Cerebellar Ataxia

What the cerebellum does

The cerebellum compares what the body intends to do with what it is actually doing and makes rapid corrections. It coordinates timing and force of muscle movements, balance, eye movements and the rhythm of speech. When it is damaged, movements become poorly timed and poorly scaled, even though muscle strength is normal.

Symptoms

• Gait ataxia: a wide-based, staggering walk, like being drunk; difficulty walking heel to toe
• Limb ataxia: overshooting or undershooting when reaching (dysmetria), clumsy fine movements
• Intention tremor: shaking that worsens as the hand approaches a target
• Difficulty with rapid alternating movements (dysdiadochokinesia)
• Dysarthria: slurred, slow or scanning speech. See slurring words
• Nystagmus: jerky eye movements, with blurred or jumping vision
• Trunk unsteadiness: difficulty sitting or standing still
• Low muscle tone and fatigue

Damage to one side of the cerebellum affects coordination on the same side of the body.

Causes

Sudden (acute) ataxia

• Cerebellar stroke or bleeding: often with vertigo, vomiting and headache. Swelling can compress the brainstem, so this is a neurosurgical emergency.
• Toxins and medicines: alcohol, sedatives, anti-seizure drugs (phenytoin, carbamazepine), lithium, some chemotherapy.
• Wernicke encephalopathy: thiamine deficiency causing ataxia, confusion and eye movement problems.
• Infections: encephalitis, cerebellar abscess.
• Acute cerebellar ataxia of childhood: usually after chickenpox or other viral infections, in children aged 2 to 7. Most recover fully within weeks.
• Head injury.

Gradual (subacute or chronic) ataxia

• Long-term alcohol misuse: alcoholic cerebellar degeneration, mainly affecting walking.
• Multiple sclerosis.
• Tumors of the cerebellum or brainstem.
• Vitamin deficiencies: vitamin E, B12 and thiamine.
• Hypothyroidism.
• Autoimmune causes: gluten ataxia, anti-GAD antibodies, and paraneoplastic cerebellar degeneration linked to cancers such as lung, ovarian and breast cancer.
• Toxins: heavy metals and solvents.
• Neurodegenerative conditions: multiple system atrophy.

Inherited ataxias

• Spinocerebellar ataxias (SCAs): dominantly inherited, usually starting in adulthood.
• Friedreich ataxia: the most common recessive ataxia, starting in childhood or adolescence, with heart problems and scoliosis.
• Ataxia-telangiectasia and episodic ataxias.
• Fragile X-associated tremor/ataxia syndrome in older male carriers.

Diagnosis

1. History: speed of onset, alcohol, medicines, family history, other symptoms.
2. Neurological examination: finger-to-nose and heel-to-shin tests, gait, eye movements and speech.
3. MRI of the brain: stroke, tumor, MS, atrophy patterns. CT is used first in emergencies.
4. Blood tests: vitamins (E, B12), thyroid, liver function, celiac and other antibodies, paraneoplastic antibodies.
5. Genetic testing when an inherited ataxia is suspected.
6. Lumbar puncture for infection or inflammation; cancer screening for paraneoplastic causes.

Treatment

• Treat the cause: stop alcohol and replace thiamine, correct vitamin deficiencies, adjust medicines, gluten-free diet for gluten ataxia, immunotherapy for autoimmune ataxias, surgery for tumors or bleeds.
• Friedreich ataxia: omaveloxolone is FDA-approved for adults and teens 16 and older.
• Physical therapy: balance and gait training, which improves function even in degenerative ataxias.
• Occupational therapy: home adaptations, weighted utensils and fall prevention.
• Speech therapy for speech and swallowing.
• Mobility aids: canes, walkers and wheelchairs as needed.
• Symptom medicines: for tremor, spasticity or fatigue in some people.

Outlook

Outlook depends entirely on the cause. Ataxia from post-viral illness in children, medicines or vitamin deficiency often improves significantly. Stroke-related ataxia often improves with rehabilitation. Inherited and degenerative ataxias usually progress slowly, but therapy maintains independence for longer.

Frequently asked questions

What is the most common cause of cerebellar ataxia?

In adults, common causes include alcohol, stroke, multiple sclerosis and medicine toxicity. In young children, acute cerebellar ataxia after a viral infection is common. Inherited ataxias are less common overall but important in people with a family history.

Is cerebellar ataxia serious?

It depends on the cause. Sudden ataxia can mean a stroke or bleed and needs emergency care. Ataxia from medicines or vitamin deficiency can often be reversed. Inherited forms are long-term, but therapies help people stay active and safe.

Can cerebellar ataxia be cured?

Some causes can be cured or reversed, such as medicine toxicity, vitamin deficiency, gluten ataxia and post-viral ataxia in children. Degenerative and inherited ataxias have no cure yet, though treatments like physical therapy, and for Friedreich ataxia omaveloxolone, can help.

What does cerebellar ataxia feel like?

People describe feeling unsteady or drunk, needing to widen their stance, bumping into things, difficulty with buttons or handwriting, and slurred speech. Vision may jump with eye movements. Muscle strength usually feels normal.