Cerebral palsy is a group of neurological conditions that affect how a person moves, maintains balance, and holds their posture. It happens when the developing brain is damaged or doesn’t develop as expected, most often before birth. This condition is the most common motor disability in childhood, affecting movement in ways that vary widely from one person to another.

What Is Cerebral Palsy?

Cerebral palsy, often shortened to CP, is not just one single condition. Instead, it refers to a group of disorders that all affect a person’s ability to control their muscles and coordinate their movements. The word “cerebral” refers to the brain, while “palsy” means weakness or problems with using the muscles. These disorders occur because something went wrong with brain development, or because the brain was injured during the time it was still developing.

The brain damage or abnormal development that causes CP is permanent. This means the condition lasts for a person’s entire life. However, it’s important to understand that CP does not get worse as time goes on. The brain damage itself stays the same, though the exact symptoms a person experiences may change over their lifetime as they grow and age. Some symptoms might become more noticeable, while others might improve with treatment and therapy.

People with CP face challenges mainly with movement and posture. However, many also have other related conditions. These can include problems with intellectual development, seizures, difficulties with vision or hearing, trouble speaking, changes in the spine such as scoliosis (a curved spine), and joint problems such as contractures (when muscles become permanently shortened and tight). Not everyone with CP will have all of these additional conditions, and the combination varies greatly from person to person.

How Common Is Cerebral Palsy?

Cerebral palsy is the most common motor disability diagnosed in children. In the United States, approximately one out of every 345 children has been diagnosed with CP. Each year, between 5,500 and 13,100 children are born with this condition in the U.S. alone. More than 500,000 people in the United States live with cerebral palsy, and research from 2019 showed that over 1 million adults in the country are living with CP. This number is expected to continue growing as people with cerebral palsy are living longer, fuller lives thanks to advances in medical care and technology.

Cerebral palsy affects boys slightly more often than girls. It also occurs more frequently in certain situations, such as when babies are born prematurely, are very small at birth, or are part of a multiple birth like twins or triplets.

What Are the Different Types of Cerebral Palsy?

Doctors classify cerebral palsy according to the main type of movement problem a person has. Depending on which areas of the brain are affected, one or more movement disorders can occur. There are four main types of CP.

Spastic cerebral palsy is the most common type, affecting about 75 to 80 percent of people with CP. In spastic CP, muscles are stiff and tight because of increased muscle tone (the amount of tension in muscles). This stiffness makes movements awkward and difficult. Spastic CP is further described by which parts of the body are most affected. Spastic diplegia mainly affects the legs, with the arms less affected or not affected at all. Tight hip and leg muscles can cause the legs to pull together, turn inward, and cross at the knees, which is sometimes called scissoring. This makes walking very difficult. Spastic hemiplegia affects only one side of the body, usually with the arm more affected than the leg. Spastic quadriplegia is the most severe form and affects all four limbs, the trunk, and the face. People with spastic quadriplegia often cannot walk and frequently have other developmental problems such as intellectual disabilities, seizures, or problems with vision, hearing, or speech.

Dyskinetic cerebral palsy involves problems controlling the movement of the hands, arms, feet, and legs, making it difficult to sit and walk. In this type, movements are uncontrollable and can be slow and writhing, or rapid and jerky. Sometimes the face and tongue are affected, making it hard to suck, swallow, and talk. Muscle tone in dyskinetic CP can change from too tight to too loose, not only from day to day but even during a single day.

Ataxic cerebral palsy causes problems with balance and coordination. People with this type might be unsteady when they walk. They might struggle with quick movements or movements that need a lot of control, like writing. They might also have difficulty controlling their hands or arms when reaching for something.

Mixed cerebral palsy means a person has symptoms of more than one type of CP. The most common combination is spastic-dyskinetic CP.

What Causes Cerebral Palsy?

Cerebral palsy is caused by abnormal brain development or damage to the developing brain. This damage disrupts the brain’s ability to control movement and maintain posture and balance. The specific areas of the brain involved in muscle movement may not develop as expected while the baby is still in the womb, or they may be injured before, during, or after birth.

The problems in brain development that lead to CP can include damage to the brain’s white matter (the part of the brain that helps transmit signals), interruption of brain growth caused by changes in genes, bleeding in the brain, or a lack of oxygen reaching the brain. In many cases, however, doctors cannot identify the exact cause of a child’s cerebral palsy. This can be frustrating for families who want answers, but it’s simply the reality that sometimes the cause remains unknown.

When CP is caused by abnormal development or damage that happens before birth, it is called congenital CP. Most cases of CP are congenital. The potential causes during pregnancy include poor brain development in the womb, infections or medical conditions in the pregnant parent, disruption of blood flow to the developing brain, genetic conditions, or exposure to toxins or drugs during pregnancy. Damage can also occur during delivery, such as from injury to the head or skull or complications related to premature delivery.

CP can also develop during or after birth. When CP happens more than 28 days after birth, it is called acquired CP. Causes of acquired CP can include brain damage in the first few months or years of life from infections such as meningitis (inflammation of the membranes around the brain) or encephalitis (inflammation of the brain itself), problems with blood flow to the brain from a stroke or abnormal blood vessels, or head injuries from accidents, falls, or child abuse.

What Are the Risk Factors for Cerebral Palsy?

Certain medical conditions or events during pregnancy and delivery can increase a baby’s risk of developing congenital cerebral palsy. Babies who are born too small or too early face a higher risk. Being born as part of a multiple birth, such as twins or triplets, also increases the risk. Babies conceived through in vitro fertilization or other assisted reproductive technologies may have a slightly higher risk as well.

Infections during pregnancy can increase the risk of CP. Health problems in the pregnant parent, such as thyroid disorders or seizures, are also risk factors. Severe newborn jaundice, which happens when a substance called bilirubin builds up in the baby’s blood and can damage the brain, is another risk factor. Having complications during birth, such as difficulties that deprive the baby of oxygen, can lead to brain damage. Rh incompatibility, a condition where the mother’s and baby’s blood types don’t match properly, can also increase risk if not managed. Exposure to toxic chemicals during pregnancy is another potential risk factor.

It’s important to understand that having one or more risk factors does not mean a baby will definitely develop CP. Many babies with these risk factors do not develop cerebral palsy, and some babies with no known risk factors do develop the condition.

What Are the Symptoms of Cerebral Palsy?

The symptoms of cerebral palsy can vary greatly. In some people, CP affects the whole body, while in others, symptoms might only affect one or two limbs or one side of the body. The hallmark symptom is problems with movement and posture, but other symptoms can appear as well.

Infants with CP frequently have developmental delays. They may be slower than other children to learn to roll over, sit, crawl, or walk. Babies might have decreased muscle tone, called hypotonia, which can make them seem “floppy.” As they get older, this can change to stiff or tight muscles. Some signs parents might notice include a baby who seems unusually fussy or irritable, or who doesn’t react much to people around them.

Children with CP often show a lack of muscle coordination when performing voluntary movements, a condition called ataxia. They may have stiff or tight muscles with exaggerated reflexes, known as spasticity. Weakness in one or more arms or legs is common. Many children develop an unusual walking style, or gait. This might include walking on their toes, walking with a crouched posture, or walking with a “scissored” gait where the legs cross. Some children have tremors or random involuntary movements, called dystonia.

Children with CP may have delays in reaching movement milestones, such as sitting up or taking first steps. They often have difficulty with precise movements, called fine motor skills, such as writing, buttoning a shirt, or picking up small objects. Problems with vision are common, including trouble with eye muscle balance where the eyes don’t focus on the same object. Hearing loss, speech and language challenges, and difficulty swallowing can also occur.

In addition to movement symptoms, people with cerebral palsy may have intellectual or learning difficulties, though not everyone with CP has these problems. Seizures and epilepsy are common associated conditions. Delays in growth and development may occur. Problems with the spine, such as scoliosis, and joint problems such as osteoarthritis (wearing down of the joints) can develop over time. Some people with CP experience incontinence, meaning difficulty controlling the bladder or bowels. People with CP are at higher risk for heart and lung disease and pneumonia.

How Can Cerebral Palsy Be Prevented?

Because many cases of cerebral palsy occur from unknown causes or from factors that cannot be controlled, prevention is not always possible. However, there are steps that can reduce the risk.

During pregnancy, maintaining good health is important. This includes managing any chronic health conditions such as thyroid problems or seizures. Pregnant women should avoid infections when possible, practice good hygiene, and follow their healthcare provider’s advice about vaccinations. Avoiding exposure to toxic substances, drugs, and alcohol during pregnancy is crucial. Getting proper prenatal care throughout pregnancy allows healthcare providers to monitor the baby’s development and address any problems early.

During delivery, good medical care is essential. Healthcare providers should monitor the baby for signs of distress and take action quickly if problems arise. In some situations, performing a cesarean section promptly can prevent brain damage from lack of oxygen or other complications. After birth, protecting babies from head injuries, treating severe jaundice quickly, and preventing or promptly treating infections can help reduce the risk of acquired CP.

How Does Cerebral Palsy Affect the Body?

The changes in normal bodily functions caused by cerebral palsy stem from the brain’s inability to properly control muscles and movement. The brain damage that causes CP disrupts the signals between the brain and the muscles. This means that even though the muscles themselves are not necessarily damaged, they don’t receive the right instructions from the brain.

In spastic cerebral palsy, the brain sends too many signals to the muscles, causing them to contract and stay tight. This increased muscle tone makes movement stiff and awkward. Over time, tight muscles can become shortened, leading to contractures where joints become stuck in uncomfortable positions. The bones may not grow properly if muscles are constantly pulling on them in abnormal ways. This can lead to problems such as hip dislocation, where the hip joint comes out of its socket, or scoliosis, where the spine curves abnormally.

In dyskinetic cerebral palsy, the brain sends the wrong signals or sends signals at the wrong times. This causes uncontrolled movements that the person cannot stop. Muscle tone fluctuates unpredictably, making it very difficult to control movements precisely.

In ataxic cerebral palsy, the part of the brain that controls balance and coordination is affected. This makes it hard to judge distances, control the speed of movements, or maintain steady posture.

The brain areas affected by CP may also control other functions. When areas involved in speech are damaged, a person may have trouble forming words or controlling the muscles needed for speaking. When areas involved in swallowing are affected, eating and drinking become difficult and dangerous because food or liquid can go into the lungs instead of the stomach. Vision problems occur when the parts of the brain that process visual information or control eye movements are damaged.

People with cerebral palsy often need more energy to do everyday activities because their movements are less efficient. This can lead to fatigue and can affect nutrition if eating itself is difficult and tiring. Poor nutrition combined with reduced mobility can lead to weak bones and other health problems.