These disorders are caused by injuries to the brain that occur during fetal development or near the time of birth. The incidence of cerebral palsy is approximately 2 to 4 individuals for every 1000 births. Initially cerebral palsy was thought to be related to birth asphyxia and trauma but in a study of 45,000 births it was shown that birth asphyxia is an uncommon cause of cerebral palsy.
Premature infants have a slightly higher incidence of cerebral palsy.
Injury to the cerebrum can result in the loss of nerve functions in widely different areas. Speech abnormalities are common and seizures may occur. Intellectual function may range from extremely bright normal to severe mental retardation . Symptoms are usually evident before age 2 and in severe cases may appear as early as three months. Classifications of cerebral palsy include spastic, dyskinetic, ataxic, and mixed cerebral palsy.