Kirsten C. Wagener

Design, optimization and evaluation of a Danish sentence test in noise.

The Danish sentence test DANTALE II was developed in analogy to the Swedish sentence test by Hagerman and the German Oldenburg sentence test as a new Danish sentence test in noise to determine the speech reception threshold in noise (SRT, i.e. the signal-to-noise ratio (SNR) that yields 50% intelligibility). Each sentence is generated by a random combination of the alternatives of a base list. This base list consists of 10 sentences with the same syntactical structure (name, verb, numeral, adjective, object). The test sentences were recorded and segmented in such a way that the coarticulation effects were taken into account in order to achieve a high perceived sound quality of the resynthesized sentences: 100 sentences were recorded, each coarticulation between each word and the 10 possible following word alternatives were recorded, and the correct coarticulation was used to generate the test sentences. Word-specific speech recognition curves were measured for each recorded word to optimize the homogeneity of the speech material and the measurement accuracy. Level corrections of particular words and a careful selection of the test lists produced a noticeable reduction in the variation in the distribution of word-specific SRT (standard deviation 1.75 dB instead of 3.78 dB). Therefore, the slope of the total intelligibility function was expected to increase from 8.3%/dB (raw test material) to 13.2%/dB (after modification). These theoretical expectations were evaluated by independent measurements with normal-hearing subjects, and, for the most part, confirmed. The reference data for the DANTALE II are: SRT=-8.43 dB SNR; slope at SRT, s50= 13.2%/dB. The training effect was 2.2 dB and could be reduced to less than 1 dB if two training lists of 20 sentences were performed prior to data collection. Sumario: La prueba Danesa de frases DANTALE II fue desarrollada análogamente a la prueba de frases Sueca de Hagerman y la prueba alemana de frases de Oldenburg, como la nueva prueba Danesa de frases en ruido, para determinar el umbral de reconocimiento del lenguaje (SRT, p. ej.: el nivel de relación señal/ruido que permite un 50% de inteligibilidad) Cada frase es generada por una combinación al azar de las alternativas de una lista de base. Esta lista de base consiste en 10 frases con la misma estructura sintáctica (nombre, verbo, numeral, adjetivo, objeto). Las frases de la prueba fueron registradas y segmentadas en tal forma que los efectos de coarticulación se tomaron en cuenta con objeto de lograr una cualidad de sonido altamente percibida en las frases resintetizadas. Se registraron 100 frases, asi como cada coarticulación entre cada palabra y las 10 posibles alternativas de palabras que seguian. La correcta coarticulación fue usada para generar las frases de la prueba. Se midieron las curvas de reconocimiento especifico de palabras para cada una de las palabras grabadas con objeto de lograr la optima homogenización del material lingüistico y la precisión de la medición. Los niveles de corrección de palabras en particular y la cuidadosa selección de las listas de la prueba produjeron una notable reducción en la variación de la distri-bución de niveles SRT especificos para palabras (D.S. de 1,75 dB en vez de 3.78 dB). Por ello, el perfil de la función total de inteligibilidad se esperó creciera de 8.3% dB (material crudo de prueba) a 13.2% dB (después de la modificación). Estas expectativas teóricas fueron evaluadas por medio de mediciones independientes con sujetos normo-oyentes y confirmados en la mayoria de los casos. Los datos de referenda para el DANTALE II son: SRT =-8.43 dB SNR; perfil en SRT, s50= 13.2%/dB. El efecto de entrenamiento fue de 2.2 dB y podria reducirse a menos de 1 dB si se presentaran dos listas de entrenamiento de 20 frases antes de la recolección de los datos.

The role of silent intervals for sentence intelligibility in fluctuating noise in hearing-impaired listeners

Fluctuating interfering noises are highly suitable for speech audiometry because of the large inter-individual variability in intelligibility results. This study explores the maximum duration of silent intervals in the masker as an important factor underlying sentence intelligibility in fluctuating noise. Three versions of speech-simulating fluctuating interfering noises based on the icra noises (Dreschler et al, ) were explored: The original noise which simulates one interfering speaker and contains pause durations up to two seconds, as well as two modified versions with pause durations limited to 250 ms and 62.5 ms, respectively. In addition, a stationary speech-shaped noise was used. Test-retest reliability as well as speech reception threshold (SRT) and speech intelligibility function slope were determined with hearing-impaired subjects. All fluctuating noises differentiated very well between subjects. Partial rank correlation analysis showed that SRTs in fluctuating noise with longest maximum pause durations mostly depended on SRTs in quiet. SRTs in fluctuating noises with smaller maximum pause durations correlated both with SRTs in quiet and in stationary noise. Sumario Los ruidos fluctuantes de interferencia son muy apropiados en logoaudiometría debido a la gran variabilidad inter-individuos en los resultados de inteligibilidad. Este estudio explora la duración máxima de intervalos de silencio en el enmascarador, como un importante factor subyacente en la inteligibilidad de frases en medio de ruido fluctuante. Se exploraron tres versiones de ruidos fluctuantes de interferencia simulando lenguaje, con base en los ruidos icra (Dreschler y col., 2001): el ruido original que simula la interferencia de un hablante y contiene pausas de hasta 2 segundos de duración, y también dos versiones modificadas con pausas de duración limitadas a 250 mseg y 62.5 mseg, respectivamente. Además, se utilizó un ruido estacionario moldeado como lenguaje. Se determinó la confiabilidad test-retest al igual que la pendiente de las funciones del SRT y la inteligibilidad del lenguaje, en sujetos hipoacúsicos. Todos los ruidos fluctuantes se diferenciaron muy bien entre los sujetos. Un análisis de correlación de rango parcial mostró que los SRT en ruido fluctuante con las duraciones más prolongadas de pausa máxima, dependían del SRT en silencio. Los SRT en ruido fluctuante con duraciones menores de pausa máxima, correlacionaron tanto con los SRT en silencio como con el ruido estacionario.

The multilingual matrix test: Principles, applications, and comparison across languages: A review

Objective: A review of the development, evaluation, and application of the so-called ‘matrix sentence test’ for speech intelligibility testing in a multilingual society is provided. The format allows for repeated use with the same patient in her or his native language even if the experimenter does not understand the language. Design: Using a closed-set format, the syntactically fixed, semantically unpredictable sentences (e.g. ‘Peter bought eight white ships’) provide a vocabulary of 50 words (10 alternatives for each position in the sentence). The principles (i.e. construction, optimization, evaluation, and validation) for 14 different languages are reviewed. Studies of the influence of talker, language, noise, the training effect, open vs. closed conduct of the test, and the subjects’ language proficiency are reported and application examples are discussed. Results: The optimization principles result in a steep intelligibility function and a high homogeneity of the speech materials presented and test lists employed, yielding a high efficiency and excellent comparability across languages. The characteristics of speakers generally dominate the differences across languages. Conclusion: The matrix test format with the principles outlined here is recommended for producing efficient, reliable, and comparable speech reception thresholds across different languages.

Comparison of three types of French speech­in­noise tests: A multi­center study

Abstract Objective: To compare results on the everyday sentence test ‘FIST’, the new closed-set sentence test ‘FrMatrix’, and the digit triplet screening test ‘FrDigit3’. Design: First, the FrMatrix was developed and normative values were obtained. Subsequently, speech reception thresholds (SRTs) for the three types of tests were gathered at four study centers representing different geographic regions in Belgium and France. Study sample: Fifty-seven normal-hearing listeners took part in the normative study of the FrMatrix, and 118 subjects, with a wide range of hearing thresholds, participated in the comparative study. Results: Homogenizing the individual words of the FrMatrix with regard to their intelligibility resulted in a reference SRT of −6.0 (±0.6) dB SNR and slope at the SRT of 14.0 %/dB. The within-subject variability was only 0.4 dB. Comparison of the three tests showed high correlations between the SRTs mutually (>0.81). The FrMatrix had the highest discriminative power, both in stationary and in fluctuating noise. For all three tests, differences across the participating study centers were small and not significant. Conclusions: The FIST, the FrMatrix, and the FrDigit3 provide similar results and reliably evaluate speech recognition performance in noise both in normal-hearing and hearing-impaired listeners.

The French digit triplet test: A hearing screening tool for speech intelligibility in noise

Abstract A French speech intelligibility screening test in noise that applies digit triplets as stimuli has been developed and evaluated for both telephone and broadband headphone use. After optimizing the speech material based on the intelligibility of the individual digits, norms for normal-hearing subjects were established. speech reception thresholds (SRTs) of −6.4 ± 0.4 and −10.5 ± 0.3 dB SNR, and slopes of 17.1 and 27.1 %/dB were obtained for telephone and broadband headphone presentation, respectively. The French digit triplet test by telephone was then implemented as an automatic self-screening test by home telephone, and further evaluated in normal-hearing and hearing-impaired listeners. A test-retest variability of 0.7 dB was found and the correlation between SRT and pure-tone average (PTA0.5,1,2,4) was 0.77. One month after launching the test, 20 000 calls were registered. It can be concluded that both versions of the newly developed test have steep slopes and small SRT differences across normal-hearing listeners. The screening test by telephone is highly reliable and proves to fulfill the need for an easily accessible and objective hearing screening. Sumario Se desarrolló y evaluó una prueba de tamiz de inteligibilidad del lenguaje en ruido, utilizando ternas de dígitos como estímulo, tanto para teléfono como para auriculares de banda ancha. Después de optimizar el material lingüístico basado en la inteligibilidad de los dígitos individuales, se establecieron las normas para los sujetos normoyentes. Se obtuvieron umbrales de recepción del lenguaje (SRTs) de -6.4 ± 0.4 y -10.5 ± 0.3dB SNR y pendientes de 17.1 y 27.1%/dB para teléfono y auriculares de banda ancha, respectivamente. Se implementó la prueba de terna de dígitos en francés por teléfono como una prueba de tamiz autoaplicable por teléfono en casa y después se evaluó en normoyentes e hipoacúsicos. Se encontró una variabilidad de test-re-test de 0.7 dB y la correlación entre SRT y el promedio de tonos puros (PTA0.5,1,2,4) fue de 0.77. Un mes después de lanzar la prueba, se registraron 20,000 llamadas. Se puede concluir que ambas versiones de la prueba recientemente desarrollada tiene pendientes pronunciadas y pequeñas diferencias del SRT entre los normoyentes. La prueba de tamiz por teléfono es altamente confiable y demuestra que satisface las necesidades de una prueba de tamiz auditivo fácil, accesible y objetiva.

Internationally comparable screening tests for listening in noise in several European languages: The German digit triplet test as an optimization prototype

Abstract Objective: A review is given of internationally comparable speech-in-noise tests for hearing screening purposes that were part of the European HearCom project. This report describes the development, optimization, and evaluation of such tests for headphone and telephone presentation, using the example of the German digit triplet test. In order to achieve the highest possible comparability, language- and speaker-dependent factors in speech intelligibility should be compensated for. Materials and methods: The tests comprise spoken numbers in background noise and estimate the speech reception threshold (SRT), i.e. the signal-to-noise ratio (SNR) yielding 50% speech intelligibility. Results: The respective reference speech intelligibility functions for headphone and telephone presentation of the German version for 15 and 10 normal-hearing listeners are described by a SRT of −9.3 ± 0.2 and −6.5 ± 0.4 dB SNR, and slopes of 19.6 and 17.9%/dB, respectively. Reference speech intelligibility functions of all digit triplet tests optimized within the HearCom project allow for investigation of the comparability due to language specificities. Conclusions: The optimization criteria established here should be used for similar screening tests in other languages.

Development of a Dutch matrix sentence test to assess speech intelligibility in noise

Abstract Objective: A Dutch matrix sentence test was developed and evaluated. A matrix test is a speech-in-noise test based on a closed speech corpus of sentences derived from words from fixed categories. An example is “Mark gives five large flowers.” Design: This report consists of the development of the speech test and a multi-center evaluation. Study sample: Forty-five normal-hearing participants. Results: The developed matrix test has a speech reception threshold in stationary noise of − 8.4 dB with an inter-list standard deviation of 0.2 dB. The slope of the intelligibility function is 10.2 %/dB and this is slightly lower than that of similar tests in other languages (12.6 to 17.1 %/dB). Conclusions: The matrix test is now also available in Dutch and can be used in both Flanders and the Netherlands.

Contribution to the discussion surrounding the Freiburg speech test

Die Intention einer multizentrischen Studie zur Sprachaudiometrie ist – angesichts der Bedeutung der Sprachaudiometrie für Hördiagnostik, Anpassung von technischen Hörhilfen und Begutachtung – löblich, die Ausführung der Studie bleibt aber weit hinter diesen Erwartungen zurück: Die in der Arbeit von Löhler et al. [14] dargestellten multizentrischen Untersuchungen stellen einen unzureichenden Versuch dar, den nicht mehr zeitgemäßen Freiburger Sprachtest von 1953 zu rehabilitieren, obwohl er der international gültigen Norm für Sprachaudiometrieverfahren (DIN EN ISO 8253-3, [5]) nicht mehr entspricht. Insbesondere soll in der Studie von Löhler et al. die Einsetzbarkeit des Freiburger Einsilbertests [8] im Störschall belegt werden. Angesichts der großen Bedeutung des Sprachverstehens im Störschall im Alltag erscheint dies durchaus sinnvoll. Dabei werden die wesentlichen Argumente, die gegen die Verwendung des Freiburger Tests im Störschall sprechen, in der vorgelegten Arbeit allerdings weder ausreichend dargestellt noch diskutiert: F Der Freiburger Sprachtest weicht aufgrund seiner Konstruktion in mehrere Punkten so erheblich von der gültigen internationalen Norm ISO 8253-3 ab, dass auch zusätzliche Messungen oder Korrekturen keine Abhilfe bieten. Beispielsweise weist er keine normale Artikulation auf, die Testlisten sind weder phonemisch noch perzeptiv ausgewogen, es gibt weder ein zugehöriges normierbares Störgeräusch noch verlässliche Daten zur Test-Retest-Reliabilität. F Bei vergleichbarer Messzeit ergibt der Test eine wesentlich geringere Auflösung bzw. geringere Genauigkeit als Satztestverfahren (. Tab. 1, aus [13]). Für die gleiche Genauigkeit muss man daher wesentlich länger messen als mit einem Satztest – insbesondere, wenn es um Schwellenmessungen im Störschall geht. F Die Äquivalenz der Testlisten wurde in der Literatur bisher weder mit der für eine Normierung notwendigen Genauigkeit belegt, noch konnten die von verschiedenen Autoren bisher gefundenen signifikanten Listenunterschiede widerlegt werden. Die vorliegende Studie von Löhler et al. kann diese Listenunterschiede ebenfalls nicht widerlegen (s. u.). F Aufgrund eines fehlenden Ankündigungssatzes ist der Freiburger Einsilber für den Einsatz im Störschall nur mit starken Einschränkungen geeignet, da keinerlei Hinweise auf den Anfang des zu detektierenden Wortes gegeben werden. Aus diesem Grund wurde von Döring u. Hamacher [7] die „Dreinsilber-Variante“ entwickelt, die das „Verpassen“ des gesuchten Wortes vermeidet, allerdings mehr Darbietungszeit benötigt. F Aufgrund des offenen Testformats und der nicht alltäglichen Sprechweise sind die Wörter im Mittel deutlich schlechter verständlich als ein gemäß der aktuellen Norm validierter geschlossener Einsilbertest mit Alltagssprache (verkürzter WaKo-Einsilber-Reimtest, [3]), d. h. der Sprachpegel muss um 20 dB höher angeboten werden, um die gleiche Verständlichkeit zu erzielen [16, 17]. Die daraus resultierenden, beim Freiburger Einsilbertest überhöhten Testpegel können in der audiometrischen Praxis und in der Begutachtung zu Fehleinschätzungen des Sprachverstehens im Alltag führen. Bei der Anpassung und Überprüfung von Hörgeräten können Abweichungen der eingestellten Pegelabhängigkeit gegenüber der Notwendigkeit im täglichen Gebrauch resultieren.

Vergleich des Göttinger Satztests und des Einsilber-Reimtests nach von Wallenberg und Kollmeier mit dem Freiburger Sprachtest

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.

How much does language proficiency by non-native listeners influence speech audiometric tests in noise?

Objective: The current study investigates the extent to which the linguistic complexity of three commonly employed speech recognition tests and second language proficiency influence speech recognition thresholds (SRTs) in noise in non-native listeners. Design: SRTs were measured for non-natives and natives using three German speech recognition tests: the digit triplet test (DTT), the Oldenburg sentence test (OLSA), and the Göttingen sentence test (GÖSA). Study sample: Sixty-four non-native and eight native listeners participated. Results: Non-natives can show native-like SRTs in noise only for the linguistically easy speech material (DTT). Furthermore, the limitation of phonemic-acoustical cues in digit triplets affects speech recognition to the same extent in non-natives and natives. For more complex and less familiar speech materials, non-natives, ranging from basic to advanced proficiency in German, require on average 3-dB better signal-to-noise ratio for the OLSA and 6-dB for the GÖSA to obtain 50% speech recognition compared to native listeners. Conclusions: In clinical audiology, SRT measurements with a closed-set speech test (i.e. DTT for screening or OLSA test for clinical purposes) should be used with non-native listeners rather than open-set speech tests (such as the GÖSA or HINT), especially if a closed-set version in the patients own native language is available.