Age-related changes in attended and unattended P3 latency in normal subjects.

Event-related potentials to visual attended and unattended stimuli were studied in 37 normal subjects between the ages of 19 and 91. The components of the P3 responses to rare nontarget stimuli and rare target stimuli were measured as P3a and P3b, respectively. Both the P3a and P3b latencies were significantly and positively correlated with age. The N2 finding of age-related latency prolongation was comparable to the P3a changes with age. From the standpoint of the theory of automatic and controlled processing, these results suggest that both automatic processing, as reflected by the P3a, and attentional controlled processing, as reflected by the P3b, are impaired with normal aging.