Long-term results of deep brain stimulation in a cohort of eight children with isolated dystonia.

Pallidal deep brain stimulation (DBS) is an established treatment for patients with severe isolated dystonia. However, clinical evidence for the long-term use of DBS in children is limited and controlled trials have not yet been conducted. Here, we provide the long-term results of up to 13 years of pallidal DBS in eight pediatric patients with generalized idiopathic or hereditary isolated dystonia (five males, mean age at surgery 12.5 ± 3.5 years), as assessed by retrospective video rating. Video rating was performed at three time points: pre-operative, 1-year short-term follow-up (1y-FU) and long-term last FU (LT-FU, up to 13 years). Symptom severity and disability were assessed using the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS). Disability scores were obtained from clinical charts and during the last FU. The mean improvement in BFMDRS motor score was 54.4 ± 8.9 % at 1y-FU and 42.9 ± 11.6 % at LT-FU; the disability scores improved by 59.8 ± 10.3 and 63.3 ± 7.8 %, respectively. Electrode dislocation was noted in one patient and implantable pulse generator dislocation in another, both requiring surgical intervention; no further serious adverse events occurred. Our study presents the first blinded video rating assessment of the short- and long-term effects of pallidal DBS in children with idiopathic or hereditary isolated dystonia. Results confirm that pallidal DBS is a safe and efficacious long-term treatment in children, with overall motor improvement similar to that described in controlled trials in adults.