What is cerebral palsy?
Cerebral palsy is the term given to a group of disorders affecting movement or posture. It is caused by damage to areas of the brain that are involved in controlling muscles. Each child with cerebral palsy is affected differently and the difficulties in controlling posture and movement may vary from being hardly noticeable to very obvious.
Cerebral palsy is a non-progressive, permanent condition and is the most common cause of disability in children. It occurs in approximately 1 in 400 live births.
Causes of cerebral palsy
A range of factors are linked to the development of cerebral palsy. Most are believed to be associated with pre-natal events such as brain mal-development, exposure to infections or placental insufficiency. Critical insults to the brain can also occur around the time of the birth (e.g. birth asphyxia), or during the first few years of life (e.g. meningitis, acquired brain injury or near drowning).
Classification of cerebral palsy
One way of classifying cerebral palsy is according to the type of movement disorder it causes. Commonly these types of disorders are divided into three clinical pictures: spastic, dyskinetic and ataxic.
- Spastic cerebral palsy describes a disorder where there is excessive involuntary muscle activity. This problem is caused by damage to the part of the brain known as the motor cortex, which is responsible for controlled (voluntary) muscle movements such as the muscle movements necessary to enable you to ride a bike or walk. Spastic cerebral palsy is further divided based on the actual muscles affected.
- Spastic hemiplegia is the most common form of cerebral palsy and predominately affects one side of the body (i.e. one arm and one leg).
- Spastic diplegia affects both sides of the body, predominately the legs.
- Spastic quadriplegia is the most severe form of cerebral palsy where both arms, both legs and the trunk are affected.
- Dyskinetic cerebral palsy refers to a group of movement disorders where there are involuntary, uncontrolled and recurring movement patterns.
- Ataxic cerebral palsy is the least common form of cerebral palsy and children with this type exhibit a lack of balance and coordination; they may stagger when they walk and tend to have frequent falls. They may also have unsteady hands and unclear speech patterns.
The different patterns can co-exist and this is called mixed cerebral palsy.
More recently an effort has been made to classify children with cerebral palsy based on their functional ability. Some children with cerebral palsy have little more than a slight limp. Others experience difficulties crawling, walking, talking or using their hands while others cannot sit up unaided.
Identification (diagnosis) of cerebral palsy
Cerebral palsy may not be detected until the child experiences delays in developing the movement, posture and balance necessary for sitting and standing. In children with hemiplegia and diplegia this usually becomes apparent between the ages of 1 and 2 years. The diagnosis of cerebral palsy is made based on the clinical signs of the child.
The importance of moving as normally as possible
Encouraging children to walk and move as well as possible is one of the key aims of physiotherapy. Children with spastic leg muscles may adopt an abnormal style of walking due to excessive tightness in certain muscle groups.
Patterns such as excessive bending at the knees or toe walking are common. Eventually the tight muscles may shorten and joints become stiff. Progressive muscle tightening can lead to bone deformities. Often the growth of the muscle is slower than the growth of the bone. This leads to an increased difference between the length of the limb and the length of the muscle and tendons. Young muscles need to be in a stretched, relaxed condition in order to grow.
A common example is spasticity in the calf muscles. This causes increased pull on the Achilles tendon (heel cord) and leads to children walking on their toes. Children with feet in this position are likely to trip frequently, stumble or fall. If these calf muscles are left untreated they may become permanently shortened in this position leaving limbs in a fixed, abnormal position. This can lead to early wear and tear of the bones and joints, causing arthritis and pain. These shortened muscles (called fixed contractures) are one of the most common problems with cerebral palsy. An important goal is to prevent this situation from occurring by early intervention.