Increased multisensory integration in older adults during speech and semantic tasks

When individuals perceive sensory inputs through multiple sensory modalities, they incur perceptual and behavioural benefits. Older adults have been found to benefit more from such multisensory integration than younger adults. However, such findings have been inconsistent in the context of speech processing. In the current study, we examined age-related differences in multisensory gain using two tasks: a speech-in-noise task and a semantic discrimination task. In the first task, participants identified a single noun embedded in multi-talker babble. Stimuli were presented in auditory-only, visual-only, or audiovisual conditions, and perceptual accuracies were recorded. In the second task, participants identified whether they perceived a red or blue stimulus in either auditory-only (spoken word), visual-only (a red or blue circle), and audiovisual conditions, with response times recorded. Older adults exhibited more multisensory gain relative to younger adults in both speech perception and semantic processing tasks, even when accounting for unisensory declines associated with aging.