Exploring the sensitivity of speech-in-noise tests for noise-induced hearing loss

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 PTA(2,3,4,6) (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.