Quantitative evaluation of smooth pursuit eye movements by personal computer. I) Normative data and effect of aging

We recorded the smooth pursuit eye movements (SPEM) of 52 healthy subjects by binocular electrooculographic technique. The 52 subjects were homogeneously distributed from the 2nd to the 6th decade. The target moved over 60 deg of amplitude at constant velocity (ramp); different target velocities were used ranging from 10 to 50 deg/sec. All subjects were tested with the same 58 pseudo-random ramp sequence under the control of a Personal Computer (PC). The quantitative analysis of SPEM was carried out by an interactive program implemented on the same PC. Different equations were tested by a multiple regression analysis in order to describe the relationship between SPEM gain values and target velocities; two of these equations were chosen and used in order to find out if SPEM gain was influenced by target direction (the direction effect) and/or by subject age (the age effect). The statistical analyses we performed, demonstrated that SPEM gain values were influenced by aging but not by target direction: SPEM gain decreased as age increased.