Positional and optokinetic nystagmus in healthy old people.

Positional nystagmus and asymmetry of the optokinetic response were each found in four of 10 symptomless subjects aged 69 to 76 years who had normal balance function as demonstrated on the Kistler force platform. Positional nystagmus was also found in one of 10 healthy young subjects, none of whom had an abnormal optokinetic response. Abnormalities of these responses are therefore common in healthy old people and lack diagnostic specificity.