SHORT-LATENCY VISUAL-EVOKED POTENTIALS TO FLASHES FROM LIGHT-EMITTING-DIODES

Short latency visual evoked potentials (SVEPs) have been described in response to high-intensity, strobe flashes. High-intensity flashes can now be generated from goggle-mounted light emitting diodes (LEDs) and the SVEPs to such flashes have been shown to be reproducible across s ubjects, avoiding photic spread to the examination room and acoustical artifacts from the strobe stimulator. In this study, SVEPs from multi channel records are described in terms of normative latencies and ampl itudes, as well as scalp distributions, to explore their generators. P otentials were recorded from 10 young male subjects, from 16 scalp loc ations, in response to flashes from goggle-mounted LEDs. Flashes were presented to each eye in turn, as well as binocularly. The latencies, scalp distributions and intersubject variabilities of the LED evoked S VEPs were similar to those obtained with strobe flashes. SVEP componen ts were divided into 3 groups, according to their latency and the elec trodes at which they were recorded with the largest amplitudes: perioc ular (under 40 msec latency), fronto-central (40-55 msec) and parieto- occipital (55-80 msec latency). The scalp distributions observed in th is study suggest subcortical generators along the visual pathway, begi nning at the retina. The use of goggle-mounted LEDs should promote rou tine evaluation of the integrity of the visual pathway between retina and cortex using SVEPs.