Shorter Disease Duration Correlates With Improved Long-term Deep Brain Stimulation Outcomes in Young-Onset DYT1 Dystonia

BACKGROUND: Treatment with deep brain stimulation (DBS) of the globus pallidus internus in children with DYT1 primary torsion dystonia is highly effective; however, individual response to stimulation is variable, and a greater understanding of predictors of long-term outcome is needed. OBJECTIVE: To report the long-term outcomes of subjects with young-onset DYT1 primary torsion dystonia treated with bilateral globus pallidus DBS. METHODS: Fourteen subjects (7 male, 7 female) treated consecutively from 2000 to 2010 at our center were included in this retrospective study. The Burke-Fahn-Marsden Dystonia Rating Scale was performed at baseline and at 1, 2, and up to 6 years postoperatively. RESULTS: Pallidal DBS was well tolerated and highly effective, with mean Burke-Fahn-Marsden Dystonia Rating Scale movement scores improving from baseline by 61.5% (P < .001) at 1 year, 64.4% (P < .001) at 2 years, and 70.3% (P < .001) at the final follow-up visit (mean, 32 months; range, 7-77 months). Disability scores also improved significantly. Multiple linear regression analysis revealed a significant influence of duration of disease as a predictor of percent improvement in Burke-Fahn-Marsden Dystonia Rating Scale movement score at long-term follow-up (duration of disease, P < .05). Subjects with fixed orthopedic deformities (4) had less improvement in these regions. Location of the active DBS electrode used at final follow-up visit was not predictive of clinical outcome. CONCLUSION: Our findings highlight the sustained benefit from DBS and the importance of early referral for DBS in children with medically refractory DYT1 primary torsion dystonia, which can lead to improved long-term benefits.