Ataxia is a condition characterized by muscular incoordination, producing irregular and inaccurate movements of the body. The result may be a clumsy manner of walking, with feet wide apart, a lack of balance, tremor (shakiness) of the arms, or slurring of speech.

Causes

Ataxia can be caused by anything that affects the motor control centers of the brain or the nerve pathways leading from them. One of the most common causes of ataxia is a stroke in the brainstem (the portion of the brain that controls the most basic body functions, such as breathing and circulation) or cerebellum (the portion of the brain responsible for fine control of muscle movements).

Drunkenness can produce a temporary staggering ataxia. Permanent ataxia is caused by damage to the brain, spinal cord, or spinal nerves. It is sometimes a symptom of Parkinson's disease.

Locomotor ataxia may be a late result of untreated syphilis. Its symptoms include sharp, stabbing pains, usually in the legs; an unsteady walk; and a feeling of walking on foam rubber. There also may be an increased sensitivity of the skin, sometimes with sensations of burning, prickling, creeping, or crawling.

Ataxia occurs in one case in ten of cerebral palsy, which is a movement disorder caused by damage to the brain or nerve pathways before or around the time of birth. Weakness, unsteadiness, clumsy walking, and difficulty with fine or rapid movements are typical. Physical and occupational therapies help patients handle daily life despite their condition.

Ataxia may also be caused by any one of a group of hereditary diseases that attack the central nervous system. They cause degeneration of the spinal cord and cerebellum and also frequently damage the brain stem and various nerves. Inherited disorders of body chemistry and body chemicals are believed to be involved, but little is known about them. Only one of these disorders -- Refsum's syndrome -- can be treated, by reducing the excessive level of a body chemical known as phytanic acid.

Symptoms and Treatment

Symptoms of the hereditary ataxias include unsteadiness in walking, tremor of the arms, muscle weakness, and wasting away of muscles. Various other abnormalities may be present, depending on the disease. For example, Friedreich's ataxia causes scoliosis (curvature of the spine) and damages heart tissue.

All of these diseases continue throughout life. With the exception of Refsum's syndrome, none can be treated effectively.