Deep Brain Stimulation Reduced Tardive Dyskinesia and Dystonia Symptoms

Andreas Kupsch, MD, PhD

Clinical rating scores improved at the 3- and 6-month mark after treatment with pallidal deep brain stimulation for tardive dystonia and dyskinesia, according to a new study.

Researchers from Germany originally set out to test 25 tardive dyskinesia patients’ ability to tolerate pallidal deep brain stimulation and determine the percentage change of dystonia severity after 3 months. The study authors also measured the change in clinical rating scores for movement disorders.

The investigators set up a randomized trial, where 12 patients were assigned to active treatment and 13 were assigned to sham neurostimulation. This was important work, the study authors wrote, because there are few randomized controlled trials that compare dystonia and dyskinesia severity after pallidal neurostimulation.

The study authors noted that tardive dystonia can have clinical overlap with tardive dyskinesia, tardive akathisia, and tardive myoclonus. It can affect between .04-21% of neuroleptic-treated patients, the researchers said.

One of the challenges of this investigation, study author Andreas Kupsch, MD, PhD, told MD Magazine®, was how difficult it was to recruit eligible patients. The researchers would have ideally liked to have 48 patients involved in the study, but due to the extremely long time it took to recruit the patients, they performed the analysis after 2 and a half years. During the study period of May 2006 to July 2010, 2 patients dropped out of the study.

After 3 months, the researchers reported significantly improved dystonia severity in the neurostimulation group (22.8%) but said that the improvement in the sham group (12%) was not significant, compared to the groups’ respective baseline severity measures. During the open-label treatment period, there was a significant improvement of 41.5% as observed by blind evaluation.

The neurostimulation group showed significant improvement at 3 months on the Abnormal Involuntary Movement Scale (AIMS) score compared to sham patients: 29.6% compared to -2.6%, respectively.

After 6 months, moods assessed via patient-rated Hospital Anxiety and Depression Score (HADS) scale improved by 26%, the researchers found, including measures for anxiety. Active neurostimulation also improved quality of life, according to the Short Form 36 item quality of life survey (SF 36) measurement.

There were 10 adverse events observed in 10 patients at the 6-month evaluation point, the study authors reported. Most of these were in relation to the surgical implantation of the device. They were all resolved without further complication.

The study authors wrote that their study showed a greater involvement of the orofacial region compared to other studies on the subject. The region accounted for about a third of the Burke-Fahn-Marsden-Dystonia-Rating-Scale (BFMDRS) total score compared to just 4.5% and 6.5% in other studies.

“Overall, the 23% reduction of dystonic symptoms measured by the BFMDRS motor score in neurostimulation group at 3 months, which is supported by significant and possibly more sensitive movement disorder scores such as AIMS, is clinically relevant, especially with respect to limited or non-existing treatment options in tardive dystonia, and is accompanied by improved life satisfaction and patient- and physician-related dystonia severity,” the study authors concluded.

Kupsch said that information on pallidal deep brain stimulation should be distributed to patients with tardive dyskinesia.

The paper, “Neurostimulation in tardive dystonia/dyskinesia: A delayed start, sham stimulation-controlled randomized trial,” was published in Brain Stimulation.