Aging Reduces Attentional Modulation of Speech-Evoked Cortical Responses While Preserving Adaptation

BACKGROUND: This study examined age-related differences in repetition-related adaptation and attentional modulation of cortical auditory evoked potentials elicited by meaningful speech stimuli. METHODS: Younger (18-35 years) and older (50-70 years) adults with clinically normal hearing were tested under active and passive listening conditions. N1 peak amplitudes were analyzed across early (first 30) and late (last 30) stimulus trials. RESULTS: Repetition-related reductions in N1 amplitude were observed in both groups, indicating preserved adaptation. However, younger adults showed significant attentional enhancement of N1 amplitude, whereas older adults did not. CONCLUSIONS: These findings suggest that aging selectively reduces top-down attentional modulation while preserving repetition-related sensory adaptation.