Age Effects on Concurrent Speech Segregation by Onset Asynchrony.

Purpose For elderly listeners, it is more challenging to listen to 1 voice surrounded by other voices than for young listeners. This could be caused by a reduced ability to use acoustic cues-such as slight differences in onset time-for the segregation of concurrent speech signals. Here, we study whether the ability to benefit from onset asynchrony differs between young (18-33 years) and elderly (55-74 years) listeners. Method We investigated young (normal hearing, N = 20) and elderly (mildly hearing impaired, N = 26) listeners' ability to segregate 2 vowels with onset asynchronies ranging from 20 to 100 ms. Behavioral measures were complemented by a specific event-related brain potential component, the object-related negativity, indicating the perception of 2 distinct auditory objects. Results Elderly listeners' behavioral performance (identification accuracy of the 2 vowels) was considerably poorer than young listeners'. However, both age groups showed the same amount of improvement with increasing onset asynchrony. Object-related negativity amplitude also increased similarly in both age groups. Conclusion Both age groups benefit to a similar extent from onset asynchrony as a cue for concurrent speech segregation during active (behavioral measurement) and during passive (electroencephalographic measurement) listening.