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

Abstract

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 (S(50)) were determined in normal-hearing subjects. It was found that the mean SRT and mean list-specific S(50list) for the first set were equal to -6.1 dB and 25.5%/dB, respectively. The mean SRT and the mean list-specific S(50list) 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.

The Influence of the Semantic Material on the Assessment of Speech Reception Threshold

“…This noise was created by summing up the waveforms of all the test sentences, where all sentences were shifted in time by a random value, and half of them were reversed in time. The result is a 15-s noise, whose random time periods were presented in the measurements of speech intelligibility (Ozimek et al, 2009). BN spectrum is shown in Fig.…”

“…Because power spectra for BN and BSN are nearly identical, the power spectrum curve for BSN was shifted upwards by 2 dB. Adopted from (Ozimek et al, 2009). …”

“…One of the recently developed tests for determining speech intelligibility is the Polish Sentence Test, (PST) (Ozimek et al, 2009), which was based on the method proposed by Plomp and Mimpen (1979). This test consists of 37 lists of 13 sentences each (a total of 481 sentences).…”

“…The subject was always presented with 18, similarly sounding words. Therefore, the aim of this study was to determine whether the number and the type of alternative words used by Ozimek et al (2009), had a significant influence on the speech intelligibility. The aim was also to determine an optimal number of alternative words: i.e., the number that did not affect the speech reception threshold (SRT) and not unduly lengthened the duration of the test.…”

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To determine speech intelligibility using the test suggested by Ozimek et al (2009), the subject composed sentences with the words presented on a computer screen. However, the number and the type of these words were chosen arbitrarily.

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