Auditory averaged evoked potentials and aging: factors of stimulus, task and topography.

The averaged evoked potential to brief tones was compared for 10 young and 10 elderly female subjects. The amplitudes of the sensory components (P1, N1 and P2) were not affected by an infrequent change in pitch of the tones or instructing subjects to count or ignore them; but overall the elderly had a larger P1 and smaller P2 amplitude and a difference in the scalp distribution of P2. Repetition of the tones produced a decrement in these sensory components and a differential one for young and old subjects A slow potential complex consisting of components N2, P3 and SW appeared to changes in tone pitch and became more pronounced when attention was directed to the tones. Overall smaller SPs for oder subjects were interpreted as evidence for a change with age in the cortical representation of the orienting response. Topographical analysis of SPs indicated diminished activity in frontal (Fz) electrodes for elderly persons, suggestive of an enhanced aging process in the frontal cortices.