1. A system for measuring cognitive performance, comprising: a display; a measurement apparatus to measure the individual's gaze point over a period of time while viewing an object moving smoothly along a target path on the display; and a computer system including one or more processors, the computer system storing one or more programs, which when executed by the one or more processors, cause the system to perform a set of operations including: during a test period: presenting to the individual, on the display, the object moving smoothly along the target path; and while presenting to the individual the object moving smoothly on the display and while the individual visually tracks the object, measuring the individual's gaze point; determining a radial distance of the gaze point of the individual with respect to the object; determining a radial inbounding performance metric based on the radial distance of the gaze point of the individual with respect to the object, wherein the radial inbounding performance metric reflects an assessment of how frequently the gaze point of the individual, while visually tracking the object moving along the target path, is within a predefined radius or distance from the object; and producing a diagnostic output based on the radial inbounding performance metric.