Modelling the speech reception threshold in non-stationary noise in hearing-impaired listeners as a function of level

Abstract

The extended speech intelligibility index (ESII) model () forms an upgrade to the conventional speech intelligibility index model. For normal-hearing listeners the ESII model is able to predict the speech reception threshold (SRT) in both stationary and non-stationary noise maskers. In this paper, a first attempt is made to evaluate the ESII with SRT data obtained by , and of hearing-impaired listeners in stationary, 10-Hz interrupted, and non-stationary speech-shaped noise measured at different noise levels. The results show that the ESII model is able to describe the SRT in different non-stationary noises for normal-hearing listeners at different noise levels reasonably well. However, the ESII model is less successful in the case of predicting the SRT in non-stationary noise for hearing-impaired subjects. As long as the present audibility models cannot describe the auditory processing in a listener with cochlear hearing loss accurately, it is difficult to distinguish between raised SRTs due to supra-threshold deficits or factors such as cognition, age, and language skills.

Sumario

El modelo del Índice extendido de inteligibilidad del lenguaje (ESII) () constituye una actualización del modelo de índice convencional de inteligibilidad del lenguaje. Para oyentes con audición normal, el modelo del ESII es capaz de predecir el umbral de recepción del lenguaje (SRT) tanto ante enmascaradores de ruido estacionario y como no estacionario. En este trabajo, se realiza un primer intento para evaluar el ESII con datos del SRT obtenidos por Laat y Plomp (1983) y a partir de sujetos con hipoacusia, en ruido estacionario, con interrupciones de 10-Hz, y en ruido no estacionario con conformación de lenguaje, medido a diferentes niveles de intensidad. Los resultados muestran que el modelo ESII es capaz de describir el SRT razonablemente bien, para diferentes ruidos no estacionarios en sujetos normo-oyentes, a diferentes niveles de intensidad. Sin embargo, el modelo ESII es menos exitoso para predecir el SRT en ruido no estacionario con sujetos hipoacúsicos. En tanto que los modelos presentes de audibilidad no puedan describir el procesamiento auditivo en un sujeto con pérdida auditiva coclear en forma exacta, es difícil distinguir entre un SRT elevado debido a una deficiencia supra-umbral o a factores tales como cognición, edad o habilidad para el lenguaje.     

Development and preliminary evaluation of a new test of ongoing speech comprehension

Objective: The overall goal of this work is to create new speech perception tests that more closely resemble real world communication and offer an alternative or complement to the commonly used sentence recall test. Design: We describe the development of a new ongoing speech comprehension test based on short everyday passages and on-the-go questions. We also describe the results of an experiment conducted to compare the psychometric properties of this test to those of a sentence test. Study sample: Both tests were completed by a group of listeners that included normal hearers as well as hearing-impaired listeners who participated with and without their hearing aids. Results: Overall, the psychometric properties of the two tests were similar, and thresholds were significantly correlated. However, there was some evidence of age/cognitive effects in the comprehension test that were not revealed by the sentence test. Conclusions: This new comprehension test promises to be useful for the larger goal of creating laboratory tests that combine realistic acoustic environments with realistic communication tasks. Further efforts will be required to assess whether the test can ultimately improve predictions of real-world outcomes.     

A Spanish matrix sentence test for assessing speech reception thresholds in noise

Objective: To develop, optimize, and evaluate a new Spanish sentence test in noise. Design: The test comprises a basic matrix of ten names, verbs, numerals, nouns, and adjectives. From this matrix, test lists of ten sentences with an equal syntactical structure can be formed at random, with each list containing the whole speech material. The speech material represents the phoneme distribution of the Spanish language. The test was optimized for measuring speech reception thresholds (SRTs) in noise by adjusting the presentation levels of the individual words. Subsequently, the test was evaluated by independent measurements investigating the training effects, the comparability of test lists, open-set vs. closed-set test format, and performance of listeners of different Spanish varieties. Study sample: In total, 68 normal-hearing native Spanish-speaking listeners. Results: SRTs measured using an adaptive procedure were 6.2 ± 0.8 dB SNR for the open-set and 7.2 ± 0.7 dB SNR for the closed-set test format. The residual training effect was less than 1 dB after using two double-lists before data collection. Conclusions: No significant differences were found for listeners of different Spanish varieties indicating that the test is applicable to Spanish as well as Latin American listeners. Test lists can be used interchangeably.     

Influence of noise type on speech reception thresholds across four languages measured with matrix sentence tests

Objective: To compare speech reception thresholds (SRTs) in noise using matrix sentence tests in four languages: German, Spanish, Russian, Polish. Design: The four tests were composed of equivalent five-word sentences and were all designed and optimized using the same principles. Six stationary speech-shaped noises and three non-stationary noises were used as maskers. Study sample: Forty native listeners with normal hearing: 10 for each language. Results: SRTs were about 3 dB higher for the German and Spanish tests than for the Russian and Polish tests when stationary noise was used that matched the long-term frequency spectrum of the respective speech test materials. This general SRT difference was also observed for the other stationary noises. The within-test variability across noise conditions differed between languages. About 56% of the observed variance was predicted by the speech intelligibility index. The observed SRT benefit in fluctuating noise was similar for all tests, with a slightly smaller benefit for the Spanish test. Conclusions: Of the stationary noises employed, noise with the same spectrum as the speech yielded the best masking. SRT differences across languages and noises could be attributed in part to spectral differences. These findings provide the feasibility and limits of comparing audiological results across languages.     

A comparison of CIC and BTE hearing aids for three-dimensional localization of speech

Abstract

Three-dimensional sound localization of speech in anechoic space was examined for eleven listeners with sensorineural hearing loss. The listeners were fitted bilaterally with CIC and BTE hearing aids having similar bandwidth capabilities. The goal was to determine whether differences in microphone placement for these two styles (CICs at the ear canal entrance; BTEs above the pinna) would influence the availability of pinna-related spectral cues and hence localization performance. While lateral and polar angle localization was unaffected by the hearing aid style, the rate of front-back reversals was lower with CICs. This pattern persisted after listeners accommodated to each set of aids for a six week period, although the overall rate of reversals declined. Performance on all measures in all conditions was considerably poorer than in a control group of listeners with normal hearing.

Sumario

Se evaluó la localización tridimensional de sonidos del habla en un espacio anecoide en once personas con pérdida auditiva sensorineural. A los once se les adaptaron CIC y BTE bilateralmente con capacidad de ancho de banda similar. El objetivo fue determinar si las diferencias en la colocación del micrófono con ambos tipos (CIC en el ingreso del conducto auditivo; BTE sobre el pabellón auricular) podría influenciar la disponibilidad de claves espectrales relacionadas con el pabellón y por ello, el rendimiento para la localización. Mientras que la localización del ángulo lateral y polar no fue afectada por el tipo de auxiliar, la tasa de inversiones frente-atrás fue menor con los CIC. Este patrón persistió después de que estas personas se acostumbraron a cada set de auxiliares por un período de seis semanas, a pesar de que declinó la tasa global de reversiones. El rendimiento en todas las mediciones y condiciones fue considerablemente más pobre que en el grupo control de personas con audición normal.     

Adaptation of the STARR test for adult Italian population: A speech test for a realistic estimate in real-life listening conditions

Objectives: To introduce the Italian adaptation of the STARR test based on a roving-level adaptive method to mimic challenging real-life listening conditions for use in people with auditory prostheses. Design: Normative data were collected and interlist-variability, as well as learning effects, were investigated using a within-subject design with repeated measures. Study sample: A group of 32 normal-hearing (NH) adults participated in the study. Results: The average speech reception threshold (SRT) for NH subjects was??8.4 dB SNR. The variability of mean SRTs across test lists was relatively small (≤1 dB for all test lists). The statistically significant differences between lists were eliminated after applying correction factors. On the basis of variability for the corrected SRTs within each subject, a difference of 2.8 dB in SRT was meaningful for outcome comparisons using one test list per condition and 2 dB using two lists per condition. Statistical analysis did not show any significant learning effects. Conclusions: Findings in NH listeners suggested that the Italian STARR test could be a promising supplement to existing speech assessment tools. Further studies in populations with hearing impairment could contribute to cross-language studies.     

Prior exposure to a reverberant listening environment improves speech intelligibility in adult cochlear implant listeners

Objectives: The goal of this study is to investigate whether prior exposure to reverberant listening environment improves speech intelligibility of adult cochlear implant (CI) users.

Methods: Six adult CI users participated in this study. Speech intelligibility was measured in five different simulated reverberant listening environments with two different speech corpuses. Within each listening environment, prior exposure was varied by either having the same environment across all trials (blocked presentation) or having different environment from trial to trial (unblocked).

Results: Speech intelligibility decreased as reverberation time increased. Although substantial individual variability was observed, all CI listeners showed an increase in the blocked presentation condition as compared to the unblocked presentation condition for both speech corpuses.

Conclusion: Prior listening exposure to a reverberant listening environment improves speech intelligibility in adult CI listeners. Further research is required to understand the underlying mechanism of adaptation to listening environment.     

Evaluation of the NAL Dynamic Conversations Test in older listeners with hearing loss

Objective: The National Acoustic Laboratories Dynamic Conversations Test (NAL-DCT) is a new test of speech comprehension that incorporates a realistic environment and dynamic speech materials that capture certain features of everyday conversations. The goal of this study was to assess the suitability of the test for studying the consequences of hearing loss and amplification in older listeners. Design: Unaided and aided comprehension scores were measured for single-, two- and three-talker passages, along with unaided and aided sentence recall. To characterise the relevant cognitive abilities of the group, measures of short-term working memory, verbal information-processing speed and reading comprehension speed were collected. Study sample: Participants were 41 older listeners with varying degrees of hearing loss. Results: Performance on both the NAL-DCT and the sentence test was strongly driven by hearing loss, but performance on the NAL-DCT was additionally related to a composite cognitive deficit score. Benefits of amplification were measurable but influenced by individual test SNRs. Conclusions: The NAL-DCT is sensitive to the same factors as a traditional sentence recall test, but in addition is sensitive to the cognitive factors required for speech processing. The test shows promise as a tool for research concerned with real-world listening.     

Psychometrically equivalent trisyllabic words for speech reception threshold testing in Mandarin

The aim of this investigation was to develop, digitally record, evaluate, and equate Mandarin trisyllabic words, which could then be used to measure the SRT. A selection of 90 frequently utilized trisyllabic words were digitally recorded by male and female talkers of Standard Mandarin and presented to 20 normally hearing subjects at 13 intensity levels (?10 to 14?dB?HL) in 2?dB increments. Using logistic regression, psychometric functions were then calculated for all words. Twenty-four trisyllabic words with steep psychometric function slopes were selected, and their intensities were digitally adjusted to match the mean subject PTA (3.0?dB?HL). The mean slopes for the 24 selected male and female trisyllabic Mandarin Chinese words were 11.3%/dB and 12.1%/dB, respectively. Thus we developed a list of words which were homogeneous with respect to audibility and slope. Digital recordings of the psychometrically equivalent trisyllabic words are available on compact disc.     

Learning effect observed for the speech reception threshold in interrupted noise with normal hearing listeners

Traditionally, the speech reception threshold (SRT) for sentences in noise is measured in stationary speech-shaped noise; however, non-stationary masking noises are gradually becoming more common. A previous study by Rhebergen et al. () suggested that a learning effect might be present for the SRT in interrupted noise but not in stationary noise. The current study tested if a stable SRT for female or male speech is reached by determining SRTs in listeners with normal hearing in either stationary or 8-Hz interrupted noise after five replications. Contrary to repeated SRT measurements in stationary noise, a significant improvement was observed for SRTs in interrupted noise with replication. For both speech materials, after five replications, the SRT in interrupted noise improved about 3 to 4 dB in comparison to the first SRT. Stable thresholds seem to be reached after about two replications. This experiment shows that there is a substantial learning effect present in SRT measurements with interrupted noise but not in stationary noise. With non-stationary noise, it is recommended to include a repeated measures design.     

Tolerable delay for speech production and perception: effects of hearing ability and experience with hearing aids

Objective: Processing delay is one of the important factors that limit the development of novel algorithms for hearing devices. In this study, both normal-hearing listeners and listeners with hearing loss were tested for their tolerance of processing delay up to 50?ms using a real-time setup for own-voice and external-voice conditions based on linear processing to avoid confounding effects of time-dependent gain. Design: Participants rated their perceived subjective annoyance for each condition on a 7-point Likert scale. Study sample: Twenty normal-hearing participants and twenty participants with a range of mild to moderate hearing losses. Results: Delay tolerance was significantly greater for the participants with hearing loss in two out of three voice conditions. The average slopes of annoyance ratings were negatively correlated with the degree of hearing loss across participants. A small trend of higher tolerance of delay by experienced users of hearing aids in comparison to new users was not significant. Conclusion: The increased tolerance of processing delay for speech production and perception with hearing loss and reduced sensitivity to changes in delay with stronger hearing loss may be beneficial for novel algorithms for hearing devices but the setup used in this study differed from commercial hearing aids.     

Adaptation of the speech,spatial, and qualities of hearing scale for use with children,parents, and teachers

Abstract

Subjective assessment of hearing ability in everyday life complements more objective forms of evaluation. A broad evaluation of the additional benefit provided to children by a second bilateral cochlear implant required such an assessment. As no paediatric tool provided detailed evaluation of performance in the areas of daily listening in which benefit was likely to be demonstrated, an adult questionnaire was adapted. Items of the Speech, Spatial and Qualities of Hearing Scale (SSQ) focused mainly, although not exclusively, on hearing functions requiring the binaural system. The adapted child, parent, and teacher versions of the SSQ retained the structure of rating listening performance in everyday scenarios across the domains of speech perception, spatial hearing, and other qualities of hearing. Modifications were minimized, although deletion of some items and wording changes were required, and some subdomains could not be included. Observation periods were introduced so that parents and teachers observe performance prior to providing ratings. The suggested minimum age is 11 years for the child version and 5 years for the parent and teacher versions. Instructions indicate interview-style administration in which interpretation of the described listening scenarios can be clarified and use of the ruler-style response format demonstrated. Researchers applying the SSQ for parents have reported higher performance ratings for bilateral over unilateral cochlear implants, particularly in the spatial hearing domain. Further research should provide evidence for the target age range, compare child and parent responses, and evaluate modifications for use with younger children.     

A longitudinal study of changes in evoked otoacoustic emissions and pure-tone thresholds as measured in a hearing conservation program

Non-linear transient-evoked otoacoustic emissions (TEOAEs) at 74 dB pSPL, distortion-product otoacoustic emissions (DPOAEs) at 65/45 dB SPL and pure-tone audiometry were used to detect noise-induced, inner ear changes in a longitudinal study. Repeated-measures ANOVAs were made on the Noise (n=69) and Quiet (n=42) groups. The Noise group's hearing thresholds increased by 1.2 dB and DPOAE amplitude decreased by ?0.9 dB. For both groups, TEOAE amplitude decreased by approximately ?0.6 dB. Eight of 12 ears with permanent threshold shift (PTS) and 10 of 13 ears with temporary threshold shift (TTS) showed TEOAE decrements or low baseline TEOAE amplitudes. Fewer TTS and PTS ears also showed DPOAE decrements, and there was never a DPOAE decrement without a corresponding TEOAE decrement or low TEOAE baseline. Some TTS ears showed permanent emission decrements. Although otoacoustic emissions show promise in detecting noise-induced inner ear changes, it is premature to use them in hearing conservation programs.     

Assessing speech recognition abilities with digits in noise in cochlear implant and hearing aid users

Objective: The primary objective of the study was to investigate the feasibility, reliability, and validity of the Dutch digits in noise (DIN) test for measuring speech recognition in hearing aid and cochlear implant users and compare results to the standard sentences-in-noise (SIN) test. Design: The relation between speech reception thresholds for DIN test and SIN test was analysed to determine the validity of the DIN test. As linguistic skills were expected to make different contributions in these tests, their influence was analysed. Study sample: Participants were 12 normal-hearing listeners, 24 hearing aid users, and 24 cochlear implant users. Results: The DIN test was feasible for more participants than the SIN test. Intraclass correlation coefficients showed high reliability. The standard error of measurement was smaller for the DIN test than for the SIN test. DIN test and SIN test were highly correlated (r = 0.95 and r = 0.56 for NH+ HA and CI users respectively). In the regression analysis no significant contribution of basic linguistic skills or personal factors was found. Conclusion: In the assessment of speech recognition in noise of aided hearing-impaired listeners with hearing aids or cochlear implants, the DIN test is a feasible, reliable and valid test.     

Sex-specific predictors of hearing-aid use in older persons: The age,gene/environment susceptibility - Reykjavik study

Objective: We estimate the prevalence of hearing-aid use in Iceland and identify sex-specific factors associated with use. Design: Population-based cohort study. Study sample: A total of 5172 age, gene/environment susceptibility - Reykjavik study (AGES-RS) participants, aged 67 to 96 years (mean age 76.5 years), who completed air-conduction and pure-tone audiometry. Results: Hearing-aid use was reported by 23.0% of men and 15.9% of women in the cohort, although among participants with at least moderate hearing loss in the better ear (pure-tone average [PTA] of thresholds at 0.5, 1, 2, and 4 kHz ≥ 35 dB hearing level [HL]) it was 49.9% and did not differ by sex. Self-reported hearing loss was the strongest predictor of hearing-aid use in men [OR: 2.68 (95% CI: 1.77, 4.08)] and women [OR: 3.07 (95% CI: 1.94, 4.86)], followed by hearing loss severity based on audiometry. Having diabetes or osteoarthritis were significant positive predictors of use in men, whereas greater physical activity and unimpaired cognitive status were important in women. Conclusions: Hearing-aid use was comparable in Icelandic men and women with moderate or greater hearing loss. Self-recognition of hearing loss was the factor most predictive of hearing-aid use; other influential factors differed for men and women.     

Electrocochleographic documentation of temporal findings of speech perception in normal and hearing-impaired individuals

Compound action potentials (CAPs) evoked by the short Japanese syllables /a/ and /ka/ were recorded by extratympanic electrocochleography in 17 subjects with normal hearing (17 ears) and 34 patients with sensorineural hearing losses (35 ears) to investigate the temporal aspects of speech coding for perception. In normal ears, three characteristics were found common to the temporal patterns of all CAPs: (1) a prominent CAP at the beginning of both stimuli; (2) periodic CAPs with the same interval as the pitch period through the vowel part of both stimuli; (3) absence of a prominent CAP at the onset of voice. These characteristics may help to produce consonant recognition. Among the subjects with sensorineural hearing loss, some ears showed the following two characteristics different from those with normal hearing: (1) a significantly lower CAP at the onset of both stimuli than in those with normal hearing; (2) decay of CAPs during the voiced part. These findings may result in abnormal loudness perception in sensorineural hearing loss as produced by loudness recruitment and pathological adaptation. Such different temporal patterns of CAPs may have an adverse influence on the speech discrimination of patients with sensorineural hearing impairments. Received: 16 February 1999 / Accepted: 17 June 1999     

The clinical utility of expressing hearing thresholds in terms of the forward-going sound pressure wave

Abstract

Objective: To assess the clinical utility of quantifying pure-tone hearing thresholds in terms of the forward-going sound pressure wave. Design: Sound pressure measurements in the ear canal were used to derive, with hearing threshold measurements, hearing thresholds expressed in terms of the forward-going sound pressure wave, hearing thresholds based on coupler-based calibration, and hearing thresholds expressed in terms of the sound pressure measured at the microphone. Study sample: Fifty-two adults, 18 to 34 years of age, served as the study group. Results: Audiogram configurations were similar up to 2000 Hz for the three expressions of hearing threshold, consistent with the ear canal acting as a simple volume up to this frequency. Above 2000 Hz, notable differences in hearing threshold were found, consistent with the acoustic input impedance of the ear differing from a rigid, hard-walled cavity. Repeat testing showed all three expressions of hearing threshold to be repeatable. High density measurements of hearing threshold from 3000 to 6000 Hz provided qualified support for the derivation of the forward-going sound pressure wave. Conclusions: Hearing thresholds expressed in terms of the forward-going sound pressure wave are repeatable, and with in-situ calibration, may be superior to the current coupler-based method.     

Amplification of transcutaneous and percutaneous bone-conduction devices with a test-band in an induced model of conductive hearing loss

Objective: Transcutaneous devices have a disadvantage, the dampening effect by soft tissue between the bone and devices. We investigated hearing outcomes with percutaneous and transcutaneous devices using test-bands in an induced unilateral conductive hearing loss. Design: Comparison of hearing outcomes of two devices in the same individuals. Study sample: The right ear was plugged in 30 subjects and a test-band with devices (Cochlear? Baha® BP110 Power and Sophono® Alpha-2 MPO?) was applied on the right mastoid tip with the left ear masked. Sound-field thresholds, speech recognition thresholds (SRTs), and word recognition scores (WRSs) were compared. Results: Aided thresholds of Sophono were significantly better than those of Baha at most frequencies. Sophono WRSs (86?±?12%) at 40?dB SPL and SRTs (14?±?5?dB HL) were significantly better than those (73?±?24% and 23?±?8?dB HL) of Baha. However, Sophono WRSs (98?±?3%) at 60?dB SPL did not differ from Baha WRSs (95?±?12%). Conclusion: Amplifications of the current transcutaneous device were not inferior to those of percutaneous devices with a test-band in subjects with normal bone-conduction thresholds. Since the percutaneous devices can increase the gain when fixed to the skull by eliminating the dampening effect, both devices are expected to provide sufficient hearing amplification.