Cerebral palsy is classified into three main types based on the kind of movement problem: spastic, dyskinetic, and ataxic. A fourth category, mixed cerebral palsy, applies when features of more than one type are present. Each type traces back to damage in a different part of the developing brain, and the specific area affected shapes how movement is disrupted. Overall, cerebral palsy occurs in roughly 1.6 per 1,000 live births in high-income countries.
Spastic Cerebral Palsy
Spastic cerebral palsy is the most common type, accounting for the majority of all cases. Its hallmark is stiff muscles and exaggerated reflexes. The underlying problem is damage to the motor cortex or the white matter pathways that carry signals from the brain to the muscles. Instead of smooth, controlled movement, the muscles resist stretching and can feel rigid or tight.
Children with spastic CP may walk on their toes, hold their arms close to their body, or have difficulty with fine motor tasks like gripping a pencil. The stiffness can range from mild (noticeable mainly during running or fast movements) to severe (limiting the ability to sit or stand without support). Muscle tone that is consistently too high can pull joints out of alignment over time, which is why many children with spastic CP work with physical therapists from an early age.
Dyskinetic Cerebral Palsy
Dyskinetic cerebral palsy is characterized by involuntary, uncontrolled, and recurring movements. Muscle tone fluctuates, sometimes too tight and sometimes too loose, often within the same minute. This type results from damage to the basal ganglia, a cluster of structures deep in the brain that help regulate voluntary movement. Brain imaging studies have consistently found lesions in the putamen, a key part of that region, in children with this diagnosis.
Dyskinetic CP breaks down further into two subtypes, though they frequently overlap in the same child. Dystonia involves sustained muscle contractions that force the body into twisting or repetitive postures. Choreoathetosis produces unpredictable, flowing movements of the hands, feet, or face that the child cannot suppress. These involuntary movements tend to intensify during stress or deliberate effort and often quiet down during sleep. Speaking and swallowing can be affected because the same fluctuating muscle control extends to the mouth and throat.
Ataxic Cerebral Palsy
Ataxic cerebral palsy is the least common type. It stems from damage to the cerebellum, the part of the brain that fine-tunes coordination, balance, and spatial awareness. Children with ataxic CP typically have low muscle tone rather than stiffness. Their movements appear shaky or imprecise, especially during tasks that require accuracy, like reaching for a cup or buttoning a shirt.
Walking tends to be unsteady, with a wider stance than usual (feet placed farther apart than hip width) to compensate for poor balance. Depth perception is often affected, making it harder to judge how far away objects are or how large they are. Quick, precise movements like writing may look tremor-like, and learning new motor skills generally takes longer.
Mixed Cerebral Palsy
When brain damage extends across more than one region, a child may show features of two or more types simultaneously. The most common combination is spastic and dyskinetic. In these cases, a child might have the stiff muscles and exaggerated reflexes of spastic CP alongside the involuntary movements of dyskinetic CP. Brain scans of children with mixed CP often reveal a combination of white matter and deeper cortical or subcortical lesions, reflecting the broader area of injury.
Mixed CP with spastic features carries a higher rate of certain complications. In one study, epilepsy occurred in about 34% of children with the mixed spastic-dyskinetic profile, compared to roughly 13% of those with purely dyskinetic CP. Microcephaly and cortical visual problems also appear more frequently in this group. Classification can be tricky because muscle spasms and dystonia sometimes look similar on examination, so clinicians use specialized scales and repeated observation to determine which movement pattern dominates.
Where the Body Is Affected
Separate from the type of movement problem, cerebral palsy is also described by which limbs are involved. These topographical labels apply most often to spastic CP but can describe any type:
- Hemiplegia: One arm and one leg on the same side of the body are affected. This is strongly linked to neonatal stroke or bleeding that damages one hemisphere of the brain.
- Diplegia: Both legs are affected more than the arms. The child may walk independently but with noticeable stiffness in the legs, while upper-body function remains relatively intact.
- Quadriplegia: All four limbs are involved, often with significant trunk and head control challenges. This pattern tends to result from more widespread brain injury, such as severe oxygen deprivation or brain malformations, and is associated with higher levels of functional limitation.
- Monoplegia: Only one limb is noticeably affected. This is rare and is generally considered a mild form of hemiplegia where one limb is far more impaired than the other.
What Causes Each Type
The type of cerebral palsy a child develops depends heavily on what caused the brain injury and where it occurred. Neonatal stroke, where a blood clot blocks flow to part of the brain, tends to affect one side and is strongly associated with unilateral spastic CP (hemiplegia). These children are often diagnosed earlier and generally have milder functional limitations because the damage is localized.
Oxygen deprivation around birth (hypoxic-ischemic encephalopathy) damages the deep gray matter, particularly the thalamus and basal ganglia. This pattern is more likely to produce dyskinetic CP and tends to result in greater overall motor impairment. Brain malformations present before birth also skew toward dyskinetic features and higher severity. Infections affecting the brain tend to produce bilateral spastic CP, meaning both sides of the body are involved.
Premature birth is a major risk factor across types, partly because the developing white matter around the brain’s ventricles is especially vulnerable in preterm infants. Damage to this tissue, called periventricular leukomalacia, is a common pathway to spastic diplegia.
How Severity Is Measured
The Gross Motor Function Classification System (GMFCS) is the standard tool for describing how cerebral palsy affects a child’s mobility in daily life. It uses five levels, and a child’s level tends to remain stable over time rather than shifting dramatically.
At Level I, a child walks without limitations and can handle stairs, curbs, and community distances independently, though running and jumping may be somewhat limited. Level II means walking is possible in most settings, but uneven terrain, long distances, or stairs without a railing pose challenges. Wheeled mobility may be used for longer outings. By Level III, walking indoors with a handheld device (like a walker) is typical, but a wheelchair is needed for community travel and longer distances. Stairs require assistance.
Level IV involves significant reliance on a wheelchair. Children at this level can sit with support and may walk very short distances with a device and help, but powered or manual wheelchair use is the primary means of getting around. At Level V, head and trunk control are substantially limited, and independent movement is only possible with a power wheelchair and extensive adaptations. All transfers require full assistance.
Common Associated Conditions
Cerebral palsy rarely affects movement alone. The same brain injury that disrupts motor control often impacts other systems. In a hospital-based study of 383 children with CP, 93% had some degree of visual impairment, about 30% had hearing problems, and nearly 89% showed cognitive impairment on developmental assessments. Epilepsy was present in 64% of the group.
The likelihood and severity of these associated conditions tend to increase with the extent of brain injury. A child with mild hemiplegia from a small stroke may have no cognitive or sensory issues at all, while a child with quadriplegic CP from widespread oxygen deprivation is far more likely to experience epilepsy, vision problems, and learning difficulties together.
Early Signs in Infants
Cerebral palsy is not always obvious at birth. The earliest clues tend to appear as missed or delayed motor milestones in the first year. Before six months, a baby who cannot hold up their head when lifted from lying down, who feels unusually stiff or floppy, or whose legs stiffen and cross when held upright may be showing early signs. Some infants constantly arch their back and neck when held, as if pushing away.
After six months, inability to roll over, difficulty bringing hands together or to the mouth, and reaching with only one hand while keeping the other fisted are notable red flags. By ten months, a child who cannot stand even while holding onto furniture, who crawls lopsidedly by dragging one side, or who scoots on their bottom instead of crawling on all fours warrants evaluation. These asymmetries and delays do not always mean cerebral palsy, but they are the patterns that prompt clinicians to look more closely at brain development and motor function.