Mismatch Negativity as a Marker of Auditory Pattern Separation Integrity in Aging

How does auditory perception interact with precision in memory (i.e., mnemonic discrimination) in aging? This study examined how the mismatch negativity (MMN), an electrophysiological marker of change detection and encoding, relates to age differences in mnemonic discrimination. The MMN was recorded from 33 young (18–32 years, 18 females) and 30 older (55–86 years, 14 females) adults in a passive oddball paradigm using tone sequences. Participants then completed an incidental recognition test for old targets against similar lures and dissimilar foils. Older adults showed attenuated MMN amplitudes and poorer performance discriminating targets from lures and foils than young adults. Across participants, smaller MMN amplitude predicted worse recognition performance. Notably, MMN amplitude partially explained age-related declines in target-lure discriminability, but not target-foil discriminability. Findings reinforce the MMN as a marker of pattern separation integrity, and clarify how age-related declines in mnemonic discrimination are explained by age differences at encoding.