Perceptual separation of sensorineural hearing loss and auditory neuropathy spectrum disorder

Effects of nonlinear frequency compression on Mandarin speech and sound-quality perception in hearing-aid users

Objective: The purpose of the present study was to examine the effects of NLFC fitting in hearing aids and auditory acclimatisation on speech perception and sound-quality rating in hearing-impaired, native Mandarin-speaking adult listeners.Design: Mandarin consonant, vowel and tone recognition were tested in quiet and sentence recognition in noise (speech-shaped noise at a +5 dB signal-to-noise ratio) with NLFC-on and NLFC-off. Sound-quality ratings were collected on a 0-10 scale at each test session. A generalised linear model and correlational analyses were performed.Study sample: Thirty native Mandarin-speaking adults with moderate-to-severe sensorineural hearing loss were recruited.Results: The hearing-impaired listeners showed significantly higher accuracy with NLFC-on than with NLFC-off for consonant and sentence recognition and the recognition performance improved with both NLFC-on and off as a function of increased length of use. The satisfaction score of sound-quality ratings for different types of sounds significantly increased with NLFC-on than with NLFC-off. The speech recognition results showed moderate to strong correlation with the unaided hearing thresholds.Conclusion: For native Mandarin-speaking listeners with hearing loss, the NLFC technology provided modest but significant improvement in Mandarin fricative and sentence recognition. Subjectively, the naturalness and overall preference of sound-quality satisfaction judgement also improved with NLFC.

Mandarin lexical tone recognition in bimodal cochlear implant users

Objective: To assess the recognition of lexical tones in Mandarin-speaking bimodal cochlear implant (CI) subjects.Design: Lexical tone recognition in quiet and noise (SNR= +5 dB) was measured with electric stimulation (CI alone) or bimodal stimulation (CI + hearing aid (HA)). The recognition and confusion rates of the four tones (T1, T2, T3 and T4) were analysed. Spearman correlation analysis was performed to examine the relationship between hearing levels in the contralateral ear and bimodal benefits.Study sample: Twenty native Mandarin-speaking bimodal CI users, with ages ranging from 16-49 years.Results: Relative to the CI alone, mean tone recognition with the CI + HA improved significantly from 84.1-92.1% correct in quiet (+8 points) and from 57.9-73.1% correct in noise (+15.2 points). Tone confusions between T2 and T3 were the most prominent in all test conditions, and T4 tended to be labelled as T3 in noise. There was no significant correlation between the bimodal benefits for tone recognition and the unaided or HA-aided pure-tone thresholds at 0.25 kHz.Conclusion: Listeners with CI + HA exhibited significantly better tone recognition than with CI alone. The bimodal advantage for tone recognition was greater in noise than in quiet, perhaps due to a ceiling effect in quiet.

Contributions to Speech-Cue Weighting in Older Adults With Impaired Hearing

Purpose In a previous paper (Souza, Wright, Blackburn, Tatman, & Gallun, 2015), we explored the extent to which individuals with sensorineural hearing loss used different cues for speech identification when multiple cues were available. Specifically, some listeners placed the greatest weight on spectral cues (spectral shape and/or formant transition), whereas others relied on the temporal envelope. In the current study, we aimed to determine whether listeners who relied on temporal envelope did so because they were unable to discriminate the formant information at a level sufficient to use it for identification and the extent to which a brief discrimination test could predict cue weighting patterns. Method Participants were 30 older adults with bilateral sensorineural hearing loss. The first task was to label synthetic speech tokens based on the combined percept of temporal envelope rise time and formant transitions. An individual profile was derived from linear discriminant analysis of the identification responses. The second task was to discriminate differences in either temporal envelope rise time or formant transitions. The third task was to discriminate spectrotemporal modulation in a nonspeech stimulus. Results All listeners were able to discriminate temporal envelope rise time at levels sufficient for the identification task. There was wide variability in the ability to discriminate formant transitions, and that ability predicted approximately one third of the variance in the identification task. There was no relationship between performance in the identification task and either amount of hearing loss or ability to discriminate nonspeech spectrotemporal modulation. Conclusions The data suggest that listeners who rely to a greater extent on temporal cues lack the ability to discriminate fine-grained spectral information. The fact that the amount of hearing loss was not associated with the cue profile underscores the need to characterize individual abilities in a more nuanced way than can be captured by the pure-tone audiogram.

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

Mandarin sentence recognition using natural-tone and flat-tone sentences was tested in 22 subjects with sensorineural hearing loss (SNHL) and 25 listeners with normal hearing (NH) in quiet, speech-shaped noise, and two-talker-babble conditions. While little effects of flat tones on sentence recognition were seen in the NH listeners when the signal-to-noise ratio (SNR) was ≥0 dB, the SNHL listeners showed decreases in flat-tone-sentence recognition in quiet and at +5-dB SNR. Such declined performance was correlated with their degrees of hearing loss. Lexical tone contributes greatly to sentence recognition in hearing-impaired listeners in both quiet and in noise listening conditions.

Categorical perception of lexical tones in native Mandarin-speaking listeners with sensorineural hearing loss

BACKGROUND

Categorical perception (CP) of lexical tones was examined in normal hearing (NH) people, but it was unclear whether lexical tones can be perceived categorically in sensorineural hearing loss (SNHL) people.

OBJECTIVES

To explore the characteristic of lexical tone perception in native Mandarin speakers with SNHL.

MATERIALS AND METHODS

Three types of continuum (Tone1/Tone2, Tone1/Tone4 and Tone2/Tone3) were constructed and each of them includes 15 stimuli which were resynthesized by applying the pitch-synchronous overlap and add (PSOLA) method implemented in Praat to the same Mandarin syllable, /a/, with a high-level tone produced by a female speaker. Forty native Mandarin NH speakers and 23 native Mandarin speakers with mild to moderate SNHL were recruited. A two alternative-forced-choice identification task was used to acquire the tonal perceptual data.

RESULTS

All tone perception curves owns the characteristic of CP in SNHL subjects. All tone perception curves were S-shape in SNHL subjects same as those in NH subjects. No significant difference of each continuum was observed between SNHL and NH.

CONCLUSIONS

CP of lexical tone perception could be observed in native Mandarin speakers with mild to moderate SNHL. The slight damage in the peripheral auditory system did not change characteristic of lexical tone perception.

Relative contributions of acoustic temporal fine structure and envelope cues for lexical tone perception in noise

Previous studies have shown that lexical tone perception in quiet relies on the acoustic temporal fine structure (TFS) but not on the envelope (E) cues. The contributions of TFS to speech recognition in noise are under debate. In the present study, Mandarin tone tokens were mixed with speech-shaped noise (SSN) or two-talker babble (TTB) at five signal-to-noise ratios (SNRs; -18 to +6 dB). The TFS and E were then extracted from each of the 30 bands using Hilbert transform. Twenty-five combinations of TFS and E from the sound mixtures of the same tone tokens at various SNRs were created. Twenty normal-hearing, native-Mandarin-speaking listeners participated in the tone-recognition test. Results showed that tone-recognition performance improved as the SNRs in either TFS or E increased. The masking effects on tone perception for the TTB were weaker than those for the SSN. For both types of masker, the perceptual weights of TFS and E in tone perception in noise was nearly equivalent, with E playing a slightly greater role than TFS. Thus, the relative contributions of TFS and E cues to lexical tone perception in noise or in competing-talker maskers differ from those in quiet and those to speech perception of non-tonal languages.