Cerebral palsy (CP), or static encephalopathy, is the name for a collection of movement disorders caused by brain damage that occurs before, during, or shortly after birth. A person with CP is often also affected by other conditions caused by brain damage.
The affected muscles of a person with CP may become rigid or excessively loose, or the person may lose control of muscles, or have problems with balance and coordination. A combination of these is also possible. The person may be primarily affected in the legs (paraplegia or diplegia), or in the arm and legof one side of the body (hemiplegia), or all four limbs may be involved (quadriplegia).
A person with CP may also be affected by a number of other problems, including seizure disorder, visual deficits, hearing problems, mental retardation, learning disabilities, and attention-deficit/hyperactivity disorder. None of these is necessarily part of CP, however, and a person with CP may have no other impairments except for the movement disorder.
CP affects approximately 500,000 children and adults in the United States, and is diagnosed in more than 6,000 newborns and young children each year. CP is not an inherited disorder, and as of yet there is no way to predict with certainty which children will develop it. It is not a disease, and is not communicable. CP is a nonprogressive disorder, which means that symptoms neither worsen nor improve over time. However manifestation of the symptoms may becomemore severe over time; for example, rigidity of muscles can lead to contractures and deformities that require a variety of interventions.
Cerebral palsy is caused by damage to the motor control centers of the brain.When the nerve cells (neurons) in these regions die, the appropriate signalscan no longer be sent to the muscles under their control. The resulting poorcontrol of these muscles causes the symptoms of CP.
The symptoms of CP are usually not noticeable at birth; as children develop through the first 18 months of life, though, they progress through a predictable set of developmental milestones. Children with CP will develop these skills more slowly because of their motor impairments, and delay in reaching milestones is usually the first symptom of CP. The more severe the CP, the earlierthe diagnosis is usually made.
Children do not consistently favor one hand over the other before 18 months,and doing so may be a sign that the child has difficulty using the other hand. This same preference for one side of the body may show up as an asymmetriccrawling effort, or continuing to use only one leg for the work of stair climbing after age three.
It must be remembered that children normally progress at somewhat different rates, and slow beginning accomplishment is often followed by normal development. There are also other causes for delay in reaching some milestones, including problems with vision or hearing. Because CP is a nonprogressive disease,loss of previously acquired milestones indicates that CP is not the cause ofthe problem.
- The impairments of CP become recognizable in early childhood. The type ofmotor impairment and its location are used as the basis for classification.There are five generally recognized types of impairment:
- Spastic--Musclesare rigid, posture may be abnormal, and fine motor control is impaired
- Athetoid--Marked by slow, writhing, involuntary movements
- Hypotonic--Muscles are floppy, without tone
- Ataxic--Balance and coordination are impaired
- The location of the impairment usually falls into one of three broad categories:
- Hemiplegia--One arm and one leg on the same side of the body involved
- Diplegia--Both legs; arms may be partially involved
- Quadriplegia--All four extremities involved.
Therefore, a person with CP may be said to have spastic diplegia, or ataxic hemiplegia, for instance. CP is also termed mild, moderate, or severe, although these are subjective categories with no firm boundaries.
Loss of muscle control, especially of the spastic type, can cause serious orthopedic problems, including scoliosis (spine curvature), hip dislocation, orcontractures. A contracture is a shortening of a muscle, caused by an imbalance of opposing force from a neighboring muscle. Contractures begin as prolonged contractions, but can become fixed or irreversible without regular range of motion exercises. A fixed contracture occurs when the contracted muscle adapts by reducing its overall length. Fixed contractures may cause postural abnormalities in the affected limbs, including clenched fists, tightly pressed or crossed thighs, or equinus. In equinus, the most common postural deformity,the foot is extended by the strong pull of the rear calf muscles, causing the toes to point. The foot is commonly pulled inward as well, a condition called equinovarus. Contractures of all kinds may be painful, and may interfere with normal activities of daily living, including hygiene and mobility.
- As noted, the brain damage that causes CP may also cause a large number of other disorders. These may include:
- Mental retardation
- Attention-deficit/hyperactivity disorder
- Seizure disorder
- Visual impairment, especially strabismus ("cross-eye")
- Hearing loss
- Speech impairment.
These problems may have an even greater impact on the child's life than the physical impairment of CP, although not all children with CP are affected by other problems. About one-third of children with CP have moderate-to-severe mental retardation, one-third have mild mental retardation, and one-third havenormal to above average intelligence.
The tracking of developmental progress is the most important test the physician has in determining whether a child has cerebral palsy. Most children withCP can be confidently diagnosed by 18 months. However, diagnosing CP is not always easy, since variations in child development may account for delays in achieving milestones, and since even children who are obviously delayed may continue to progress through the various developmental stages, and attain a normal range of skills later on. Serious or prolonged childhood illness may cause delays that are made up later on.
Evidence of other risk factors may aid the diagnosis. The Apgar score, evaluated immediately after birth, measures the newborn's heart rate, cry, color, muscle tone, and motor reactions. Apgar scores of less than 3 out a possible 10 are associated with a highly increased risk for CP. Presence of abnormal muscle tone or movements may signal CP, as may the persistence of infantile reflexes. A child with seizures or congenital organ malformation has an increased likelihood of CP. Ultrasound examination, a diagnostic technique that creates a two-dimensional image of internal body structures, may help to identifybrain abnormalities, such as enlarged ventricles (chambers containing fluid)or periventricular leukomalacia (an abnormality of the area surrounding the ventricles), which may be associated with CP.
X rays, MRIs, and CT scans are often used to look for scarring, cysts, expansion of the cerebral ventricles (hydrocephalus), or other brain abnormalitiesthat may indicate the cause of the symptoms. Blood tests and genetic tests may be used to rule out other possible causes, including muscular dystrophy (adisease characterized by the progressive wasting of muscles), mitochondrial (cellular) disease, other inherited disorders, or infection.
Cerebral palsy cannot be cured, but many of the disabilities it causes can bemanaged through planning and timely care. Treatment for a child with CP depends on the severity, nature, and location of the impairment, as well as the associated problems the child has. Optimal care of a child with mild CP may involve regular interaction with only a physical therapist and occupational therapist, whereas care for a more severely affected child may include a speech-language therapist, special education teacher, adaptive sports therapist, nutritionist, orthopedic surgeon, and neurosurgeon. Since CP is not a progressive disorder, its symptoms will not worsen with time. Nonetheless, the way in which those symptoms affect the growing child will change over time, and may require new strategies for treatment, adaptation, and compensation.
Cerebral palsy can affect every stage of maturation, from childhood through adolescence to adulthood. At each stage, the person with CP and his or her caregivers must strive to achieve and maintain the fullest range of experiencesand education consistent with the person's abilities. The advice and intervention of professionals remains crucial for many people with CP.
Although CP is not a terminal disorder, it can affect a person's lifespan byincreasing the risk of infection, especially lung infections. Poor nutritioncan contribute to the likelihood of infection. People with mild cerebral palsy may have near-normal lifespans. The lifespan of those with more severe forms, especially spastic quadriplegia, is often considerably shortened. However,over 90% of infants with CP survive into adulthood.
The cause of most cases of CP is unknown, but it has become clear in recent years that birth difficulties are not to blame in most cases. Rather, developmental problems before birth, usually unknown and generally undiagnosable, areresponsible for most cases. Although the incidence of CP caused by Rh factorincompatibility has declined markedly, the incidence of CP as a consequenceof prematurity has increased, because of the increasing success of medical intervention in keeping premature babies alive.