La maturation des potentiels evoques visuels chez l'enfant normal

Abstract An investigation of the various phases of maturation of the visual evoked response (VER) in 449 normal, awake children aged between 3 days and 15 years. VER was recorded at the inion and elicited by an intense and brief flash. All subjects were awake, with their eyes open. 1. (1) The VER of the newborn infant shows an ‘immature’ morphology, differing widely from that of the adult. As observed by other authors, the VER of the newborn is characterized by a large and delayed surface positive deflection with a culmination time of about 190 msec. During the first week of post-natal life this surface-positive deflection may be preceded by much earlier deflections that can be classed as N 0 , P 1 and N 2 . 2. (2) After the second month of post-natal life, VERs of a very different morphology from the former can be recorded, with a large surface negative wave culminating around 175 msec. 3. (3) No large and late surface-positive VERs of the immature type are observed after the sixth month of post-natal life. 4. (4) The frequency at which the 4 earliest deflections are observed increases markedly with age during the first year of life. 5. (5) The average values of the culmination times of the N 0 , P 1 , N 1 and N 2 deflections decrease markedly with age. They reach minimal and fairly constant values after 1 year. 6. (6) The deflections occurring after P 2 display a marked individual variability. However they can be classified into 3 types which group at least 90% of all responses, the proportions of which vary with age. 7. (7) The percentage of VERs in which the surface positive deflections (P 2 , P 3 ) are equal to or of longer amplitude than the surface negative waves (N 1 , N 2 , N 3 ) increases markedly with age and approaches 50% in the 3–15 years class. The authors stress the differences between the maturation pattern of VERs and that of the somesthetic responses.