Prognostic significance of neurologic examination findings in Wilson disease

Abstract

BackgroundWilson disease patients present with any of several neurologic phenotypes, and their treated outcomes vary widely. Our goal was to determine whether presenting clinical features of neurologic Wilson disease (WD) predict longer term neurologic outcomes in patients receiving anticopper treatment. MethodsPatients enrolled in four WD treatment trials received a standardized neurologic examination at trial enrollment and then at pre-specified intervals following anticopper therapy, initially with tetrathiomolybdate or trientine and then with zinc. The examination scored patients’ motor signs, including tremor, rigidity, dystonia, dyarthria, and gait. The Total Score was obtained by summing these subscores.Eighty-six patients were included in our analysis, with a mean follow-up of 34.7 months. Retrospectively, the analysis compared scaled and unscaled sign subscores at enrollment and follow-up with change in the Total Score, using a generalized estimating equations approach. ResultsIn the primary analysis, improvement in the Total Score was best predicted by sign subscores for tremor (beta −0.7, p = 0.006), gait abnormalities (beta −3.7, p < 0.001), and speech (beta = −1.3, p = 0.05). Dystonia (beta = 1.8, p < 0.001) and facial expression (beta = 1.9, p = 0.03) were associated with worsening Total Score. Of the motor signs followed individually, dystonia proved most resistant to treatment. ConclusionsThis is the first large-scale prospectively acquired study assessing prognostic significance of specific neurologic signs in WD. Our data support the historical observations that tremor is a favorable prognostic sign while dystonia is relatively refractory to treatment in WD.