(locomotor ataxia) a form of neurosyphilis occurring 5–20 years after the original sexually transmitted infection. The infecting organisms progressively destroy the sensory nerves. Severe stabbing pains in the legs and trunk, an unsteady gait, and loss of bladder control are common. Some patients have blurred vision caused by damage to the optic nerves. Penicillin is used to arrest the progression of this illness. See also syphilis; general paralysis of the insane.