Age-related change in neural processing of time-dependent stimulus features.

Aging is associated with changes in automatic processing of task-irrelevant stimuli, and this may lead to functional disturbances including repeated orienting to nonnovel events and distraction from task. The effect of age on automatic processing of time-dependent stimulus features was investigated by measurement of the auditory mismatch negativity (MMN) in younger (18-23) and older (55-85) adults. Amplitude of MMN recorded during a paradigm involving low-probability deviation in interstimulus interval (from 500 ms to 250 ms) was found to be reduced in the older group at fronto-central sites.