A pilot trial of square biphasic pulse deep brain stimulation for dystonia: The BIP dystonia study

Abstract

Background: Dystonia often has inconsistent benefits and requires more energy-demanding DBS settings. Studies suggest that squared biphasic pulses could provide significant clinical benefit; however, dystonia patients have not been explored.

Objectives: To assess safety and tolerability of square biphasic DBS in dystonia patients.

Methods: This study included primary generalized or cervical dystonia patients with bilateral GPi DBS. Square biphasic pulses were implemented and patients were assessed at baseline, immediately postwashout, post-30-minute washout, 1 hour post- and 2 hours postinitiation of investigational settings.

Results: Ten participants completed the study. There were no patient-reported or clinician-observed side effects. There was improvement across time on the Toronto Western Spasmodic Torticollis Rating Scale (χ² = 10.7; P = 0.031). Similar improvement was detected in objective gait measurements.

Conclusions: Square biphasic stimulation appears safe and feasible in dystonia patients with GPi DBS. Further studies are needed to evaluate possible effectiveness particularly in cervical and gait features. © 2016 International Parkinson and Movement Disorder Society.

Keywords: deep brain stimulation; dystonia; square biphasic stimulation.