Grant: CIHR Fellowship

Segregating a target voice from concurrent sounds in a «cocktail party» environment is one of the most complex operations performed by the auditory system. Older adults very often report difficulties understanding speech in such challenging situations and this can enhance their experienced level of social handicap. Although age-related changes in hearing sensitivity clearly affect speech comprehension, impairments in the ability to segregate and identify a target sound are also associated with age-related changes at the central, or cortical, level. In challenging auditory situations, listeners can rely on various cues to improve their ability to segregate and understand speech sounds. For instance, listeners can more easily separate sounds at different frequencies (acoustic cue) or sounds with which they are familiar (knowledge-based, non-acoustic, cue). The proposed project includes both behavioral and neuroimaging experiments designed to investigate how acoustic and non-acoustic cues improve speech segregation and comprehension in younger and older listeners. Listeners will be asked to segregate and identify a target voice presented concurrently with a masker voice. The acoustic (i.e., fundamental frequency) and non-acoustic (i.e., familiarity) properties of the target voice will be independently manipulated. This project will explore how these different, very common cues improve speech segregability and how this is reflected within the cortical network subserving auditory and speech perception. This project will be the first investigation of how acoustic cues interact with knowledge-based cues to improve speech segregation and comprehension in younger and older adults. This research question is particularly relevant in aging considering the negative consequences of impaired communication in social situations on older listeners.