Cerebral palsy is a group of disorders that affect movement and muscle tone or posture. It's caused by damage that occurs to the immature brain as it develops, most often before birth. Signs and symptoms appear during infancy or preschool years. In general, cerebral palsy causes impaired movement associated with abnormal reflexes, floppiness or rigidity of the limbs and trunk, abnormal posture, involuntary movements, unsteady walking, or some combination of these. People with cerebral palsy can have problems swallowing and commonly have eye muscle imbalance, in which the eyes don't focus on the same object. They also might have reduced range of motion at various joints of their bodies due to muscle stiffness.Cerebral palsy's effect on function varies greatly. Some affected people can walk; others need assistance. Some people show normal or near-normal intellect, but others have intellectual disabilities. Epilepsy, blindness or deafness also might be present.