Inhibitory rTMS in Dystonic Wilson Patients

Overview

Wilson disease is a genetic disorder resulting in copper accumulation in liver, brain and eye. The neurologic complications include dystonic syndrome, which is a prolonged and excessive muscle activation responsible for abnormal postures. Hand dystonia prevents daily life activities such as writing, which is particularly disabling, since writing is the only mean of communication in these patients with significant slurred speech. Treatment is limited and only partially effective. Low frequency (\<or=1Hz) repetitive transcranial magnetic stimulation (rTMS) has shown inhibiting properties when applied over the cortex. Since dystonia has been correlated to hyperactivation of the neurons of the somatosensory cortex (SSC), we hypothesize that one single 20-minute session of 1 Hz rTMS applied on left SSC will improve writing of the right dystonic hand, assessed immediately at the end of the session.

This study investigates the handwriting performance of an homogeneous cohort of patients with Wilson disease and right handed dystonia, after one single inhibitory repetitive transcranial magnetic stimulation (rTMS). Fifteen patients with focal right hand dystonia will receive randomly either active or sham rTMS (1 Hz) to the left somatosensory cortex (SSC) in one single 20 minutes session. Handwriting performance will be measured immediately after this unique session (Visual analogic scale of subjective discomfort in writing, DPRE and WCRS scales, pen pressure and pen velocity measured on touchpad), compared to scores obtained 24 hours before the session. Three days later, the patient will receive the other session (sham rTMS or active rTMS) and the same parameters will be evaluated. This is a single-center, randomized, crossover, prospective, clinical and double-blind study (the rTMS session is performed by the neurophysiologist, but the patient and the neurologist who will perform the handwriting evaluation are blind to the session).