[Visual evoked potentials (VEP's) obtained by black and white or red and black checkerboard inversion. Results in healthy subjects and in multilocular sclerosis patients].

Visual evoked potentials (VEPs) were elicited in a control group and in 125 multiple sclerosis (MS) patients by reversal of TV black and white checkerboard patterns with two different check sizes and contrasts (44'/contrast 50%; 22'/contrast 20%), and also by a display of red light emitting diodes (LEDs) generating a 'true' pattern reversal. In control subjects LED pattern reversal produced responses of lower amplitude and of longer latency compared to responses to TV black and white checkerboards. The interindividual variability of P100 latency was lower with the LED display than with the low contrasted TV pattern. In 18 patients with definite or suspected MS, VEPs were normal with the two TV patterns when delayed or absent with the LED display. Thus LED pattern reversal was a more effective stimulus than black and white pattern reversal for the detection of demyelinating lesions of the optic nerves in MS. LED stimulation proved to be particularly useful in patients with progressive spastic paraparesis or with previous history of isolated optic neuritis.