Bilateral pallidal deep brain stimulation in myoclonus-dystonia: our experience in three cases and their follow-up

Abstract

DBS of bilateral GPi is an effective and safe therapy to be considered in MDS refractory cases. Careful neuropsychological evaluation is essential inside the presurgery planning. Correct location of the DBS electrodes and individualized selection of stimulation parameters in each case are the main determinants of the best clinical response.

A Case of Myoclonus–Dystonia Responding to Low-frequency Pallidal Stimulation

“…Improvements in the Unified Myoclonus Rating Scale also improved from 11% to 100% 1–12. Our patient had a reduction in her BFMDS by 96% with low-frequency, high pulse width pallidal stimulation, similar to two recent cases of MD that responded to 60 Hz pallidal stimulation 13. Unlike these recent cases, however, our case was not positive for the SGCE gene, yet demonstrated a robust reduction in clinical severity, as seen in the reduction of her CGI from 7 to 1.…”

Long‐term GPi‐DBS improves motor features in myoclonus‐dystonia and enhances social adjustment

“…These results are congruent with our previous short‐term studies and smaller‐cohort long‐term studies . Nevertheless, to our knowledge, the current study represents the longest mean follow‐up in M‐D patients with DBS that has been reported so far (DBS studies including at least 3 patients with M‐D are shown in Table ). Interestingly, we report better improvement in both myoclonus and dystonia than in the previous reports of M‐D and similar or better improvement in dystonia compared with the long‐term follow‐up of larger groups that were clinically and etiologically heterogeneous .…”

“…All variables in this group were evaluated in a crosssectional manner. Based on MMSE and daily functioning, all patients had normal cognitive function (mean MMSE, 28.6 ± 1.9; range, [25][26][27][28][29][30] and no frontal lobe dysfunction (mean FAB, 16.6 ± 1.3; range, [15][16][17][18]. With the exception of 1 patient with self-reported depression and anxiety, none of the patients were depressed or anxious (mean BDI-II, 5.7 ± 6.1; range, 0-19; mean HADS-A, 7.7 ± 3.7; range, 2-14; mean HADS-D, 3.3 ± 2.8; range, 0-8).…”

Medical treatment of dystonia

“…Valproic acid was found to be ineffective in several studies [43, 51]. In severe medically refractory cases, pallidal (GPi) deep brain stimulation (DBS) should be considered [52–56], earlier rather than later [57, 58]. …”

“…As a general rule, less invasive modalities such as medications and/or BoNT are usually tried before DBS, although the dramatic response of DYT1 generalized dystonia or DYT11 dystonia to DBS supports early intervention [52–61]. The list of indications for DBS in dystonia has been expanding.…”