QUANTITATIVE ASSESSMENT OF INFLUENCE OF AGING ON OPTOKINETIC NYSTAGMUS

A quantitative assessment of the influence of aging on optokinetic nys tagmus (OKN) was investigated using 50 normal adults in ages ranging f rom 30 to 70 years. In linear stimulus-induced OKN, a statistically si gnificant difference was demonstrated in slow-phase OKN velocity only between the 30-59 year old age group and the 70-79-year-old age group, when OKN stimulus was more than 60 degrees/s. Step stimulus-induced O KN was investigated in the same age groups in order to compare aging e ffects upon slow-phase OKN velocity. No statistically significant diff erence was found in slow-phase OKN velocity between younger age groups and the oldest age group. There was no significant difference in fast -phase velocity among the age groups. Thus, step-induced OKN has a wid er clinical application than linear stimulus-induced OKN.