Development and evaluation of the Turkish matrix sentence test

Abstract

Objectives: The Turkish matrix sentence test, TURMatrix, was developed for precise, internationally comparable speech intelligibility testing. Design: The TURMatrix comprises a base matrix of ten well-known Turkish names, numbers, adjectives, objects, verbs, from which syntactically fixed sentences were randomly composed. Test conduction may be in an open-set (standard), or closed-set response format. Homogeneity in intelligibility of the test material was optimized by applying level adaptations (maximal ± 3 dB) based on word-specific speech reception thresholds (SRTs). Test list equivalence was verified and reference values were determined. Study sample: Thirty-eight native listeners of Turkish with normal hearing. Results: After training, mean SRT and slope of the final test lists were − 8.3 ± 0.2 dB SNR and 14.1 ± 1.0%/dB, respectively (fixed SNR measurements; inter-list variability). For adaptive measurements, average across listeners was − 7.2 ± 0.7 dB SNR in the open-set and − 7.9 ± 0.7 dB SNR in the closed-set response format. Mean SRT for adaptive measurements in the open-set response format in quiet was 20.3 ± 4.1 dB. Individual SRTs in quiet correlated more closely with audiograms than with SRTs in noise. Conclusions: The TURMatrix was developed according to European standards and provides reliable speech intelligibility measurements in noise and quiet.

Key Words::

• Speech audiometry
• speech recognition in noise
• signal-to-noise ratio (SNR)
• speech reception threshold (SRT)
• matrix sentence test, Turkish

Acknowledgements

The authors would like to thank İclâl Ergenç for lending her voice to the test. We express our gratitude to Müge Kaya (Hörzentrum Oldenburg GmbH, Oldenburg, Germany) and Pinar Koç (University of Oldenburg, Germany) for conducting the measurements. Thanks also to Müge Kaya for her support during post-processing and re-synthesis of the sound files. This work was supported by the European regional development fund (EFRE, Project ‘Network for multilingual hearing and speech intelligibility diagnostics’, HurDig), and by the Deutsche Forschungsgemeinschaft (KO 942-13, EXC 1077 Hearing4all). The copyright of the Turkish matrix sentence test audio material is owned by the non-profit organization HörTech gGmbH (owned in majority by the University of Oldenburg). The test is available as a medical product for modern audiometers of different brands. For research purposes, sample sentences and free trial versions of the research version of the software are available from www.hoertech.de.

Declaration of interest: The authors confirm that they have no conflicts of interest to declare.

Supplementary material available online

Supplementary Appendix 1 to be found online at http://informahealthcare.com/doi/abs/10.3109/14992027.2015.1074735.