Ataxia is a neurological sign consisting of lack of voluntary coordination of muscle movements that can include gait abnormality, speech changes, and abnormalities in eye movements. Ataxia is a clinical manifestation indicating dysfunction of the parts of the nervous system that coordinate movement, such as the cerebellum. Ataxia can be limited to one side of the body, which is referred to as hemiataxia. Several possible causes exist for these patterns of neurological dysfunction. Dystaxia is a mild degree of ataxia. Friedreich's ataxia has gait abnormality as the most commonly presented symptom. The word is from Greek α- [a negative prefix] + -τάξις [order] = "lack of order".