Should We Consider Deep Brain Stimulation for Cervical Dystonia?

Summary and Comment |
September 2, 2014

Should We Consider Deep Brain Stimulation for Cervical Dystonia?

  1. Michael S. Okun, MD

Patients who had otherwise treatment-resistant dystonia responded well in a randomized, sham-controlled trial.

  1. Michael S. Okun, MD

A growing number of cases of cervical dystonia resistant to medications and botulinum toxin are presenting to clinicians for advanced management. This study was a randomized, sham-controlled, manufacturer-funded trial of bilateral globus pallidus deep brain stimulation (DBS) in this population (an investigational use not specifically approved by the FDA). Participants had to have at least a 3-year disease duration and a Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) severity score of ≥15 and be free of significant medical or psychiatric comorbidities. The 62 patients were randomized 1:1 to active or sham stimulation. Patients were unaware of their treatment assignment, and outcomes were blindly compared at 3 months. After 3 months, the sham group underwent DBS activation, and outcome measurements were repeated at 6 months. Standardized blinded videotapes were used to assess the 3-month primary outcome.

An intention-to-treat analysis revealed that the neurostimulation group improved by 5.1 points (26%) and the sham group by 1.3 points (6%) at 3 months. Following activation, the sham group improved 5 points (26%) at 6 months, whereas the active-stimulation group improved 0.4 points. Similar adverse events were reported in the active- and sham-stimulation groups. Eleven of 16 serious adverse events resolved without sequelae. Dysarthria, dyskinesia, worsening of dystonia, and depression were the most common adverse effects.

Comment

Although a 26% improvement on the cervical dystonia severity score may not seem impressive, the trial was randomized and had a sham-stimulation arm. Additionally, post hoc analysis showed a 40% improvement in the overall TWSTRS rating, and the benefits were clinically relevant. Clinicians should keep DBS as an option for medication- and botulinum toxin–resistant cervical dystonia patients. However, other targets such as the subthalamic nucleus may in the future be alternative DBS targets. Patients considering these types of invasive procedures must undergo complete multidisciplinary screening and follow-up, particularly to rule out psychogenic dystonia.

Editor Disclosures at Time of Publication

  • Disclosures for Michael S. Okun, MD at time of publication Grant / Research support NIH; National Parkinson Foundation; Michael J. Fox Foundation; Tourette Syndrome Association; Bachmann-Strauss; Dystonia Medical Research Foundation Editorial boards National Parkinson Foundation; Parkinsonism and Related Disorders; Tremor and Hyperkinetic Disorders Leadership positions in professional societies National Parkinson Foundation (National Medical Director); Tourette Syndrome Association (Co-Chair Medical Advisory Board); The International Parkinson and Movement Disorder Society (International Executive Committee)

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