According to the National Ataxia Foundation website, http://www.ataxia.org/:
The word “ataxia”, comes from the Greek word, ” a taxis” meaning “without order or incoordination”. The word ataxia means without coordination. People with ataxia have problems with coordination because parts of the nervous system that control movement and balance are affected. Ataxia may affect the fingers, hands, arms, legs, body, speech, and eye movements. The word ataxia is often used to describe a symptom of incoordination which can be associated with infections, injuries, other diseases, or degenerative changes in the central nervous system. Ataxia is also used to denote a group of specific degenerative diseases of the nervous system called the hereditary and sporadic ataxias which are the National Ataxia Foundation’s primary emphases.