Evoked potentials in cerebrotendinous xanthomatosis and effect induced by chenodeoxycholic acid.

Evoked potentials are reported in 10 patients with cerebrotendinous xanthomatosis, eight of whom had peripheral neuropathy. Four subjects showed delayed N13 to N20 interpeak latencies for arm somatosensory evoked potentials, and five showed moderately prolonged I to III and I to V interpeak latencies of brain-stem auditory evoked potentials. Six of seven patients showed marked delay and desynchronization of visual evoked potentials. All five patients undergoing transcutaneous magnetic stimulation of the motor cortex presented greatly delayed central motor conduction time, especially of the lower limbs. After treatment with chenodiol (750 mg/d for at least 2 years), there was a significant improvement in nerve conduction velocities, N13 to N20 interpeak latencies, and visual evoked potential latencies. Brain-stem auditory evoked potentials remained unchanged.