Understanding Cerebral Palsy - Basic Information

Cerebral palsy (CP) is a broad term used to describe a group of chronic "palsies" — disorders that impair control of movement — due to damage to the developing brain. CP usually develops by age 2 or 3 and is a nonprogressive brain disorder, meaning the brain damage does not continue to worsen throughout life. However, the symptoms due to the brain damage often do change over time; sometimes getting better and sometimes getting worse. CP is one of the most common causes of chronic childhood disability. It affects between two and four of every 1,000 live births. The United Cerebral Palsy Association estimates that more than 500,000 Americans have CP.  

Between 35% and 50% of all children with CP will have an accompanying seizure disorder and some level of mental retardation. They also may have learning disabilities and vision, speech, hearing or language problems.  

Much remains unknown about the disorder's causes, but evidence supports theories that infections, birth injuries and poor oxygen supply to the brain before, during, and immediately after birth result in up to 15% of cases. Premature infants are particularly vulnerable. Severe illness (such as meningitis) during the first years of life, physical trauma and severe dehydration can cause brain injury and result in CP.

What Causes It?

Congenital CP is present at birth and accounts for 80% of cases. It may be caused by the following:

• Infections during pregnancy that may damage a fetus' developing nervous system. These include rubella (German measles), cytomegalovirus (a herpes-type virus) and toxoplasmosis (an infection caused by a parasite that can be carried in cat feces or inadequately cooked meat). Other infections in pregnant women that may go undetected are being recognized now as an important cause of developmental brain damage of the fetus.  
• Severe jaundice in the infant. Jaundice is caused by excessive bilirubin in the blood. Normally, bilirubin is filtered out by the liver.  But often, newborns' livers need a few days to start doing this effectively, so it's not uncommon for infants to have jaundice for a few days after birth. In most cases, phototherapy (light therapy) clears up jaundice, and there are no lasting health effects.  However, in rare cases, severe, untreated jaundice can damage brain cells.  
• Rh incompatibility between mother and infant. In this blood condition, the mother's body produces antibodies that destroy the fetus's blood cells. This, in turn, leads to a form of jaundice in the newborn and may cause brain damage.  
• The physical and metabolic trauma of being born. This can precipitate brain damage in a fetus whose health has been threatened during development.  
• Severe oxygen deprivation to the brain or significant trauma to the head during labor and delivery.

According to the National Institute of Neurological Disorders and Stroke (NINDS), up to 20% of children with CP acquire the disorder after birth. It results from brain damage in the first few months or years of life. CP often follows infections of the brain, such as bacterial meningitis or viral encephalitis, or it may be the result of a head injury.