Diagnostic utility of clinical neurophysiology in Wilson's disease with hyperkinetic movements

Movement disorders (MD) are frequent in Wilson's disease (WD). Surface electromyography (sEMG) with accelerometry is commonly used to analyze hyperkinetic MD, as clinical examination may be insufficiently sensitive. We present here the first neurophysiological description of MD in WD patients to: (1) assess the sensitivity of neurophysiology relative to clinical evaluation; (2) correlate MD diagnosed by neurophysiology with the biological and radiological data of patients.

WD patients with hyperkinetic MD not fully characterized by clinical examination alone were included from December 2012 to December 2021. Clinical, biological, brain MRI and neurophysiology evaluations were conducted at inclusion and during follow-up.

We included 12 WD patients (3.9 % of the total cohort, and 11 % of the patients with neurological complications). During follow-up, neurophysiological evaluation identified 10 patients as having either isolated or combined tremors (seven postural, six resting, four orthostatic, four functional, two kinetic and one dystonic tremors), and five myoclonus. Four cases of pseudo orthostatic tremors, five of myoclonus and two functional tremors were not detected clinically. Action tremor on sEMG was the only MD significantly associated with a mild-to-moderate midbrain FLAIR hypersignal.

Postural and resting tremors were the most frequent MD, whereas myoclonus was the most frequent MD that had remained clinically uncharacterized and diagnosed at neurophysiological evaluation.

This study emphasizes the undeniable added value of neurophysiological evaluation in these patients.