Abnormalities of chromatic and luminance critical flicker frequency in multiple sclerosis.

Critical flicker frequency (CFF) was measured for stimuli varying in chromaticity only and in luminance only for patients with multiple sclerosis (MS) and for matched normal controls. The two CFF measurements showed different underlying linear interdependencies for the two groups, consistent with a greater loss of temporal luminance function than of temporal chromatic function in MS patients. These results are discussed in relation to the pathophysiology of demyelinated nerve fibers. It is suggested that demyelination affects all types of nerve fiber unselectively; in particular, no support is found for the notion of a special vulnerability of fibers carrying time-varying chromatic information.