Dariusz Kutzner

Polish sentence matrix test for speech intelligibility measurement in noise

Abstract The purpose of this study was to develop the Polish sentence matrix test (PSMT) to measure intelligibility of speech presented against a background noise. The PSMT consists of five columns containing: 10 names, 10 verbs, 10 numerals, 10 adjectives, and 10 nouns. Since each word was available as a separate sound file, it was possible to generate different sentences by juxtaposing randomly selected words taken from respective columns. This approach allows 100 000 unique sentences of a fixed grammatical structure to be generated. The speech reception threshold (SRT), i.e. the signal-to-noise ratio (SNR) providing 50% speech intelligibility and S50, the slope of an intelligibility function at the SRT point, were shown to be −9.6 dB and 17.1 %/dB, respectively. Note that in this study dB is regarded as dB SNR, otherwise reference is given. PSMT was also evaluated using an adaptive 1-up/ 1-down staircase procedure in investigations with and without participation of an experimenter. No significant differences were shown for SRTs obtained in these investigations. Sumario El propósito de este estudio fue desarrollar la prueba matriz de frases en polaco (PSMT) para medir la inteligibilidad de lenguaje presentado contra ruido de fondo. El PSMT consiste de cinco columnas que contienen: 10 nombres, 10 verbos, 10 numerales, 10 adjetivos y 10 palabras. Dado que cada palabra estaba disponible como un archivo de sonido separado, fue posible generar diferentes frases por medio de la yuxtaposición aleatoria de palabras seleccionadas tomadas de las respectivas columnas. Este enfoque permite la generación de 100.000 frases singulares con una estructura gramatical fija. El umbral de recepción del lenguaje (SRT), p.e., la tasa de señal-ruido (SNR) brindando el 50% de inteligibilidad del lenguaje, y el S50, la pendiente de una función de inteligibilidad en el punto del SRT, fueron –9.6 dB y 17.1%/dB, respectivamente. Note que en este estudio los dB corresponden a dB SNR, a menos que se brinde otra referencia. También se evaluó el PSMT usando un procedimiento adaptativo en escalera de 1 hacia arriba y 1 hacia abajo, en investigaciones con y sin un experimentador. No se encontraron diferencias significativas para los SRT obtenidos en estas investigaciones.

Polish sentence tests for measuring the intelligibility of speech in interfering noise

The aim of this study was to develop Polish sentence tests for accurate measuring of speech intelligibility in masking interfering noise. Two sets of sentence lists have been developed. The first set was composed of 25 lists and was used for sentence intelligibility scoring. The second set was composed of 22 lists and was used for word intelligibility scoring. The lists in each set have been phonemically and statistically balanced. The speech reception threshold (SRT) and slope of the psychometric function at the SRT point (S50) were determined in normal-hearing subjects. It was found that the mean SRT and mean list-specific S50list for the first set were equal to −6.1 dB and 25.5%/dB, respectively. The mean SRT and the mean list-specific S50list for the second set were:−7.5 dB and 20.8%/dB. Due to a relatively steep slope of the psychometric functions, the Polish sentence tests were shown to be accurate materials for speech intelligibility measurements against interfering noise. They are the first sentence speech-in-noise tests developed for Slavonic languages.

Speech intelligibility tested by the Pediatric Matrix Sentence test in 3-6year old children

Objective: The present study was aimed at the development and application of the Polish Pediatric Matrix Sentence Test (PPMST) for testing speech intelligibility in normal-hearing (NH) and hearing-impaired (HI) children aged 3-6. Methods & Procedures: The test was based on sentences of the subject-verb-object pattern. Pictures illustrating PPMST utterances were prepared and the picture-point (PP) method was used for administering the 1-up/1-down adaptive procedure converging the signal to noise ratio (SNR) to the speech reception threshold (SRT). The correctness of verbal responses (VR), preceding PP responses, was also judged. Outcomes & Results: The normative SRT for the PP method was shown to decrease with age. The guessing rate (@c) turned out to be close to the theoretical value for forced-choice procedures, @c=1/n, where n=6 for the six-alternative PP method (@c~0.166) and n=4 for the four-alternative PP method (@c~0.25). Test optimization resulted in minimizing the lapse rate (@l) (ratio @c/@l~8.0 for n=4 and @c/@l~5.6 for n=6, both for NH and HI children). Significantly higher SRTs were observed for HI children than for the NH group. Conclusions & Implications: For children aged 3-6, tested by the developed PPMST, speech intelligibility performance, for both the VR and PP method, increases with age. For each age group, significantly worse intelligibility was observed for HI children than for NH children. The PPMST combined with the PP method is a reliable tool for pediatric speech intelligibility measurements.

Speech intelligibility determined with various tests presented against noise

The paper describes three Polish tests for assessment of speech intelligibility under noisy conditions: the matrix test, the sentence test and the digit triplet test. The matrix test contains semantically unpredictable sentences of fixed syntactical structures. This test is very useful for long‐term intelligibility measurements and is applicable for subjects with profound hearing loss or cochlear implants users. The sentence test comprises utterances taken from everyday speech and aims at clinical speech intelligibility measurements. The digit triplet test contains sequences of three digits that are spoken separately and is aimed at screening measurements, especially via telephone. The statistical and phonemic properties of the tests are analyzed and compared. The correlation between results obtained in the respective tests and the tests applicability are also discussed.