Objective: Using a dual task paradigm, two experiments were conducted to: (1) quantify the listening effort that young and older adults expend to recognize speech in noise when presented under audio-only (Experiment 1) and audiovisual conditions (Experiment 2) and, (2) determine the influence visual cues have on listening effort. Listening effort refers to the attentional and cognitive resources required to understand speech.
Design: All participants performed a closed-set word recognition task and tactile pattern recognition task separately and concurrently. Accuracy and reaction time data were collected. The criterion for single task word recognition performance was set to 80% correct across experiments and across age groups.
Study sample: For each experiment, 25 young and 25 older adults with normal hearing and normal (or corrected normal) vision participated.
Results: Under equated performance conditions, older adults expended more listening effort than young adults with both audio-only and audiovisually presented speech. Furthermore, the processing demands of audiovisual speech recognition were greater than audio-only speech recognition for all participants.
Conclusions: These results suggest that while visual cues can improve audiovisual speech recognition, they can also place an extra demand on processing resources with performance consequences for the word and tactile tasks under dual task conditions.