Older Listeners' Perception of Speech With Strengthened and Weakened Dynamic Pitch Cues in Background Noise

Abstract

Purpose Dynamic pitch, which is defined as the variation in fundamental frequency, is an acoustic cue that aids speech perception in noise. This study examined the effects of strengthened and weakened dynamic pitch cues on older listeners' speech perception in noise, as well as how these effects were modulated by individual factors including spectral perception ability. Method The experiment measured speech reception thresholds in noise in both younger listeners with normal hearing and older listeners whose hearing status ranged from near-normal hearing to mild-to-moderate sensorineural hearing loss. The pitch contours of the target speech were manipulated to create four levels of dynamic pitch strength: weakened, original, mildly strengthened, and strengthened. Listeners' spectral perception ability was measured using tests of spectral ripple and frequency modulation discrimination. Results Both younger and older listeners performed worse with manipulated dynamic pitch cues than with original dynamic pitch. The effects of dynamic pitch on older listeners' speech recognition were associated with their age but not with their perception of spectral information. Those older listeners who were relatively younger were more negatively affected by dynamic pitch manipulations. Conclusions The findings suggest the current pitch manipulation strategy is detrimental for older listeners to perceive speech in noise, as compared to original dynamic pitch. While the influence of age on the effects of dynamic pitch is likely due to age-related declines in pitch perception, the spectral measures used in this study were not strong predictors for dynamic pitch effects. Taken together, these results indicate next steps in this line of work should be focused on how to manipulate acoustic cues in speech in order to improve speech perception in noise for older listeners.