When you hear the words cerebral palsy (CP), you might think of someone who's physically disabled. If you've ever known someone with CP, he or she may have used a cane, braces, a walker or a wheelchair to get around. But in reality, there might be more people in your life with cerebral palsy -- you just don't know it because they're only mildly affected. They seem "normal" to you, but maybe you've noticed that they're very uncoordinated or walk on their toes sometimes. The image of a person in a wheelchair is just one of the many misconceptions surrounding the group of disorders known as cerebral palsy.
Cerebral palsy isn't a disease; it's an umbrella term for several different related conditions or disorders that cause problems with movement. The first part of the name "cerebral palsy" refers to the part of the brain originally thought to be affected: the cerebrum (although we now know that it affects other parts of the brain as well). "Palsy" refers to the involuntary shaking, stiffness, lack of feeling and paralysis in body parts. Cerebral palsy isn't contagious and it doesn't get worse over time, although some symptoms can lead to secondary conditions.
People with cerebral palsy have an injury to the brain that occurred during pregnancy, during childbirth or shortly after childbirth. Damage to the brain is irreversible, which is why cerebral palsy can be treated and managed but not cured. About 8,000 children are born with it every year, and there are currently more than 750,000 children and adults in the United States living with CP [source: United Cerebral Palsy].
Let's start by looking at the many potential causes of cerebral palsy.
Cerebral Palsy Causes
Cerebral palsy occurs when a child's brain is injured and permanently damaged. About 70 to 80 percent of the time, this damage happens sometime during pregnancy. Complications during childbirth account for 5 to 10 percent of all cerebral palsy cases, with the rest of the cases stemming from damage that occurred after birth up to age 2 or 3 [source: Wu]. There's no way of knowing exactly what caused a specific case, but researchers are aware of several conditions that impact the blood flow, and therefore the oxygen flow, to the baby's brain and cause the brain damage specific to CP. We'll start with looking at the cerebral palsy causes that happen during pregnancy.
Sometimes, cerebral palsy occurs when the baby's brain simply doesn't develop properly due to a genetic disorder or other problem in the womb. However, sometimes diseases, infections or other conditions carried by the mother are a factor. Mothers with conditions such as diabetes and epilepsy have a higher risk of having a baby with cerebral palsy. The same is true of mothers who acquire infections like rubella (German measles), toxoplasmosis (a parasite), kidney infections or herpes. Drinking alcohol, smoking and taking certain drugs during pregnancy can also cause the brain damage that leads to cerebral palsy.
There are also some conditions specific to pregnancy that can cause CP. Preeclampsia, a disorder that causes high blood pressure, can affect the blood flow in the umbilical cord and placenta and deprive the fetus of oxygen. The same is true for other placental conditions like abruptio placenta, when the placenta becomes detached from the uterine wall. Rh factor incompatibility, which happens when the mother's blood type is positive and the baby's is negative (or vice versa), can result in the baby being jaundiced upon birth. Babies with severe jaundice who don't receive proper treatment are susceptible to a specific type of brain damage called kernicterus.
Birth injuries account for some cases. If labor is prolonged and the baby gets "stuck" in the birth canal, or if there's an emergency C-section, babies are at a higher risk of experiencing a brain injury that can lead to cerebral palsy. The same holds true for breech births, prolapsed cords (when the umbilical cord goes below the baby in the birth canal) or the doctor's use of forceps during delivery.
About half of all children with cerebral palsy are born prematurely (at less than 37 weeks) and weigh less than 3.3 pounds (1,510 grams) at birth. Premature babies are susceptible to a host of complications and infections that can cause cerebral palsy. One of these is intraventricular hemorrhage (IVH), or bleeding in the brain. If the bleeding is severe enough to cause swelling, pressure on the brain can lead to damage. Premature babies can also have brain damage due to breathing problems -- which keeps enough oxygen from reaching the brain -- and poor blood circulation in general.
But it's not just babies in danger. Children can acquire cerebral palsy as older infants or toddlers due to:
- A physical head injury, such as hitting their head after falling off a bicycle
- Near drowning or choking on toys or food (which can cut off the brain's oxygen supply)
- The form of child abuse known as shaken baby syndrome
- Severe infections of the brain such as meningitis
Next, we'll look at the four major types of cerebral palsy.
Types of Cerebral Palsy
Generally, cerebral palsy is diagnosed by the time a child is 2 or 3 years old. Doctors perform a detailed physical examination and look for certain signs. For example, some children with cerebral palsy have very weak muscles, or very tight or stiff muscles. They may also have poor or exaggerated reflexes, poor posture and difficulty balancing. Children with CP may drag one leg when they crawl or walk, walk on their toes, or "scissor" their legs (cross them at the knee) when they walk or get picked up.
After the initial diagnosis, the doctor often suggests a brain imaging scan -- an MRI, CT scan or ultrasound. A brain scan might show the cause as well as the type and severity, but many children with mild cerebral palsy have normal brain scans because their area of brain damage is likely too small to be detected.
There are three basic types of cerebral palsy: spastic, athenoid/dyskenetic and ataxic. These types are differentiated by their symptoms, which often reflect the area of the brain that is damaged. Most -- about 70 to 80 percent -- of people with cerebral palsy have spastic cerebral palsy. This means that they have brain damage in the motor cortex or the corticospinal tract (the bundle of nerve fibers between the cerebral cortex and the spinal cord).
People with spastic CP have mobility issues due to their rigid muscles, which may also twitch involuntarily. There are three subtypes of spastic CP:
- Quadriplegia - all four limbs and the entire body are affected. Some children with this subtype also experience seizures and tremors, and they're often not able to walk or talk at all. This is the most severe form of CP, leaving many children intellectually disabled.
- Hemiplegia - one side of the body is affected. If it's the right side, that typically means that the brain is damaged on the left side. People with this type may require braces, and the limbs on their affected side may not grow at the same rate as the unaffected limbs. They are usually able to walk.
- Diplegia - the lower part of the body is affected, which can result in leg "scissoring" and toe walking. Many people with this subtype have crossed eyes and generally poor vision.
The second most common type of cerebral palsy is athetoid/dyskenetic. A person with athetosis has slow, writhing, involuntary movements, especially in the arms, while dyskinesia means that these movements can be repetitive, almost like a tic. People with this form of CP have varied muscle tone. Sometimes their muscles are stiff and rigid, and other times they are loose and floppy. Athetoid/dsykenetic CP results from damage to one or more of these areas of the brain: the basal ganglia, the corticospinal tract and the motor cortex. People with athenoid/dyskenetic CP may have difficulty walking, talking and eating, sitting upright, and performing basic motor skills.
Ataxic CP is the least common diagnosis (about 5 to 10 percent of all cases) and results from damage to the cerebellum. People with this type of CP have low muscle tone and difficulty coordinating their muscles to perform fine motor skills such as writing. They also usually have difficulty balancing while walking, and walk with their feet spread widely apart. A specific type of tremor known as an intention tremor is common with this type of CP. This means that a voluntary movement, such as reaching for an object, produces a tremor in the arm that gets worse as the hand gets closer to the object.
Some people with CP have symptoms of one or more of these three types and are said to have mixed CP.
There is no cure for cerebral palsy, but there are many different treatments and therapies to help manage the symptoms. We'll explore these next.
Cerebral Palsy Treatment
Once a doctor diagnoses a child with cerebral palsy, he or she discusses a course of treatment with the parents. Early intervention gives the child the best chance of learning how to manage his or her impairments and find alternate ways to perform tasks that may be challenging.
Even when children are diagnosed with CP as infants, they begin physical therapy as soon as possible to strengthen their muscles. Some people with CP suffer from muscle contractures, which occur when the muscles shorten due to spasticity. Stretching the muscles can keep this from happening. It also gives children a better chance of sitting, walking and performing other physical tasks as efficiently as possible. Many people with CP also receive massages and learn yoga positions to help stretch their muscles and keep them flexible.
Other therapy can also be helpful, depending on the child's particular type of CP. For example, children with athetoid/dyskenetic CP often have trouble breathing, speaking and eating, so working with a speech/language pathologist can help them to strengthen their facial muscles and speak clearly. Some children with CP use alternate methods of communication, such as Blissymbols, a symbolic writing system, or computerized voice synthesizers. Occupational therapy can help children with basic skills like bathing and feeding themselves.
There are some drugs that people with CP can take to decrease their spasticity and limit their tremors, such as the muscle relaxer Benzodiazepine, but they aren't always effective and may have unwanted side effects. Recently, doctors have begun injecting Botox into tight muscles to relax them. Some children with severely spastic CP have pumps surgically implanted in their abdomens as young adults, which continuously deliver a stream of an antispasmodic drug called Baclofen.
Children with spastic cerebral palsy sometimes have surgery to loosen tight muscles and joints. Over time, spastic muscles can also cause bone deformities, which require surgery to fix. For example, sometimes the tibia, or shin bone, becomes permanently twisted, which can lead to further difficulties in walking. A surgeon can cut the bone and realign it. Some people with severe spasticity end up having surgery that involves identifying and cutting nerve fibers, called selective dorsal rhizotomy, which can improve their mobility. It's usually a last resort.
There are also alternative therapies available for people with CP. Biofeedback involves recording the body functions of a patient, including muscle tension, and conveying this information to the patient. The idea is that they can control some of these unconscious functions once they are made aware of them, but its effectiveness hasn't been proven in CP patients.
Cord blood therapy has been touted as a possible cure for cerebral palsy, but there haven't yet been scientific trials to prove its effectiveness. The possibility got a boost, however, when the family of a 2-year-old child named Dallas Huxtell appeared on the Today Show in March 2008. They claimed that treating Dallas with his own stem cells has caused a reversal of his cerebral palsy symptoms. Prior to his treatment, Dallas had very poor muscle tone and motor skills and was behind in his development. Now his doctors state that he may have no symptoms of CP at all by the time he is 7 years old. This is just one case, but it has given new hope to people with CP.
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