Ataxia is an inability to coordinate voluntary muscle movements. A person with ataxia will appear to be off-balance when standing and unsteady or staggering when walking.

The most common causes of ataxia are alcohol and drug use, inflammation of the inner ear (labyrinthitis), and stroke. Ataxia can also be caused by other problems, such as tumors, trauma, medicines, toxins, certain infections, benign paroxysmal positional vertigo (BPPH), seizures, or some nervous system disorders.