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Poster A17, Thursday, August 16, 10:15 am – 12:00 pm, Room 2000AB

Aging diminishes auditory activation for single spoken words: evidence from fMRI

Chad Rogers1, Michael S. Jones1, Sarah M. McConkey1, Brent Spehar1, Nichole Runge1, Kristin J. Van Engen1, Mitchell S. Sommers1, Jonathan E. Peelle1;1Washington University in St. Louis

Normal aging is associated with changes in not only cognitive functioning, but sensory ability. Hearing loss is one of the most common complaints in adults aged 60 and over, and is the third most chronic medical condition aside from arthritis and hypertension. Despite the relative prevalence of hearing loss, older adults’ language processing is generally quite good, with age-related declines in performance typically observed only in situations presenting enhanced perceptual or cognitive challenge (Wingfield & Stine-Morrow, 2000). A central question is how older adults are able to maintain such good performance despite significant changes in cortical anatomy and related changes in cognitive ability. Although it is widely accepted that understanding spoken words relies on bilateral temporal cortex in young adults (e.g., Lee et al., 2016; Hearing Res), relatively few studies have directly investigated age-related changes in the processing of spoken words. In the current study, we examined age-related changes in neural recruitment for spoken word processing. Using sparse functional magnetic resonance imaging (fMRI), brain activity patterns were compared between samples of young (N=32) and older adults (N=32), who performed two speech perception tasks: repetition of spoken words and passive listening of spoken words. Words were presented in the clear, with no additional noise masking. While older adults were less successful than young adults while identifying words in the scanner (Young M = 0.93, SD = 0.03; Older M = 0.73, SD = 0.17), both young and older adults showed significant speech-related activation in bilateral superior temporal gyrus (STG). Comparisons between the young and older adult groups suggested that young adults had stronger and wider speech-related activation of regions in bilateral STG than older adults. Comparisons of word repetition vs. passive listening revealed that young adults produced stronger activation in bilateral motor areas when repeating words than passive listening compared to older adults. The current study thus provides preliminary evidence that even under conditions of minimal linguistic and acoustic challenge (i.e. when listening to spoken words in quiet conditions), older adults with normal hearing for their age activate auditory processing regions less robustly than young adults (see also Vaden et al., 2016; Exp Aging Res). This pattern also held for motor-related activations when participants repeated words aloud. Future directions and potential relationships between patterns of observed activation and subthreshold hearing loss will be discussed.

Topic Area: Perception: Speech Perception and Audiovisual Integration