The visual evoked potential in the first six years of life.

With routine techniques the flash-evoked VEPs in 11 consecutive age groups between 0--6 years, each consisting of 8 children, were measured under clinical circumstances. The children were carefully screened to fit within predetermined normal limits. The main results are: (1) The primary part, consisting of 3 components, is well discernible at birth and its latency declines exponentially with age and reaches adult values between 3--4 years. (2) The secondary part is barely discernible at birth and its latency increases until the age of 2--4 months, after which a sharp decline occurs. At the age of 6 years the latencies remain longer than adult values. (3) The integrated amplitude is small until the age of 2--4 months, after which a sharp increase is seen. Thereafter it remains rather constant but shows a sudden increase after the age groups 5--6 years. (4) Generally, values which were compared with those in the literature agreed well. (5) It is suggested that the development of the secondary part of the VEP reflects the increase in complexity of the connections within the visual cortex as well as between the cortex and subcortical centres.