The term cerebral palsy refers to a group of neuromuscular disorders that can be caused by brain injuries, or malformations of the brain that occur during fetal development. In general, cerebral palsy disorders impair a person’s control over movement.
What Is Cerebral Palsy Caused By?
Cerebral palsy can be caused by a number of different factors, or a combination of causes working together. Children can develop or sustain brain damage that leads to a cerebral palsy disorder before birth, during labor and delivery or years after birth.
Some children will be born with a cerebral palsy disorder due to a birth defect, or congenital malformation, that impeded the growth of their brain in the womb. Other kids sustain head trauma during labor or delivery, making severe birth injuries a possible cause of cerebral palsy. In still other cases, a child’s oxygen supply was interrupted at some point during pregnancy or childbirth, leading to the death of brain tissue and permanent damage.
Potential Causes Of Cerebral Palsy Disorders
While children can suffer brain damage at any age, most kids who develop cerebral palsy disorders will have sustained brain damage sometime during pregnancy, or shortly after birth.
White Matter Damage
The most common cause of cerebral palsy disorders is damage to what doctors call periventricular white matter – a type of brain tissue that communicates signals from the brain to the body’s muscles. Periventricular white matter surrounds the ventricles, channels that produce cerebrospinal fluid inside the brain.
Migration Of Brain Cells
During fetal development, brain cells don’t stay in the same place. The cells have to move, or migrate, from where they begin to their proper locations in the brain. Both genetic and environmental factors play a role in this process of neural migration, and can also impede it.
Birth Trauma & Birth Injuries
Even when a child’s brain development has proceeded normally during pregnancy, severe trauma at or around the time of birth can lead to the death of brain cells.
In some cases, this trauma takes the form of mechanical shocks to the head. Forceps, for example, are often used to assist in difficult deliveries, but can also seriously injure a child’s vulnerable brain. Birth asphyxia, or oxygen deprivation, is another potential contributor to the development of cerebral palsy, since brain cells cannot survive without oxygen.
To learn more about birth asphyxia and the forms of brain damage it can cause, click here.
Brain damage can also be triggered by abnormal surges in some brain chemicals, according to the National Institute of Neurological Disorders and Stroke. Researchers believe that epileptic seizures, breathing problems, circulation issues and internal bleeding inside the brain can all lead to dangerous increases in some chemicals, which themselves can kill off brain cells.
Glutamate, for example, is a necessary chemical that allows neurons to communicate with one another. But a sudden rise in glutamate, which scientists think can be caused by brain bleeding, overstimulates neurons, leading to their death.
Inadequate Myelination Of Nerve Fibers
Many nerve cells in the body are surrounded by a protective coating of myelin, a fatty substance that also improves the nerve’s ability to transmit electrical signals. In some children, though, these nerve cells are inadequately protected, often due to a genetic abnormality. That inhibits their ability to send stimulating impulses, including ones that would control body movements, and also leaves them open to damage.
Before birth, a fetus’ nervous system is still developing. The process of myelination, for example, only begins during the third trimester. Thus an unborn child’s nerve cells are exposed to injury until relatively late in fetal development. Some infections, after being passed from mother to child, can impair brain growth. Rubella and cytomegalovirus, which is closely related to the herpes virus, are examples of infections that have been linked to cerebral palsy disorders.
Bilirubin is a yellowish pigment found in bile, which is produced naturally as the liver breaks apart old blood cells. In many newborns, though, the liver is still too immature to filter bilirubin out properly.
Jaundice is a common result. As bilirubin builds up in the blood, an infant’s skin can begin to appear yellow. Usually, jaundice is a temporary condition and, in moderate to severe cases, effective treatments like light therapy can cure it altogether. But untreated, and particularly severe, cases of jaundice can lead to brain damage and cerebral palsy disorders.
In a related condition, called Rh incompatibility, a mother’s body creates immune system cells that mistakenly attack her growing child’s blood cells. This can lead to a specific type of jaundice which may cause brain damage.
In some cases, a child’s brain has already been made vulnerable to injury by a maternal health condition or genetic predisposition. But for serious damage to occur, an additional factor is required.
Sometimes, the basic pressures of labor and delivery are enough to cause significant brain damage. For other children, negligent healthcare plays a role, and a doctor’s mistaken diagnosis or excessive force during the childbirthing process can inflict severe trauma.
Spastic, Athetoid & Ataxic Cerebral Palsy
The effects of cerebral palsy are largely determined by which portion of a child’s brain has been damaged or failed to develop properly.
Researchers define three basic forms of cerebral palsy: spastic, athetoid and ataxic. While each of these disorders can result in very different symptoms, and come to affect a person’s life and abilities in different ways, most cerebral palsy disorders have an impact on:
- muscle control
- muscle tone (the ability of muscle to be taut or relaxed)
- reflex responses
- coordination and balance
“Palsy” is another word for medical conditions that cause a loss or impairment of a person’s muscle control.
How Common Is Cerebral Palsy?
Cerebral palsy is the most common cause of childhood disability in the United States, the United Cerebral Palsy Association reports. Government estimates suggest that around 764,000 kids and adults in America have at least one symptom of a cerebral palsy disorder.
In 2009, a Centers for Disease Control study found that around 3.3 out of every 1,000 children born in the US are affected by a cerebral palsy disorder. The condition is significantly more common in boys than girls.
When Does Cerebral Palsy Appear?
Cerebral palsy disorders are usually diagnosed fairly early. About 10,000 infants are diagnosed with some form of cerebral palsy every year, according to the United Cerebral Palsy Association. Less commonly, children of preschool age are diagnosed with the condition; between 1,200 and 1,500 annually.
Cerebral palsy is a chronic disorder, and currently, there is no cure for the brain damage, often sustained during fetal development, that causes it. Physical and occupational therapies, however, can help many people with cerebral palsy improve their muscle functioning. Early interventions are especially important.