Ageing effects on flash visual evoked potentials (FVEP) recorded from parietal and occipital electrodes

The effects of ageing on flash visual evoked potentials (FVEP) recorded from 6 posterior parietal and occipital sites were studied in a sample of 73 healthy subjects of between 20 and 86 years of age. Latencies of components P1, N1 and P2, and amplitudes of components P1 and P3 increased linearly with age at all emplacements. The results obtained from occipital electrodes are in line with previous reports and additionally show that i) the effects of age constantly increase over time, and ii) age affects not only the early but also the later components (> 150 ms) of the FVEP. The overall pattern of results suggests that elderly subjects show slower transmission of visual information and deficiencies in the inhibitory regulation of activity generated during the arrival of repetitive non-attended visual stimulation. The findings with parietal electrodes show that ageing effects are more marked at these emplacements than at occipital electrodes. Furthermore, this raises the question of a possible differential involvement of primary and nonprimary visual cortex by age, but this hypothesis can only be explored with high-intensity multichannel recordings and dipolar modelling.