Temporal and spatial properties of the pattern-reversal VEPs in infants below 2 months of age.

Pattern VEP measurements in infants below 2 months of age do not seem to show appreciable developmental changes in contrast sensitivity and cut-off spatial frequency in spite of the marked structural maturation that takes place in the visual system. This paper investigates the temporal parameters of the pattern VEP in order to establish electrophysiological criteria in detecting developmental changes of the visual pathway in this age range. In comparison with the adult, the neonatal response latency is delayed about 155 ms. The delay shortens during the first two months with a slope of around 1 ms/day. The neonatal temporal and spatial tuning functions, as compared with the adult ones, are markedly shifted towards lower temporal and spatial frequencies respectively, and do not show measurable changes in the early post-natal period.