Maturation of steady-state flicker VEPs in infants: fundamental and harmonic temporal response frequencies

Transient flash VEPs allow objective assessment of visual function and are easily recorded in young infants. However, due to their high variability, they are an insensitive surrogate marker of visual development. The aim of our study was to investigate the early maturation of temporal characteristics of steady-state flicker VEPs. Data from 53 VEP sessions were analyzed in term-born infants between birth and 20 months of age. The stimulus was a square-wave modulated luminance flicker with 80% modulation depth at temporal frequencies of 4.7, 7.5, 12.5, and 19 Hz. A total of 18 healthy adults aged between 21 and 54 years served as controls. Contingent on the stimulus frequency, we found pronounced changes of the flicker VEP with age. Regression lines fit to the first harmonic VEP magnitude as a function of age between 3 and 88 weeks of age indicated increases at 7.5 ( P = 0.004), 12.5 ( P