The French National Cochlear Implant Registry (EPIIC): Bilateral cochlear implantation.

OBJECTIVES: Assessment of the incidence and results of bilateral cochlear implantation in adults and children in France. MATERIALS AND METHODS: Multicenter retrospective study of data in the French national registry of cochlear implantations from January 1st 2012 to December 31st 2016. Functional results from CAP (Category of Auditory Performance) questionnaires and speech audiometry tests, with mono- and di-syllabic word-lists, were compared before and after implantation. Speech audiometry tests were carried out against a noisy background, except before simultaneous implantations. RESULTS: Nine hundred and forty two bilateral cochlear implantations were performed during this period, that is, 16.4% of all cochlear implantations. Five hundred and eighty eight bilateral implantations were performed sequentially. 59% of the bilateral implantations were performed in children. Bilateral implants significantly improved CAP scores in all cases (P<0.001). Auditory performance, with the two types of word-list, were significantly improved after simultaneous implantation (P<0.01). After sequential implantation, the speech discrimination score, already very good with the first implant, reached 63±26% [0-100] with monosyllabic word lists, and 72±28% [0-100] with dissyllabic words. There were more complications due to surgery in bilateral cases than in the entire population of cochlear recipients (9.1% vs 6.4%, P<0.02). CONCLUSION: Hearing is significantly improved by simultaneous cochlear implantation. For sequential implantation, at one year, when auditory results were already excellent from the first implant, in the bimodal condition CAP scores were significantly improved, although there was no further change in speech audiometry in noise.

Adult normative data for the speech in babble (SiB) test.

Objective: The Speech in Babble (SiB) test assesses the perception of speech in noise in UK adults. Here, we define the normal range of SiB scores to enable the use of the test in clinic.Design: In each test, 25 monosyllabic words were played in background multi-talker babble. Listeners had to repeat the word they heard. An adaptive procedure was used to determine the signal-to-noise ratio needed to reach 50% correct responses (i.e. the Speech Reception Threshold). Eight distinct equivalent lists were available.Study sample: Sixty-nine normal-hearing adults (aged 20-57 years) with no reported listening difficulties participated in the study and completed the SiB test twice in both ears.Results: Normative SiB scores varied from -0.8 dB to 3.7 dB suggesting that patients outside these limits should be considered as having abnormal scores. No statistically significant difference between ears and no effect of age or sex was found. There was "fair" test-retest reliability.Conclusion: The SiB test is a short, valid and reliable test that can be used in UK clinics, e.g. as part of a standard APD battery or evaluating the performance of hearing impaired patients.

The effect of presentation level on spectrotemporal modulation detection.

The understanding of speech in noise relies (at least partially) on spectrotemporal modulation sensitivity. This sensitivity can be measured by spectral ripple tests, which can be administered at different presentation levels. However, it is not known how presentation level affects spectrotemporal modulation thresholds. In this work, we present behavioral data for normal-hearing adults which show that at higher ripple densities (2 and 4 ripples/oct), increasing presentation level led to worse discrimination thresholds. Results of a computational model suggested that the higher thresholds could be explained by a worsening of the spectrotemporal representation in the auditory nerve due to broadening of cochlear filters and neural activity saturation. Our results demonstrate the importance of taking presentation level into account when administering spectrotemporal modulation detection tests.

La fluidez verbal en personas mayores y su relación con variables psicosociales y de funcionamiento cognitivo / Verbal fluency in older people and its relationship with psychosocial variables and cognitive performance

Introducción: El análisis de la fluidez verbal en la vejez ha sido una de las principales estrategias como parte del diagnóstico de la demencia. Así, los estudios han demostrado que, en comparación con ancianos sanos, las personas con demencia muestran un deterioro significativo en fluidez verbal -especialmente en fluidez semántica- incluso después de controlar estadísticamente variables como la edad y el nivel educativo. Objetivo: El objetivo del estudio realizado es analizar la ejecución de personas mayores en una tarea de fluidez semántica y relacionarla con su rendimiento en otras tareas cognitivas (memoria de trabajo, atención y una prueba de screening), así como determinar la influencia de variables como el nivel educativo, la edad y el sexo en el rendimiento en la tarea de fluidez. Método: En el estudio han participado un total de 264 personas con una edad media de 79.57 años de la provincia de Granada. Los participantes han sido evaluados con una entrevista estructurada de variables psicosociales, una batería de evaluación neuropsicológica que incluye pruebas de fluidez, memoria, atención, y funcionamiento cognitivo general. Resultados: Los resultados muestran diferencias significativas en fluidez verbal en función del estatus cognitivo de las personas y del rango de edad. Igualmente se observan correlaciones significativas entre la fluidez y el resto de pruebas cognitivas aplicadas, siendo una prueba de screening cognitivo la que mejor predice la ejecución en fluidez. Conclusiones: Los datos obtenidos corroboran la importancia de la utilización de pruebas de fluidez en la evaluación psicológica de las personas mayores

Introduction: The analysis of verbal fluency in old age has been one of the main strategies as part of the diagnosis of dementia. Thus, studies have shown that, compared to healthy elderly people, those with dementia show a significant deterioration in verbal fluency -especially in semantic fluency- even after the statistical control of variables such as age and educational level. Objective: The objective of the study is to analyze the performance of older people in a task of semantic fluency and relate it to their performance in other cognitive tasks (working memory, attention task and a screening test) as well as to determine the influence of variables such as educational level, age and gender in the fluency task performance. Method: A total of 264 people with an average age of 79.57 years from the province of Granada participated in the study. Participants were evaluated with a structured interview of psychosocial variables, a battery of neuropsychological assessment that included tests of fluency, memory, attention, and general cognitive functioning. Results: The results showed significant differences in verbal fluency based on the cognitive status of the persons and the age range. Likewise, significant correlations were observed between fluency and the rest of past cognitive tests, the cognitive screening test being the best predictor of fluency performance. Conclusions: The data obtained corroborate the importance of the use of fluency tests in the psychological assessment of the elderly

Cochlear implantation in early deafened, late implanted adults: Do they benefit?

OBJECTIVES: The aim of this study was to quantify the benefit gained from cochlear implantation in pre- or peri-lingually deafened patients who were implanted as adults Methods: This was a retrospective case-control study. Auditory (BKB/CUNY/3AFC/Environmental sounds), quality of life (GBI/HUI3) and cognitive (customized questionnaire) outcomes in 26 late implanted pre- or peri-lingually deafened adults were compared to those of 30 matched post-lingually deafened, traditional cochlear implant users. RESULTS: There was a statistically significant improvement in all scores in the study group following cochlear implantation. BKB scores for cases was 49.8% compared to 83.6% for controls (p=0.037). CUNY scores for cases was 61.7% compared to 90.3% for controls (p=0.022). The 3AFC and environmental sounds scores were also better in controls compared to cases but the difference was not statistically significant. Quality of life scores improved following implantation in cases and controls but the improvement was only statistically significant in the controls. There was a 7.7% non-user rate in the cases. There were no non-users in the control group. DISCUSSION: Early deafened,,late implanted patients can benefit audiologically from cochlear implantation and in this study the improvement in speech discrimination scores was greater than expected perhaps reflecting careful selection of patients. Nevertheless, audiological benefits are limited compared to traditional cochlear implant recipients with the implant acting as an aid to lip reading in most cases. CONCLUSION: With careful selection of candidates, cochlear implantation is beneficial in early deafened, late implanted patients.

Quantification of the effects of Mandarin dialect differences on the use of norm-referenced speech perception tests.

OBJECTIVE: Determine the effects of Chinese dialects on results for the Mandarin HINT recorded with a talker speaking Standard Mandarin (Putonghua). DESIGN: Normally-hearing subjects with different dialect exposure histories and usage preferences were administered the Mandarin HINT, and results were compared with published norms. Additional published measures of the intelligibility and mutual intelligibility of Chinese dialects were used to identify dialects for which Putonghua is highly intelligible. STUDY SAMPLE: One sample (N = 19) was exposed to a variety of dialects throughout China during childhood, and used Putonghua as adults. A second sample (N = 22) was exposed to Sichuanhua (the dialect found in Sichuan province) during childhood, and used Sichuanhua as adults. RESULTS: The average difference in SRTs for the Putonghua and Sichuanhua groups was 0.66 dB, with the Sichuanhua group's SRTs slightly higher. Means for neither group fell outside the confidence intervals for the norms. Putonghua is intelligible for 98% of Sichuanhua dialect users, and for over 90% of the users of two-thirds of the remaining Chinese regional dialects. CONCLUSIONS: Norm-referenced speech perception tests, such as the Mandarin HINT, can be used with speakers of Chinese regional dialects for whom Putonghua is highly intelligible. Small differences in dialect-specific norms are not clinically significant.

Prediction of IOI-HA scores using speech reception thresholds and speech discrimination scores in quiet.

BACKGROUND: Outcome measures can be used to improve the quality of the rehabilitation by identifying and understanding which variables influence the outcome. This information can be used to improve outcomes for clients. In clinical practice, pure-tone audiometry, speech reception thresholds (SRTs), and speech discrimination scores (SDSs) in quiet or in noise are common assessments made prior to hearing aid (HA) fittings. It is not known whether SRT and SDS in quiet relate to HA outcome measured with the International Outcome Inventory for Hearing Aids (IOI-HA). PURPOSE: The aim of the present study was to investigate the relationship between pure-tone average (PTA), SRT, and SDS in quiet and IOI-HA in both first-time and experienced HA users. RESEARCH DESIGN: SRT and SDS were measured in a sample of HA users who also responded to the IOI-HA. STUDY SAMPLE: Fifty-eight Danish-speaking adult HA users. DATA COLLECTION AND ANALYSIS: The psychometric properties were evaluated and compared to previous studies using the IOI-HA. The associations and differences between the outcome scores and a number of descriptive variables (age, gender, fitted monaurally/binaurally with HA, first-time/experienced HA users, years of HA use, time since last HA fitting, best ear PTA, best ear SRT, or best ear SDS) were examined. A multiple forward stepwise regression analysis was conducted using scores on the separate IOI-HA items, the global score, and scores on the introspection and interaction subscales as dependent variables to examine whether the descriptive variables could predict these outcome measures. RESULTS: Scores on single IOI-HA items, the global score, and scores on the introspection (items 1, 2, 4, and 7) and interaction (items 3, 5, and 6) subscales closely resemble those previously reported. Multiple regression analysis showed that the best ear SDS predicts about 18-19% of the outcome on items 3 and 5 separately, and about 16% on the interaction subscale (sum of items 3, 5, and 6) CONCLUSIONS: The best ears SDS explains some of the variance displayed in the IOI-HA global score and the interaction subscale. The relation between SDS and IOI-HA suggests that a poor unaided SDS might in itself be a limiting factor for the HA rehabilitation efficacy and hence the IOI-HA outcome. The clinician could use this information to align the user's HA expectations to what is within possible reach.

Some factors underlying individual differences in speech recognition on PRESTO: a first report.

BACKGROUND: Previous studies investigating speech recognition in adverse listening conditions have found extensive variability among individual listeners. However, little is currently known about the core underlying factors that influence speech recognition abilities. PURPOSE: To investigate sensory, perceptual, and neurocognitive differences between good and poor listeners on the Perceptually Robust English Sentence Test Open-set (PRESTO), a new high-variability sentence recognition test under adverse listening conditions. RESEARCH DESIGN: Participants who fell in the upper quartile (HiPRESTO listeners) or lower quartile (LoPRESTO listeners) on key word recognition on sentences from PRESTO in multitalker babble completed a battery of behavioral tasks and self-report questionnaires designed to investigate real-world hearing difficulties, indexical processing skills, and neurocognitive abilities. STUDY SAMPLE: Young, normal-hearing adults (N = 40) from the Indiana University community participated in the current study. DATA COLLECTION AND ANALYSIS: Participants' assessment of their own real-world hearing difficulties was measured with a self-report questionnaire on situational hearing and hearing health history. Indexical processing skills were assessed using a talker discrimination task, a gender discrimination task, and a forced-choice regional dialect categorization task. Neurocognitive abilities were measured with the Auditory Digit Span Forward (verbal short-term memory) and Digit Span Backward (verbal working memory) tests, the Stroop Color and Word Test (attention/inhibition), the WordFam word familiarity test (vocabulary size), the Behavioral Rating Inventory of Executive Function-Adult Version (BRIEF-A) self-report questionnaire on executive function, and two performance subtests of the Wechsler Abbreviated Scale of Intelligence (WASI) Performance Intelligence Quotient (IQ; nonverbal intelligence). Scores on self-report questionnaires and behavioral tasks were tallied and analyzed by listener group (HiPRESTO and LoPRESTO). RESULTS: The extreme groups did not differ overall on self-reported hearing difficulties in real-world listening environments. However, an item-by-item analysis of questions revealed that LoPRESTO listeners reported significantly greater difficulty understanding speakers in a public place. HiPRESTO listeners were significantly more accurate than LoPRESTO listeners at gender discrimination and regional dialect categorization, but they did not differ on talker discrimination accuracy or response time, or gender discrimination response time. HiPRESTO listeners also had longer forward and backward digit spans, higher word familiarity ratings on the WordFam test, and lower (better) scores for three individual items on the BRIEF-A questionnaire related to cognitive load. The two groups did not differ on the Stroop Color and Word Test or either of the WASI performance IQ subtests. CONCLUSIONS: HiPRESTO listeners and LoPRESTO listeners differed in indexical processing abilities, short-term and working memory capacity, vocabulary size, and some domains of executive functioning. These findings suggest that individual differences in the ability to encode and maintain highly detailed episodic information in speech may underlie the variability observed in speech recognition performance in adverse listening conditions using high-variability PRESTO sentences in multitalker babble.

[Application of new speech intelligibility tests in silence for the assessment of acquired hearing losses]. / Der Einsatz neuer Testverfahren zur Erfassung des Sprachverstehens in Ruhe bei der Begutachtung erworbener Schwerhörigkeiten.

BACKGROUND: Previous studies comparing the Freiburg speech tests (FST) currently used in Germany to assess the severity of hearing loss with two modern speech intelligibility tests [the Göttingen sentence test (GöSa) and the monosyllabic rhyme test devised by von Wallenberg and Kollmeier (WaKo)] have indicated that a replacement of the old procedure would be possible. The current study investigates the consequences of the modern test procedures for the estimation of reduction in earning capacity resulting from hearing loss, and considers the optimal presentation levels for the WaKo test. METHODS: The FST, GöSa, and WaKo speech intelligibility tests were performed on 29 volunteers with a hearing impairment. All tests were conducted in silence. The presentation levels for the Freiburg monosyllabic test were 60, 80, and for some participants also 100 dB SPL. The WaKo test was carried out once at 45, 65, and 85 dB SPL (a reduction of 15 dB relative to the FST) and again at 40, 60 and 80 dB SPL (reduction of 20 dB relative to the FST). RESULTS: A consideration across all presentation levels revealed that the best correlation match between the two monosyllabic tests was achieved at a 20-dB reduction in presentation level for the WaKo test relative to the FST. On average, the application of modern procedures and the different options for level reduction had only a minor effect on the quantitative assessment of reduction in earning capacity.

Result on speech perception after conversion from Spectra® to Freedom®.

UNLABELLED: New technology in the Freedom® speech processor for cochlear implants was developed to improve how incoming acoustic sound is processed; this applies not only for new users, but also for previous generations of cochlear implants. AIM: To identify the contribution of this technology-- the Nucleus 22®--on speech perception tests in silence and in noise, and on audiometric thresholds. METHODS: A cross-sectional cohort study was undertaken. Seventeen patients were selected. The last map based on the Spectra® was revised and optimized before starting the tests. Troubleshooting was used to identify malfunction. To identify the contribution of the Freedom® technology for the Nucleus22®, auditory thresholds and speech perception tests were performed in free field in sound-proof booths. Recorded monosyllables and sentences in silence and in noise (SNR = 0dB) were presented at 60 dBSPL. The nonparametric Wilcoxon test for paired data was used to compare groups. RESULTS: Freedom® applied for the Nucleus22® showed a statistically significant difference in all speech perception tests and audiometric thresholds. CONCLUSION: The Freedom® technology improved the performance of speech perception and audiometric thresholds of patients with Nucleus 22®.

Resultados na percepção de fala após conversão do Spectra® para Freedom® / Result on speech perception after conversion from Spectra® to Freedom®

As novas tecnologias do processador Freedom® foram criadas para proporcionar melhorias no processamento do som acústico de entrada, não apenas para novos usuários, como para gerações anteriores de implante coclear. OBJETIVO: Identificar a contribuição da tecnologia do processador de fala Freedom® para implante coclear multicanal, Nucleus22®, no desempenho de percepção de fala no silêncio e no ruído, e nos limiares audiométricos. MATERIAL E MÉTODO: A forma de estudo foi de coorte histórico com corte transversal. Dezessete pacientes preencheram os critérios de inclusão. Antes de iniciar os testes, o último mapa em uso com o Spectra® foi revisto e otimizado e o funcionamento do processador foi verificado. Os testes de fala foram apresentados a 60dBNPS em material gravado: monossílabos; frases em apresentação aberta no silêncio; e no ruído (SNR = 0dB). Foram realizadas audiometrias em campo livre com ambos os processadores de fala. A análise estatística utilizou testes não-paramétricos. RESULTADOS: Quando analisada a contribuição do Freedom® para pacientes com Nucleus22®, observa-se diferença estatisticamente significativa em todos os testes de percepção de fala e em todos os limiares audiométricos. CONCLUSÃO: A tecnologia contribuiu no desempenho de percepção de fala e nos limiares audiométricos dos pacientes usuários de Nucleus22®.

New technology in the Freedom® speech processor for cochlear implants was developed to improve how incoming acoustic sound is processed; this applies not only for new users, but also for previous generations of cochlear implants. AIM: To identify the contribution of this technology - the Nucleus 22® - on speech perception tests in silence and in noise, and on audiometric thresholds. METHODS: A cross-sectional cohort study was undertaken. Seventeen patients were selected. The last map based on the Spectra® was revised and optimized before starting the tests. Troubleshooting was used to identify malfunction. To identify the contribution of the Freedom® technology for the Nucleus22®, auditory thresholds and speech perception tests were performed in free field in sound-proof booths. Recorded monosyllables and sentences in silence and in noise (SNR = 0dB) were presented at 60 dBSPL. The nonparametric Wilcoxon test for paired data was used to compare groups. RESULTS: Freedom® applied for the Nucleus22® showed a statistically significant difference in all speech perception tests and audiometric thresholds. CONCLUSION: The reedom® technology improved the performance of speech perception and audiometric thresholds of patients with Nucleus 22®.

[Hearing loss determination and assessment of the reduction in earning capacity taking speech discrimination tests in noise into account]. / Hörverlustbestimmung und MdE-Abschätzung unter Einbezug von Sprachverständlichkeitsmessungen im Störgeräusch.

BACKGROUND: In Germany the guideline for the hearing loss quantification and the resulting assessment of the reduction in earning capacity is the Königsteiner Merkblatt (KM). The quantification depends on the results of the tone and speech audiogram in silence. However, speech discrimination tests in noise may provide additional information about the impairment of the ENT patients. Especially, the impairment of persons with a slight hearing loss, characterized by high-frequency hearing loss, in noisy environment can not be indicated by the measurement in silence, which is proposed in the KM. METHODS UND PATIENTS: The Göttingen sentence test in noise was applied as a supplement to the routine ENT procedures of the medical estimate in 135 test persons. Based on these measurement results a table for the percentage hearing loss in noise is defined. Furthermore, an integration of the hearing loss in noise in the assessment of the reduction in earning capacity is proposed in addition to the hearing loss in silence. RESULTS: Using the newly introduced hearing loss for speech in noise, a suitable assessment for persons with a slight hearing loss is achieved. By integrating it into the assessment procedure additionally to the hearing loss in silence, the hearing impairment of all patients can be rated depending on their speech test results in silence and in noise. In comparison to the results obtained by the KM, the new procedure does not lead to higher values for the proposed reduction in earning capacity in general, but instead seems to be equally suitable for all groups of patients.

Clinical experience with the words-in-noise test on 3430 veterans: comparisons with pure-tone thresholds and word recognition in quiet.

BACKGROUND: Since the 1940s, measures of pure-tone sensitivity and speech recognition in quiet have been vital components of the audiologic evaluation. Although early investigators urged that speech recognition in noise also should be a component of the audiologic evaluation, only recently has this suggestion started to become a reality. This report focuses on the Words-in-Noise (WIN) Test, which evaluates word recognition in multitalker babble at seven signal-to-noise ratios and uses the 50% correct point (in dB SNR) calculated with the Spearman-Kärber equation as the primary metric. The WIN was developed and validated in a series of 12 laboratory studies. The current study examined the effectiveness of the WIN materials for measuring the word-recognition performance of patients in a typical clinical setting. PURPOSE: To examine the relations among three audiometric measures including pure-tone thresholds, word-recognition performances in quiet, and word-recognition performances in multitalker babble for veterans seeking remediation for their hearing loss. RESEARCH DESIGN: Retrospective, descriptive. STUDY SAMPLE: The participants were 3430 veterans who for the most part were evaluated consecutively in the Audiology Clinic at the VA Medical Center, Mountain Home, Tennessee. The mean age was 62.3 yr (SD = 12.8 yr). DATA COLLECTION AND ANALYSIS: The data were collected in the course of a 60 min routine audiologic evaluation. A history, otoscopy, and aural-acoustic immittance measures also were included in the clinic protocol but were not evaluated in this report. RESULTS: Overall, the 1000-8000 Hz thresholds were significantly lower (better) in the right ear (RE) than in the left ear (LE). There was a direct relation between age and the pure-tone thresholds, with greater change across age in the high frequencies than in the low frequencies. Notched audiograms at 4000 Hz were observed in at least one ear in 41% of the participants with more unilateral than bilateral notches. Normal pure-tone thresholds (≤20 dB HL) were obtained from 6% of the participants. Maximum performance on the Northwestern University Auditory Test No. 6 (NU-6) in quiet was ≥90% correct by 50% of the participants, with an additional 20% performing at ≥80% correct; the RE performed 1-3% better than the LE. Of the 3291 who completed the WIN on both ears, only 7% exhibited normal performance (50% correct point of ≤6 dB SNR). Overall, WIN performance was significantly better in the RE (mean = 13.3 dB SNR) than in the LE (mean = 13.8 dB SNR). Recognition performance on both the NU-6 and the WIN decreased as a function of both pure-tone hearing loss and age. There was a stronger relation between the high-frequency pure-tone average (1000, 2000, and 4000 Hz) and the WIN than between the pure-tone average (500, 1000, and 2000 Hz) and the WIN. CONCLUSIONS: The results on the WIN from both the previous laboratory studies and the current clinical study indicate that the WIN is an appropriate clinic instrument to assess word-recognition performance in background noise. Recognition performance on a speech-in-quiet task does not predict performance on a speech-in-noise task, as the two tasks reflect different domains of auditory function. Experience with the WIN indicates that word-in-noise tasks should be considered the "stress test" for auditory function.

Predicting the intelligibility of vocoded speech.

OBJECTIVES: The purpose of this study is to evaluate the performance of a number of speech intelligibility indices in terms of predicting the intelligibility of vocoded speech. DESIGN: Noise-corrupted sentences were vocoded in a total of 80 conditions, involving three different signal-to-noise ratio levels (-5, 0, and 5 dB) and two types of maskers (steady state noise and two-talker). Tone-vocoder simulations and combined electric-acoustic stimulation (EAS) simulations were used. The vocoded sentences were presented to normal-hearing listeners for identification, and the resulting intelligibility scores were used to assess the correlation of various speech intelligibility measures. These included measures designed to assess speech intelligibility, including the speech transmission index (STI) and articulation index based measures, as well as distortions in hearing aids (e.g., coherence-based measures). These measures employed primarily either the temporal-envelope or the spectral-envelope information in the prediction model. The underlying hypothesis in the present study is that measures that assess temporal-envelope distortions, such as those based on the STI, should correlate highly with the intelligibility of vocoded speech. This is based on the fact that vocoder simulations preserve primarily envelope information, similar to the processing implemented in current cochlear implant speech processors. Similarly, it is hypothesized that measures such as the coherence-based index that assess the distortions present in the spectral envelope could also be used to model the intelligibility of vocoded speech. RESULTS: Of all the intelligibility measures considered, the coherence-based and the STI-based measures performed the best. High correlations (r = 0.9 to 0.96) were maintained with the coherence-based measures in all noisy conditions. The highest correlation obtained with the STI-based measure was 0.92, and that was obtained when high modulation rates (100 Hz) were used. The performance of these measures remained high in both steady-noise and fluctuating masker conditions. The correlations with conditions involving tone-vocoded speech were found to be a bit higher than the correlations with conditions involving EAS-vocoded speech. CONCLUSIONS: The present study demonstrated that some of the speech intelligibility indices that have been found previously to correlate highly with wideband speech can also be used to predict the intelligibility of vocoded speech. Both the coherence-based and STI-based measures have been found to be good measures for modeling the intelligibility of vocoded speech. The highest correlation (r = 0.96) was obtained with a derived coherence measure that placed more emphasis on information contained in vowel/consonant spectral transitions and less emphasis on information contained in steady sonorant segments. High (100 Hz) modulation rates were found to be necessary in the implementation of the STI-based measures for better modeling of the intelligibility of vocoded speech. We believe that the difference in modulation rates needed for modeling the intelligibility of wideband versus vocoded speech can be attributed to the increased importance of higher modulation rates in situations where the amount of spectral information available to the listeners is limited (eight channels in our study). Unlike the traditional STI method that has been found to perform poorly in terms of predicting the intelligibility of processed speech wherein nonlinear operations are involved, the STI-based measure used in the present study has been found to perform quite well. In summary, the present study took the first step in modeling the intelligibility of vocoded speech. Access to such intelligibility measures is of high significance as they can be used to guide the development of new speech coding algorithms for cochlear implants.

Comparing two methods for reducing variability in voice quality measurements.

PURPOSE: Interrater disagreements in ratings of quality plague the study of voice. This study compared 2 methods for handling this variability. METHOD: Listeners provided multiple breathiness ratings for 2 sets of pathological voices, one including 20 male and 20 female voices unselected for quality and one including 20 breathy female voices. Ratings for each listener were averaged together, mean ratings were z transformed, and the likelihood that 2 listeners would agree exactly in their ratings was calculated as a function of averaging and standardizing condition. Data were also multidimensionally scaled to examine similarities among listeners in perceptual strategy. Results were compared with parallel analyses of existing breathiness ratings of the same voices gathered using a method-of-adjustment task. RESULTS: Three-way interactions between the mean rating for a voice, standardization condition, and the number of voices averaged together were observed, but no main effect of averaging condition emerged. Multidimensional scaling revealed significant residual differences in perceptual strategy across listeners after averaging and standardizing. Ratings from the method-of-adjustment task showed both high agreement levels and consistent perceptual strategies across listeners, as theoretically predicted. CONCLUSION: Averaging multiple ratings and standardizing the mean are inadequate in addressing variations in voice quality perception.

Left hemisphere specialization for duration discrimination of musical and speech sounds.

Hemispheric asymmetries for processing duration of non-verbal and verbal sounds were investigated in 60 right-handed subjects. Two dichotic tests with attention directed to one ear were used, one with complex tones and one with consonant-vowel syllables. Stimuli had three possible durations: 350, 500, and 650 ms. Subjects judged whether the duration of a probe was same or different compared to the duration of the target presented before it. Target and probe were part of two dichotic pairs presented with 1s interstimulus interval and occurred on the same side. Dependent variables were reaction time and accuracy. Results showed a significant right ear advantage for both dependent variables with both complex tones and consonant-vowel syllables. This study provides behavioural evidence of a left hemisphere specialization for duration perception of both musical and speech sounds in line with the current view based on a parameter--rather than domain-specific structuring of hemispheric perceptual asymmetries.

A comparison of recognition performances in speech-spectrum noise by listeners with normal hearing on PB-50, CID W-22, NU-6, W-1 spondaic words, and monosyllabic digits spoken by the same speaker.

BACKGROUND: So that portions of the classic Miller, Heise, and Lichten (1951) study could be replicated, new recorded versions of the words and digits were made because none of the three common monosyllabic word lists (PAL PB-50, CID W-22, and NU-6) contained the 9 monosyllabic digits (1-10, excluding 7) that were used by Miller et al. It is well established that different psychometric characteristics have been observed for different lists and even for the same materials spoken by different speakers. The decision was made to record four lists of each of the three monosyllabic word sets, the monosyllabic digits not included in the three sets of word lists, and the CID W-1 spondaic words. A professional female speaker with a General American dialect recorded the materials during four recording sessions within a 2-week interval. The recording order of the 582 words was random. PURPOSE: To determine-on listeners with normal hearing-the psychometric properties materials presented in speech-spectrum noise. RESEARCH DESIGN: A quasi-experimental, repeated-measures design was used. STUDY SAMPLE: Twenty-four young adult listeners (M = 23 years) with normal pure-tone thresholds (< or = 20-dB HL at 250 to 8000 Hz) participated. The participants were university students who were unfamiliar with the test materials. DATA COLLECTION AND ANALYSIS: The 582 words were presented at four signal-to-noise ratios (SNRs; -7-, -2-, 3-, and 8-dB) in speech-spectrum noise fixed at 72-dB SPL. Although the main metric of interest was the 50% point on the function for each word established with the Spearman-Kärber equation (Finney, 1952), the percentage correct on each word at each SNR was evaluated. The psychometric characteristics of the PB-50, CID W-22, and NU-6 monosyllabic word lists were compared with one another, with the CID W-1 spondaic words, and with the 9 monosyllabic digits. RESULTS: Recognition performance on the four lists within each of the three monosyllabic word materials were equivalent, +/- 0.4 dB. Likewise, word-recognition performance on the PB-50, W-22, and NU-6 word lists were equivalent, +/- 0.2 dB. The mean recognition performance at the 50% point with the 36 W-1 spondaic words was approximately 6.2 dB lower than the 50% point with the monosyllabic words. Recognition performance on the monosyllabic digits was 1-2 dB better than mean performance on the monosyllabic words. CONCLUSIONS: Word-recognition performances on the three sets of materials (PB-50, CID W-22, and NU-6) were equivalent, as were the performances on the four lists that make up each of the three materials. Phonetic/phonemic balance does not appear to be an important consideration in the compilation of word-recognition lists used to evaluate the ability of listeners to understand speech. A companion paper examines the acoustic, phonetic/phonological, and lexical variables that may predict the relative ease or difficulty for which these monosyllable words were recognized in noise (McArdle and Wilson, this issue).

Predicting word-recognition performance in noise by young listeners with normal hearing using acoustic, phonetic, and lexical variables.

PURPOSE: To analyze the 50% correct recognition data that were from the Wilson et al (this issue) study and that were obtained from 24 listeners with normal hearing; also to examine whether acoustic, phonetic, or lexical variables can predict recognition performance for monosyllabic words presented in speech-spectrum noise. RESEARCH DESIGN: The specific variables are as follows: (a) acoustic variables (i.e., effective root-mean-square sound pressure level, duration), (b) phonetic variables (i.e., consonant features such as manner, place, and voicing for initial and final phonemes; vowel phonemes), and (c) lexical variables (i.e., word frequency, word familiarity, neighborhood density, neighborhood frequency). DATA COLLECTION AND ANALYSIS: The descriptive, correlational study will examine the influence of acoustic, phonetic, and lexical variables on speech recognition in noise performance. RESULTS: Regression analysis demonstrated that 45% of the variance in the 50% point was accounted for by acoustic and phonetic variables whereas only 3% of the variance was accounted for by lexical variables. These findings suggest that monosyllabic word-recognition-in-noise is more dependent on bottom-up processing than on top-down processing. CONCLUSIONS: The results suggest that when speech-in-noise testing is used in a pre- and post-hearing-aid-fitting format, the use of monosyllabic words may be sensitive to changes in audibility resulting from amplification.