[Application of the matrix sentence test Russian version in children]. / Primenenie russkoiazychnoi versii matriksnogo frazovogo testa u detei.

The Russian version of the matrix sentence test (RUMatrix test) has been shown to be suitable for accurate assessment of speech intelligibility in adults. AIM: To approve the RUMatrix for measurements in children and to evaluate its simplified version (Simplified RUMatrix). MATERIAL AND METHODS: 20 normal-hearing adults and 81 normal-hearing children aged from 5 to 10 years were involved into the study. Both versions of the test were developed by the University of Oldenburg, Germany. The tests contain syntactically homogeneous, semantically unpredictable sentences/phrases presented under the background noise. Each test list is composed of 20 sentences of 5 words for RUMatrix and of 14 speech phrases of 3 words for Simplified RUMatrix. RESULTS: A limitation in the use of the RUMatrix test in children under 10 years of age has been revealed. Evaluation of Simplified RUMatrix test in adults confirmed the perceptual homogeneity of the test list. The results of the RUMatrix test and the Simplified RUMatrix test in children were lower than in adults; they were improving with age and reach adult values by 10 years. One training track of Simplified RUMatrix test should be carried out before the assessment. CONCLUSION: The RUMatrix can be used for children of 10 years and older. The normative data of Simplified RUMatrix both for adults and children of the different ages have been obtained.

[The application of the screening questionnaires for the diagnostics of the central auditory processing disorders in the pediatric practice]. / Ispol'zovanie skriningovykh anket dlia vyiavleniia tsentral'nykh slukhovykh rasstroistv v pediatricheskoi praktike.

Identification and diagnostics of auditory processing disorders (APD) in the children continues to be a challenge. Screening tools help to decide the need for evaluation. However, none of them are used routinely in Russia, nor are there thus far auditory checklist questionnaires in the Russian language. The aim of his study was to approve Children's Auditory Performance Scale (CHAPS) and Fisher's Auditory Checklist in Russian for the children at the age of 5-10 years. The study included 52 children at the age from 5 to 11 years. All of them were native Russian speakers. Pure tone audiometry, immitancemetry, and the Simplified RuMatrix test were performed for all the children. All of them had normal hearing thresholds, speech and language development, and normal academic achievement at school. The parents filled in the CHAPS and Fisher's Auditory Checklist questionnaires in Russian. The mean value of Fisher's Auditory Checklist was 85.7 ± 9.3, the mean value of CHAPS questionnaire was equal to 0.08 ± 0.26. The results obtained with the use of the Russian language questionnaires are in excellent agreement with the test data yielded by the respective English language versions. It is recommended that the clinical assessment for APD should be performed for children with the result of the Fisher questionnaire less than 67 points and with the result of the CHAPS questionnaire less than -1 point. It is concluded that Fisher's questionnaire was more convenient for the parents to fill in.

[The speech audiometry using the matrix sentence test]. / Rechevaya audiometriya s ispol'zovaniem matriksnogo frazovogo testa.

The matrix sentence test in which the five-word semantically unpredictable sentences presented under the background noise conditions are used as the speech material was designed and validated for many languages. The objective of the present study was to evaluate the Russian version of the matrix sentence test (RuMatrix test) in the listeners of different ages with normal hearing. At the first stage of the study, 35 listeners at the age from 18 to 33 year were examined. The results of the estimation of the training effect dictated the necessity of conducting two training tracks before carrying out the RuMatrix test proper. The signal-to-noise ratio at which 50% speech recognition (SRT50) was obtained was found to be -8.8±0.8 dB SNR. A significant effect of exposure to the background noise was demonstrated: the noise level of 80 and 75 Db SPL led to a considerably lower intelligibility than the noise levels in the range from 45 to 70 dB SPL; in the subsequent studies, the noise level of 65 dB SPL was used. The high test-retest reliability of the RuMatrix test was proved. At the second stage of the study, 20 young (20-40 year old) listeners and 20 aged (62-74 year old) ones were examined. The mean SRT50 in the aged patients was found to be -6.9±1.1 dB SNR which was much worse than the mean STR50 in the young subjects (-8.7±0.9 dB SNR). It is concluded that, bearing in mind the excellent comparability of the results of the RUMat rix test across different languages, it can be used as a universal tool in international research projects.

[The Russian-language version of the matrix test (RUMatrix) in free field in patients after cochlear implantation in the long term]. / Russkoyazychnaya versiya matriksnogo frazovogo testa RUMatrix v svobodnom zvukovom pole u patsientov posle kokhlearnoi implantatsii.

The deterioration of speech intelligibility in the patients using cochlear implantation (CI) systems is especially well apparent in the noisy environment. It explains why phrasal speech tests, such as a Matrix sentence test, have become increasingly more popular in the speech audiometry during rehabilitation after CI. The Matrix test allows to estimate speech perception by the patients in a real life situation. The objective of this study was to assess the effectiveness of audiological rehabilitation of CI patients using the Russian-language version of the matrix test (RUMatrix) in free field in the noisy environment. 33 patients aged from 5 to 40 years with a more than 3 year experience of using cochlear implants inserted at the National Research Center for Audiology and Hearing Rehabilitation were included in our study. Five of these patients were implanted bilaterally. The results of our study showed a statistically significant improvement of speech intelligibility in the noisy environment after the speech processor adjustment; dynamics of the signal-to-noise ratio changes was -1.7 dB (p<0.001). CONCLUSION: The RUMatrix test is a highly efficient method for the estimation of speech intelligibility in the patients undergoing clinical investigations in the noisy environment. The high degree of comparability of the RUMatrix test with the Matrix tests in other languages makes possible its application in international multicenter studies.

Relations between psychophysical measures of spatial hearing and self-reported spatial-hearing abilities.

OBJECTIVE: The aim of the present study was to investigate how well the virtual psychophysical measures of spatial hearing from the preliminary auditory profile predict self-reported spatial-hearing abilities. DESIGN: Virtual spatial-hearings tests (conducted unaided, via headphones) and a questionnaire were administered in five centres in Germany, the Netherlands, Sweden, and the UK. Correlations and stepwise linear regression models were calculated among a group of hearing-impaired listeners. STUDY SAMPLE: Thirty normal-hearing listeners aged 19-39 years, and 72 hearing-impaired listeners aged 22-91 years with a broad range of hearing losses, including asymmetrical and mixed hearing losses. RESULTS: Several significant correlations (between 0.24 and 0.54) were found between results of virtual psychophysical spatial-hearing tests and self-reported localization abilities. Stepwise linear regression analyses showed that the minimum audible angle (MAA) test was a significant predictor for self-reported localization abilities (5% extra explained variance), and the spatial speech reception threshold (SRT) benefit test for self-reported listening to speech in spatial situations (6% extra explained variance). CONCLUSIONS: The MAA test and spatial SRT benefit test are indicative measures of everyday binaural functioning. The binaural SRT benefit test was not found to predict self-reported spatial-hearing abilities.

Do we need STRFs for cocktail parties? On the relevance of physiologically motivated features for human speech perception derived from automatic speech recognition.

Complex auditory features such as spectro-temporal receptive fields (STRFs) derived from the cortical auditory neurons appear to be advantageous in sound processing. However, their physiological and functional relevance is still unclear. To assess the utility of such feature processing for speech reception in noise, automatic speech recognition (ASR) performance using feature sets obtained from physiological and/or psychoacoustical data and models is compared to human performance. Time-frequency representations with a nonlinear compression are compared with standard features such as mel-scaled spectrograms. Both alternatives serve as an input to model estimators that infer spectro-temporal filters (and subsequent nonlinearity) from physiological measurements in auditory brain areas of zebra finches. Alternatively, a filter bank of 2-dimensional Gabor functions is employed, which covers a wide range of modulation frequencies in the time and frequency domain. The results indicate a clear increase in ASR robustness using complex features (modeled by Gabor functions), while the benefit from physiologically derived STRFs is limited. In all cases, the use of power-normalized spectral representations increases performance, indicating that substantial dynamic compression is advantageous for level-independent pattern recognition. The methods employed may help physiologists to look for more relevant STRFs and to better understand specific differences in estimated STRFs.

[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.

[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.

[Indication for and verification of hearing aid benefit using modern methods of speech audiometry in German]. / Hörgeräteindikation und -überprüfung nach modernen Verfahren der Sprachaudiometrie im Deutschen.

The current guidelines for hearing aid supply in Germany employ the often criticised Freiburg monosyllabic speech test (FBE) in quiet. This test can be replaced with the monosyllabic rhyme test by von Wallenberg and Kollmeier (WaKo) in quiet and by the measurement of a speech reception threshold in an interfering noise at a moderate level (45 dB SPL) using either the Göttingen or the Oldenburg sentence test (criterion: 2 dB improvement in SNR, "signal-to-noise ratio"). This procedure was investigated in a group of 38 participants with a sensorineural hearing impairment (mild, moderate or severe hearing loss) and 11 volunteers with normal hearing. On average, comparable indications were achieved. Participants with a mild hearing loss and a selective problem with listening in interfering noise were assessed more fairly.

[Comparison of the Göttingen sentence test and the monosyllabic rhyme test by von Wallenberg and Kollmeier with the Freiburg speech test : Investigation in a clinically representative group of listeners]. / Vergleich des Göttinger Satztests und des Einsilber-Reimtests nach von Wallenberg und Kollmeier mit dem Freiburger Sprachtest : Untersuchung bei einem klinisch repräsentativen Probandenkollektiv.

BACKGROUND: In a previous study [12] we compared the Freiburg speech test (number test and monosyllabic test) with the Göttingen sentence test and the monosyllabic rhyme test developed by von Wallenberg and Kollmeier. For a small group of participants we were able to demonstrate that the often criticized Freiburg speech test could be replaced by more modern test procedures. In the current study we verified this for a larger and more heterogeneous group of participants. METHOD: A total of 145 participants with hearing impairments were tested with the Freiburg speech test and the modern procedures. Both monosyllabic tests were carried out at three different presentation levels. Based on the findings of the previous study the monosyllabic rhyme test was performed in each case with a presentation level reduced by 15 dB relative to the Freiburg monosyllabic test levels. RESULTS: The feasibility to replace both parts of the Freiburg speech test by more modern test procedures could be confirmed. The comparison of both monosyllabic tests showed that a reduction in the presentation level by 20 dB for the monosyllabic rhyme test would be most appropriate to achieve on average the same results with both procedures.

[Comparison of different speech intelligibility tests in German language (Freiburg speech test vs. Göttingen sentence test and monosyllabic rhyme test)]. / Untersuchung zur Vergleichbarkeit des Freiburger Sprachtests mit dem Göttinger Satztest und dem Einsilber-Reimtest nach von Wallenberg und Kollmeier.

BACKGROUND: For assessing a noise-induced hearing loss, the Freiburg speech test (Freiburger Sprachtest) is traditionally used to examine speech recognition in silence. However, for many years this test has been shown to have serious shortcomings. Various modern procedures in German language are available as alternatives. METHODS: The aim of the current study was to compare the Freiburg number test (FBZ) with the Göttingen sentence test (GöSa) and the Freiburg monosyllabic test (FBE) with the monosyllabic rhyme test developed by von Wallenberg and Kollmeier (WaKo), all applied in silence. Overall, 31 participants with various degrees of hearing loss were tested in this study. Speech intelligibility was determined with both monosyllabic tests at presentation levels of 60 and 80 dB SPL and for some listeners also at 100 dB SPL. The maximum intelligibility was also determined. In addition, for the combination FBZ and FBE and for the combination FBZ and WaKo, the percentage of hearing loss based on speech audiometry was calculated. RESULTS: The results show that both of the modern speech tests can be used as an alternative to the Freiburg speech test. Altogether the monosyllabic rhyme test leads to higher speech intelligibility than the Freiburg monosyllabic test. Therefore, a reduction of the presentation level by 15 dB is recommended if it is intended to retain the existing tables for calculating the percentage of hearing loss. Reducing the presentation level also has the advantage that measurements at 100 dB SPL are not required anymore. A level of 100 dB SPL is assessed as unpleasant by many listeners.

[Evaluation of the Oldenburg children's rhyme test in silence and in noise]. / Evaluation des Oldenburger Kinder-Reimtests in Ruhe und im Störgeräusch.

BACKGROUND: The Oldenburg children's rhyme test (OlKi) was designed and optimized for speech intelligibility measurements for primary school pupils in silence [8, 3]. In the optimization, the intelligibility of the particular test words was equalized. METHODS: The evaluation of the test with 147 primary school pupils with normal hearing in silence and 107 pupils in noise is presented in this article. The comparability between test lists for speech intelligibility was investigated and age dependent reference functions were determined. RESULTS: The evaluation showed that intelligibility differences are larger across children within one grade than across different test lists. The reference functions of first grade pupils are shifted to slightly higher presentation levels and signal-to-noise ratios both in silence and noise. CONCLUSIONS: The 12 optimized test lists of the OlKi test are equally intelligible both in silence and noise. No list effects are expected. The degree of difficulty of the Oldenburg children's rhyme test can be compared with the Göttingen children's test II and the Mainz children's test III.

Modeling temporal and compressive properties of the normal and impaired auditory system.

Three modifications of a psychoacoustically and physiologically motivated processing model [Dau et al., J. Acoust. Soc. Am. 102 (1997a) 2892-2905] are presented and tested. The modifications aim at simulating sensorineural hearing loss and incorporate a level-dependent peripheral compression whose properties are affected by hearing impairment. Model 1 realizes this difference by introducing for impaired listeners an instantaneous level-dependent expansion prior to the adaptation stage of the model. Model 2 and Model 3 realize a level-dependent compression with time constants of 5 and 15 ms, respectively, for normal hearing and a reduced compression for impaired hearing. In Model 2, the compression occurs after the envelope extraction stage, while in Model 3, envelope extraction follows compression. All models account to a similar extent for the recruitment phenomenon measured with narrow-band stimuli and for forward-masking data of normal-hearing and hearing-impaired subjects using a 20-ms, 2-kHz tone signal and a 1-kHz-wide bandpass noise masker centered at 2 kHz. A clear difference between the different models occurs for the processing of temporally fluctuating stimuli. A modulation-rate-independent increase in modulation-response level for simulating impaired hearing is only predicted by Model 1 while the other two models realize a modulation-rate-dependent increase. Hence, the predictions of Model 2 and Model 3 are in conflict with the results of modulation-matching experiments reported in the literature. It is concluded that key properties of sensorineural hearing loss (altered loudness perception, reduced dynamic range, normal temporal properties but prolonged forward-masking effects) can effectively be modeled by incorporating a fast-acting expansion within the current processing model prior to the nonlinear adaptation stage. Based on these findings, a model of both normal and impaired hearing is proposed which incorporates a fast-acting compressive nonlinearity, representing the cochlear nonlinearity (which is reduced in impaired listeners), followed by an instantaneous expansion and the nonlinear adaptation stage which represent aspects of the retro-cochlear information processing in the auditory system.

Auditory brainstem responses with optimized chirp signals compensating basilar-membrane dispersion.

This study examines auditory brainstem responses (ABR) elicited by rising frequency chirps. The time course of frequency change for the chirp theoretically produces simultaneous displacement maxima by compensating for travel-time differences along the cochlear partition. This broadband chirp was derived on the basis of a linear cochlea model [de Boer, "Auditory physics. Physical principles in hearing theory I," Phys. Rep. 62, 87-174 (1980)]. Responses elicited by the broadband chirp show a larger wave-V amplitude than do click-evoked responses for most stimulation levels tested. This result is in contrast to the general hypothesis that the ABR is an electrophysiological event most effectively evoked by the onset or offset of an acoustic stimulus, and unaffected by further stimulation. The use of this rising frequency chirp enables the inclusion of activity from lower frequency regions, whereas with a click, synchrony is decreased in accordance with decreasing traveling velocity in the apical region. The use of a temporally reversed (falling) chirp leads to a further decrease in synchrony as reflected in ABR responses that are smaller than those from a click. These results are compatible with earlier experimental results from recordings of compound action potentials (CAP) [Shore and Nuttall, "High synchrony compound action potentials evoked by rising frequency-swept tonebursts," J. Acoust. Soc. Am. 78, 1286-1295 (1985)] reflecting activity at the level of the auditory nerve. Since the ABR components considered here presumably reflect neural response from the brainstem, the effect of an optimized synchronization at the peripheral level can also be observed at the brainstem level. The rising chirp may therefore be of clinical use in assessing the integrity of the entire peripheral organ and not just its basal end.

Within-channel cues in comodulation masking release (CMR): experiments and model predictions using a modulation-filterbank model.

Experiments and model calculations were performed to study the influence of within-channel cues versus across-channel cues in comodulation masking release (CMR). A class of CMR experiments is considered that are characterized by a single (unmodulated or modulated) bandpass noise masker with variable bandwidth centered at the signal frequency. A modulation-filterbank model suggested by Dau et al. [J. Acoust. Soc. Am. 102, 2892-2905 (1997)] was employed to quantitatively predict the experimental data. Effects of varying masker bandwidth, center frequency, modulator bandwidth, modulator type, and signal duration on CMR were examined. In addition, the effect of band limiting the noise before or after modulation was shown to influence the CMR in the same way as a systematic variation of the modulation depth. It is demonstrated that a single-channel analysis, which analyzes only the information from one peripheral channel, quantitatively accounts for the CMR in most cases, indicating that an across-channel process is generally not necessary for simulating results from this class of CMR experiments. True across-channel processes may be found in another class of CMR experiments.

Continuous assessment of time-varying speech quality.

This paper addresses the question of whether subjects are able to assess the perceived time-varying quality of speech material continuously. A method is introduced which is characterized by a subjective continuous rating of the perceived speech quality by moving a slider along a graphical scale. The usability of this method is illustrated with an experiment in which different sequences of sentences were degraded in quality with a Modulated Noise Reference Unit. The modulation depth was varied with time and the subject's task was to assess the perceived quality. The results indicate that subjects can monitor speech quality variations very accurately with a delay of approximately 1 s. An objective speech quality measure based on an auditory processing model was applied to predict the subjective speech quality results. The speech quality measure qC was modified to allow for time-dependent objective measurement of the speech quality. The averaged subjective response data could be modeled by the scale transformed and low-pass filtered measure qC(t) with a high degree of accuracy.

A model of auditory perception as front end for automatic speech recognition.

A front end for automatic speech recognizers is proposed and evaluated which is based on a quantitative model of the "effective" peripheral auditory processing. The model simulates both spectral and temporal properties of sound processing in the auditory system which were found in psychoacoustical and physiological experiments. The robustness of the auditory-based representation of speech was evaluated in speaker-independent, isolated word recognition experiments in different types of additive noise. The results show a higher robustness of the auditory front end in noise, compared to common mel-scale cepstral feature extraction. In a second set of experiments, different processing stages of the auditory front end were modified to study their contribution to robust speech signal representation in detail. The adaptive compression stage which enhances temporal changes of the input signal appeared to be the most important processing stage towards robust speech representation in noise. Low-pass filtering of the fast fluctuating envelope in each frequency band further reduces the influence of noise in the auditory-based representation of speech.

Evidence for the distortion product frequency place as a source of distortion product otoacoustic emission (DPOAE) fine structure in humans. I. Fine structure and higher-order DPOAE as a function of the frequency ratio f2/f1.

Critical experiments were performed in order to validate the two-source hypothesis of distortion product otoacoustic emissions (DPOAE) generation. Measurements of the spectral fine structure of DPOAE in response to stimulation with two sinusoids have been performed with normal-hearing subjects. The dependence of fine-structure patterns on the frequency ratio f2/f1 was investigated by changing f1 or f2 only (fixed f2 or fixed f1 paradigm, respectively), and by changing both primaries at a fixed ratio and looking at different order DPOAE. When f2/f1 is varied in the fixed ratio paradigm, the patterns of 2 f1-f2 fine structure vary considerably more if plotted as a function of f2 than as a function of fDP. Different order distortion products located at the same characteristic place on the basilar membrane (BM) show similar patterns for both, the fixed-f2 and fDP paradigms. Fluctuations in DPOAE level up to 20 dB can be observed. In contrast, the results from a fixed-fDP paradigm do not show any fine structure but only an overall dependence of DP level on the frequency ratio, with a maximum for 2f1-f2 at f2/f1 close to 1.2. Similar stimulus configurations used in the experiments have also been used for computer simulations of DPOAE in a nonlinear and active model of the cochlea. Experimental results and model simulations give strong evidence for a two-source model of DPOAE generation: The first source is the initial nonlinear interaction of the primaries close to the f2 place. The second source is caused by coherent reflection from a re-emission site at the characteristic place of the distortion product frequency. The spectral fine structure of DPOAE observed in the ear canal reflects the interaction of both these sources.