[Visual evoked potentials in reversal and motion-onset stimulation of visual fields in patients with retrobulbar...

In 21 patients with unilateral retrobulbar neuritis the pattern reversal evoked potentials and motion-onset visual potentials were investigated with the aim to find out whether there is some difference in affection of pattern detecting (parvocellular) and motion detecting (magnocellular) visual pathways in this disease. The pattern reversal potentials were found to be abnormal in all 21 patients: they showed either significantly prolonged latencies and reduced amplitudes of the main positive P100 peak or no clear response (in one patient) upon the stimulation of the eye with neuritis. In contrast, the main negative peak of the motion-onset potentials was significantly delayed only in 15 patients and its amplitude was distinctly reduced only in 3 patients. The results indicate that in retrobulbar neuritis the pattern detecting nerve fibres from the central part of the retina (tested by reversal potentials) are affected earlier and to a greater extent than the more peripherally distributed motion detecting fibres (tested by motion-onset potentials).