Cerebellum and brainstem
Persistent ataxia usually results from damage to the part of your brain that controls muscle coordination (cerebellum).
Ataxia describes poor muscle control that causes clumsy voluntary movements. It may cause difficulty with walking and balance, hand coordination, speech and swallowing, and eye movements.
Ataxia usually results from damage to the part of the brain that controls muscle coordination (cerebellum) or its connections. Many conditions can cause ataxia, including alcohol misuse, stroke, tumor, brain degeneration, multiple sclerosis, certain medications and genetic disorders.
Treatment for ataxia depends on the cause. Adaptive devices, such as walkers or canes, might help maintain independence. Physical therapy, occupational therapy, speech therapy and regular aerobic exercise also might help.
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Ataxia can develop over time or come on suddenly. Ataxia is a sign of several neurological disorders and can cause:
- Poor coordination
- Walking unsteadily or with the feet set wide apart
- Poor balance
- Difficulty with fine motor tasks, such as eating, writing or buttoning a shirt
- Change in speech
- Involuntary back-and-forth eye movements (nystagmus)
- Difficulty swallowing
When to see a doctor
If you don't have a condition that causes ataxia, such as multiple sclerosis, see your doctor as soon as possible if you:
- Lose balance
- Lose muscle coordination in a hand, arm or leg
- Have difficulty walking
- Slur your speech
- Have difficulty swallowing
Damage to the part of your brain that controls muscle coordination (cerebellum) or its connections can cause ataxia. The cerebellum, located at the base of the brain, connects to the brainstem. The cerebellum helps control balance, eye movements, swallowing and speech. There are three major groups of ataxia causes: acquired, degenerative disease and hereditary causes.
- Alcohol. Long-term excess alcohol intake may cause persistent ataxia. It's possible it may improve by avoiding alcohol completely.
- Medications. Ataxia is a potential side effect of certain medications, especially barbiturates, such as phenobarbital; sedatives, such as benzodiazepines; antiepileptic drugs, such as phenytoin; and some types of chemotherapy.
- Toxins. Heavy metal poisoning, such as from lead or mercury, and solvent poisoning, such as from paint thinner, also can cause ataxia.
- Vitamins. Not getting enough vitamin E, vitamin B-1, vitamin B-12 or thiamine can lead to ataxia. A deficiency or excess of Vitamin B-6 deficiency also may cause ataxia. These causes are important to identify because ataxia caused by these deficiencies can often be reversed.
- Thyroid problems. Hypothyroidism and hypoparathyroidism can cause ataxia.
- Stroke. Sudden onset of ataxia occurs with a stroke. This may be either due to a blood vessel blockage or bleeding on the brain.
- Multiple sclerosis. This neurological disorder may cause ataxia.
- Autoimmune diseases. Sarcoidosis, celiac disease, certain types of encephalomyelitis and other autoimmune diseases may cause ataxia.
- Infections. Ataxia can be an uncommon complication of chickenpox in childhood, and other viral infections such as HIV and Lyme disease. It might appear in the healing stages of the infection and last for days or weeks. Normally, the symptoms get better over time.
- COVID-19 infection. Ataxia most commonly results from severe COVID-19 cases.
- Paraneoplastic syndromes. These are rare degenerative disorders triggered by the immune system response to a cancerous tumor (neoplasm), most commonly from lung, ovarian or breast cancer or lymphoma. Ataxia can appear months or years before the cancer is diagnosed.
- Abnormalities in the brain. An infected area (abscess) in the brain may cause ataxia. A growth on the brain, a cancerous (malignant) or noncancerous (benign) tumor, can damage the cerebellum.
- Head trauma. Severe brain damage may cause cerebellar ataxia weeks to months after the trauma.
- Cerebral palsy. This is a general term for a group of disorders caused by damage to a child's brain during early development — before, during or shortly after birth — that affects the child's ability to coordinate body movements.
- Multiple system atrophy. This affects adults around age 50. In addition to ataxia, other problems associated with this condition include bladder incontinence, low blood pressure or fainting on standing, and REM sleep behavior disorder (yelling, kicking or punching in sleep).
Some types of ataxia and some conditions that cause ataxia are hereditary. If you have one of these conditions, you may have been born with a mutation in a certain gene that makes irregular proteins.
The abnormal proteins hamper the function of nerve cells, primarily in the cerebellum and spinal cord, and cause them to degenerate. As the disease progresses, coordination problems worsen.
You can inherit a genetic ataxia from either a dominant gene from one parent (autosomal dominant disorder) or a recessive gene from both parents (autosomal recessive disorder). In a recessive disorder, the parents are unaffected, and there may be affected siblings.
Different gene mutations cause different types of ataxia, most of which are progressive. Each type causes poor coordination, but each has specific signs and symptoms.
Autosomal dominant ataxias
Autosomal dominant inheritance pattern
In an autosomal dominant disorder, the altered gene is a dominant gene located on one of the nonsex chromosomes (autosomes). You need only one altered gene to be affected by this type of disorder. A person with an autosomal dominant disorder — in this case, the father — has a 50% chance of having an affected child with one altered gene (dominant gene) and a 50% chance of having an unaffected child with two typical genes (recessive genes).
- Spinocerebellar ataxias. Researchers have identified more than 40 autosomal dominant ataxia genes, and the number continues to grow. Cerebellar ataxia and cerebellar degeneration are common to all types, and there may be other neurological signs and symptoms.
- Episodic ataxia (EA). There are eight recognized types of ataxia that are episodic rather than progressive — EA1 through EA7, plus late-onset episodic ataxia. EA1 and EA2 are the most common. EA1 involves brief ataxic episodes that may last seconds or minutes. The episodes are triggered by stress, being startled or sudden movement, and often are associated with muscle twitching. EA2 involves longer episodes, usually lasting from 30 minutes to six hours, which also are triggered by stress. There may be dizziness (vertigo), fatigue and muscle weakness during the episodes. In some cases, symptoms resolve in later life. Episodic ataxia doesn't shorten life span, and symptoms may respond to medication.
Autosomal recessive ataxias
Autosomal recessive inheritance pattern
To have an autosomal recessive disorder, you inherit two changed genes (mutations), one from each parent. These disorders are usually passed on by two carriers. Their health is rarely affected, but they have one changed gene (recessive gene) and one unaffected gene (dominant gene) for the condition. Two carriers have a 25% chance of having an unaffected child with two unaffected genes (left), a 50% chance of having an unaffected child who also is a carrier (middle), and a 25% chance of having an affected child with two recessive changed genes (right).
Friedreich's ataxia. This is the most common hereditary ataxia. It involves damage to the cerebellum, spinal cord and peripheral nerves. Peripheral nerves carry signals from the arms and legs to the brain and spinal cord. In most cases, signs and symptoms appear well before age 25. The cerebellum usually appears normal on a brain scan.
The first indication generally is difficulty walking. The condition typically progresses to the arms and trunk. There are often deformities of the feet, such as high arches, and curvature of the spine (scoliosis).
Other signs and symptoms that might develop include slurred speech (dysarthria); fatigue; involuntary eye movements (nystagmus); hearing loss; heart enlargement (cardiomyopathy) and heart failure, and diabetes. Early treatment of heart problems can improve quality of life and survival.
- RFC1 associated ataxia: This is the most common cause of late-onset ataxia. The ataxia symptoms are usually accompanied by dizziness, numbness or tingling in the body, and sometimes unexplained cough.
Ataxia-telangiectasia. This rare, progressive childhood disease causes degeneration in the brain and the immune system. This increases the risk of other diseases, including infections and tumors.
Telangiectasia is the formation of tiny red "spider" veins that might appear in the corners of your child's eyes or on the ears and cheeks. Delayed motor skill development, poor balance and slurred speech are often the first signs. Frequent sinus and respiratory infections are common.
Children with ataxia-telangiectasia are at high risk of developing cancer, particularly leukemia or lymphoma.
- Congenital cerebellar ataxia. This type of ataxia results from damage to the cerebellum that's present at birth.
- Wilson's disease. People with this condition accumulate copper in the brain, liver and other organs. This can cause ataxia and other neurological problems.