Cerebral Palsy

As we said earlier, a person with cerebral palsy has damage to the area of the brain that is in charge of muscle control. Depending on where the brain injury is, and how large it is, the person's muscle tone may be too tight, too loose, or a combination of both. Muscle tone is what lets us keep our bodies in a certain position, like sitting with our heads up to watch a movie in a theater. Changes in muscle tone are what allow us to move.

Spastic diplegia, the disorder first described by William Little, is only one of several disorders called cerebral palsy. Today, doctors classify cerebral palsy into four categories: spastic, athetoid, ataxic, and mixed.

Spastic cerebral palsy

If muscle tone is too high or too tight, the term “spastic”—stiffness or tightness of the muscles—is used to describe the type of cerebral palsy. Spastic cerebral palsy is the most common type of CP—about 70 to 80 percent of people with CP have this particular form. With spastic cerebral palsy, the muscles of the body are stiffly and permanently contracted. When a person without cerebral palsy performs a movement, some groups of muscles become tighter and some relax. When people with spastic cerebral palsy perform a movement, both groups of muscles may become tighter. These people may have difficulty moving from one position to another or letting go of something in their hands.

Doctors will often describe which type of spastic cerebral palsy a person has based on which limbs are affected. For example:

• Spastic diplegia affects either both arms or both legs. “Di” means two. In cases of diplegia, it's more common to have only the lower two limbs (legs) affected.
• Spastic hemiplegia, affects only one side of the body. “Hemi” means half. In hemiplegia, just the right arm and leg, or just the left arm and leg, are affected.
• Spastic quadriplegia affects all limbs on both sides of the body. “Quad” means four. With quadriplegia, there is difficulty with moving all parts of the body—face and trunk, as well as arms and legs.
• Spastic monoplegia is a rare condition that affects only one limb. “Mono” means one.
• Spastic triplegia which affects three limbs, is also fairly rare. “Tri” means three.

Athetoid cerebral palsy

If muscle tone is mixed—sometimes too high and sometimes too low—the term “athetoid” is used. Athetoid cerebral palsy affects about 10 to 20 percent of people who have CP. This form of cerebral palsy is characterized by uncontrolled, slow, or twisting movements of the body. Children and adults with athetoid cerebral palsy may have trouble holding themselves in an upright, steady position for sitting and walking, and often perform lots of involuntary movements. These movements are usually big and can affect the hands, feet, arms, or legs. In some cases, they also affect the muscles of the face and tongue, causing odd facial expressions, frowning, or drooling.

Ataxic cerebral palsy

If muscle tone is too low or too loose, the term “ataxic” is used. Affecting only 5 to 10 percent of persons with cerebral palsy, this form is the least common. Ataxia is the word used for unsteady, shaky movements, or tremors. Those with ataxic cerebral palsy often have poor coordination and balance, place their feet unusually far apart and walk unsteadily, and have trouble making quick or precise movements, such as writing, turning a page in a book, or buttoning a shirt.

Mixed

When muscle tone is too high in some specific muscles and too low in other specific muscles, the type of cerebral palsy is called mixed. It is quite common for persons with cerebral palsy to have symptoms of more than one of the previous three forms. The most common mixed form includes spasticity and athetoid movements, but other combinations are also possible.