Saccade reaction test for the assessment of cognitive readiness.

Background: Cognitive performance such as rapidly reacting to a target or making correct decisions can directly impact task effectiveness in military, emergency, or athletic settings. Saccades are rapid changes in gaze that support recognition and analysis of objects of potential interest in human vision whose acuity rapidly degrades away from the center. The saccade behavior is highly selective and controlled and thus is an expression of attention. We implemented a two-dimensional reactive saccade task to quantify attention performance. Methods: We studied a sample of 169 healthy individuals aged 8-82 years old (39% male), 37 of whom were retested 1-3 months later. Subjects viewed a target presented in a randomized spatiotemporal sequence, and associated timings of saccade initiation and gaze arrival were registered. Individuals' performance was characterized with the mean and standard deviation of the reciprocals of these measures (1/time, postulated to represent the cortical decision speed). Results: The intraclass correlation between the test and retest measures varied from 0.60 to 0.74. The reaction speed showed a tendency to become faster and less variable during development in childhood through young adulthood and thereafter become slower and more variable, with best performance tending to be seen in the 20s. Conclusion: We verified inter-individual variability, within-individual stability, and across-age differences in the performance on a reactive saccade task. A quick assessment of attentional traits or states with saccade reaction metrics, aided by rapidly developing technology, may provide utility in a cognitive readiness test that can inform task assignment or return-to-duty/play decisions.