AGE EFFECTS ON DURATION DISCRIMINATION WITH SIMPLE AND COMPLEX STIMULI

This study examined age-related changes in temporal processing by meas uring DLs for signal duration using simple and complex stimuli. Previo us research has shown that elderly listeners exhibit difficulty discri minating duration changes in simple sounds, suggesting the possibility of age-related changes incentral timing mechanisms. The present exper iments examined the interactive effects of aging, hearing loss, and st imulus complexity on duration discrimination. Four groups participated : young and elderly listeners with normal hearing, and young and elder ly listeners with hearing loss. Duration DLs were measured for 250-ms tone bursts and for silent gaps between tone bursts that were presente d either in isolation or embedded as target stimuli within tonal seque nces, The tone sequences were composed of five sequential 250-ms compo nents. Stimulus complexity was varied by changing the sequential order of tone frequencies and the location of an embedded target component across listening conditions. Analyses of results revealed the followin g: Elderly listeners performed more poorly than younger listeners in n early all stimulus conditions, the effects of stimulus complexity on d iscrimination were greatest among elderly listeners, and hearing loss had no systematic effect on discrimination performance. (C) 1995 Acous tical Society of America.