Visual evoked responses in multiple sclerosis: comparison of two methods for pattern reversal

S UM MARY Visual evoked responses have been elicited by reversal of a black and white checkerboard pattern and also by a display of light-emitting diodes (LED) generating a reversal of a pattern of illuminated red circular areas. In a control group the LED display produced responses of lower amplitude and shorter latency compared to responses to checkerboard stimulation. In patients with a definite or probable diagnosis of multiple sclerosis the stimulators were equally effective in evoking pathological responses; in patients with a possible but less certain diagnosis abnormal responses were found in a higher percentage when the LED stimulus was used. Differences in stimulus field size and in stimulus colour are discussed as possible reasons for this result. Although the visual evoked response (VER) to flash stimulation may be changed pathologically in multiple sclerosis (Feinsod and Hoyt, 1975; Paty et al., 1976), the diagnostic value of VER in de-myelinating disease was considerably enhanced when Halliday et al. (1972, 1973) demonstrate