies from these segments are used to explicitly adjust the CV ratio.…”

Speech Perception in Older Hearing Impaired Listeners: Benefits of Perceptual Training

“…Older hearing impaired (OHI) listeners exhibit deficits in consonant identification [ 1 – 5 ] that contribute to problems in understanding connected speech, including sentences. Hearing aids (HAs) improve consonant identification in OHI listeners [ 6 ], with the magnitude of HA benefit on consonant identification correlating with improvements in sentence reception thresholds (SeRTs) [ 7 , 8 ]. However, aided OHI listeners continue to show large deficits in consonant identification in comparison to older listeners with normal hearing (ONH), particularly for harder-to-identify consonants [ 7 ].…”