Ataxic cerebral palsy is the rarest form of cerebral palsy, caused by damage to the cerebellum, the part of the brain that controls coordination, balance, and movement timing. It accounts for roughly 4% of all cerebral palsy cases in Europe, about 5% in Australia, and 2% in Canada. Unlike the more common spastic type, which causes stiff muscles, ataxic CP primarily affects a person’s ability to coordinate movements smoothly and maintain balance.
What Causes It
The cerebellum sits at the back of the brain and acts as the body’s coordination center. It fine-tunes the timing and precision of every movement, from reaching for a cup to walking in a straight line. When this region is damaged or doesn’t develop properly before, during, or shortly after birth, the result is ataxic cerebral palsy. The brain injury itself is a one-time event and does not get worse over time, though its effects on the body can evolve as a child grows.
Several things can injure the cerebellum during these critical windows:
- Stroke before or during birth: either a loss of blood flow (ischemic stroke) or bleeding in the brain (hemorrhagic stroke)
- Infection: an infection during pregnancy that reaches the baby or placenta can damage developing brain tissue
- Traumatic brain injury: physical trauma to the brain around the time of birth
- Genetic variants: some cases are linked to gene mutations, though research into which specific genes are involved is still developing
Certain pregnancy and birth factors raise the risk. Premature birth, low birth weight, carrying multiples (twins or triplets), complications like placental abruption or uterine rupture, and severe untreated jaundice after birth all increase the likelihood of the type of brain injury that leads to cerebral palsy.
How It Affects Movement and Balance
The hallmark of ataxic CP is unsteady, poorly coordinated movement. Because the cerebellum can no longer fine-tune motor commands, every action that requires precision becomes more difficult. Walking tends to have a wide-based, unsteady quality, with feet placed far apart to compensate for poor balance. It can look similar to the way someone walks on an unsteady boat.
Children and adults with ataxic CP often experience intention tremors, meaning their hands shake more as they try to reach for something specific rather than when at rest. This makes tasks like writing, buttoning a shirt, or using utensils particularly challenging. Many also have low muscle tone (hypotonia), which means their muscles feel floppy rather than stiff. This combination of shaky, imprecise movements and loose muscle tone distinguishes ataxic CP from the stiffness seen in spastic forms.
Depth perception and spatial awareness can also be affected, making it harder to judge distances when reaching or stepping.
Beyond Movement: Speech and Cognition
The cerebellum does more than coordinate physical movement. It also plays a significant role in language production and processing. Children with ataxic CP are roughly four times more likely to have a communication impairment compared to children with other CP subtypes. Speech may sound slow, irregular in rhythm, or slurred, sometimes described clinically as “scanning speech,” where words come out in choppy, uneven bursts.
Intellectual disability is also more common in this group. About 51% of children with ataxic CP have an intellectual disability, compared to around 38% of children with other CP subtypes. After adjusting for differences in physical function, children with ataxic CP are still more than three times as likely to have an intellectual disability as children with the dyskinetic form. That said, the other half of children with ataxic CP do not have intellectual disability, so the range of cognitive ability varies widely from person to person. Rates of epilepsy and chronic pain are similar to those seen in other forms of CP.
How It’s Diagnosed
Diagnosis typically involves a combination of clinical observation and brain imaging. Doctors look for the characteristic signs: unsteady gait, poor coordination on reaching tasks, low muscle tone, and tremors that worsen with intentional movement. An MRI scan can reveal whether the cerebellum shows structural abnormalities or evidence of past injury. In some cases, genetic testing may be recommended to look for underlying mutations, especially when imaging doesn’t show a clear cause.
Because ataxic CP is so uncommon (just under 4% of all CP cases across European registries, with rates varying from 0% to nearly 13% between individual centers), it can sometimes take longer to identify than more common subtypes. Some children are initially described as having general low muscle tone before the coordination problems become more apparent with age.
Physical Therapy and Coordination Training
There is no cure for ataxic CP, but physical therapy is the cornerstone of management. The goals are practical: improve balance, strengthen the core muscles that support posture, and practice the specific movements a person needs for daily life. Therapy typically includes exercises to strengthen the muscles of the trunk, shoulders, and pelvis, since proximal stability (a solid, controlled center of the body) is the foundation for steadier arm and leg movements. Task-specific training, where a child practices real activities like walking, reaching, or grasping, helps the brain develop the best possible workarounds for damaged coordination pathways.
Balance training takes many forms. Therapists may challenge a child’s postural control in different positions while reducing visual information (for example, performing head movements with eyes closed) to force the balance system to rely more on internal body-position signals. Stretching and gait training, sometimes using walking aids, are also standard components.
Video games and computer-assisted training have shown promise as engaging ways to build coordination. Systems like the Nintendo Wii with a balance board or Xbox Kinect have been used in studies to deliver coordination and balance exercises in a format that keeps children motivated. Computerized tracking tasks can also help improve hand dexterity over time.
Assistive Devices for Daily Life
For people whose tremors and coordination difficulties interfere with everyday tasks, assistive tools can make a real difference. Weighted vests have been used to improve balance during standing and walking. By placing small amounts of weight strategically on the torso, some individuals show less sway during standing, improved body alignment, and steadier walking. In one documented case, a patient fitted with a lightweight vest containing about 1.5 pounds of additional weight placed at the front of the torso demonstrated immediate improvements in stability, and later sessions showed carryover improvements even without the vest on.
Adaptive utensils with built-up handles, weighted pens, and non-slip mats can help compensate for hand tremors during meals and schoolwork. Orthotics and walking aids may also be recommended depending on the severity of balance difficulties.
Long-Term Outlook
The brain injury behind ataxic CP does not progress, but that doesn’t mean the condition stays exactly the same throughout life. Most people with cerebral palsy have a typical life expectancy. However, without ongoing physical activity and rehabilitation, functional abilities tend to decline over time. Across all CP types, roughly 50% of individuals report a decrease in daily functional activities by their 40s. This is not because the brain injury worsens, but because secondary complications build up: joints stiffen, muscles weaken from less use, and fatigue increases.
Staying physically active and continuing some form of therapy or structured exercise into adulthood is one of the most effective ways to maintain mobility and independence. Many children with ataxic CP walk independently or with minimal support, and with consistent therapy, improvements in coordination and balance can continue well beyond childhood.