Cerebral palsy is the term used to designate movement impairment caused by brain damage or brain malformations which are present at birth or develop soon thereafter. Physicians distinguish nine different forms of cerebral palsy. The most common forms are the spastic forms: hemiplegia, quadriplegia, and diplegia. Spastic forms of this disorder are marked by stiff muscles. The dyskinetic forms of cerebral palsy, athetoid, choreoathetiod, and dystonic, are marked by slow, involuntary writhing movements. Ataxic cerebral palsy affects balance and depth perception. Sometimes two or more forms of cerebral palsy affect one patient--a condition called mixed cerebral palsy.
Forms of Cerebral Palsy most Likely to Occur Together
The spastic forms are most likely to occur together with athetoid cerebral palsy. This means that the child will have the stiffness of spasticity with the writhing, involuntary movements of athetoid cerebral palsy. Generally the spasticity will be identified before the athetoid component; the involuntary movements of athetoid CP usually appear between the ages of nine months and three years.
Other forms of CP may occur together. For example, a child with both a spastic form and hypotonic cerebral palsy will have some muscles which are spastic and others which are “floppy.”
Complications of Mixed Cerebral Palsy
Cerebral palsy can lead to many medical complications; in the case of mixed CP, the patient may experience complications that are specific to either form. This makes treating mixed cerebral palsy more complicated.
Seizures are a common complication of CP. Seizures are caused by abnormal electrical activity in the brain. They can range from mild to severe and affect approximately a third of CP patients.
Mental retardation is another extremely common condition associated with mixed cerebral palsy. It can range from mild to profound. Because patients with CP frequently have severe communication difficulties, it can be difficult to properly assess mental capacity.
The neurological difficulties of mixed cerebral palsy frequently cause difficulty with speaking and swallowing. CP patients may have difficulty getting adequate nutrition. They may experience drooling or facial grimaces. Children with CP may have difficulty enunciating words. They may also have difficulty with processing and understanding the spoken word.
Communication difficulties may be increased by hearing problems. In addition, patients with mixed CP are prone to vision difficulties. Strabismus (“cross-eyes” or “lazy eye”) is common and may need surgical correction. Some patients with mixed cerebral palsy have “cortical blindness.” Although the eyes are perfectly normal, the person cannot see because of damage to the part of the brain which controls vision.
Causes of Mixed Cerebral Palsy
All forms of CP are caused by brain damage or abnormal brain development and mixed cerebral palsy is no exception. The degree and kind of disability is determined by the location and extent of the brain damage or abnormality.
Maternal infections and fetal infections are a primary cause of brain damage. When a woman has inflammatory pelvic disease, her risk of having a child with CP greatly increases. Other infections also can lead to brain damage or abnormal brain development.
The body fights infection by producing more cytokines—a type of immune cell. Increased cytokines lead to inflammation, a key part of the disease fighting process; however, inflammation can cause brain damage. Brain damage and brain malformation from infection are most likely to occur in the first two trimesters and can also be caused by exposure to toxins.
A condition called Rh incompatibility is another cause of mixed CP. In this condition the mother and the fetus’s blood types are in conflict, causing the mother’s body to make anti-bodies against the baby’s blood. In the United States Rh incompatibility is routinely tested for during prenatal care; the condition can then be treated before the baby is harmed.
In addition babies with low birth weights and babies who are premature are at higher risk for brain abnormalities or damage that can cause CP. Premature babies are more prone to developing brain malformations called periventricular leukomalacias—which slow blood circulation in the brain and cause less oxygen to be delivered to the brain. As many as a 100 percent of babies with periventricular leukomalacias develop some form of CP and the risk for mixed CP increases if the damage is also in other areas of the brain.
Maternal thyroid problems, mental retardation, or seizures also, put the unborn baby at higher risk of developing mixed cerebral palsy. Oxygen deprivation during delivery can also cause cerebral palsy, but less than 10 percent of CP cases are caused by oxygen deprivation at birth; oxygen deprivation while the baby is still in the womb is more likely to cause brain damage and lead to CP.
Age of Diagnosis
The age of diagnosis varies in mixed cerebral palsy, depending on the form of CP which predominates. As mentioned earlier, spasticity is usually apparent before the writhing moments of athetoid CP appear. Delayed development is frequently the first indicator that a child has mixed cerebral palsy. Suspicions of mixed cerebral palsy are confirmed with ECGs and brain imaging scans.
Treatments for Mixed Cerebral Palsy
Mixed cerebral palsy is treated according to the symptoms present. Spasticity may be reduced with medications. Contractures (stiffened muscles which deform the bones or impair mobility) may be treated with surgery. Vision and hearing problems may be corrected or eased with assistive devices (eyeglasses, hearing aids and so on).
As in any case of cerebral palsy, mixed cerebral palsy is primarily treated with physical therapy. Physical therapy strengthens the muscles and prevents them from atrophying