DEVELOPMENT OF PATTERN VISUAL-EVOKED POTENTIALS - LONGITUDINAL MEASUREMENTS IN HUMAN INFANTS

Purpose. This experiment used longitudinal testing to trace the emerge nce of the major components of pattern visual evoked potentials (VEPs) in infants, using two paradigms: large-checkerboard pattern reversal and low spatial frequency pattern onset, Methods, Testing with both pa ttern-reversal and pattern-onset stimuli was performed on the same inf ants, Testing was conducted at weekly intervals during the first three postnatal months, and at intervals of 2 weeks to 1 month thereafter, Results, The pattern-reversal and early pattern-onset responses record ed within individual subjects showed remarkably systematic development al sequences, The broad, positive component seen at 200 to 250 ms in i nfants could be traced readily through the developmental sequence, to become the more sharply tuned positive component seen at about 100 ms in adults, Responses to low spatial frequency pattern onsets in infant s were larger and more reliable than those in adults, The late compone nts of the pattern-onset response, generally attributed to pattern off set, emerged later and with more complex changes, In all cases, respon se amplitude was much more variable than response latency, both within and between subjects, Conclusions, Frequent VEP recording in a longit udinal design can reveal systematic and detailed transitions of wave-f orm during development.