IMPORTANCE: Current upper-extremity therapies provide inconsistent outcomes for children with unilateral cerebral palsy. Noninvasive brain stimulation, specifically transcranial direct current stimulation, may enhance motor gains when combined with therapy. OBJECTIVE: To determine whether the addition of neurostimulation to upper-extremity therapy enhances motor function in children with perinatal stroke and unilateral cerebral palsy. DESIGN, SETTING, AND PARTICIPANTS: This multicenter, randomized, sham-controlled phase 3 trial was conducted from July 2017 through March 2023. Investigators, treating therapists, outcome assessors, parents, and participants were blinded to intervention allocation. The study took place at 3 tertiary care Canadian pediatric rehabilitation hospitals. From a population-based sample of children 6 to 18 years old with perinatal stroke and disabling unilateral cerebral palsy, 196 children were approached and 107 were excluded. INTERVENTION: Participants were randomly assigned in permuted blocks of 2 (1:1) to receive daily sham or cathodal stimulation to the contralesional motor cortex during 10 days of high-dose, child-centered intensive upper-extremity therapy. MAIN OUTCOMES AND MEASURES: The primary end points were changes from baseline to 6 months posttherapy in affected hand function and attainment of child-identified functional goals assessed by the Assisting Hand Assessment and Canadian Occupational Performance Measure. Safety was assessed, including any decrease in the function of either hand. Analysis was intention to treat. RESULTS: Eighty-nine children were enrolled with 45 randomized to sham (62% male, 38% female
mean [SD] age, 10.7 [2.8] years) and 44 to stimulation (52% male, 48% female
mean [SD] age, 10.7 [2.1] years). Eighty-three participants had complete outcome data (42 sham, 41 stimulation). High proportions of children in both groups demonstrated significant functional gains sustained at 6 months (P <
.001) with large effect size (Cohen d >
1). There were no differences between groups for mean (SD) change in hand function (5.2 [5.3] vs 4.6 [5.7]
P = .63) or goal attainment (3.0 [2.0] vs 3.6 [2.3]
P = .25). Procedures were safe and well tolerated with no serious adverse events. CONCLUSIONS AND RELEVANCE: In this study, results showed that patient-centered intensive motor learning programs could produce marked and sustained improvements in upper-extremity function in children with perinatal stroke and unilateral cerebral palsy. The addition of 1 milliampere contralesional motor cortex transcranial direct current stimulation did not improve outcomes compared with sham stimulation. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03216837.