Last modified: 2018-09-09
Abstract
Introduction: Non-invasive brain stimulation technologies like transcranial direct-current stimulation (tDCS) can alter cortical excitability, providing an opportunity for therapeutic neuromodulation. TDCS can safely enhance motor skill acquisition in children, however, refined forms such as high-definition (HD)-tDCS have not been studied. The KINARM robot quantifies sensorimotor function and may examine functional changes associated with motor learning. Here, we characterized changes in sensorimotor function induced by tDCS and HD-tDCS paired motor learning.
Methods: Randomized, blinded, sham-controlled trial. Healthy, right-handed children (12-18y) were recruited. A validated KINARM protocol and motor function assessments were completed before and after five consecutive days of left hand Purdue Pegboard Test (PPTL) training. Participants received primary motor cortex (M1) anodal tDCS, M1 anodal HD-tDCS, or sham concurrent with training.
Results: All participants (n=24, median 15.5y, 54.2% female) improved their PPTL scores (p<0.001). Both stimulation groups showed greater improvement in PPTL compared to sham (p<0.05), with enhanced rates of learning (p<0.05) and moderate effect sizes (Cohen’s d >0.7). The untrained hand also showed improvements with stimulation effects. Following training, visually-guided reaching was faster and required fewer corrective movements in the trained arm (p=0.010). Kinesthesia improvements in end-point variability were seen across all groups (p=0.011). Procedures were well-tolerated with no adverse events.
Conclusion: Both tDCS and HD-tDCS can safely enhance motor learning in children. Altered sensorimotor function may be measured with robotics. Optimizing stimulation while exploring mechanisms of action may advance therapeutic neuromodulation in children with cerebral palsy.