Neurostimulation of GPi in Dystonia-Choreoathetosis--New Trial Is Encouraging Bilateral Pallidal Deep Brain Stimulation for the Treatment of Patients With Dystonia-Choreoathetosis Cerebral Palsy: A Prospective Pilot Study

Background/Objective: Dystonia-choreoathetosis is highly resistant to medical treatment and is associated with major disability in patients with normal intelligence. Since deep brain simulation (DBS) has been shown to improve movement disorder in patients with dystonia, will it be equally useful in dystonia-choreoathetosis? Design: Prospective, multicenter, open-label study. Participants/Methods: 13 adults with established dystonia combined with chorea and/or athetosis were recruited. None of the patients had any cognitive impairment (as determined by the mini-mental state examination) or psychiatric disorders (according to the Beck inventory scale). The etiology of the movement disorder was neonatal, hypoxic, or ischemic encephalopathy. Stereotaxic placement of electrodes, one in each posterolateroventral globus pallidus internus (GPi), was based on MRI and, in some centers, was combined with perioperative recordings. Results: On average, 24% improvement was reported with large interpatient variability. The greatest improvement was an increase in well-being; there was also a decrease in body pain and an increase in quality of life. Four patients had an improvement of their disability score of ≥40%. One patient had fewer benefits from stimulation 1 year after implantation for no clear reasons. In 4 patients, either no improvement from the stimulation was seen or the dystonia worsened. Conclusions: Significant improvement can be expected in >50% of DBS-treated dystonia-choreoathetosis patients. This improvement was more obvious on the self-rating of the effect of stimulation than on objective measures. Reviewer's Comments: Given the severity and the intractability of the motor disorder afflicting these patients, the results of this preliminary study are encouraging. In view of the fact that DBS for dystonia has shown consistent results, a larger trial is warranted for dystonia-choreoathetosis. The sample of patients in the present study is too small to conclude that DBS is a useful procedure for these patients. The degree of improvement between individuals varied so much that one could ask whether, in some cases, the poor outcome could have been predicted. Hopefully, the parameters associated with a positive or negative outcome will be clarified after a larger study is performed. (Reviewer-Luc Jasmin, MD).