Selection of test-setup parameters to target specific signal-to-noise regions in speech-on-speech intelligibility testing

Abstract

Objective: To investigate the magnitude of the change in speech-reception threshold (SRT) provided by altering four different test-setup parameters. Furthermore, to determine whether these changes in SRT are of a sufficient magnitude, such that they can be used to design a test-setup in future experiments that target a predefined signal-to-noise ratio (SNR) region. This could be particularly important if the test contrast investigated is confounded with test SNR. Design: The investigated test-setup parameters were: Spatial separation between target (0°) and maskers (±15°, ±30°, ±45°, or ±75°), number of maskers (two, four or six), scoring method (scoring percent-correct words or sentences) and masker gender (same or opposite to target). Twenty SRTs were measured per test subject. Study sample: Twenty hearing-impaired test subjects participated over two visits. Results: Alteration of masker gender, spatial separation between target and masker (±15°, ±30°, ± 45°), and scoring method was shown to offer SRT changes of a sufficient magnitude. The different test setups resulted in average SRTs ranging from −4.0 to 3.3 dB. Conclusion: Deliberately selecting test setup parameters can change the overall difficulty of the test by up to 7.3 dB SRT. Thus, a future experiment can, to this extent, be designed to target a specific SNR region.

Key Words:

• Speech perception
• behavioral measures
• hearing aids
• psychoacoustics/hearing science

Acknowledgements

The authors wish to thank our colleagues Maria Grube Sorgenfrei, Julie Hefting Pedersen, and Renskje Klaske Hietkamp, for their substantial work with experiment design and data collection. The data from this study and some preliminary analyses were presented at the International Congress on Acoustics (ICA), Montreal, Canada, 2–7 June 2013 (Rønne et al, 2013). Filip M. Rønne and Niels Søgaard Jensen are now at Widex A/S, Lynge, Denmark, and Søren Laugesen is at Interacoutics Research Unit, Lyngby, Denmark.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.