Evoked Potentials in Patients With Wilson Disease

Wilson disease (WD) is an inherited disorder of copper metabolism presenting with a variety of symptoms but commonly as a liver or neuropsychiatric disease. Abnormal evoked responses are constantly found among patients with neurologic manifestations and sometimes in patients with hepatic presentation or in presymptomatic siblings. The aim of our study was to assess visual and brainstem auditory evoked potentials (BAEP) in patients with various presentation of WD.

Visual evoked potentials (VEP) were performed in 36 WD patients and BAEP were done in 37 WD patients.

Brainstem auditory evoked potentials were normal in patients with isolated hepatic presentation, whereas they were abnormal in 93.5% of patients with neurologic symptoms. There was significant prolongation of the latencies of the III and V waves and of the interpeak III-V and I-V latencies in comparison with the healthy controls (T-test P = 0). Abnormal VEP were observed in 81% of the patients including six of seven neurologically asymptomatic patients. The values of N75, P100, and N145 latencies were significantly longer in all patients than in healthy controls (T-test).

The data showed that VEP and BAEP are more frequently abnormal in WD than previously reported. The abnormal VEP and BAEP even without clinical signs and brain MRI abnormalities point to subclinical involvement of visual and auditory pathways caused by copper toxicity. Because VEP and BAEP are noninvasive and widely available, they should be performed in all patents with WD.