P30Session 2 (Friday 12 January 2024, 09:00-11:30)Predicting supra-threshold speech reception deficits using the Audible Contrast Threshold test
Background: The pure-tone audiogram is the main clinical diagnostic used for assessing hearing loss and provides the basis for the hearing-loss compensation applied in hearing aids. However, the audiogram does not necessarily reflect the hearing deficits that remain when audibility has been restored, for instance the crucial ability of individuals to understand speech in adverse conditions. These supra-threshold speech reception deficits can be measured using speech tests, but it has proven challenging to test speech reception directly in clinical settings due to limitations with respect to equipment, testing time, and standardized speech materials. A clinically viable test that is connected to supra-threshold speech reception deficits would thus represent a highly useful addition to the clinical assessment of an individual’s hearing abilities.
Methods: The present study assessed to what extent the Audible Contrast Threshold (ACTTM) test, a novel quick-and-simple clinical spectro-temporal modulation detection test with built-in audibility compensation, can predict supra-threshold speech reception in noise. One hundred eight hearing-impaired participants, consisting of 81 native speakers of German and 27 native speakers of Japanese, participated in the study. The audiogram and ACT were obtained along with speech-reception thresholds (SRTs). SRTs were measured with the participants using hearing aids in a challenging setting with spatially distributed speech interferers. Four different hearing-aid settings were tested: amplification only, mild directionality and noise reduction (DIR+NR), medium DIR+NR, and strong DIR+NR.
Results: On the group level, SRTs were highest for the amplification-only setting and decreased with increasing levels of DIR+NR processing. The individual SRTs collected with amplification only were strongly correlated with ACT and – to a lesser extent – with the 4-frequency pure-tone average (PTA4). The predictive power of ACT and PTA4 was found to be complementary, as they both contributed significantly to predicting the amplification-only SRT in a two-predictor linear regression model. Furthermore, the two measures were also associated with the individual SRT benefit induced by the DIR+NR processing.
Conclusions: The results indicate that the ACT test yields a measure of spectro-temporal modulation (or audible contrast) sensitivity that is predictive of aided speech reception in a realistic environment. The ACT yielded better SRT predictions than the audiogram while also adding significantly to the predictive power of the audiogram. This suggests that the ACT indeed represents a clinical measure that predicts supra-threshold speech reception deficits, which may be used to complement the information obtained from the audiogram in the clinic. More research is needed to identify meaningful interventions for individuals with substantial supra-threshold speech reception deficits and to assess said deficits in different populations of listeners, including those with audiometrically normal hearing.
Funding: This project was funded by the William Demant Foundation (20-2461).