The results of this study suggest that, on the average, hearing aids can reduce objectively measured listening effort. Furthermore, people who are slow verbal processors are more likely to derive hearing aid benefit for listening effort, perhaps because hearing aids improve the auditory input. Although background noise increased objective listening effort, no listener characteristic predicted susceptibility to noise. With regard to visual cues, while there was no effect on average of providing visual cues, there were some listener characteristics that were related to changes in listening effort with vision. Although these relationships are exploratory, they do suggest that these inherent listener characteristics like working memory capacity, verbal processing speed, and lipreading ability may influence susceptibility to changes in listening effort and thus warrant further study.

Overall, the results support the hypothesis that integrating auditory and visual cues requires cognitive resources in some participants. The data indicate that low lipreading ability or low WMC is associated with relatively effortful integration of auditory and visual information in noise.

None of the dual-task paradigms were sensitive to the effects of visual cues. Furthermore, changing the complexity of the secondary task did not change dual-task paradigm sensitivity to the effects of background noise on listening effort for either group of listeners. However, the paradigm whose secondary task involved deeper processing was more sensitive to the effects of background noise for both groups of listeners. While this paradigm differed from the others in several respects, depth of processing may be partially responsible for the increased sensitivity. Therefore, this paradigm may be a valuable tool for evaluating other factors that affect listening effort.