Age effects on perceptual organization of speech: Contributions of glimpsing, phonemic restoration, and speech segregation.

In realistic listening environments, speech perception requires grouping together audible fragments of speech, filling in missing information, and segregating the glimpsed target from the background. The purpose of this study was to determine the extent to which age-related difficulties with these tasks can be explained by declines in glimpsing, phonemic restoration, and/or speech segregation. Younger and older adults with normal hearing listened to sentences interrupted with silence or envelope-modulated noise, presented either in quiet or with a competing talker. Older adults were poorer than younger adults at recognizing keywords based on short glimpses but benefited more when envelope-modulated noise filled silent intervals. Recognition declined with a competing talker but this effect did not interact with age. Results of cognitive tasks indicated that faster processing speed and better visual-linguistic closure were predictive of better speech understanding. Taken together, these results suggest that age-related declines in speech recognition may be partially explained by difficulty grouping short glimpses of speech into a coherent message.