Das Signal-Rausch-Verhältnis (SNR) von alltäglichen Hörsituationen ist in der Regel positiv. Um Hörgeräte in diesen Situationen zu evaluieren, wurde ein Sprachtest eingeführt, der zeitkomprimierte Sprache bei festen positiven SNRs präsentiert. Basierend auf dem Oldenburger Satztest wurden dabei Sprachverständlichkeitsschwellen als Funktion des SNRs und der Sprechrate bestimmt. Ein uniformer und ein nicht-uniformer Zeitkompressionsalgorithmus wurden untersucht. Subjektive und objektive Analysen zeigen Vorteile des uniformen Algorithmus auf. Lerneffekte zeitkomprimierter und originaler Sprache wurden verglichen. Das Testverfahren wurde optimiert, um bei adaptiver Sprechrate Verständlichkeit effektiv zu messen. Die Evaluation von zwei Störgeräuschreduktionen zeigte das Potential der Methode, zwischen den Hörgerätealgorithmen bei positiven SNRs zu unterscheiden. Die Methode kann Tests von Sprache im Störgeräusch und des Hörgerätenutzens auf einen positiven SNR-Bereich erweitern. <dt.>
In daily communication the signal-to-noise ratio (SNR) of speech and background noise is usually positive. To evaluate the performance of hearing aids in such situations, a speech-in-noise test was introduced that presents time-compressed speech at fixed positive SNRs. Based on the Oldenburg sentence test, speech recognition thresholds were determined as a function of SNR and of the speech rate. A uniform and a non-uniform time compression algorithm were tested. Subjective and objective analysis indicated advantages of the uniform algorithm. Learning effects of the time-compressed and the original speech test were compared. A test procedure using adaptive speech rate was optimized for effective recognition measurements. Evaluating two single-microphone noise reduction algorithms showed the potential of the method for discriminating across these hearing aid algorithms at positive SNRs. The method can extend tests of speech in noise and of hearing aid benefit to a range of positive SNRs. <engl.>
Acoustical Society of America The journal of the Acoustical Society of America Melville, NY : AIP Publ., 1929 138(2015), 5, Seite 3320-3331 Online-Ressource
For assessing hearing aid algorithms, a method is sought to shift the threshold of a speech-in-noise test to (mostly positive) signal-to-noise ratios (SNRs) that allow discrimination across algorithmic settings and are most relevant for hearing-impaired listeners in daily life. Hence, time-compressed speech with higher speech rates was evaluated to parametrically increase the difficulty of the test while preserving most of the relevant acoustical speech cues. A uniform and a non-uniform algorithm were used to compress the sentences of the German Oldenburg Sentence Test at different speech rates. In comparison, the non-uniform algorithm exhibited greater deviations from the targeted time compression, as well as greater changes of the phoneme duration, spectra, and modulation spectra. Speech intelligibility for fast Oldenburg sentences in background noise at different SNRs was determined with 48 normal-hearing listeners. The results confirmed decreasing intelligibility with increasing speech rate. Speech had to be compressed to more than 30% of its original length to reach 50% intelligibility at positive SNRs. Characteristics influencing the discrimination ability of the test for assessing effective SNR changes were investigated. Subjective and objective measures indicated a clear advantage of the uniform algorithm in comparison to the non-uniform algorithm for the application in speech-in-noise tests.
Acoustical Society of America The journal of the Acoustical Society of America Melville, NY : AIP Publ., 1929 135(2014), Seite 1541-1555 Online-Ressource