Pattern disappearance visually evoked cortical potential in the diseases of visual pathway

Visually evoked cortical potentials in response to pattern-appearance, -disappearance, and -reversal stimuli were studied in normal subjects and in patients suffering from optic neuritis. It was found in normal subjects that pattern disappearance VECPs were as reliable as the pattern reversal ones. On the other hand, the appearance response showed interindividual differences which made its evaluation rather difficult. The same was true in the records of the patients. Both the mean peak latencies of the disappearance responses and those of the pattern reversal ones were prolonged significantly in optic neuritis, compared with those obtained from normal subjects. We concluded that the peak latencies of the disappearance response could be more confidently used than those of the appearance response for diagnosing optic neuritis.