Other countries have reported higher rates. Improved obstetric techniques over the past few decades have reduced the likelihood of brain injury during birth. But increased survival of premature infants, those born after only 25 to 37 weeks of pregnancy and weighing less than 2500 grams some of whom develop cerebral palsy, has kept the incidence in the United States fairly stable. From birth, a year or more may pass before the signs of cerebral palsy are recognized and diagnosed.
The three most common forms of cerebral palsy are spastic, athetoid, and ataxic. An individual may exhibit a combination of these forms, called the mixed type. Spasticity occurs in about 60 percent of all individuals with cerebral palsy. Symptoms typically include reduced movement due to stiff or permanently contracted muscles.
Spasticity is associated with damage to nerve fibers in the brain that carry messages for voluntary motor control. Twenty percent of individuals with cerebral palsy have the athetoid type, characterized by uncontrolled movements. This form of cerebral palsy is caused by injury to brain nerve fibers that are responsible for inhibition of muscle movement. The ataxic type of cerebral palsy is unusual, occurring in only 1 percent of cases. It results when the cerebellum, an area at the base of the brain, is injured.
Since the cerebellum maintains balance and precision of body movements, affected individuals have difficulty with coordination while walking and moving the upper limbs. Although the term cerebral palsy refers primarily to problems with muscle tone and movement, other disorders may be present. Mental retardation is common but does not necessarily result in all cases. Other associated problems include epilepsy, visual disturbances, hearing impairment, language difficulty, and slow growth.
Advances in diagnostic technology have led to a much better understanding of the causes of cerebral palsy. Over half of the cases are now thought to be due to prenatal causes such as an infection that spreads from the mother to the fetus, maternal stroke that prevents proper blood supply to the fetus, exposure to environmental toxins, or problems in brain development. The remaining cases are due to adverse events such as traumatic birth delivery, premature birth and its complications, meningitis, infection of the brain or its protective coverings, or head injury due to child abuse. Very rarely, heredity plays a role. In some cases, it is difficult to pinpoint a single event that may have caused cerebral palsy.
Injury to the brain in individuals with cerebral palsy is permanent, and full recovery is not possible. Damaged brain tissue does not regenerate, but to some extent, normal nerve cells and nerve pathways can take over some function from injured areas, with some limitations. The degree of severity varies so greatly from case to case that it is difficult to make a general prognosis. Successful treatment of cerebral palsy requires input from a variety of professionals. Physicians address health issues such as poor eyesight or restrictions in joint motion.
Physical and occupational therapists help the child develop skills necessary to the activities of daily living. Speech pathologists deal with swallowing and speech dysfunction. Psychologists and educators work with emotional or learning difficulties. Nutritionists ensure normal growth.
These professionals and numerous others work together as a team with the child or adult to help the individual achieve as much independence and competence as possible. In addition, family involvement in treatment, especially with children, is an essential component. With therapy, training, and community support, most individuals with cerebral palsy can lead meaningful and productive lives. Many causes of cerebral palsy are preventable, especially those that occur at or after birth.
Good prenatal care has been shown to minimize the likelihood of premature birth; new vaccines against Hemophilus influenzae have reduced the incidence of meningitis; and family support programs have reduced the number of cases of severe child abuse. Such preventive measures are cost-effective in that they reduce the expense of supporting individuals with cerebral palsy. Bibliography:Works CitedAaseng, Nathan. Cerebral Palsy.
New York: Prentice, 1991. Crothers, Bronson. The Natural History of Cerebral Palsy. Philadelphia: Oxford, 1988.
McDonald, Eugene. Treating Cerebral Palsy; For Clinicians byClinicians. Austin: Pro-ed, 1987.