Cerebral palsy is a name given to a group of different nervous system disorders that are present at birth or appear in the first 3 years of life. What these disorders have in common is that the underlying brain damage doesn't get worse over the years. They also all cause some degree of damage in the motor neurons of the brain, affecting coordination and muscle strength.
Overall, cerebral palsy affects somewhere between 1 in 500 and 1 in 1,000 newborns, though some of these are only mildly affected. The risk is highest in premature and underweight babies. The number of new cases of cerebral palsy has actually risen slightly in recent years, partly because better intensive care is keeping more premature babies alive but also because fertility treatments have led to a rise in twin and multiple births, which are more likely to result in a baby with cerebral palsy.
Other risk factors for the development of cerebral palsy include:
Although cerebral palsy is often considered a congenital (present at birth) syndrome, it can also develop after birth. A brain injury resulting from a brain infection (e.g., meningitis, encephalitis) or from a fall or accident is termed acquired cerebral palsy. On the other hand, congenital cerebral palsy is a result of something going wrong during fetal development or during the birth process itself. It used to be believed that lack of oxygen during delivery was the main cause, but researchers now think this only account for about 10% of cases.
A fetus develops from a single cell, which divides repeatedly to eventually become billions of cells. During the process, groups of cells become specialized to form all the different body tissues. Likewise, various types of nerve cells form and migrate to take up their proper places throughout the brain. This process is highly complex and, not surprisingly, errors sometimes occur that disturb the normal architecture of the brain.
Errors could occur as a result of the following:
We are only now beginning to understand some of the issues surrounding the development of the fetal brain. Hopefully, more research in this area will allow us to eventually explain the exact causes of cerebral palsy.
The signs of cerebral palsy are usually first noticed by the parents after the child is 6 months old. Likely first signs include:
There is no set pattern of symptoms in cerebral palsy because it's an umbrella term covering many symptoms. However, there are certain broad categories that distinguish the various motor (muscle) symptoms.
A great many people with cerebral palsy have mixtures of these forms. The most common mixture is spastic-athetoid cerebral palsy. In all types, the symptoms can be very mild or very severe. Some people's only challenge is shaky writing, while others are paralyzed from the neck down.
A wide range of other problems can go along with nerve and muscle symptoms in cerebral palsy. By far the most important is intellectual impairment. One-third of all people with cerebral palsy have severe intellectual impairment, with a mental age that will never advance beyond 3 or 4. Another one-third have mild intellectual impairment, and the remaining one-third are unaffected intellectually. But even with normal intelligence, the vision, hearing, and speech problems; social isolation; resentment; and depression that can accompany cerebral palsy can lead to learning disabilities unless the child is helped and encouraged every step of the way.
Strabismus is a common problem for people with cerebral palsy. This symptom is often described as crossed eyes. But in young children whose eyes aren't aligned, there's a tendency for the brain to completely ignore signals from one eye, leading to major deterioration of eyesight in that eye. Deafness, while not common, is more common in children with cerebral palsy than in the general population. Sometimes, the sense of touch is also deficient.
Bladder and bowel function are often impaired by the lack of proper nervous signals coming from the brain. This can lead to constipation or, most likely, urinary incontinence, which can take several forms. Bedwetting, a sudden release upon exercise or coughing, or a constant dribble are all possible. The same lack of nervous signals can make chewing and swallowing difficult.
Epilepsy is common in people with cerebral palsy. Seizures may be mild or severe.
The most common complication of cerebral palsy is muscle contracture, which generally occurs in children. As the bones grow, the muscles normally keep pace. In cerebral palsy, there's a tendency for sufferers not to use their weaker or less coordinated limbs, leading to muscle atrophy. This can prevent the muscle from growing with the bone, which can cause the joint to become permanently flexed and paralyzed. Once this happens, surgery is usually required to fix it.
Symptoms don't generally get worse over time, as the underlying disease isn't progressive. Atrophy, however, can worsen muscular symptoms and, in children, prevent proper growth. Weaker, less coordinated limbs often end up withered or undersized.
There's a lack of research on the effects of cerebral palsy in older adults. Some doctors believe that people with cerebral palsy may age faster after middle age, but for the moment there's no evidence one way or the other. Statistics on life expectancy for people with this disease are also lacking.
Despite these unknowns, cerebral palsy is certainly not considered a fatal condition.