What is cerebral palsy (CP)?
Cerebral palsy, also known as CP, is a term used to describe a group of chronic conditions affecting the body’s movement and muscle coordination. It is caused by damage to one or more specific areas of the brain, which usually occurs during fetal development, before, during, or shortly after birth, or during infancy. These disorders are not caused by problems in the muscles or nerves. They are caused by faulty development or damage to motor areas in the brain, which disrupts the brain’s ability to adequately control movement and posture.
“Cerebral” refers to the brain and “palsy” to muscle weakness or poor control. Cerebral palsy itself is not progressive (brain damage does not get worse). However secondary conditions, such as muscle spasticity, can develop which over time may get better, worse, or remain the same. Cerebral palsy is not communicable. It is not a disease and should not be referred to as such. Although cerebral palsy is not curable in the accepted sense, training and therapy can help improve function.
What are the effects?
Cerebral palsy is characterized by an inability to fully control motor function, particularly muscle control and coordination. Depending on which areas of the brain have been damaged, one or more of the following may occur: muscle tightness or spasticity, involuntary movement, disturbance in gait or mobility, difficulty in swallowing, and problems with speech. In addition, the following may occur: abnormal sensation and perception, impairment of sight, hearing, or speech, seizures, and mental retardation. Other problems that may arise are difficulties in feeding, bladder and bowel control, problems with breathing (because of postural difficulties), skin disorders (because of pressure sores), and learning disabilities.
What are the causes?
Cerebral palsy is not a disorder with a single cause. It is a group of disorders with similar problems in control of movement, but probably with a variety of causes.
Congenital cerebral palsy results from a brain injury during intra-uterine life. It is present at birth, although it may not be detected for months. It is responsible for about 70% of cases of children with cerebral palsy. An additional 20% of children are diagnosed with congenital cerebral palsy due to a brain injury during the birthing process. In most cases, the cause of congenital cerebral palsy is unknown.
In the United States, about ten percent of children who have cerebral palsy acquire the disorder after birth (The figures are higher in underdeveloped countries.). Acquired cerebral palsy results from brain damage in the first few months or years of life, and can follow brain infections, such as bacterial meningitis or viral encephalitis, or a head injury – most often from a motor vehicle accident, a fall, or child abuse.
A large number of risk factors, which can injure the developing brain, may produce cerebral palsy. A risk factor is not a cause; it merely increases the chance of something occurring – in this case, cerebral palsy. Just because a risk factor is present does not mean cerebral palsy will occur, nor does the absence of a risk factor mean that cerebral palsy will not occur. If a risk factor is present, it serves to alert parents and physicians to be even more observant to the infant’s development.
Risk factors for cerebral palsy include the following: a premature birth, low birth weight, inability of the placenta to provide the developing fetus with oxygen and nutrients, lack of growth factors during intra-uterine life, RH or A-B-O blood type incompatibility between mother and infant, infection of the mother with German measles or other viral diseases in early pregnancy, bacterial infection of the mother, a fetus or infant that directly or indirectly attacks the infant’s central nervous system, prolonged loss of oxygen during the birthing process, and severe jaundice shortly after birth.
Are there different types of cerebral palsy?
Yes. Spastic diplegia, the disorder first described by Dr. Little in the 1860’s, is only one of several disorders called cerebral palsy. Today, doctors classify cerebral palsy into three principal categories — spastic, athetoid, and ataxic — according to the type of movement disturbance. A fourth category can be a mixture of these types.
Spastic cerebral palsy: In this form of cerebral palsy, which affects 70 to 80 percent of patients, the muscles are stiffly and permanently contracted. Doctors will often describe which type of spastic cerebral palsy a patient has based on which limbs are affected. For example, spastic diplegia means of both legs, and left hemi-paresis means the left side of the body. The names given to these types of CP combine a Latin description of the affected limbs with the term plegia or paresis, meaning paralyzed or weak. In some cases, spastic cerebral palsy follows a period of poor muscle tone (hypotonia) in a young infant.
Athetoid or dyskinetic cerebral palsy: This form of cerebral palsy is characterized by uncontrolled, slow writhing movements. These abnormal movements usually affect the hands, feet, arms, or legs, and, in some cases, the muscles of the face and tongue, causing grimacing or drooling. The movements often increase during periods of emotional stress and disappear during sleep. Patients may also have problems coordinating the muscle movements needed for speech, a condition known as dysarthria. Athetoid cerebral palsy affects about 10 to 20 percent of patients.
Ataxic cerebral palsy: This rare form of CP affects a person’s sense of balance and depth perception. They often have poor coordination or walk unsteadily with a wide-based gait, placing their feet unusually far apart. They also experience difficulty when attempting quick or precise movements such as writing or buttoning their shirt. Another possible symptom is an intention tremor. In this form of tremor, beginning a voluntary movement, such as reaching for a book, causes a trembling that affects the body part being used and that worsens as the individual gets nearer to the desired object. Ataxic CP affects an estimated 5 to 10 percent of patients.
Mixed forms: It is not unusual for patients to have symptoms of more than one of the previous three forms. The most common mixed form includes spasticity and athetoid movements, but other combinations are also possible.
What are the early signs?
Early signs of cerebral palsy usually appear before 18 months of age, and parents are often the first to suspect that their infant is not developing motor skills normally. Infants with cerebral palsy are frequently slow to reach developmental milestones such as: learning to roll over, sit, crawl, smile, or walk. This is sometimes called developmental delay.
Some affected children have abnormal muscle tone. Decreased muscle tone is called hypotonia, the baby may seem flaccid and relaxed, even floppy. Increased muscle tone is called hypertonia, and the baby may seem stiff or rigid. In some cases, the baby has an early period of hypotonia that progresses to hypertonia after the first two to three months of life. Affected children may also have unusual posture or favor one side of their body.
Parents who are concerned about their baby’s development for any reason should contact their physician, who can help distinguish normal variation in development from a developmental disorder.
How is cerebral palsy diagnosed?
Doctors diagnose cerebral palsy by testing an infant’s motor skills and looking carefully at the mother’s and infant’s medical history. In addition to checking for the symptoms described above – slow development, abnormal muscle tone, and unusual posture – a physician also tests the infant’s reflexes and looks for the early development of a hand preference.
Reflexes are movements that the body makes automatically in response to a specific cue. For example, if a newborn baby is held on its back and tilted so that its legs are above its head, the baby will automatically extend its arms in a gesture called the Moro reflex, which looks like an embrace. Babies normally lose this reflex after they reach six months, but those with cerebral palsy may retain it for an abnormally long period. This is just one of several reflexes that a physician can check.
Doctors can also look for hand preference – a tendency to use either the right or left hand more often. When the doctor holds an object in front of and to the side of the infant, an infant with a hand preference will use the favored hand to reach for the object, even when it is held closer to the opposite hand. During the first twelve months of life, babies do not usually show a hand preference. But infants with spastic hemiplegia in particular may develop a preference much earlier, because the hand on the unaffected side of their body is stronger and more useful.
The next step in diagnosing CP is to rule out other disorders that can cause movement problems. Most importantly, doctors must determine that the child’s condition is not getting worse. Although its symptoms may change over time, cerebral palsy by definition is not progressive. If a child is continuously losing additional motor skills, the problem likely springs from elsewhere including: genetic diseases, muscle diseases, disorders of the metabolism, or tumors in the nervous system. The child’s medical history, special diagnostic tests, and, in some cases, repeated check-ups can help confirm that other disorders are not at fault.
The doctor may also order specialized tests to learn more about the possible cause of a patient’s cerebral palsy. One such test is computed tomography, or a CT scan, a sophisticated imaging technique that uses x-rays and a computer to create an anatomical picture of the brain’s tissues and structures. A CT scan may reveal brain areas that are underdeveloped, abnormal cysts (sacs often filled with liquid) in the brain, or other physical problems. With the information from CT scans, doctors may be better equipped to judge the long-term outlook for an affected child.
Magnetic resonance imaging, or an MRI, is a more recent brain imaging technique that is rapidly gaining widespread use for identifying brain disorders. This technique uses a magnetic field and radio waves, rather than x-rays. An MRI produces better pictures of structures or abnormal areas located near bone than a CT scan.
A third test that can expose problems in brain tissues is ultrasonography. This technique bounces sound waves off of the brain and uses the pattern of echoes to form a picture, or sonogram, of its structures. Ultrasonography can be used in infants before the bones of the skull harden and close. Although it is less precise than CT and MRI scanning, this technique can detect cysts and structures in the brain, is less expensive, and does not require long periods of immobility.
Finally, physicians may want to look for other conditions that are linked to cerebral palsy including seizure disorders, mental impairment, and vision or hearing problems.
When the doctor suspects a seizure disorder, an electroencephalogram, or EEG, may be ordered. An EEG uses special patches called electrodes that are placed on the scalp to record the electrical currents inside the brain. This recording can help the doctor see telltale patterns in the brain’s electrical activity that suggest a seizure disorder.
How many people have cerebral palsy?
It is estimated that some 764,000 children and adults in the United States manifest one or more of the symptoms of cerebral palsy. Currently, about 8,000 babies and infants are diagnosed with the condition every year. In addition, some 1,200 – 1,500 preschool age children each year are recognized to have CP.
Can it be prevented?
Yes. Measures of prevention are increasingly possible today. Pregnant women are tested routinely for the Rh factor and, if Rh negative, they can be immunized within 72 hours after the birth (or after the pregnancy terminates) and thereby prevent the adverse consequences of blood incompatibility in a subsequent pregnancy. If a woman has not been immunized, the consequences of blood incompatibility in the newborn can be prevented by exchange transfusion in the baby. If a newborn baby has jaundice, this can be treated with phototherapy (light therapy) in the hospital nursery. Immunization against measles for all women who have not had measles and are susceptible to becoming pregnant is an essential preventive measure. Other preventive programs are directed towards: the prevention of prematurity, reducing the exposure of pregnant women to viruses and other infections, recognition and treatment of bacterial infections of the maternal reproductive and urinary tracts, avoiding unnecessary exposure to x-rays, drugs, and medications, and the control of diabetes, anemia, and nutritional deficiencies. Of great importance is optimal well being prior to conception, adequate prenatal care, and protecting infants from accidents or injury.
Can cerebral palsy be treated?
“Management” is a better word than “treatment.” Management consists of helping the child achieve maximum potential growth and development. This should be started as early as possible with identification of the very young child who may have a developmental brain disorder. A management program can then be started promptly wherein programs, physicians, therapists, educators, nurses, social workers, and other professionals assist the family as well as the child. Certain medications, surgery, and braces may be used to improve nerve and muscle coordination and to prevent or minimize dysfunction.
As individuals mature, they may require support services such as: personal assistance services, continuing therapy, educational and vocational training, independent living services, counseling, transportation, recreational/leisure programs, and employment opportunities, which are all essential to the developing adult. People with cerebral palsy can go to school, have jobs, get married, raise families, and live in homes of their own. Most of all, people with cerebral palsy need the opportunity for independence and full inclusion in our society.
Is research being done on cerebral palsy?
Yes. Active national programs of research are being vigorously pursued to prevent cerebral palsy and improve the quality of life for persons with cerebral palsy. The four organizations with major research programs are: the United Cerebral Palsy Research and Educational Foundation in the private sector, and the National Institutes of Health, the Centers for Disease Control and Prevention, and the National Institute of Disability and Rehabilitation Research in the government sector. The research questions being addressed include:
- What are the factors that predispose the developing fetal brain to injury? Can these factors be eliminated or minimized?
- What are the causes of injury to the developing fetal brain? Can the developing fetal and newborn brain be protected? What are the causes of developmental delays and failure to thrive?
- Why is a low birth weight in the full-term and premature infant an important risk factor for cerebral palsy?
- Can cerebral palsy be diagnosed before birth and better diagnosed shortly after birth?
- Which available treatments are most effective for the specific disabilities of persons with cerebral palsy?
- Based on new knowledge now available in the medical, surgical, behavioral, and bioengineering sciences, what improvements can be made in the quality of life of people with cerebral palsy?
- What are the effects of aging on a person with disabilities due to cerebral palsy?
- Can the damaged brain be repaired?