Athetoid cerebral palsy is a form of cerebral palsy defined by involuntary, uncontrollable movements that interfere with posture, coordination, and voluntary motor control. It falls under the broader category of dyskinetic cerebral palsy and accounts for a relatively small share of all CP cases, yet it presents some of the most distinctive challenges in daily life, from speech to fine motor tasks. The underlying damage sits in a specific part of the brain, and the causes, treatments, and long-term outlook differ meaningfully from the more common spastic type.
What the Movements Actually Look Like
The hallmark of athetoid CP is movement that the person does not intend. These involuntary movements can take several forms, and most people with the condition experience more than one type. Athetosis itself refers to slow, writhing, twisting motions, often most visible in the hands, arms, and face. Dystonia produces sustained muscle contractions that force the body into abnormal postures. Chorea shows up as quick, jerky movements that look almost random. When chorea and athetosis overlap, clinicians call it choreoathetosis.1ABC Law Centers. Introduction to Athetoid/Dyskinetic Cerebral Palsy
These movements tend to increase during stress, excitement, or attempts at purposeful action, and they often lessen during sleep. That pattern can be confusing for people unfamiliar with the condition, because a person who appears calm at rest may suddenly struggle to hold a cup or sign their name. The fluctuating nature of the movements is not a sign of inconsistency or exaggeration; it reflects how the brain’s damaged motor circuits respond differently depending on arousal and intent.
Where the Damage Is in the Brain
Athetoid CP traces to injury in a cluster of deep brain structures collectively known as the basal ganglia. These structures normally act as a gatekeeper for movement, filtering and refining motor signals so that your muscles do what you intend and nothing more. When they are damaged, that filtering breaks down, and involuntary movements leak through.
Imaging studies have mapped the damage in detail. A review pooling data from multiple studies found that the putamen, one of the central basal ganglia nuclei, was damaged in about 69% of people with dyskinetic CP. The subthalamic nucleus was affected in roughly two-thirds of cases, and the thalamus, which relays motor signals to the cortex, showed damage in about 62%.2PubMed. Localization of Basal Ganglia and Thalamic Damage in Dyskinetic Cerebral Palsy A separate study using MRI found that about half of patients with dyskinetic CP had visible lesions in both the putamen and thalamus.3PubMed Central. Neuroradiological and neurophysiological characteristics of patients with dyskinetic cerebral palsy
Diffusion-based brain imaging has added another layer. Compared to both healthy controls and people with spastic CP, those with athetoid CP show significantly more widespread disruption of both deep gray matter and white matter tracts.4PubMed. Athetotic and spastic cerebral palsy: anatomic characterization based on diffusion-tensor imaging This helps explain why athetoid CP often affects the whole body rather than just the legs or one side, as happens more commonly in spastic forms.
What Causes It
The two main culprits are oxygen deprivation around birth and severe newborn jaundice. Both can target the basal ganglia selectively, because those structures are among the most metabolically active regions in the developing brain and therefore among the most vulnerable when something goes wrong.
Acute, profound oxygen deprivation during labor and delivery can cause a pattern of injury that preferentially hits the basal ganglia and thalamus while sometimes sparing the cortex.5PubMed Central. Anatomic localization of dyskinesia in children with “profound” perinatal hypoxic-ischemic injury A case study using metabolic brain imaging showed that right after a hypoxic birth injury, the basal ganglia were abnormally overactive, but by age four they had shifted to severe underactivity, reflecting permanent tissue loss.6PubMed. Transient hypermetabolism of the basal ganglia following perinatal hypoxia
Severe jaundice, or hyperbilirubinemia, works through a different mechanism but hits the same targets. When bilirubin levels climb high enough in a newborn, the pigment crosses into the brain and is toxic to basal ganglia neurons. This condition, historically called kernicterus, was once a leading cause of athetoid CP. It is now far less common in countries with routine newborn screening and phototherapy, but it still occurs, especially where those services are limited.7PubMed Central. Movement disorders due to bilirubin toxicity
A Dramatic Historical Shift
The decline of kernicterus-related athetoid CP is one of the most striking success stories in pediatric neurology. In the mid-20th century, a large share of CP cases were athetoid. A historical review found that athetoid CP dropped from about 38% of all cerebral palsy to roughly 3%, driven almost entirely by the elimination of erythroblastosis fetalis (Rh disease) as a cause of severe jaundice.8PubMed. Etiological factors in cerebral palsy: an historical review The introduction of Rh immunoglobulin in the late 1960s, combined with better phototherapy and exchange transfusion protocols, effectively wiped out the most common pathway to bilirubin-induced brain damage. As a result, the athetoid subtype went from being one of the most common forms of CP to one of the rarest in high-income countries.
How It Affects Speech
Speech difficulties are among the most functionally limiting aspects of athetoid CP. The same involuntary movements that affect the limbs also affect the muscles of the jaw, tongue, lips, and soft palate. The resulting speech pattern, known as dysarthria, tends to be variable and hard to predict from one moment to the next.
Detailed studies of speech in athetoid CP have identified several specific problems. The jaw often moves through an excessively large range during speech. The tongue has trouble reaching the right positions for different sounds, especially in the front-to-back dimension. The soft palate, which normally seals off the nasal passages during speech, opens and closes inconsistently, giving the voice an unpredictable nasal quality. And transitions between speech sounds take longer than usual.9Journal of Speech and Hearing Disorders. Articulatory Abnormalities in Athetoid Cerebral Palsy
One question researchers have explored is whether the speech problems come mainly from random involuntary bursts or from abnormal voluntary patterns. Muscle-activity recordings during speech suggest that it is actually the voluntary motor pattern itself that is abnormal, not just the involuntary interruptions layered on top. Involuntary bursts tend to appear between syllables rather than during them, but the underlying voluntary speech movements are consistently distorted.10PubMed. Reproducibility and variability of speech muscle activity in athetoid dysarthria of cerebral palsy Acoustic analysis confirms that voice pitch is less stable, with frequent pitch breaks and reduced ability to sustain a steady tone.11Annals of Rehabilitation Medicine. A Study on Acoustic Characteristics of Dysarthria in Athetoid Cerebral Palsy
For many people with athetoid CP, augmentative and alternative communication (AAC) devices become essential tools. Because fine motor control is also impaired, standard keyboards and touchscreens may not work well. Research has tested several alternative computer-access methods for people with severe athetoid CP, including camera-based head tracking, head-mounted mouse emulators, scanning interfaces, and eye-tracking systems. Individual comfort and accuracy varied across devices, underlining why a personalized evaluation matters rather than a one-size-fits-all recommendation.12PubMed. Evaluation of computer-access solutions for students with quadriplegic athetoid cerebral palsy
Other Common Associated Features
Drooling is a frequent concern, especially in children. It results not from overproduction of saliva but from poor coordination of the swallowing muscles and reduced lip closure. Surgical approaches exist: one procedure targeting sympathetic nerves near the cervical spine showed short-term improvement in drooling severity in most children who received it, but the benefit gradually faded over the following months.13European Journal of Paediatric Neurology. Evaluation of the efficacy of cervical perivascular sympathectomy on drooling in children with athetoid cerebral palsy That pattern of diminishing returns is common with drooling interventions across the board.
Hearing loss is a particular concern when the athetoid CP stems from bilirubin toxicity. The classic kernicterus syndrome includes sensorineural hearing loss, impaired upward gaze, and dental enamel problems in addition to the movement disorder.14PubMed. Birth-related syndromes of athetosis and kernicterus The hearing loss can be especially tricky because it primarily affects the auditory nerve pathway rather than the inner ear itself, which means standard hearing aids may not be enough and cochlear implants or auditory brainstem implants may need to be considered.
Cognitive Ability Is Often Underestimated
A persistent misconception about athetoid CP is that it is always accompanied by severe intellectual disability. In reality, cognitive ability varies widely across individuals with the condition, and the involuntary movements themselves can mask a person’s true intellectual capacity. When someone struggles to speak, point, or write, it is easy for observers to assume cognitive impairment that may not exist.
That said, intellectual disability does occur in a significant number of cases. One clinical series of 13 patients with athetoid CP found that 11 had intellectual disability while 2 had borderline IQ scores.15Paediatrica Indonesiana. Association between type of cerebral palsy and the cognitive levels But this was a small clinical sample, and selection bias likely skewed it toward more severely affected individuals. When bilirubin toxicity is the cause, cognitive function is sometimes relatively preserved compared to motor function, because bilirubin preferentially damages the basal ganglia while sparing the cortex. The bottom line is that assumptions based on outward motor impairment are unreliable, and formal cognitive testing using adapted methods remains important.
Getting to a Diagnosis
CP in general is most reliably diagnosed by age two, though earlier identification is increasingly possible using a combination of clinical history, standardized neuromotor assessments, and brain imaging.16PubMed. Cerebral palsy in children: A clinical practice review For the athetoid subtype specifically, the involuntary movements that define it may not become clearly apparent until the child is a year old or older, because young infants have limited voluntary movement for the involuntary patterns to disrupt.
An important diagnostic consideration is ruling out metabolic and genetic conditions that can mimic CP. In populations with high rates of consanguinity, certain inherited metabolic disorders present with dyskinesia and spasticity that look very much like CP at a young age. A key difference is that these conditions are progressive, meaning they worsen over time, while true CP, by definition, results from a one-time brain injury and does not get worse at the neurological level (even though secondary physical complications can develop).17PubMed Central. Metabolic and genetic disorders mimicking cerebral palsy Any child with a CP-like presentation and no clear history of brain injury should be screened for treatable metabolic conditions.
Treatment Options
Treating athetoid CP is harder than treating spastic CP, and the evidence base is thinner. The stiffness of spastic CP responds reasonably well to muscle relaxants, botulinum toxin, and orthopedic procedures, but the fluctuating, involuntary quality of dyskinetic movements resists these approaches. There is no single drug that reliably controls athetosis.
A systematic review of oral medications for dyskinetic CP found contradictory results across studies. The two most studied drugs, trihexyphenidyl (an anticholinergic) and levodopa, showed mixed outcomes, with some patients improving and others showing no benefit or experiencing side effects.18PubMed. Efficacy of oral pharmacological treatments in dyskinetic cerebral palsy: a systematic review In practice, medication trials tend to be individual and empirical: clinicians try a drug for a defined period, measure whether it helps, and continue or stop based on each person’s response.
Intrathecal baclofen, delivered through a surgically implanted pump that releases the drug directly into the spinal fluid, has shown more promising results for severe cases. A randomized, placebo-controlled trial found that intrathecal baclofen was significantly better than placebo at achieving individualized treatment goals. About 59% of people in the treatment group met at least one clinically meaningful goal, compared to 13% in the placebo group. Dystonia scores during rest also improved.19PubMed Central. The Effect of Intrathecal Baclofen in Dyskinetic Cerebral Palsy: The IDYS Trial This is one of the strongest pieces of evidence for any medical intervention in dyskinetic CP.
Deep brain stimulation (DBS) is a surgical option for severe dystonia that does not respond to other treatments. Electrodes are implanted in the globus pallidus internus, a basal ganglia structure involved in movement regulation, and deliver continuous electrical pulses to modulate its activity. A pooled analysis of 68 patients who received DBS found an average improvement of about 24% on a standard dystonia severity scale at one year of follow-up.20PubMed. Effects of deep brain stimulation in dyskinetic cerebral palsy: a meta-analysis That is a modest but meaningful reduction, and the results vary considerably from person to person. Case reports also suggest that early DBS can create a window for other interventions, such as cochlear implantation for hearing loss, by reducing the involuntary movements enough for the child to benefit from auditory rehabilitation.21PubMed. Bilateral globus pallidus internus deep brain stimulation for dyskinetic cerebral palsy supports success of cochlear implantation
Physical therapy remains fundamental, though the goals differ from spastic CP. Rather than stretching tight muscles or preventing contractures, therapy for athetoid CP focuses on trunk stability, postural control, and functional movement strategies. Treadmill training, cycling, and structured sit-to-stand exercises have all been used to improve gross motor function and walking ability.
Growing Up and Growing Older With Athetoid CP
CP is a lifelong condition, and while the underlying brain injury does not progress, the body’s response to it changes with age. For people with athetoid CP, one of the most important long-term concerns is the cervical spine. Decades of involuntary head and neck movements place abnormal stress on the vertebrae and discs, leading to premature wear. Cervical spondylosis, or degenerative changes in the neck, develops earlier and often affects different vertebral levels than in the general population, with more involvement of the lower cervical spine.22PubMed. Cervical spondylotic myelopathy in athetoid cerebral palsy patients: about five cases
When cervical spondylosis progresses to the point where it compresses the spinal cord, it causes myelopathy: new weakness, numbness, or loss of coordination in the arms and legs. The tricky part is that these symptoms can be mistaken for worsening of the original CP, since the person already has abnormal motor function as a baseline. If a person with athetoid CP experiences a noticeable decline in their abilities during adulthood, cervical myelopathy should be considered and evaluated with spinal imaging. The diagnosis is frequently delayed because clinicians attribute the decline to the known disability rather than looking for a new and treatable cause.23PubMed. Cervical spondylotic myelopathy in athetoid cerebral palsy patients: about five cases
Other musculoskeletal problems accumulate too. Hip dysplasia can progress over time in people who bear weight on their legs, eventually causing pain and arthritis. Abnormal kneecap positioning can become particularly painful in early adulthood.24PubMed. Cerebral palsy lifetime care – four musculoskeletal conditions Proactive musculoskeletal surveillance throughout adulthood, rather than waiting for pain to develop, is a consistent recommendation from specialists in adult CP care.
The Caregiver Side
The impact of athetoid CP extends beyond the person who has it. In a study of 92 children with CP (average age around seven and a half), over a third experienced moderate pain and nearly a quarter had severe pain. Among their parents, more than three quarters rated their own quality of life as only “fair,” and a statistically significant link was found between the child’s functional disability and the parent’s reported quality of life.25Pakistan Journal of Physical Therapy. Correlation of Health Related Quality of Life and Functional Disability of Athetoid Cerebral Palsy Patients with Health Related Quality of Life of Their Caregivers This is not surprising, but it is a useful reminder that support systems, respite care, and mental health resources for caregivers are not extras. They are part of the management plan.
The daily demands of caring for someone with athetoid CP differ from those of spastic CP in ways that are not always recognized. Spasticity creates predictable resistance; athetosis creates unpredictable movement. Feeding, dressing, and transferring someone whose body moves in sudden, uncontrolled ways requires a different set of skills and a different kind of patience. Therapists working with families often need to teach specific handling techniques that account for these fluctuations rather than applying generic CP care strategies.
When the Diagnosis Might Be Wrong
Not every child who moves abnormally has CP. Several rare metabolic and genetic conditions can produce a nearly identical picture, especially in the first few years of life. Conditions involving neurotransmitter metabolism, mitochondrial function, or metal transport can all cause dyskinesia that looks like athetoid CP on a clinical exam.26PubMed Central. Metabolic and genetic disorders mimicking cerebral palsy Some of these are treatable if caught early, which makes the distinction clinically important rather than academic.
Red flags that should prompt a closer look include worsening over time (true CP should be stable at the neurological level), episodes of metabolic crisis, a family history of unexplained neurological disease, and brain imaging that does not match the expected pattern of injury. Whole-exome sequencing and metabolic panels are increasingly used when the clinical picture does not fit a straightforward CP diagnosis. For a subset of these children, arriving at the correct diagnosis opens the door to specific treatments, including dietary modifications, enzyme replacement, or targeted medications, that would never be tried under a CP label.