Development of a Danish speech intelligibility test.

A Danish speech intelligibility test for assessing the speech recognition threshold in noise (SRT(N)) has been developed. The test consists of 180 sentences distributed in 18 phonetically balanced lists. The sentences are based on an open word-set and represent everyday language. The sentences were equalized with respect to intelligibility to ensure uniform SRT(N) assessments with all lists. In contrast to several previously developed tests such as the hearing in noise test (HINT) where the equalization is based on scored (objective) measures of word intelligibility, the present test used an equalization method based on subjective assessments of the sentences. The new equalization method is shown to create lists with less variance between the SRT(N)s than the traditional method. The number of sentence levels included in the SRT(N) calculation was also evaluated and differs from previous tests. The test was verified with 14 normal-hearing listeners; the overall SRT(N) lies at a signal-to-noise ratio of -3.15 dB with a standard deviation of 1.0 dB. The list-SRT(N)s deviate less than 0.5 dB from the overall mean.