Audiovisual speech in older and younger adults: integrating a distorted visual signal with speech in noise.

Age-related changes to sensation and cognition may contribute to the differences found between younger and older adults using audiovisual speech. To evaluate this issue, younger and older adults repeated the final word of audio or audiovisual sentences in background noise. Although younger adults performed better than older adults, both age groups demonstrated the same level of visual enhancement in normal audiovisual conditions. However, when the visual speech was blurred, older adults had almost no audiovisual enhancement, whereas younger adults' enhancement was unaffected. These findings are discussed in terms of their implications for audiovisual integration over the course of the life span.