Pattern-reversal visual evoked potentials in the hereditary ataxias and spinal degenerations.

Pattern-reversal visual evoked potentials (PRVEP) were evaluated in 24 patients from 18 separate families with various forms of hereditary ataxia and spinal degeneration. Abnormally delayed latencies were found in 3 of 5 patients with classic Friedreich's ataxia, 1 patient with dominant spastic paraparesis, and 1 patient with recessive dentatorubrospinal degeneration. Fifteen other patients with several different types of dominant and recessive hereditary ataxias had normal PRVEP latencies, including 1 patient with bilateral optic atrophy. Testing of PRVEP will be useful in the clinical delineation of the genetic ataxias and spinal degenerations, and, when interpreted with caution, should be an additional variable evaluated in the differentiation of these disorders from multiple sclerosis.