Cerebral palsy is caused by damage to the infant brain. This damage can involve not only the motor parts of the brain, but also the parts that deal with vision. This is not related to damage to the eye but is related to damage of the parts of the brain that process visual information.
Spasticity is a condition of muscles that is a velocity resistance to stretch. What that means to a child and to a parent is that if you move the limb slowly, you have a difference than if you move that limb fast. Spasticity restricts movement and it creates a break on the system. It's as if they're trying to move, but they're held back. By treating spasticity, you may improve the range of motion or the action of the movement.
Children with cerebral palsy experience brain damage around birth or before birth. So the language of the brain in other words, the way they will move, will be different from typical movements. So by looking at their movements, we will understand that there is something that is wrong in the brain.