PURPOSE: To evaluate the functional goal-directed outcomes of Deep Brain 
Stimulation (DBS) in childhood dystonia according to aetiology and to explore 
relationship with a traditional impairment-based measure.
METHOD: This is a prospective case series study involving thirty children with 
dystonia with a 1-year follow-up post-DBS. The Canadian Occupational Performance 
Measure (COPM) and Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) were used 
as primary outcome measures. Results were analysed based on aetiology in 3 
groups: 1. primary/primary plus dystonia; 2. secondary dystonia-cerebral palsy 
(CP); 3. secondary dystonia-non-CP group. Correlation between functional outcome 
using COPM and dystonia improvement as captured by BFMDRS was measured.
RESULTS: All groups demonstrated significant improvement in individualised goal 
attainment, measured with the COPM, at 1-year post-DBS. The secondary 
dystonia-CP group also achieved significant improvement at 6 months for 
performance and satisfaction scores. In the majority of secondary dystonias, the 
BFMDRS failed to demonstrate significant improvement. A linear correlation 
between change in BFMDRS and COPM scores was observed when the entire cohort was 
analysed.
INTERPRETATION/CONCLUSIONS: DBS improved functional performance, independently 
of the dystonic phenotype. Improvements in individualized COPM functional goal 
areas were seen in the absence of significant changes in BFMDRS scores, 
highlighting the relative insensitivity of impairment scales in this patient 
group.