Cortical Activation Patterns to Speech Differ Between Two Age Groups of Older Adults

Area of Science:

• Neuroscience
• Gerontology
• Speech and Hearing Sciences

Background:

• Speech perception integrates sensory, cognitive, and linguistic functions, declining with age.
• Research on speech-in-noise (SIN) perception has often excluded the very elderly (80-91 years old).
• This demographic is rapidly growing, necessitating research into their unique challenges.

Purpose of the Study:

• To investigate age-related differences in cortical activation patterns during speech perception in quiet and noisy environments.
• To compare neural responses between less elderly (65-77 years) and very elderly (80-91 years) adults.
• To assess behavioral performance in SIN recognition and related cognitive and auditory abilities.

Main Methods:

• Functional Near-Infrared Spectroscopy (fNIRS) was used to measure cortical activation.
• Participants completed speech tasks in quiet and noisy conditions.
• SIN recognition tests and auditory, cognitive, and linguistic assessments were performed.

Main Results:

• Significant differences in cortical activation patterns were observed between age groups.
• Very elderly adults showed heightened activation in the left temporopolar region (semantic processing).
• Less elderly adults exhibited greater activation in the left dorsolateral prefrontal cortex (executive functions).
• Very elderly adults performed worse on SIN recognition and showed declines in auditory resolution, attention, and inhibition.

Conclusions:

• Advanced aging is associated with distinct neural adaptations in speech processing.
• A shift occurs from executive control reliance (less elderly) to semantic processing (very elderly) due to functional declines.
• Age-specific auditory rehabilitation strategies are needed, focusing on residual capacities in the very elderly.