Abstract
Objective: Recently, the digit triplet test was shown to be a sensitive speech-in-noise test for early high-frequency hearing loss in noise-exposed workers. This study investigates if a further improvement is achieved when using a closed set of consonant-vowel-consonant (CVC) speech items with the same vowel, and/or a low-pass (LP) filtered version of the standard speech-shaped noise. Design: Speech reception thresholds in noise were gathered for the digit triplet, CVC, and CVC_LP test and compared to the high-frequency pure-tone average (PTA). Study sample: 118 noise-exposed workers showing a wide range of high-frequency hearing losses. Results: For the 84 Dutch-speaking participants, the CVC test showed an increased measurement error and a decreased between-subject variation, leading to a weaker correlation with the PTA2,3,4,6 (R = 0.64) and thus a lower sensitivity compared to the digit triplet test (R = 0.86). However, the use of LP-filtered noise resulted in a sensitivity improvement (R = 0.79 versus R = 0.64) due to the large increase in between-subject spread. Similar trends were found for the 34 French-speaking workers. Conclusions: Using CVC words with the same vowel could not increase the sensitivity to detect isolated high-frequency hearing loss. With LP-filtered noise, test sensitivity improved, but it did not surpass the original digit triplet test.
Acknowledgements
The authors would like to thank Lena Vanoirbeek, Annelies Devriendt, and Sophie Radoux for administering the evaluation measurements in normal-hearing listeners for the digit triplet and CVC tests. The occupational health physicians Johan De Pooter and Patricia Boulanger (NMBS/SNCB-holding), Ginette Van Walle (Bombardier Transportation), Anne Guyssens (Heijmans Infra NV), Rose-Mary Roussel (FN Herstal), and Jean-Michel Huberlant (ArcelorMittal Liège) are gratefully acknowledged for recruiting the noise-exposed participants of this study. To conclude, we thank the audiologists Annelies Martens, Christiane Coryn, and Reinharda Van Gool for administering the measurements in the noise-exposed participants.
Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.