Cerebral palsy (CP) is a group of movement disorders caused by damage to the developing brain, typically before or during birth. It affects roughly 1 in 345 children in the United States, making it the most common motor disability in childhood. The brain injury itself doesn’t get worse over time, but its effects on movement, posture, and muscle control are lifelong.
What Happens in the Brain
Cerebral palsy results from injury to the parts of the brain that control movement. This damage can happen anytime from early fetal development through age 3, though 85% to 90% of cases are linked to events before or during birth. The specific area of brain damage determines which muscles are affected and how severely.
One particularly vulnerable region is the white matter surrounding the brain’s fluid-filled cavities. In premature infants, the tiny blood vessels in this area are especially fragile and prone to damage when oxygen supply drops. When injury spreads beyond this zone, it can reach the nerve pathways that carry signals from the brain’s motor cortex down to the muscles, producing more widespread movement problems.
Causes and Risk Factors
No single event causes cerebral palsy in most cases. Instead, a combination of risk factors raises the likelihood of brain injury during development.
Premature birth is one of the strongest risk factors. Babies born before 37 weeks, and especially before 32 weeks, face a significantly higher chance of developing CP. Low birthweight plays a related role: children weighing less than 5 pounds 8 ounces at birth are at greater risk, and the risk climbs further for those under 3 pounds 5 ounces.
Infections during pregnancy can trigger inflammation that damages fetal brain tissue. Linked infections include chickenpox, rubella, cytomegalovirus, and bacterial infections of the placenta or fetal membranes. Birth complications that cut off oxygen, such as placental detachment, uterine rupture, or umbilical cord problems, can also cause the kind of brain injury that leads to CP. Twins and other multiple births carry higher risk, particularly if one baby dies before or shortly after birth. Severe untreated jaundice in newborns can lead to a condition called kernicterus, which damages brain areas involved in movement.
Types of Cerebral Palsy
Spastic CP is the most common type. It causes stiff, tight muscles that produce jerky or repetitive movements. Depending on which limbs are involved, it may primarily affect the legs (spastic diplegia), one side of the body (spastic hemiplegia), or all four limbs (spastic quadriplegia).
Dyskinetic CP involves slow, uncontrollable movements of the hands, feet, arms, or legs. The muscles of the face and tongue can also be overactive, sometimes causing drooling or involuntary facial expressions. Sitting upright and walking are often difficult.
Ataxic CP affects balance and depth perception. People with this type walk unsteadily and struggle with quick or precise movements like writing, buttoning a shirt, or reaching for objects.
Mixed CP combines features of more than one type. A child might have both stiff muscles and involuntary movements, for example.
Early Signs in Infants
Developmental delays are the main early clue. A child who is slow to roll over, sit, crawl, or walk may be showing signs of CP. Abnormal muscle tone is another red flag: the body may feel unusually floppy or unusually stiff.
Before 6 months, warning signs include an inability to hold the head up when lifted from lying down, legs that stiffen or cross when the baby is picked up, and a tendency to arch the back and neck as if pushing away. After 6 months, a baby who cannot roll over, cannot bring hands to mouth, or reaches with only one hand while keeping the other in a fist may need evaluation. After 10 months, signs include lopsided crawling (pushing with one side and dragging the other), scooting on the buttocks instead of crawling on all fours, and being unable to stand even while holding onto support.
How CP Is Diagnosed
Diagnosis begins with a careful look at the child’s motor skills, muscle tone, reflexes, and posture, combined with a detailed medical history from the parents. There is no single blood test for CP.
Brain imaging, most commonly an MRI, can reveal the specific areas of brain damage. A CT scan or EEG may also be ordered, along with genetic or metabolic testing to rule out other conditions that mimic cerebral palsy. Doctors classify the severity of motor impairment using a five-level scale called the Gross Motor Function Classification System (GMFCS). At Level I, a child can walk independently but may have trouble with advanced motor skills like running or jumping. At Level V, a child has very limited ability to move around, even with assistive devices.
Conditions That Often Accompany CP
Because cerebral palsy involves brain injury, it frequently comes with other challenges beyond movement. About half of people with CP have some degree of intellectual disability. Epilepsy occurs in 25% to 45% of cases. Hearing impairment affects 10% to 20%, and roughly 10% experience blindness. These associated conditions often have a bigger impact on daily life than the movement disorder itself, and they shape the kind of support a person needs.
Therapies and Daily Management
There is no cure for cerebral palsy, but a range of therapies can significantly improve function and quality of life. Most children with CP work with a team of specialists starting early in life.
Physical therapy targets strength, balance, and mobility. Sessions may include resistance training, treadmill walking, stretching, and aquatic exercises. Physical therapists also help families select and fit adaptive equipment like braces, walkers, or wheelchairs to support posture and movement.
Occupational therapy focuses on the fine motor skills needed for daily tasks. One well-studied technique, constraint-induced movement therapy, involves temporarily restraining the stronger hand to encourage the weaker one to develop. Therapists also work on hand-eye coordination, sensory processing, and the use of adaptive tools for eating and dressing.
Speech-language therapy helps with communication and, in many cases, with eating and swallowing. Therapists use play-based activities with pictures, books, and objects to build language skills. For children whose mouth muscles are affected, oral exercises including facial massage and tongue, lip, and jaw strengthening can improve both speech clarity and the ability to eat safely.
Managing Spasticity
For children whose tight muscles interfere with daily life, several medical options can help. Botulinum toxin injections are FDA-approved for children over age 2 and work by relaxing specific muscles for several months at a time. They’re useful when spasticity is concentrated in particular areas, like the calves or forearms.
When spasticity is more widespread, affecting multiple limbs, oral medications that relax muscles throughout the body may be prescribed. For children with the most severe forms who don’t respond well to other treatments, a small pump can be surgically placed under the skin of the abdomen. This pump delivers muscle-relaxing medication directly to the spinal fluid in tiny, continuous doses, which is far more effective than taking the same drug by mouth. The pump needs regular refills, so families must be able to return to the clinic on a set schedule.
Surgical Options
Selective dorsal rhizotomy (SDR) is a surgery that permanently reduces spasticity by cutting selected nerve fibers in the spinal cord. It is most effective for children with spastic diplegia, where stiffness mainly affects the legs. In these children, SDR can improve walking ability, balance, stamina, and posture while reducing pain from chronically tight muscles. For children with spastic quadriplegia, the goals are different: sitting more comfortably, using a toilet seat independently, or powering a wheelchair on their own.
Not every child with spastic CP is a candidate. A thorough screening process determines whether the surgery is likely to help, and children with diplegia tend to see better results than those with quadriplegia. Orthopedic surgery may also be recommended separately to correct bone deformities or release severely contracted muscles that have shortened over time.
Life Expectancy and Long-Term Outlook
The two factors that matter most for long-term health in cerebral palsy are the ability to walk and the ability to eat independently. Children who can walk on their own and feed themselves have life expectancies not dramatically shorter than the general population, and this holds true even into older age. People with more severe motor limitations, particularly those who cannot walk or who need help eating, face a shorter life expectancy, though even among this group there is evidence that longevity has been improving in recent decades.
Less significant but still relevant factors include hand function, cognitive ability, and whether the person has epilepsy. Because the brain injury behind CP doesn’t progress, many people find that the right combination of therapy, adaptive equipment, and medical management allows them to live active, fulfilling lives well into adulthood.