Zellers

Cerebral palsy is a name given to a group of different nervous disorders that are present at birth or appear in the first three 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 one in 1,000 and one in 500 newborns, though some of these develop only very mild disabilities. The risk is highest in premature and underweight babies. Babies who weigh under 1.6 kg (3.5 lb) at birth are at 100 times the risk of normal-weight 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.

Although cerebral palsy is often a congenital (present at birth) syndrome, it's not genetically inherited. Rather, something goes wrong in the development of the fetus or during the birth process itself. It used to be believed that lack of oxygen during delivery was the main cause, but today researchers think that only accounts for about 10% of cases.

A fetus develops from a single cell, which divides repeatedly to eventually become billions of cells. At various times, some of those cells specialize to form all the different body tissues. 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 which disturb the normal architecture of the brain. We are only now beginning to understand the normal development of the fetal brain, and hopefully this will allow us to eventually explain goes wrong in the various types of cerebral palsy.

Risk factors that increase the likelihood of cerebral palsy include:

• premature/underweight delivery - the greatest single contributor to risk
• multiple births - may increase the chance of cerebral palsy by up to 10 times
• feet-first (breech) delivery
• any kind of complication or difficulty in pregnancy
• maternal bleeding or proteinuria (excess protein in the urine) after the sixth month of pregnancy
• maternal hyperthyroidism
• maternal mental retardation
• maternal epilepsy
• infection in the mother during pregnancy:
  • German measles (rubella) is probably the number one infectious cause of cerebral palsy.
  • Toxoplasmosis is another infection that can threaten fetal brain development.
• Rh incompatibility is an immune problem in which the mother generates antibodies that attack and destroy red blood cells in the fetus, interfering with oxygen supply to the child's organs. It rarely happens in first pregnancies.

Since all newborn babies lack the abilities that are sometimes impaired by cerebral palsy, it's usually impossible to diagnose the condition until the child starts missing developmental milestones, like crawling or grasping objects. However, by observing a newborn infant, it's sometimes possible to predict which babies are at higher risk of having cerebral palsy. Signs of increased risk include:

• abnormally small head or lower jaw
• hernia in the groin
• low Apgar score - this is a test carried out several times in the hours after delivery that assigns a score based on heart rate, reflexes, skin colour, and muscle tone
• low levels of the thyroid hormone thyroxine
• malformations of the spine
• seizures
• severe jaundice at birth or shortly after birth - while many babies are slightly jaundiced and yellow at birth (a sign of red blood cell destruction), severe jaundice can be a sign of Rh incompatibility and a risk factor for cerebral palsy

Having one or more of these risk factors in either the mother or the baby certainly doesn't guarantee that cerebral palsy will later appear, but doctors use these criteria to decide which babies' development should be most closely followed.

There may be dozens of different ways the fetal brain can be damaged that will result in cerebral palsy, but many of them appear to involve blood problems.

Rh incompatibility is one such problem. Fetuses themselves destroy a lot of red blood cells around delivery, as they begin to switch from fetal to adult hemoglobin (fetal hemoglobin may be thought of as the blood equivalent of baby teeth). The destroyed cells release bilirubin, the yellow pigment that causes jaundice when concentrations are too high. Excess bilirubin can cause brain damage in infants.

Delivery is also a high-risk time for stroke in the baby. The kind of strokes that sometimes affect newborns are not the typical ischemic type, when a blood clot obstructs blood flow to the brain, but the rarer hemorrhagic type, when a burst blood vessel leaks into the brain. These strokes are apparently caused by the stresses of delivery.

Among infants born at normal weight after nine-month pregnancies, those who develop cerebral palsy often have unusually high levels of various clotting agents in their blood. It may be that these children are suffering ischemic strokes, in which obstructions prevent oxygen-bearing blood from reaching brain tissue. This is an area of active research.

All these problems occur late in pregnancy, but it seems the bulk of developmental problems causing cerebral palsy occur earlier in fetal development.

About one in six people with cerebral palsy was born with good neurological health but suffered damage as a baby due to accident or infection. The main causes of postnatal (after birth) cerebral palsy are meningitis and brain trauma from falls or traffic accidents.

The signs of cerebral palsy are usually first noticed by the parents after the child is six months old. Likely first signs include:

• adopting unusual positions, excessive rigidity or floppiness, permanently bent joints
• crossed eyes
• failure to develop at a normal rate, not reaching milestones like sitting up, smiling, or walking
• muscle wasting, slow or uneven growth
• seizures
• unresponsiveness or apparent deafness

There is no set pattern of symptoms in cerebral palsy, because it's an umbrella term covering many symptoms.

There are certain broad categories that distinguish the various motor (muscle) symptoms.

• Spastic cerebral palsy is the most common symptom, affecting about three-quarters of sufferers. Muscles tend to be permanently contracted. This may be severe enough to bend the joint permanently or to cause paralysis. The spasticity may affect both legs, both arms, all four limbs, or one leg and one arm. Affected limbs may grow more slowly than healthy ones, producing unusually small feet, legs, and hands. People with spastic cerebral palsy who are able to walk often have a scissors gait, in which the knees almost touch and the feet cross inwards over an imaginary line drawn down the centre of the body.
• Athetoid cerebral palsy affects one in ten sufferers. It's characterized by slow, writhing movements, usually in the limbs, but it may also affect facial muscles including the tongue. This can lead to drooling, strange facial expressions, and an inability to form some words or sounds. Speech defects due to muscle disorders (dysarthria) should be distinguished from language difficulties due to mental retardation, a very different problem.
• Ataxic cerebral palsy affects fewer than one in ten sufferers. Poor coordination and depth perception makes people with ataxic cerebral palsy unsteady walkers, with a wide-based gait. They also have difficulty with quick and precise movements like writing. They may suffer from intention tremor, in which the arm or hand trembles when reaching for an object, and the trembling gets worse the closer the hand gets to the target.

A great many people with cerebral palsy have mixtures of these symptoms. The commonest mixture is spastic-athetoid cerebral palsy. In all types, the symptoms can be very mild or very severe. Some people's only handicap is shaky writing; 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 mental retardation. One-third of all cerebral palsy sufferers are severely retarded, with a mental age that will never advance beyond three or four. Another third suffer mild retardation, and the remainder are unaffected intellectually. But even with normal intelligence, the vision, hearing, and speech problems, social isolation, resentment, and depression that accompany the disease can lead to learning disabilities unless the child is helped and encouraged every step of the way.

Strabismus is a common problem. This symptom is often described as cross-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 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 constant dribble, or sudden release upon exercise or coughing 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 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 serious lack of research on the effects of cerebral palsy in older adults. Some doctors believe that these patients may deteriorate faster after middle age, but for the moment there's no evidence one way or the other, nor are there any statistics on life expectancy for people with this disease. It's certainly not considered a fatal condition.

A few babies are obviously disabled at birth, but most are brought in to the doctor by worried parents after three to 18 months. While there's no chemical or blood test for cerebral palsy, there are several clinical tests that help in diagnosis. Because so many children with cerebral palsy have some limbs that are far more effective than others, they are likely to develop a preference (left- or right-handedness) far earlier than healthy babies, who have no preference in their first year. If a baby always grabs an object with the right hand even when it's far closer to the left, this is a possible sign of cerebral palsy.

Babies have particular reflexes that they lose after a few months, but children with cerebral palsy hold onto these baby reflexes far longer. There are several tests for this. In the Moro reflex, for example, a baby will extend both arms if laid on his back with the feet elevated above the head. If a baby still does this much after six months, it's a sign of developmental delay that may signify cerebral palsy.

Sometimes, scans such as magnetic resonance imaging (MRI) and computed tomography (CT) can reveal abscesses or other physical damage in the brain. It's important to eliminate the possibility of progressive neurological disease. There are also intelligence, sight, and hearing tests to establish if other problems accompany cerebral palsy.

There's no cure for cerebral palsy, as the brain doesn't get a second chance to grow. The aim of treatment is to provide as normal a life as possible and to maximize independence in people whose mental capacities allow it.

The first goal is to minimize disability. Above all, this means preventing or repairing muscle contractures. These are less likely if you exercise the affected limb as much as possible. Physical therapy aims to prevent contractures and poor growth caused by atrophy. While there's a lack of studies to show that physical therapy works, most doctors agree that it's clear that exercising impaired limbs is the best way to keep them healthy and get the most out of them. Once contractures occur, surgery is usually necessary. The muscle can take months to heal properly from such an operation, so prevention is far better than cure. Botulinum toxin injections are sometimes given for severe contractures. The toxin paralyzes the muscle, allowing it to relax.

As a child approaches school age, therapy tends to concentrate more on improving communication and minimizing socially problematic symptoms like drooling. Every effort is made to place children of normal intelligence in regular schools. Much of the work of therapy is actually performed by the parents, once they've learned the techniques.

Seizures and spasticity can often be controlled with anti-seizure and muscle relaxant drugs, and most children with cerebral palsy will be on some form of medication. When symptoms can't be eliminated, their effects can be minimized with modern devices like computerized speaking aids and electric wheelchairs.

While it's unlikely that cerebral palsy can be eliminated completely, there are many steps women can take to help avoid this class of birth defects. Anything that increases risk of premature birth, such as tobacco, alcohol, and illegal drugs, will also increase the risk of cerebral palsy. Birth defects are more likely when the mother smokes and drinks during pregnancy.

Getting vaccinated against German measles (rubella) is one of the easiest steps a woman can take. It's too late for this once a woman is pregnant - she should get the shot now if she is considering having a child.

Any steps that reduce the risk of head injury in a baby or infant will also reduce the risk of cerebral palsy. A properly fitted child car seat is probably the most important measure parents can take in this regard. Meningitis can't always be prevented, but the risk can be reduced by taking a child to the doctor for any ear infection or severe headache with fever. A doctor should examine any infant below the age of 4 to 6 months that has a fever.