Auditory figure-ground segregation is impaired by aging and age-related hearing loss

Abstract

Listening in a noisy environment relies on our ability to extract structure from noisy sensory input while segregating it from the rest of the scene (Figure-Ground Segregation—FGS). To assess whether FGS is impaired by aging, source localized brain activity was analyzed from young, older adults, and hearing-impaired (HI) elderly during object detection in noise. Listeners’ task was to report whether they detected a figure (rising sound stream) within either high or low noise. Individualized figure and noise levels allowed us to compare groups across the same performance levels (65% vs 85% accuracy). HI group was impaired in integrating sounds of the figures. Figures elicited an early sensory processing-related (object-related negativity- ORN) and a later perceptual decision-related (P600) brain response. In the elderly, compared to the young the ORN was delayed in general and smaller in the inferior frontal gyrus (IFG). P600 activity was generated within a less distributed network in both the elderly and HI relative to the young. In the HI, compared to the elderly the ORN was smaller in the auditory cortex and IFG. Our results suggest that early FGS processes are disturbed only neurally in the elderly and overtly in HI.