What is ataxia?
The word "ataxia" comes from the Greek word "a taxis," which means "without order or without coordination." Thus, ataxia means without coordination.
Persons who are diagnosed with ataxia experience a failure of muscle control in their arms and legs which may result in a lack of balance, coordination, and possibly a disturbance in gait. Ataxia may affect the fingers, hands, arms, legs, body, speech, and even eye movements.
The word ataxia is often used to describe the incoordination of symptoms that may accompany infections, injuries, other diseases, and/or degenerative changes in the central nervous system. It also describes a group of specific degenerative diseases of the central nervous system called the hereditary and sporadic ataxias. The term ataxia is a symptom - it is not a specific diagnosis. Ataxia may also refer to a group, or family, of disorders.
Many ataxias are hereditary; however, some can occur in families with no previous history of ataxia. In this case, the ataxia is referred to as sporadic ataxia.
What causes ataxia?
Most disorders that result in ataxia are found to have degeneration, or atrophy, of the cells in the part of the brain called the cerebellum. The cerebellum is located at the back of the head. Its function is to coordinate voluntary muscle movements and to maintain posture, balance, and equilibrium.
The spine can also be affected. The terms cerebellar degeneration and spinocerebellar degeneration may be used to refer to this type of damage to the nervous system.
The various abnormal genes that cause ataxia do have something in common: they make abnormal proteins that affect nerve cells, primarily in the cerebellum and in the spinal cord. They may also affect other parts of the brain.
The affected nerve cells begin to function poorly and ultimately degenerate. As the disease progresses, muscles become less and less responsive to the commands of the brain. This causes balance and coordination to become a greater problem.
Types of ataxia:
As discussed above, there are two types of ataxia:
- sporadic ataxias
Ataxias of this type usually begin in adulthood and have no known family history.
- hereditary ataxias
These ataxias are caused by a deficit in a gene that is present from the start of a person's life and can be either dominantly inherited or recessively inherited. Recessive disorders commonly cause symptoms to begin in childhood rather than in adulthood.
Genetic testing is now available and it is known that Friedreich's ataxia may have an adult onset. Dominant ataxia often begins in the twenties or thirties or sometimes even later in life.
Hereditary ataxias are degenerative disorders that may progress over a number of years. How severe the disability depends on the type of ataxia, the age of onset of symptoms, and other factors that are poorly understood.
What are common symptoms of ataxia?
Symptoms and time of onset may vary according to the type of ataxia. Each individual may experience symptoms differently.
Typically the most common are listed below:
- balance and coordination are affected first
- incoordination of hands, arms, and legs
- slurring of speech
- wide-based gait
- difficulty with writing and eating
- slow eye movements
The symptoms of ataxia may resemble other conditions or medical problems. Always consult your physician for a diagnosis.
How is ataxia diagnosed?
In addition to a thorough medical history, family history, and complete neurological and physical examination, the following diagnostic procedures may be performed:
- laboratory tests (including blood and urine studies)
- x-rays - a diagnostic test which uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film
- magnetic resonance imaging (MRI) - a diagnostic procedure that uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images of organs and structures within the body
- genetic testing - tests performed to determine if a person has certain gene changes (mutations) or chromosome changes which are known to increase risk for certain inherited conditions
These diagnostic procedures may also be used to rule out other conditions that can cause ataxia to appear. Certain conditions can cause ataxia to appear suddenly, such as head trauma, stroke, brain hemorrhage, brain tumor, congenital abnormalities, post infectious conditions, exposure to certain drugs, and also following cardiac or respiratory arrests.
Some conditions can cause ataxia to appear gradually, such as hypothyroidism, deficiencies of certain vitamins such as B-12 or vitamin E, exposure to certain drugs, multiple sclerosis, syphilis, and other disorders.
Treatment for ataxia:
At this time there is no cure for the hereditary ataxias. There is also no medication currently available which treats the specific symptom of ataxia.
If ataxia is due to a stroke, a low vitamin level, or exposure to a toxic drug or chemical, then treatment is aimed at treating those specific conditions.
The treatment for the incoordination or imbalance mostly involves the use of adaptive devices to allow the individual to maintain as much independence as possible. Such devices may include the use of a cane, crutches, walker, or wheelchair. Physical therapy, speech therapy, and medications to help symptoms such as tremor, stiffness, depression, spasticity, and sleep disorders may also be beneficial.
Research is being conducted on cerebellar and spinocerebellar degeneration including work aimed at finding the cause(s) of ataxias and ways to treat, cure, and ultimately prevent them, according to the National Institute of Neurological Disorders and Stroke.
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Online Resources of Nervous System Disorders