Evoked potentials in patients with non-neurological Wilson's disease

The diagnostic value of multimodal evoked potentials in the determination of subclinical neurological involvement of Wilson's disease

AIMS

Wilson's disease (WD) is a progressive degeneration of hepatolenticular tissue caused by excessive tissue-damaging copper accumulation and in which liver involvement most frequently presents in childhood. Neurological signs also accompany liver disease with time. However, subclinical neurological involvement may occur earlier and diagnostic methods that reveal this subclinical involvement are not well established. The aim of the current study is to assess the subclinical neurological involvement by using multimodality evoked potential (EP) measurements and to explore the relationship between neurological disease and the severity of liver damage.

METHODS

The patient group included 28 children (mean age 11.8 ± 2.9 years, range 5.5-17) diagnosed with WD and a control group included 24 age-matched healthy children. Multimodality EP tests (Nihon Kohden Neuropack 8 4200K) of both groups were performed at the Department of Neurology Electrophysiology Laboratory of Ege University.

RESULTS

At least one abnormal EP value was observed in 53.5% of the children in the patient group. At least on one side, there were abnormal values for visual evoked potential (VEP) P100, brainstem auditory evoked potential (BAEP) and somatosensory evoked potential (SEP), where the ratios were 25, 28.5, and 11%, respectively. Absolute latency values of patients with right-side VEP P100 and left-side BAEP I, and the interpeak latency values of right-side BAEP I-III were significantly high. The difference in right-side BAEP I-III interpeak latency between cirrhotic and noncirrhotic groups was found to be statistically significant (P<0.05).

CONCLUSION

The EP examinations can be an indicator of subclinical brain damage in non-neurological WD; however, cirrhosis because of WD does not cause an increase in the EP values. Detection of changes in the EP values periodically, especially at the time of diagnosis and during the treatment follow-up, may be valuable for revealing subclinical impairment.

A study of clinical, MRI and multimodality evoked potentials in neurologic Wilson disease

The aims of this study were evaluate motor, somatosensory, visual and auditory brainstem evoked potential (MEP, SEP, VEP, ABER) changes in Wilson disease (WD) and correlate these with magnetic resonance imaging (MRI) and clinical findings. Neurologic WD diagnosed on the basis of clinical, ceruloplasmin and Kayser-Fleischer ring were evaluated including pedigree charting, hepatic, renal, hematologic and osteoarticular manifestations. Blood counts, serum chemistry, MRI, MEP to tibialis anterior, tibial SEP, VEP and ABER were performed. Evoked potential (EP) changes were correlated with clinical and MRI findings. Eighteen WD patients were recruited from 17 families whose mean age was 16 years. Movement disorders were present in 14, cognitive decline in 12 and pyramidal signs in 12 patients. MRI revealed involvement of basal ganglia in 80%, thalamus in 40%, brain stem in 46.7% and subcortical white matter in 53.3%. MEP was abnormal in 35.7%, SEP in 30.8%, VEP in 57% and ABER in 61.5% patients; the latter three EP changes were subclinical. Frequency and number of EP abnormalities were higher with increasing severity of illness. SEP, VEP and ABER reveals subclinical abnormality and MEP helps in documenting both clinical and subclinical abnormalities. Number of EP abnormalities increases with increasing clinical severity of WD.

[Multimodal evoked potential abnormalities in patients with Wilson's disease]

The aim of this study was to investigate the involvement of the following functional systems: somatosensory evoked potentials (SSEP), visual evoked potentials (VEP), and event related potentials (ERP), in twenty patients with Wilson's disease (WD). VEP and SSEP abnormalities were discovered in 8 patients respectively (40%), whereas ERP were either absent or, in the case of 10 patients (50%), had significantly prolonged P-300 latencies. Taken together, at least one evoked potential abnormality was discovered in 17 patients (85%). Only in 3 patients (15%), involving either the isolated hepatic type of disease or short illness duration of the neurological type, were normal evoked potential findings observed. Our findings suggest the usefulness of multimodal evoked potential abnormalities in the evaluation of subclinical manifestations in patients with WD.

The diagnostic value of sensory evoked potentials in pediatric Wilson disease

We studied the sensory evoked potentials in pediatric Wilson disease to verify their subclinical neurologic involvement and to elucidate the role of cirrhosis in abnormal evoked potentials in non-neurologic Wilson disease. Thirty children (17 male, 13 female), diagnosed with Wilson disease before 18 years, were enrolled. The mean age during studies was 15.8 +/- 6.3 years, and disease duration since diagnosis was 3.0 +/- 3.3 years. In 12 neurologic Wilson disease cases, there were prolonged interpeak latencies of brainstem auditory evoked potentials III-V, I-V, somatosensory evoked potentials N13-N20 (P < 0.01 vs controls and non-neurologic cases), and P100 latency (P < 0.01 vs controls). All 12 patients had at least one abnormal evoked potential, including 91.7% brainstem auditory, 58.3% somatosensory, and 25% visual evoked potentials. In 18 non-neurologic Wilson disease cases, there were still prolonged interpeak latencies for brainstem auditory evoked potentials I-V and somatosensory evoked potentials N13-N20 (P < 0.05 vs controls), with 27.8% of them having at least one abnormal evoked potential, including 16.6% brainstem auditory, 5.6% somatosensory, and 11.1% visual evoked potentials. In those with non-neurologic Wilson disease, there were no significant differences in all the evoked potential parameters between the cirrhotic and non-cirrhotic patients.

Evoked potentials in children with Wilson's disease

We assessed multimodal evoked potentials (EPs) in 13 children with newly diagnosed neurologically symptomatic Wilson's disease (WD) and in their first degree symptom-free relatives, consisting of seven presymptomatic and 15 asymptomatic siblings and 22 asymptomatic parents. EP abnormalities of at least one modality and one side stimulation were observed in 38.5% of patients, 42.9% of presymptomatic siblings, 21.4% of asymptomatic siblings and 18.2% of parents. Patients tended to have more prolonged central latencies of EPs. However, the left I-V interpeak brainstem auditory EP latency difference was the only one to reach at the statistical significance (P = 0.001). Abnormal VEP P100 latency was detected more frequently in presymptomatic siblings than those in asymptomatic ones (42.9% vs 7.1%, P = 0.049). In all relatives, other diagnostic tests including electroencephalography, electromyography and head magnetic resonance imaging (MRI) for subclinical nervous system involvement and Kayser-Fleischer rings examination yielded normal results. In pre/asymptomatic siblings, genetic and biochemical studies may aid to initiate treatment prior to the development of permanent tissue damage. Our results indicate that abnormal EPs may signal unique pathological finding in some subjects. Importantly, these abnormalities occur earlier than Kayser-Fleischer rings and MRI lesions. In early stages of WD, EP recordings may, therefore, be used to help decide on treatment initiation and treatment efficacy evaluation. Moreover, EP recordings can readily be added to family screening studies.