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

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 (χ 2 = 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.