93. Pallidal stimulation in dystonia: Constant-current or constant-voltage stimulation?

Bilateral globus pallidus deep brain stimulation (GPi-DBS) represents a validated, effective and relatively safe therapy for different forms of medically refractory dystonia. The goal of this study was to assess the effect of GPi-DBS in a homogeneous population of dystonic patients and to compare the clinical outcome using two different stimulation settings: a constant-current stimulation versus a constant-voltage stimulation. 22 patients affected by primary generalized or multisegmental dystonia underwent bilateral GPi-DBS. 13 patients were stimulated using a voltage-controlled setting while in the other 9 patients we used a current-controlled setting. Clinical features were evaluated for each patient at baseline, 6 months and 12 months after surgery by means of the Burke–Fahn–Marsden Dystonia Rating Scale (BFMDRS). In all the patients we found a statistically significant improvement both in motor and disability scores of BFMDRS. Moreover, we didn’t find any significant difference between current- and voltage-controlled stimulation at 6 and 12 months after surgery in comparison to baseline while a better improvement occured in the last 6 months follow-up in the current-controlled group. Our study shows that current-controlled stimulation could be more effective than voltage-controlled stimulation over long-term follow-up in dystonia.