Effects of aging on sound localization and speech understanding in realistic listening situations

Abstract

The ability to localize sound in quiet and noise and understand speech in noise was measured for four groups of subjects including adults under 50 years old and over 60 years old with normal hearing, and adults under 50 years old and over 60 years old with hearing loss. Performance was measured in anechoic and reverberant listening environments at two stimulus levels (25 dB SL and 70 dB SPL). Head-related transfer functions were used to create spatialized stimuli that were presented to subjects via earphones. Results indicate that performance on both tasks is affected by age and hearing loss. Localization errors are larger in older adults than younger adults with normal hearing, and larger in older adults with hearing loss than older adults with normal hearing. The intelligibility gain is smaller in older adults than younger adults with normal hearing, and smaller in older adults with hearing loss than older adults with normal hearing. Speech understanding in noise shows a large effect of reverberation, but localization is not affected by the same amount of reverberation. Overall, results suggest that in realistic environments these tasks are more difficult for older adults. [Work supported by the American Hearing Research Foundation.]