Predictive factors of outcome in primary cervical dystonia following pallidal deep brain stimulation.

Background: Improvement after bilateral globus pallidus internus deep brain stimulation (DBS) in primary generalized dystonia has been negatively associated with disease duration and age, but no predictive factors have been identified in primary cervical dystonia (CD).

Methods: Patients treated with bilateral globus pallidus internus DBS for primary CD from 2 DBS centers with preoperative and postoperative Toronto Western Spasmodic Torticollis Rating Scales (TWSTRS) were studied retrospectively to explore possible predictors of response.

Results: Patients showed significantly improved TWSTRS total and severity scores (n = 28, mean 55.6% and 50.8%, respectively, both P < .001). Patients with lateral shift at baseline had less improvement in TWSTRS severity subscores (P = .02). No correlations between outcomes and disease duration, age at dystonia onset or surgery, baseline scores, or other included variables were found.

Conclusions: Although this is the largest study supporting efficacy of bilateral pallidal DBS in primary CD, no major clinical predictive outcomes of surgical benefit were identified.