Maturation of the pattern-reversal VEP in human infants: a theoretical framework

Visual evoked potentials to pattern reversal (PR-VEPs) are used to assess t he integrity and maturation of the visual pathways in infants and young chi ldren. To establish normal ranges and to facilitate interpolation, we consi der the maturation rate of PR-VEPs using published normative data. Curves b ased on the logistic function (a sigmoid model) are introduced and compared with three other models: (1) the power law function; (2) the sum of two de caying exponentials; and (3) a two-stage linear model. Although methods var y somewhat, remarkable consistency among laboratories is found for the matu ration of the major positivity (P-1) of PR-VEP. The P-1 occurs at approxima tely 260 ms in neonates and is quite variable. It matures rapidly before 12 -14 weeks of age and becomes much less variable. The logistic model provide s a parsimonious description of P-1 maturation with most rapid maturation a t around 6 weeks of age for large patterns and around 9 weeks for small pat terns. As inter-laboratory agreement is generally good, the normal ranges b ased on this model could be used in centres, which do not have their own no rmative databases for infant VEPs. (C) 1999 Elsevier Science Ltd. All right s reserved.