Ataxia refers to the inability to maintain normal postures and perform normal movements. Movements are jerky and uncoordinated, without the smooth flow of normal motion.
Ataxia may affect any part of the body. Onset may be at any age. Ataxia occurs when there is breakdown in communication among the brain centers responsible for coordinated movement. These include areas responsible for sensation and balance, as well as the cerebellum. The cerebellum is a large structure at the rear of the brain involved in coordinating and shaping movement. Degeneration of the cerebellum occurs in most of the hereditary ataxias. Ataxia is a symptom of a large number of neurologic disorders.
These include inherited neurodegenerative disorders, lesions, paraneoplastic syndromes (arising from specific forms of cancer), vitamin deficiencies, and others. Over two dozen hereditary forms are known. The person with ataxia may have other movement disorders such as chorea, myoclonus or dystonia, and may have other types of neurologic involvement, such as seizures. Treatments for ataxia vary with the cause of the disorder, and where possible is aimed at the underlying cause rather than the symptoms themselves. Ataxia is from the Greek word which means "not ordered".