Deep brain stimulation outcomes and management of childhood-onset dystonia and associated hyperkinetic movements disorders.

AIM: To examine longitudinal changes in self-selected goals and dystonia severity over 1 year, 2 years, and 5 years after deep brain stimulation (DBS) in children and young people (CYP) with dystonia and other hyperkinetic movement disorders, using CYP and caregiver reports. METHOD: The retrospective cohort study included follow-up to 5 years after DBS, with the number of participants varying across time points. In the CYP group, 62 participants were included at the 1-year follow-up, 50 at 2 years, and 17 at 5 years. In the parental and caregiver sample, 146 participants were included at 1 year, 125 at 2 years, and 51 at 5 years. Changes across time were assessed using Wilcoxon signed-rank tests, the Canadian Occupational Performance Measure (COPM), and Burke-Fahn-Marsden Dystonia Rating Scale - motor severity (BFMDRS-m). Analyses were stratified by key characteristics of participants, including sex, age at surgery, Manual Ability Classification System (MACS) level, Gross Motor Function Classification System (GMFCS) level, and aetiology. RESULTS: Median COPM performance increased from 2.8 to 6.1 (baseline to 5 years), while COPM satisfaction improved from 2.6 to 7.6; parent/caregiver reports showed similar trends. BFMDRS-m scores decreased from 81.0 to 70.0, with the largest improvements in the first year. COPM changes were greater in monogenic dystonia and participants classified in MACS levels I to III. BFMDRS-m improvements were more pronounced in monogenic dystonia, participants classified in GMFCS levels I to III, and those aged at least 12 years. INTERPRETATION: DBS showed sustained improvements in motor function and self-selected goals, with consistent findings across CYP and caregiver reports. Functional gains were observed despite limited dystonia reduction, particularly in dystonic cerebral palsy.