The head circumference of the newborn is about 33-34 cm at birth, and increases by about 1.5 cm per month during the first 6 months of life, and by about 0.5 cm per month in the second half of the year, and is about 46 cm at 1 year of age and 48 cm at 2 years of age. In addition, the average weight of the newborn brain is about 370 grams, and can reach 700 grams at 6 months of age and 900 grams at 1 year of age, and the adult brain is about 1500 grams. The development of the nerve conduction system begins at 7 months of age, and the nerve fibers gradually penetrate deep into the cortex from the white matter, but the number is still small at birth and increases rapidly after birth. By infancy, the formation of myelination of the outer layer of nerve fibers is not yet complete. Myelination of the spinal nerves begins at 4 months of age and is completed at 3 years of age; myelination of the pyramidal tracts begins at 5-6 months of age and is completed at 2 years of age; myelination of the cortex is the latest and is completed at about 3-4 years of age. Therefore, in terms of brain development, the earlier the intervention for children with brain injury, the better, and the best results are achieved when the intervention is carried out within 6 months of age; once the child is older than 4 years, the white matter myelination of the child is relatively fixed, and the intervention effect is relatively poor.