Cerebral palsy

Cerebral palsy

Cerebral palsy refers to a group of conditions that affect movement, balance and posture. Affected children have abnormalities in one or more parts of the brain that affect the ability to control muscles. Symptoms range from mild to severe but do not get worse as the child gets older. With treatment, most children can significantly improve their abilities.Many children with cerebral palsy have other conditions that require treatment. These include intellectual disabilities, learning disabilities, seizures, abnormal physical sensations (difficulties with sense of touch), and problems with vision, hearing and speech.How common is cerebral palsy?
Cerebral palsy usually is diagnosed by 3 years of age. About 2 to 3 children in 1,000 are affected (1). About 800,000 children and adults of all ages in the United States have cerebral palsy (2).

What are the different types of cerebral palsy?
There are three major types of cerebral palsy. Some individuals may have symptoms of more than one type.

  • Spastic cerebral palsy: About 70 to 80 percent of affected individuals have the spastic type, in which muscles are stiff, making movement difficult (1). Spastic diplegia is a form of spastic cerebral palsy in which both legs are affected. Affected children may have difficulty walking because tight muscles in the hips and legs cause legs to turn inward and cross at the knees (called scissoring). In spastic hemiplegia, only one side of the body is affected, often with the arm more severely affected than the leg. Most severe is spastic quadriplegia, in which all four limbs, the trunk and face are affected. Children with spastic quadriplegia usually cannot walk. They often have intellectual disabilities, difficulty speaking and seizures.
  • Athetoid or dyskinetic cerebral palsy: About 10 to 20 percent of affected individuals have the athetoid form, which affects the entire body (1). It is characterized by fluctuations in muscle tone (varying from too tight to too loose) and sometimes is associated with uncontrolled movements (which can be slow and writhing or rapid and jerky). Affected children often have trouble learning to control their bodies well enough to sit and walk. Because muscles of the face and tongue can be affected, there also can be difficulties with sucking, swallowing and speech.
  • Ataxic cerebral palsy: About 5 to 10 percent of affected individuals have the ataxic form, which affects balance and coordination (1). They may walk with an unsteady gait with feet far apart. They have difficulty with motions that require precise coordination, such as writing.

What are the causes of cerebral palsy?
Cerebral palsy usually is caused by factors that disrupt normal development of the brain before birth. In some cases, genetic defects may contribute to brain malformations and “miswiring” of nerve cell connections in the brain, resulting in cerebral palsy (2). Other cases are caused by injuries to the developing brain, such as a fetal stroke. Contrary to common belief, few cases of cerebral palsy are caused by a lack of oxygen reaching the fetus during labor and delivery (2).

A small number of babies develop brain injuries in the first months or years of life that can result in cerebral palsy (2). These injuries may be caused by brain infection (such as meningitis) and head injuries. In many cases, the cause of cerebral palsy in a child is not known.

Certain risk factors make it more likely that a baby will develop cerebral palsy. However, most babies with one of these risk factors do not develop cerebral palsy. Risk factors for cerebral palsy include:

  • Prematurity: Premature babies (those born before 37 completed weeks of pregnancy) who weigh less than 3 1/3 pounds are between 20 and 80 times more likely to develop cerebral palsy than full-term babies (3). Many of these tiny babies suffer from bleeding in the brain, which can damage delicate brain tissue, or develop periventricular leukomalacia, destruction of nerves around the fluid-filled cavities (ventricles) in the brain.
  • Infections during pregnancy: Certain infections in the mother can cause brain damage and result in cerebral palsy. Examples of these infections include rubellacytomegalovirus (usually mild viral infection), herpes (viral infections that can cause genital sores), and toxoplasmosis (a usually mild parasitic infection). Maternal infections involving the placental membranes (chorioamnionitis) may contribute to cerebral palsy in full-term as well as premature babies (2). A 2003 study at the University of California at San Francisco found that full-term babies were 4 times more likely to develop cerebral palsy if they were exposed to chorioamnionitis in the womb (4).
  • Insufficient oxygen reaching the fetus: This may occur when the placenta is not functioning properly or it tears away from the wall of the uterus before delivery.
  • Asphyxia during labor and delivery: Until recently, it was widely believed that asphyxia (lack of oxygen) during a difficult delivery was the cause of most cases of cerebral palsy. Studies now show that birth complications, including asphyxia, contribute to only 5 to 10 percent of cases of cerebral palsy (2).
  • Severe jaundice: Jaundice, a yellowing of the skin and whites of the eyes, is caused by the build-up of a pigment called bilirubin in the blood. Mild cases of jaundice usually clear up without treatment and do not harm the baby. However, jaundice can occasionally become severe. Affected babies have high levels of bilirubin in the blood. Without treatment, high bilirubin levels can pose a risk of permanent brain damage, resulting in athetoid cerebral palsy. Certain blood diseases, such as Rh disease, can cause severe jaundice and brain damage, resulting in cerebral palsy. Rh disease is an incompatibility between the blood of the mother and her fetus. It usually can be prevented by giving an Rh-negative woman an injection of a blood product called Rh immune globulin around the 28th week of pregnancy and again after the birth of an Rh-positive baby.
  • Blood clotting disorders (thrombophilias): These disorders in either mother or baby may increase the risk of cerebral palsy.

What are some early signs of cerebral palsy?
Some children with cerebral palsy may have delays in learning to roll over, sit, crawl or walk. The Centers for Disease Control and Prevention (CDC) recommends that parents contact their child’s provider if they see any of the following signs (5):

A child more than 2 months old who:

  • Has difficulty controlling her head when picked up
  • Has stiff legs that cross or “scissor” when picked up

A child more than 6 months old who:

  • Reaches with only one hand while keeping the other in a fist

A child more than 10 months old who:

  • Crawls by pushing off with one hand and leg while dragging the opposite hand and leg

A child more than 12 months old who:

  • Cannot crawl
  • Cannot stand with support

How is cerebral palsy diagnosed?
Cerebral palsy is diagnosed mainly by evaluating how a baby or young child moves. The provider evaluates the child’s muscle tone; children with cerebral palsy may appear floppy or stiff. Some may have variable muscle tone (too loose at times and too tight at other times).

The provider checks the child’s reflexes and look to see if the baby has developed a preference for using his right or left hand. While most babies do not develop a hand preference (become right- or left-handed) until at least 12 months of age, some babies with cerebral palsy do so before 6 months of age.

Another important sign of cerebral palsy is the persistence of certain reflexes, called primitive reflexes. These reflexes are normal in younger infants but generally disappear by 6 to 12 months of age. The provider also takes a careful medical history and attempts to rule out any other disorders that could be causing the symptoms.

The provider may suggest brain imaging tests, such as magnetic resonance imaging (MRI), computed tomography (CT scan) or ultrasound. These tests sometimes can help identify the cause of cerebral palsy. Ultrasound often is recommended in premature babies who are considered at risk for cerebral palsy to help diagnose brain abnormalities that are frequently associated with cerebral palsy. In some children with cerebral palsy, especially those who are mildly affected, brain imaging tests show no abnormalities, suggesting that microscopically small areas of brain damage can cause symptoms.

About half of babies who are suspected to be at higher risk for cerebral palsy at 12 months of age appear to outgrow their symptoms by age 2 (6).

How is cerebral palsy treated?
A team of health care professionals works with the child and family to identify the child’s needs and create an individualized treatment plan to help the child reach his or her maximum potential. The team is generally coordinated by one health care professional and may include pediatricians, physical medicine and rehabilitation physicians, orthopedic surgeons, physical and occupational therapists, ophthalmologists (eye doctors), speech/language pathologists, social workers and psychologists.

The child usually begins physical therapy soon after diagnosis. Therapy improves motor skills (such as sitting and walking) and muscle strength and helps prevent contractures (shortening of muscles that limits joint movement). Sometimes braces, splints or casts are used along with physical therapy to help prevent contractures and to improve function of the hands or legs. If contractures are severe, surgery may be recommended to lengthen affected muscles.

Drugs sometimes are recommended to ease spasticity or to reduce abnormal movement. Unfortunately, oral drug treatment often is not very helpful. Sometimes injection of drugs, such as Botox (botulinum toxin), directly into spastic muscles is helpful. The effects may last several months.

A new type of drug treatment is showing promise in children with moderate to severe spasticity. During a surgical procedure, a pump is implanted under the skin that continuously delivers the anti-spasmodic drug baclofen.

For some children with spastic cerebral palsy, a surgical technique called selective dorsal rhizotomy may permanently reduce spasticity and improve the ability to sit, stand and walk. In this procedure, doctors identify and cut some of the nerve fibers at the base of the spine that are contributing most to spasticity. This procedure usually is recommended only for children with severe spasticity who have not responded well to other treatments (2).

Occupational therapists work with the child on skills required for daily living, including feeding and dressing. Children with speech problems work with a speech therapist or, in more severe cases, learn to use a computerized voice synthesizer that can speak for them. Computers have become an important tool for children and adults with cerebral palsy in terms of therapy, education, recreation and employment.

Some children with cerebral palsy may benefit from the many mechanical aids available today, including walkers, positioning devices (to allow a child with abnormal posture to stand correctly), customized wheelchairs, and specially adapted scooters and tricycles.

Can cerebral palsy be prevented?
In many cases, the cause of cerebral palsy is not known, so there is nothing that can be done to prevent it. However, some causes of cerebral palsy can be prevented by eliminating or managing certain risk factors.

Rh disease and congenital rubella syndrome used to be common causes of cerebral palsy. Now Rh disease usually can be prevented when an Rh-negative pregnant woman receives appropriate care. Women can be tested for immunity to rubella before pregnancy and vaccinated if they are not immune. A woman can help reduce her risk of preterm delivery when she seeks early (ideally starting with a preconception visit) and regular prenatal care and avoids cigarettes, alcohol and illicit drugs.

Babies with severe jaundice can be treated with special lights (phototherapy) and blood transfusions (exchange transfusions), when indicated. Head injuries in babies and young children often can be prevented when babies ride in car seats properly positioned in the back seat of the car and when children wear helmets when riding bicycles. Routine vaccination of babies (with the Hib vaccine) prevents many cases of meningitis, another cause of brain damage in the early months.

Is the March of Dimes conducting research on cerebral palsy?
The March of Dimes supports a number of grants on prenatal brain development and factors that may disrupt it.

One grantee is studying how developing nerve cells in the fetal brain respond to prolonged oxygen deprivation. This can improve understanding of how lack of oxygen before or around the time of birth can injure the developing brain and how such brain injuries can be prevented or treated.

Another grantee is investigating how intrauterine infections may contribute to brain injuries that result in cerebral palsy, with the goal of developing drug treatments to help prevent these injuries.

A grantee also is studying specific learning disabilities in young children with cerebral palsy in order to develop improved interventions.

Many other March of Dimes grantees are seeking improved ways of preventing preterm delivery, an important risk factor for cerebral palsy.

For further information
Cerebral Palsy, Centers for Disease Control and Prevention (CDC)

References

  1. Centers for Disease Control and Prevention (CDC). Cerebral Palsy. October 4, 2004, accessed September 14, 2007.
  2. National Institute of Neurological Disorders and Stroke. Cerebral Palsy: Hope Through Research. NIH Publication Number 06-159, updated 7/13/07.
  3. Platt, M., et al. Trends in Cerebral Palsy Among Infants of Very Low Birthweight (<1500 g) or Born Prematurely (<32 Weeks) in 16 European Centres: A Database Study. Lancet, volume 369, January 6, 2006, pages 43-50.
  4. Wu, Y.W., et al. Chorioamnionitis and Cerebral Palsy in Term and Near-Term Infants. Journal of the American Medical Association, volume 290, number 20, November 26, 2003, pages 2677-2684.
  5. Centers for Disease Control and Prevention (CDC). Learn the Signs, Act Early: Cerebral Palsy Fact Sheet. December 7, 2006.
  6. Pellegrino, Louis. Cerebral palsy, in Batshaw, M.L. (ed.), Children With Disabilities, Fifth Edition, Baltimore, MD, Paul H. Brooks Publishing Company, 2002, pages 433-466.

December 2007