The goal of this study is to test the effects of transcranial direct current stimulation (tDCS) on motor learning and brain plasticity in children with unilateral spastic cerebral palsy (USCP).

Inclusion Criteria:

Children between 6-17 years old who have been diagnosed with cerebral palsy, with the following joint mobility: wrist extension 20º, metacarpophalangeal and proximal interphalangeal joints 10º. Ability to cooperate and follow simple directions.

Exclusion Criteria:

• Seizure beyond age 2, use of anti-seizure medication, history or family history of epilepsy, cranial metal implants, structural brain lesion, devices that may be affected by tDCS or TMS (pacemaker, medication pump, cochlear implant, implanted brain stimulator)
• True positive response on the Transcranial Magnetic Stimulation and MRI Safety Screen
• Current use of medications known to lower the seizure threshold
• Previous episode of unprovoked neurocardiogenic syncope
• Indwelling metal or incompatible medical devices
• Centrally-acting medications including anti-seizure medications
• Evidence of scalp disease or skin abnormalities
• Current medical illness unrelated to CP
• High motor ability in affected arm (i.e. no asymmetry in scores of hand function)
• Severe spasticity
• Lack of asymmetry in hand function
• Orthopedic surgery in affected arm
• Botulinum toxin therapy in either upper extremity during last 6 months, or planned during study period
• Currently receiving intrathecal baclofen
• History of broken arm (either arm) 1 year prior to study enrollment

If the study is funded by National Institute of Health (NIH), the investigators will share individual participant data (IPD) via the NIH Data Hub (DASH), which is sponsored by the National Institute of Child Health and Development (NICHD).