CEREBRAL PALSY

National Institute of Neurological Disorders and Stroke

Introduction

In the 1860s, an English surgeon named William Little wrote the first medical descriptions of a puzzling disorder that struck children in the first years of life, causing stiff, spastic muscles in their legs and, to a lesser degree, their arms. These children had difficulty grasping objects, crawling, and walking. They did not get better as they grew up nor did they become worse. Their condition, which was called Little's disease for many years, is now known as spastic diplegia. It is just one of several disorders that affect control of movement and are grouped together under the term cerebral palsy.

Because it seemed that many of these children were born following complicated deliveries, Little suggested their condition resulted from a lack of oxygen during birth. This oxygen shortage damaged sensitive brain tissues controlling movement, he proposed. But in 1897, the famous psychiatrist Sigmund Freud disagreed. Noting that children with cerebral palsy often had other problems such as mental retardation, visual disturbances, and seizures, Freud suggested that the disorder might sometimes have roots earlier in life, during the brain's development in the womb. "Difficult birth, in certain cases," he wrote, "is merely a symptom of deeper effects that influence the development of the fetus."

Despite Freud's observation, the belief that birth complications cause most cases of cerebral palsy was widespread among physicians, families, and even medical researchers until very recently. In the 1980s, however, scientists analyzed extensive data from a government study of more than 35,000 births and were surprised to discover that such complications account for only a fraction of cases -- probably less than 10 percent. In most cases of cerebral palsy, no cause could be found. These findings from the NINDS perinatal study have profoundly altered medical theories about cerebral palsy and have spurred today's researchers to explore alternative causes.

At the same time, biomedical research has also led to significant changes in understanding, diagnosing, and treating persons with cerebral palsy. Identification of infants with cerebral palsy very early in life gives youngsters the best opportunity for developing to their full capacity. Biomedical research has led to improved diagnostic techniques -- such as advanced brain imaging and modern gait analysis -- that are making this easier. Certain conditions known to cause cerebral palsy, such as rubella (German measles) and jaundice, can now be prevented or treated. Physical, psychological, and behavioral therapy that assist with such skills as movement and speech and foster social and emotional development can help children who have cerebral palsy to achieve and succeed. Medications, surgery, and braces can often improve nerve and muscle coordination, help treat associated medical problems, and either prevent or correct deformities.

Much of the research to improve medical understanding of cerebral palsy has been supported by the National Institute of Neurological Disorders and Stroke (NINDS), one of the federal government's National Institutes of Health. The NINDS is America's leading supporter of biomedical research into cerebral palsy and other neurological disorders. Through this publication, the NINDS hopes to help the more than 4,500 American babies and infants diagnosed each year, their families, and others concerned about cerebral palsy benefit from these research results.

What is Cerebral Palsy?

Cerebral palsy is an umbrella-like term used to describe a group of chronic disorders impairing control of movement that appear in the first few years of life and generally do not worsen over time. The term cerebral refers to the brain's two halves, or hemispheres, and palsy describes any disorder that impairs control of body movement. Thus, these disorders are not caused by problems in the muscles or nerves. Instead, faulty development or damage to motor areas in the brain disrupts the brain's ability to adequately control movement and posture.

Symptoms of cerebral palsy lie along a spectrum of varying severity. An individual with cerebral palsy may have difficulty with fine motor tasks, such as writing or cutting with scissors; experience trouble with maintaining balance and walking; or be affected by involuntary movements, such as uncontrollable writhing motion of the hands or drooling. The symptoms differ from one person to the next, and may even change over time in the individual. Some people with cerebral palsy are also affected by other medical disorders, including seizures or mental impairment. Contrary to common belief, however, cerebral palsy does not always cause profound handicap. While a child with severe cerebral palsy might be unable to walk and need extensive, lifelong care, a child with mild cerebral palsy might only be slightly awkward and require no special assistance. Cerebral palsy is not contagious nor is it usually inherited from one generation to the next. At this time, it cannot be cured, although scientific research continues to yield improved treatments and methods of prevention.

What are the different forms?

Spastic diplegia, the disorder first described by Dr. Little in the 1860s, is only one of several disorders called cerebral palsy. Today doctors classify cerebral palsy into four broad categories -- spastic, athetoid, ataxic, and mixed forms -- according to the type of movement disturbance.

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. The names given to these types combine a Latin description of affected limbs with the term plegia or paresis, meaning paralyzed or weak.

When both legs are affected by spasticity, they may turn in and cross at the knees. As these individuals walk, their legs move awkwardly and stiffly and nearly touch at the knees. This causes a characteristic walking rhythm, known as the scissors gait.

Individuals with spastic hemiparesis may also experience hemiparetic tremors, in which uncontrollable shaking affects the limbs on one side of the body. If these tremors are severe, they can seriously impair movement.

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 affects the sense of balance and depth perception. Affected persons often have poor coordination; walk unsteadily with a wide-based gait, placing their feet unusually far apart; and experience difficulty when attempting quick or precise movements, such as writing or buttoning a shirt. They may also have 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. The ataxic form affects an estimated 5 to 10 percent of cerebral palsy patients.

Mixed forms. It is common 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 causes Cerebral Palsy?

Cerebral palsy is not one disease with a single cause, like chicken pox or measles. It is a group of disorders that are related but probably have different causes. When physicians try to uncover the cause of cerebral palsy in an individual child, they look at the form of cerebral palsy, the mother's and child's medical history, and onset of the disorder.

About 10 to 20 percent of children who have cerebral palsy acquire the disorder after birth. Acquired cerebral palsy results from brain damage in the first few months or years of life and often follows brain infections, such as bacterial meningitis or viral encephalitis, or results from head injury -- most often from a motor vehicle accident, a fall, or child abuse.

Congenital cerebral palsy, on the other hand, is present at birth, although it may not be detected for several months. In most cases, the cause of congenital cerebral palsy is unknown. Thanks to research, however, scientists have pinpointed some specific events during pregnancy or around the time of birth that can damage motor centers in the developing brain. Some of these causes of congenital cerebral palsy include:

• Infections during pregnancy. German measles, or rubella, is caused by a virus that can infect pregnant women and, therefore, the fetus in the uterus, to cause damage to the developing nervous system. Other infections that can cause brain injury in the developing fetus include cytomegalovirus and toxoplasmosis.
• Jaundice in the infant. Bile pigments, compounds that are normally found in small amounts in the bloodstream, are produced when blood cells are destroyed. When many blood cells are destroyed in a short time, as in the condition called Rh incompatibility (see below), the yellow-colored pigments can build up and cause jaundice. Severe, untreated jaundice can damage brain cells.
• Rh incompatibility. In this blood condition, the mother's body produces immune cells called antibodies that destroy the fetus's blood cells, leading to a form of jaundice in the newborn.

Severe oxygen shortage in the brain or trauma to the head during labor and delivery. The newborn infant's blood is specially equipped to compensate for low levels of oxygen, and asphyxia (lack of oxygen caused by interruption in breathing or poor oxygen supply) is common in babies during the stresses of labor and delivery. But if asphyxia severely lowers the supply of oxygen to the infant's brain for lengthy periods, the child may develop brain damage called hypoxic-ischemic encephalopathy. A significant proportion of babies with this type of brain damage die, and others may develop cerebral palsy, which is then often accompanied by mental impairment and seizures.

In the past, physicians and scientists attributed most cases of cerebral palsy to asphyxia or other complications during birth if they could not identify another cause. However, extensive research by NINDS scientists and others has shown that very few babies who experience asphyxia during birth develop encephalopathy soon after birth. Research also shows that a large proportion of babies who experience asphyxia do not grow up to have cerebral palsy or other neurological disorders. Birth complications including asphyxia are now estimated to account for about 3 to 13 percent of congenital cerebral palsy cases.

Stroke. Bleeding in the brain has several causes -- including broken blood vessels in the brain, clogged blood vessels, or abnormal blood cells -- and is one form of stroke. Newborn respiratory distress, a breathing disorder that is particularly common in premature infants, is one cause. Although strokes are better known for their effects on older adults, they can also occur in the fetus during pregnancy or the newborn around the time of birth, damaging brain tissue and causing neurological problems. Ongoing research is testing potential treatments that may one day help prevent stroke in fetuses and newborns.

What are the early signs?

Early signs of cerebral palsy usually appear before 3 years 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 2 to 3 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.