ELECTRO-OCULOGRAPHIC RECORDING AND SCORING OF SMOOTH PURSUIT AND SACCADIC EYE TRACKING - PARAMETRIC STUDY USING MONOZYGOTIC TWINS

Following reports that psychiatric patients and their relatives produced deviant oculomotion, new procedural and quantitative methods were developed and applied in a parametric study of tracking proficiency in 32 monozygotic twin pairs tested twice. Subjects tracked a spot of light across an oscilloscope screen. The target was driven sinusoidally at various frequencies for smooth pursuit tracking and by a modified square wave generator for saccadic tracking. Also included were a smooth pursuit test requiring subjects to “monitor” the aperiodic appearance of a hole in the center of the oscillating target and a psychomotor test requiring subjects to manually center a dot in a moving circle. For pursuit tracking, the electro‐oculogram (EOG) and target motion were fed to a computer programmed to calculate root‐mean‐square differences between EOG and target channels. The saccadic EOG was computer‐analyzed by measuring movement latencies. Performance on the various tasks was analyzed with emphasis on the effects of the monitor requirement, which dramatically reduced tracking error. Measures of retest reliability and twin concordance suggested that observed individual differences in performance on these tasks represent stable traits. Copyright © 1979, Wiley Blackwell. All rights reserved