There are four types of cerebral palsy: spastic cerebral palsy, athetoid cerebral palsy, ataxic cerebral palsy and mixed cerebral palsy.

Development of the brain starts in early pregnancy and continues until about age three. Damage to the brain during this time may result in cerebral palsy. This damage interferes with messages from the brain to the body and from the body to the brain. Cerebral palsy is not a progressive condition–damage to the brain is a one-time event so it will not get worse.

All children with cerebral palsy have damage to the area of the brain that controls muscle tone. As a result, they may have increased muscle tone, reduced muscle tone, or a combination of the two (fluctuating tone).

While birth trauma can cause different kinds of cerebral palsy, the most common form of cerebral palsy associated with the lack of oxygen at birth is spastic cerebral palsy. Spastic cerebral palsy is the most common type of cerebral palsy, accounting for 80% of all cerebral palsy cases. Children with this type of cerebral palsy have one or more tight muscle groups which limit movement. Children with spastic cerebral palsy have stiff and jerky movements.

About 10% of children with cerebral palsy have athetoid cerebral palsy. Athetoid cerebral palsy is caused by damage to the cerebellum or basal ganglia. These areas of the brain are responsible for processing the signals that enable smooth, coordinated movements as well as maintaining body posture. Damage to these areas may cause a child to develop involuntary, purposeless movements, especially in the face, arms and trunk. Children with athetoid cerebral palsy often have low muscle tone and have problems maintaining posture for sitting and walking. They often have speech difficulties.

About 10% of children with cerebral palsy have a mixed type of cerebral palsy. Children with spastic cerebral palsy and clinical signs of other forms of cerebral palsy are described as having mixed cerebral palsy. These children have both the tight muscle tone of spastic cerebral palsy and the involuntary movements of athetoid cerebral palsy.

Ataxic cerebral palsy is the least common form of cerebral palsy. Children with ataxic cerebral palsy have low muscle tone and poor coordination of movements. Children with ataxic cerebral palsy look very unsteady and shaky. This rare form of cerebral palsy affects the sense of balance and perception.