Neural signatures of central auditory aging under sensory and cognitive loads

To investigate the neural mechanisms underlying auditory processing in older adults (OAs) under conditions of sensory-perceptual (S-P) and auditory-cognitive (A-C) loads.

Electroencephalography was recorded in 20 OAs (mean age = 69.6 ± 5.2 years) with age-appropriate hearing and preserved cognition, and 20 younger adults (YAs) (mean age = 24.9 ± 1.8 years). Participants performed tasks under S-P load (quiet vs. noise), A-C load (simple vs. demanding task), and combined load. Analyses included event-related potentials and time-frequency representations.

OAs showed delayed early (N1) and late (P3) cortical responses and slower reaction times (RTs) compared to YAs. Increased alpha-band desynchronization emerged as an age-related biomarker, reflecting OAs' reduced ability to inhibit irrelevant information. Distinct load-specific processing strategies appeared: S-P load was associated with delayed neural responses across cortical stages, longer RTs, and delta- and theta-band activity. A-C load was associated with prolonged late (P3) cortical activity, slower RTs, and broader neural recruitment across all frequency bands. Under combined load, OAs showed P3 latency prolongation, revealing vulnerability to the dual challenge of noise suppression and cognitive demand.

Integrated time- and frequency-domain electroencephalography analyses exposed distinct listening strategies in OAs, characterized by load-specific neural signatures.

Improved understanding of auditory processing strategies in OAs will advance targeted auditory rehabilitation.