Any damage to the developing brain, whether caused by genetic or developmental disorders, injury or disease, may produce CP. The damage to the brain is in the region that controls and coordinates muscular action. Most often it occurs during pregnancy, labor or shortly after birth.

Most cases of cerebral palsy are called congenital cerebral palsy because they are related to the development and childbearing processes and since the condition is not inherited. Acquired cerebral palsy, usually occurring before two years of age is less common. It is usually caused by head injury (motor vehicle accidents, falls, child abuse). Another cause is brain infection.

One important cause is an insufficient amount of oxygen reaching the fetal or newborn brain. Premature birth, low birth weight, Rh or A-B-O blood-type incompatibility between mother and infant, infection of the mother with German measles or other virus diseases in early pregnancy, and microorganisms that attack the infant's central nervous system also are risk factors for cerebral palsy.

An inability to fully control motor function, particularly muscle coordination. Depending on which areas of the brain have been damaged, one or more of the following may occur: muscle tightness or spasm, involuntary movement, disturbance in gait and mobility; abnormal sensation and perception; impairment of sight, hearing or speech; seizures; and mental retardation. In addition the following may also occur: postural difficulties, skin disorders because of pressure sores, learning disabilities.

There are three main types of cerebral palsy:

• Spastic - stiff and difficult movement.
• Athetoid - involuntary and uncontrolled movement.
• Ataxic - disturbed sense of balance and depth perception.

There may be a mixture of these types for any individual. Other types do occur, although less frequently.