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 (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.

Treatment of ADCY5-Associated Dystonia, Chorea, and Hyperkinetic Disorders With Deep Brain Stimulation: A Multicenter Case Series.

ADCY5 mutations have been reported as a cause of early onset hyperkinetic movements associated with delayed motor milestones, hypotonia, and exacerbation during sleep. The movement disorder may be continuous or episodic, and can vary considerably in severity within families and in individuals. The authors report a case series of 3 patients with ADCY5 mutations treated with deep brain stimulation after unsuccessful medication trials. All had extensive imaging, metabolic, and genetic testing prior to confirmation of their ADCY5 mutation. Two of the patients had the c.1252C>T; p.R418W mutation, while the youngest and most severely affected had a de novo c.2080_2088del; p.K694_M696 mutation. All had variable and incomplete, but positive responses to deep brain stimulation. The authors conclude that deep brain stimulation may provide benefit in ADCY5-related movement disorders. Long-term efficacy remains to be confirmed by longitudinal observation. ADCY5 should be considered in the differential diagnosis of early onset hyperkinetic movement disorders, and may respond to deep brain stimulation.