Cerebral palsy (CP) is a group of neurological conditions caused by damage to or abnormal development of the brain before, during, or shortly after birth. It affects movement, muscle tone, and posture, and it is the most common motor disability in childhood. In the United States, about 1 in 345 children have been identified with CP. The average lifespan for someone with cerebral palsy is over 70 years, though severity varies widely from person to person.
What Happens in the Brain
CP results from injury or disruption to brain areas responsible for planning, executing, and coordinating movement. The regions most commonly affected are the cerebral cortex (which handles voluntary movement), the basal ganglia (which fine-tunes movement signals), and the cerebellum (which manages balance and coordination). Depending on which area is damaged and how extensively, a person can develop very different patterns of movement difficulty.
The damage itself is non-progressive, meaning it doesn’t get worse over time. However, its effects on the body can change as a person grows, and muscle and joint problems often evolve with age.
Types of Cerebral Palsy
CP is classified by the type of movement problem it causes. Some people have a mix of more than one type.
- Spastic CP is the most common form. Muscles are stiff, causing jerky or repeated movements. It can affect one side of the body (hemiplegia), mostly the legs (diplegia), or all four limbs (quadriplegia). Spastic quadriplegia is the most severe form and often involves difficulty walking and speaking.
- Dyskinetic CP causes slow, uncontrollable movements in the hands, feet, arms, or legs. Facial muscles and the tongue may also be overactive, sometimes causing drooling or involuntary facial expressions. People with this type often have trouble sitting upright or walking but typically do not have intellectual problems.
- Ataxic CP affects balance and depth perception. Walking is unsteady, and quick or precise movements like writing or buttoning a shirt are difficult.
- Mixed CP includes features of more than one type.
Causes and Risk Factors
Most CP is congenital, meaning the brain damage happens before or during birth. A smaller portion is acquired in the first months or years of life. In many cases, no single cause is identified, but several well-established risk factors increase the likelihood.
Before and During Birth
Premature birth is one of the strongest risk factors, particularly for babies born before 32 weeks. Low birthweight also raises risk: children born under about 5.5 pounds are more vulnerable, and those under roughly 3.3 pounds face even higher odds. Multiple births (twins, triplets) carry elevated risk, especially if one baby dies before or shortly after birth.
Infections during pregnancy, including chickenpox, rubella, and cytomegalovirus, have been linked to CP, as have infections of the placenta or fetal membranes. Complications during delivery that disrupt the baby’s oxygen supply, such as placental detachment or umbilical cord problems, can also cause the kind of brain injury that leads to CP. Severe, untreated jaundice in newborns can damage the brain in a specific pattern called kernicterus, which is a preventable cause of CP.
After Birth
Acquired CP can result from infections like meningitis or encephalitis in infancy, or from head injuries. Vaccination against common bacterial causes of meningitis is one practical way to reduce this risk.
Early Signs to Watch For
Developmental delays are the main early clue. A child who is slow to roll over, sit, crawl, or walk may warrant closer evaluation. Abnormal muscle tone is another signal: the child’s body may feel unusually floppy or unusually stiff. Parents sometimes notice that a child strongly favors one side of the body when reaching or crawling.
Before 6 months, a baby with CP may not be able to hold up their head when lifted from lying down, may feel stiff or limp, or may cross their legs stiffly when picked up. After 6 months, signs include being unable to roll over, difficulty bringing hands together, or reaching with only one hand while keeping the other in a fist. After 10 months, lopsided crawling, scooting on the buttocks instead of crawling on all fours, or inability to stand even while holding onto support are red flags.
Diagnosis typically happens within the first two years of life. Brain imaging, particularly MRI, provides detailed pictures of any structural damage. Clinicians also use standardized tools to assess how much a child’s motor function is affected.
How Severity Is Measured
The Gross Motor Function Classification System (GMFCS) is the most widely used scale. It has five levels:
- Level I: Walks without limitations
- Level II: Walks with some limitations but doesn’t need a mobility device
- Level III: Walks with a hand-held mobility device
- Level IV: Limited self-mobility, may use a powered wheelchair
- Level V: Transported in a manual wheelchair
A child’s GMFCS level tends to remain stable from age 5 through 18, which makes it a useful tool for planning long-term support and setting realistic goals for independence.
Treatment and Management
There is no cure for CP, but a combination of therapies can significantly improve function and quality of life. Treatment is tailored to the individual, since the condition varies so much from person to person.
Physical therapy is considered one of the most important parts of management. It focuses on building and maintaining muscle strength, balance, and movement skills, from sitting and walking to using a wheelchair effectively. Occupational therapy targets fine motor tasks and daily living skills, while speech therapy addresses communication and, in some cases, swallowing difficulties.
Medications can help relax stiff or overactive muscles and reduce abnormal movement. These may be taken by mouth, injected directly into affected muscles, or delivered through a pump implanted near the spinal cord. For some people with severe spasticity that hasn’t responded to other approaches, a surgical procedure called selective dorsal rhizotomy can reduce stiffness by cutting specific nerve fibers.
Living With CP as an Adult
CP is a lifelong condition, and its impact on the body shifts with age. More than half of young adults with CP experience some decline in gross motor function, and motor ability, hand function, and communication skills can all decrease further in middle age. GMFCS ratings often worsen by one level during adulthood, meaning someone who walked independently as a teenager may eventually need a mobility aid.
Adults with CP also develop chronic health conditions earlier and at higher rates than the general population. This includes type 2 diabetes, high blood pressure, heart disease, osteoarthritis, osteoporosis, lung conditions, and mental health disorders. These risks are worth being aware of even for adults in their 20s, since early onset is common in this population.
Effective adult care typically involves a team of providers, including physical and occupational therapists, speech therapists, social workers, and specialists in rehabilitation medicine, neurology, and orthopedics. Because the needs of adults with CP are so varied and change over time, ongoing, individualized care planning makes a real difference in maintaining independence and health across the lifespan.
Prevalence Trends
CP rates have been slowly declining in several high-income countries. Data from 20 European registries showed prevalence dropping from 1.90 to 1.77 per 1,000 live births between 1980 and 2003. Australia reported a similar downward trend between 1995 and 2009, along with a decrease in the proportion of children with moderate to severe disability. In the U.S., prevalence among 8-year-olds fell from 3.5 to 2.9 per 1,000 between 2006 and 2010. These declines likely reflect improvements in prenatal care, neonatal intensive care, and early intervention, though CP remains one of the most common childhood disabilities worldwide.