The effect of eye closure on speech discrimination in noise when in darkness and in light

Abstract

This study evaluated whether listening with an eye closure strategy can improve speech discrimination in noise in different visual conditions. Three hypotheses were made in the present study: (1) Listening with eyes closed leads to better speech discrimination in noise than with eyes open; (2) listening in darkness (no external visual stimulus) leads to better speech discrimination in noise than in light (with external visual stimulus); and (3) an interaction effect exists between eye closure and presence of external visual stimuli for speech discrimination in noise: Listening with eyes closed leads to improved speech discrimination in noise when in light compared to in darkness. This study recruited 56 Cantonese-speaking young adults (age range 18 to 35 years) with bilaterally normal hearing. Listeners were tested under different visual conditions to gauge their speech discrimination performance, with the Cantonese Hearing in Noise Test (CHINT). Analysis of variance (ANOVA) was performed and results showed a significant effect for eye closure and presence of external visual stimulus on speech discrimination in noise. Interaction was also found between the two variables. Posthoc analysis found a statistical significance with a large effect size, indicating that eye closure resulted in the greatest improvement in speech discrimination in noise when in the presence of an external visual stimulus. All effects were compared with the previously established inter-list variability of the CHINT procedure and found to lack clinical significance. Ultimately, no changes are needed for norms or testing procedures for the CHINT and, very likely, other speech tests. However, eye closure was found significant in improving speech discrimination in noise with a large effect size and is suggested as a listening strategy for challenging listening situations, when feasible to do so. The limitations of this study and directions for future research are explored.