Evaluation of a programming algorithm for deep brain stimulation in dystonia used in a double-blind, sham-controlled multicenter study

Abstract

BackgroundProgramming deep brain stimulation in dystonia is difficult because of the delayed benefits and absence of evidence-based guidelines. Therefore, we evaluated the efficacy of a programming algorithm applied in a double-blind, sham-controlled multicenter study of pallidal deep brain stimulation in dystonia.MethodsA standardized monopolar review to identify the contact with the best acute antidystonic effect was applied in 40 patients, who were then programmed 0.5 V below the adverse effect threshold and maintained on these settings for at least 3 months, if tolerated. If no acute effects were observed, contact selection was based on adverse effects or anatomical criteria. Three-year follow-up data was available for 31 patients, and five-year data for 32 patients. The efficacy of the algorithm was based on changes in motor scores, adverse events, and the need for reprogramming.ResultsThe mean (±standard deviation) dystonia motor score decreased by 73 ± 24% at 3 years and 63 ± 38% at 5 years for contacts that exhibited acute improvement of dystonia (n = 17) during the monopolar review. Contacts without acute benefit improved by 58 ± 30% at 3 years (n = 63) and 53 ± 31% at 5 years (n = 59). Interestingly, acute worsening or induction of dystonia/dyskinesia (n = 9) correlated significantly with improvement after 3 years, but not 5 years.ConclusionsMonopolar review helped to detect the best therapeutic contact in approximately 30% of patients exhibiting acute modulation of dystonic symptoms. Acute improvement, as well as worsening of dystonia, predicted a good long-term outcome, while induction of phosphenes did not correlate with outcome.Trial registrationClinicalTrials.gov NCT00142259.