a b s t r a c t
Aging affects the interplay between peripheral and cortical auditory processing. Previous studies have
demonstrated that older adults are less able to regulate afferent sensory information and are more
sensitive to distracting information. Using auditory event-related potentials we investigated the role of
cortical inhibition on auditory and audiovisual processing in younger and older adults. Across puretone,
auditory and audiovisual speech paradigms older adults showed a consistent pattern of inhibitory deficits,
manifested as increased P50 and/or N1 amplitudes and an absent or significantly reduced N2. Older
adults were still able to use congruent visual articulatory information to aid auditory processing but
appeared to require greater neural effort to resolve conflicts generated by incongruent visual information.
In combination, the results provide support for the Inhibitory Deficit Hypothesis of aging. They
extend previous findings into the audiovisual domain and highlight older adults’ ability to benefit from
congruent visual information during speech processing.