Impact of Transcranial Magnetic Stimulation on Functional Movement Disorders: Cortical Modulation or a Behavioral Effect?

• Main Authors: Béatrice Garcin, Francine Mesrati, Cécile Hubsch, Thomas Mauras, Iulia Iliescu, Lionel Naccache, Marie Vidailhet, Emmanuel Roze, Bertrand Degos
• Format: Article
• Language: English
• Published: Frontiers Media S.A. 2017-07-01
• Series: Frontiers in Neurology
• Subjects: functional movement disorders; treatment; transcranial magnetic stimulation; suggestion; neuromodulation; psychogenic
• Online Access: http://journal.frontiersin.org/article/10.3389/fneur.2017.00338/full

IntroductionRecent studies suggest that repeated transcranial magnetic stimulation (TMS) improves functional movement disorders (FMDs), but the underlying mechanisms are unclear. The objective was to determine whether the beneficial action of TMS in patients with FMDs is due to cortical neuromodulation or rather to a cognitive-behavioral effect.MethodConsecutive patients with FMDs underwent repeated low-frequency (0.25 Hz) magnetic stimulation over the cortex contralateral to the symptoms or over the spinal roots [root magnetic stimulation (RMS)] homolateral to the symptoms. The patients were randomized into two groups: group 1 received RMS on day 1 and TMS on day 2, while group 2 received the same treatments in reverse order. We blindly assessed the severity of movement disorders before and after each stimulation session.ResultsWe studied 33 patients with FMDs (dystonia, tremor, myoclonus, Parkinsonism, or stereotypies). The median symptom duration was 2.9 years. The magnetic stimulation sessions led to a significant improvement (>50%) in 22 patients (66%). We found no difference between TMS and RMS.ConclusionWe suggest that the therapeutic benefit of TMS in patients with FMDs is due more to a cognitive-behavioral effect than to cortical neuromodulation.