This randomized controlled trial aims to compare the effects of transcranial direct current stimulation (tDCS) combined with virtual reality-based training versus conventional physical therapy on brain activity, cognitive function, and gross motor skills in children with Down syndrome. Children with Down syndrome commonly exhibit motor and cognitive impairments associated with altered neurodevelopment, which may benefit from neuroplasticity-oriented interventions.

Eligible participants will be randomly allocated into two groups. The experimental group will receive tDCS in combination with virtual reality-based training, while the control group will receive only conventional physical therapy. Interventions will be administered by licensed physiotherapists over a defined treatment period. Gross motor outcomes will be assessed using standardized measures such as the Gross Motor Function Measure (GMFM). Cognitive function will be evaluated using age-appropriate cognitive assessments, and brain activity will be assessed using electroencephalography (EEG), where applicable. Assessments will be conducted at baseline and after completion of the intervention period. The study will adhere to ethical principles, including informed consent from parents or guardians, participant confidentiality, and the right to withdraw at any stage.

Inclusion Criteria:

• Children aged 6-12 years diagnosed with Down syndrome by a pediatrician.
• Compromised gross motor performance in standing, walking, running, or jumping domains of the Gross Motor Function Measure (GMFM).
• Stable medical and neurological status.
• Parental/guardian informed consent and cooperation.
• Documented balance difficulties.
• Ability to follow simple instructions in Urdu or locally spoken language.
• Regular accessibility to the intervention site.

Exclusion Criteria:

• Neurological conditions other than Down syndrome.
• Red flag conditions such as tumors, fractures, metabolic diseases, or dislocations.
• Visual, cardiopulmonary, or severe musculoskeletal impairments requiring surgical management.
• Recent surgery in the past 12 months.
• Seizure history or sensitivity to electrical stimulation.
• Presence of metal implants or hearing aids.
• Tactile or sensory processing issues that prevent participation in therapy.