Muscle Tone and Cerebral Palsy

People with cerebral palsy have damaged the area of their brain which controls muscle tone. Muscle tone describes the state of our muscles' readiness to contract or release. The amount of tension or resistance present in our muscles allows us to move or hold our bodies in position. The brain uses electrochemical signals to control and balance muscle tone. People with cerebral palsy's brains have lost the ability to appropriately control the electrochemical signals sent to different muscle groups. They suffer from increased, decreased or fluctuating muscle control depending on what part of their brain is damaged.
What Are the Different Types of Cerebral Palsy?
Spastic Cerebral Palsy

The muscles of a person with spastic cerebral palsy have increased muscle tone, meaning their muscles and stiff and permanently contracted. Almost 80 % of cerebral palsy cases are spastic. Trying to move with continually contracted muscles makes motion short and jerky.

A normal muscle will have enough tone to counteract the force of gravity in order to maintain controlled movement or posture but still allow for flexibility. The muscle nerves are responsible for telling the brain how tense to keep the muscle while the brain tells the muscles how flexible to keep the muscle. A balance is achieved through good coordination of commands from both the muscle and the brain. The brain of a person with cerebral palsy can't appropriately tell the muscle how much flexibility to have so the muscle dominates the signals sent to the spinal cord and the muscles remain tense, or spastic.
Athetoid or Dyskinetic Cerebral Palsy

Athetoid or Dyskinetic cerebral palsy is characterized by unintentional or uncontrolled movements due to continually changing muscle tone. People with Athetoid cerebral palsy usually have movements that look slow and are sometimes circular in nature. This kind of cerebral palsy affects 10 to 20 % of sufferers. Athetoid cerebral is either caused by widespread brain damage or damage localized in an area of the brain called the Basil Ganglia. Writhing, slow movements usually affect all four limbs and sometimes the face or tongue. To some extent, the whole body is affected, resulting in continual abnormal posturing and in some cases, almost total quadriplegia. Interestingly, people with Athetoid or Dyskinetic cerebral palsy often have above average intelligence.
Ataxic Cerebral Palsy

Ataxic cerebral palsy is a relatively rare form of the disorder, affecting about 5 to 10 percent of sufferers. Ataxic cerebral palsy stems from damage to the cerebellum. It is characterized by a lack of coordination, balance and depth perception. Another characteristic of ataxic cerebral palsy is called an "intention tremor." It occurs when a person with cerebral palsy begins a deliberate movement such as reaching for an object. As they get closer to grasping the object, the tremor increases until the cerebral palsy sufferer reaches the object. Quick movements are difficult to complete. Most Ataxia sufferers have an awkward, widespread gait.
Mixed Cerebral Palsy

Many cerebral palsy sufferers have a combination of the different types. The most common is a mix of Spastic and Athetoid. The least common mixture is Athetoid and Ataxic. It's possible, though rare, to have a combination of all three types of cerebral palsy.