Transcranial Magnetic Stimulation in the Treatment of Movement Disorders

Here we review the potential use of repetitive transcranial magnetic stimulation (rTMS) as a therapeutic intervention in patients with movement disorders. Most rTMS studies have been conducted in patients with Parkinson's disease (PD). Initially, rTMS was applied in a single session targeting the primary motor cortex (M1). In most single-session studies, rTMS was given after the discontinuation of dopaminergic medication. The majority of studies found a transient clinical improvement of motor symptoms after high-frequency (>= 5 Hz) rTMS of the M1, especially when more than 1000 stimuli had been applied. Recent studies applied multiple rTMS-sessions on several days and targeted multiple cortical sites. These studies provided preliminary evidence that the use of more extended stimulation protocols can prolong the therapeutic effects of high-frequency rTMS on parkinsonism. Inhibitory low-frequency (1 Hz) rTMS was found to be beneficial in some patients with focal hand dystonia, drug-induced dyskinesia, essential tremor, chorea, or tics. While these results are encouraging, the jury is still out whether this interventional technique will emerge as a routine treatment option in PD and other movement disorders. We discuss the challenges that still have to be faced when bringing rTMS treatment into regular clinical practice.