Differential and better response to deep brain stimulation of chorea compared to dystonia in Huntington's disease.

Huntington's disease (HD) is an autosomal dominant and progressive neurodegenerative syndrome characterized by motor, cognitive and psychiatric manifestations. Chorea and dystonia are features that may be troublesome to some patients and may potentially prove unresponsive to pharmacological treatments. There are several reports on the results of globus pallidus internus deep brain stimulation (DBS) surgery for HD. In these published cases, DBS was utilized mainly to treat disabling chorea. We report our experience with 2 HD cases treated with DBS. The cases illustrate a differential response with a better outcome in the choreic presentation compared to the dystonic presentation. Additionally, DBS worsened gait features in both cases.

Low-Frequency Deep Brain Stimulation for Dystonia: Lower is Not Always Better.

BACKGROUND: It has been observed that low-frequency stimulation (LFS) may be effective for dystonia, and the use of LFS may alleviate the need for frequent battery changes in a subset of patients. The aim of this study was to analyze LFS as a strategy to treat deep brain stimulation (DBS) patients with various dystonias. METHODS: Subjects had to receive a minimum of 6 months of clinical follow-up at the University of Florida, and were required to have a minimum of 3 months on a LFS trial. Twenty-seven dystonia DBS patients were retrospectively analyzed from the UF-INFORM database. RESULTS: Thirteen subjects met inclusion criteria. Of the 13 subjects, all had bilateral internal pallidum (GPi) DBS, and five (38.5%) remained with at least one side on LFS settings at their last follow up (average follow up 24 months, range 6-46 months). Within the first 6 months, six (46%) subjects remained on LFS and seven (54%) were changed to high-frequency stimulation (HFS). Those who remained on LFS settings at 6 months were characterized by shorter disease durations than those on HFS settings. There were no significant differences in dystonia severity (Unified Dystonia Rating Scale and Burke-Fahn-Marsden Dystonia Rating Scale) at baseline between the two settings. The estimated battery life for LFS (79.9±30.5) was significantly longer than for HFS settings (32.2±13.1, p<0.001). DISCUSSION: LFS was ultimately chosen for 38.5% of all subjects. Although this study failed to yield solid predictive features, subjects on LFS tended to have shorter disease durations.