Types of cerebral palsy:

Cerebral palsy is a broad term which encompasses many different disorders of movement and posture. To describe particular types of movement disorders covered by the term, pediatricians, neurologists, and therapists use several classification systems and many labels. To understand different types of cerebral palsy more clearly, you must first understand what professionals mean by muscle tone.

Muscle tone refers to the amount of tension or resistance to movement in a muscle. Muscle tone is what enables us to keep our bodies in certain position or posture. Changes in muscle tone is what enables us to move. For example, to bend your arm to brush your teeth, you must shorten (increase the tone of) the biceps muscles on the front of your arm at the same time you are lengthening (reducing the tone of) the triceps muscles on the back of your arm. To complete a movement smoothly, the tone in all muscle groups involved must be balanced. The brain must send messages to each muscle group to actively change its resistance.

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). Which parts of their bodies are affected by the abnormal muscle tone depends upon where the brain damage occurs.

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 combination of these types for any one person)

Spastic:
Spastic cerebral palsy is the most common type of cerebral palsy. It affects about 80 percent of all children with cerebral palsy. Children with this type of cerebral palsy have one or more tight muscle groups which limit movement. If muscle tone is too high or too tight, the term spastic is used to describe the type of cerebral palsy. Children with spastic cerebral palsy have stiff and jerky movements because their muscles are too tight. They often have a hard time moving from one position to another. They may also have a hard time holding and letting go of objects. If your child has spastic cerebral palsy, it is because he or she has damage to the part of the brain that controls voluntary movements.

Ataxic:
Low muscle tone and poor coordination of movements is described as ataxic cerebral palsy. Children with ataxic cerebral palsy look very unsteady and shaky. This rare form of cerebral palsy affects the sense of balance and depth perception. Affected persons often have poor coordination and walk unsteadily with a wide based gait, placing their feet unusually far apart. They have a lot of shakiness, like a tremor you might have seen in a very old person, especially when they are trying to handle or hold a small object such as a pen. Because of the shaky movements and problems coordinating their muscles, children with ataxic cerebral palsy may take longer than other children to complete certain tasks such and writing a sentence. This form affects about 5-10 percent of the children diagnosed with cerebral palsy.

Athetoid:
About 10 percent of children with cerebral palsy have the athetoid type. Athetoid cerebral palsy is caused by damage to the cerebellum or basal ganglia. These areas of the brain normally process 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. These movements often interfere with speaking, feeding, reaching, grasping, and other skills requiring coordinated movements. For example, involuntary grimacing and tongue thrusting may lead to swallowing problems, drooling and slurred speech. The movements often increase during periods of emotional stress and disappear during sleep. In addition, children with athetoid cerebral palsy often have low muscle tone and have problems maintaining posture for sitting and walking.

Mixed cerebral palsy:
About 10 percent of children with cerebral palsy have what is known a mixed-type cerebral palsy. These children have both the tight muscle tone of spastic cerebral palsy and the involuntary movements of athetoid cerebral palsy. This is because they have injuries to both the pyramidal and extrapyramidal areas of the brain. Usually the spasticity is more obvious at first, with involuntary movements increasing when the child is between nine months and three years old. The most common mixed form includes spasticity and athetoid movements, but other combinations are also possible.