Effects of Transcranial Direct Current Stimulation Combined With Virtual Reality on Balance and Executive Functions in Children With Spastic Diplegic Cerebral Palsy

This study is a three-arm, parallel-group, randomized controlled trial designed to evaluate the effects of active transcranial direct current stimulation (tDCS) combined with virtual reality (VR) rehabilitation on balance and executive functions in children with spastic diplegic cerebral palsy. The active intervention will be compared with sham tDCS combined with the same VR rehabilitation and with conventional physical therapy.

Forty-two children aged 8-16 years with spastic diplegic cerebral palsy and Gross Motor Function Classification System (GMFCS) levels I-III will be enrolled and randomly allocated in a 1:1:1 ratio, with 14 participants in each intervention arm. Outcome assessment will be performed by an assessor blinded to group allocation.

Participants in the active tDCS plus VR group will receive transcranial direct current stimulation at an intensity of 1 mA for 20 minutes per session using saline-soaked sponge electrodes, together with structured VR rehabilitation. The stimulation montage will target the lower-limb motor cortical region with a supraorbital reference electrode. Participants in the sham tDCS plus VR group will receive the same electrode setup and VR rehabilitation programme; sham stimulation will be delivered for the initial 30 seconds to reproduce the early sensory experience of active stimulation without continued therapeutic stimulation.

VR rehabilitation will include progressively challenging activities targeting postural control, balance, movement coordination, obstacle navigation, dual-task performance, visual attention, and cognitive-motor integration. Participants in the conventional physical therapy group will receive a structured rehabilitation programme incorporating lower-limb stretching, strengthening, balance training, gait-related activity, motor-control exercises, and progressive functional mobility training.

All groups will receive 18 sessions over six weeks at a frequency of three sessions per week. Assessments will be conducted before treatment at baseline (S0), after nine treatment sessions at the midpoint of the programme (S9), and after completion of 18 sessions (S18).

Balance outcomes will include the Pediatric Balance Scale and Functional Reach Test. Executive-function outcomes will include Trail Making Test measures of processing speed and cognitive flexibility, Stroop Test measures of inhibitory control and interference processing, and Digit Span measures of attention and working memory. Lower-limb spasticity will be assessed using the Modified Tardieu Scale as a secondary impairment-level outcome.

The study is intended to determine whether active tDCS provides an additional therapeutic effect when combined with VR beyond the effects of matched VR with sham stimulation, while also comparing the combined technology-assisted rehabilitation approach with conventional physical therapy.

Inclusion criteria

• Diagnosed with spastic cerebral palsy (spastic diplegia). Age 8-16 years. Gross Motor Function Classification System (GMFCS) levels I-III. Presence of mild to moderate lower-limb spasticity, defined as a Modified Tardieu Scale (MTS) score between 1 and 3 in at least one major lower-limb muscle group, such as the gastrocnemius, hamstrings, or hip adductors. Able to understand and follow verbal instructions. Parent or guardian provides informed consent and the child provides assent

Exclusion criteria

• History of seizures or epilepsy. Implanted metal or electronic devices, such as a pacemaker. Severe cognitive impairment that prevents comprehension of study tasks. Skin allergies, lesions, or other conditions affecting the electrode application sites. Current use of antispasticity medication that could directly influence spasticity outcomes. Botulinum toxin injection within the previous 3 months. Recent orthopedic surgery or change in medication regimen within the previous 5 days. Concurrent participation in alternative or adjunct therapies outside the study protocol. Refusal to participate or withdrawal of consent/assent