ATAXIA

inability to coordinate voluntary muscular movements. In common usage, the term describes an unsteady gait. Most hereditary ataxias of neurological origin are caused by degeneration of the spinal cord and cerebellum; other parts of the nervous system are also frequently involved. The most common of these is Friedreich's ataxia, with a poorly understood mode of transmission. During the patient's first three to five years of life, only a few physical deformities (e.g., hammertoe) may be present. Later, by adolescence, the unsteady gait beginsfrequently interpreted as clumsinessbut, as the ataxia progresses, the unsteadiness becomes a broad-based, lurching gait, with sudden turns extremely difficult without falling. Tremors develop in the upper extremities and in the head. Speech is slow and slurred, and the tone is monotonous. Skeletal deformities are common, as is muscle weakness. Although the course of the disease is slow, it is progressive. Spontaneous remissions occur rarely, and ordinarily there is almost complete incapacity by age 20. There is no specific therapy, and death is usually the result of another complicating disease or heart failure.