Sensory evoked potentials in Wilson's disease.

Somatosensory, brainstem auditory and pattern-reversal visual evoked potentials (SEP, BAEP and VEP) were studied in 16 patients with Wilson's disease and 16 family members. In 13 patients with neurological manifestations, median nerve stimulation elicited cervical potentials with normal N13 latency. Scalp-recorded components of the median and tibial SEPs were absent bilaterally in 1 patient and unilaterally in another. The median conduction time (N13 to N20 peaks) was bilaterally prolonged in 3 patients and unilaterally prolonged in 5. In the tibial SEPs from 9 patients with neurological symptoms, the N22 latency of the lumbar evoked responses was within normal limits, but conduction time from N22 to P40 peaks was unilaterally prolonged in 5. Overall, 9 of 13 patients with neurological manifestations had SEP abnormalities. The BAEPs were bilaterally abnormal in 12 of 13 patients with neurological symptoms, mainly due to prolongation in the III-V and I-V intervals. In the VEPs from 8 patients with the neurological form, the P100 latency was delayed bilaterally in 2 patients and unilaterally in 1. Abnormalities in evoked potentials were not observed in 3 patients with other forms of Wilson's disease and in the family members. The present study indicates that the majority of the patients with neurological manifestations had subclinical dysfunction in three major sensory pathways. They are consistent with neuropathological and neuroradiological findings of widespread degeneration of the brain in Wilson's disease.