Reliability of computerized eye-tracking reaction time tests in non-athletes, athletes, and individuals with traumatic brain injury

Background: Eye tracking technologies and methodologies have advanced significantly in recent years. Specifically, the use of eye tracking to quantitatively measure oculomotor and psychophysiological constructs is gaining momentum. Reaction time has been measured in a number of different ways from a simple response to a stimulus to more challenging choice or discrimination responses to stimuli. Traditionally, reaction time is measured from the beginning of a stimulus event to a response event and includes both visual and motor response times. Eye tracking technology can provide a more discrete measurement of reaction time to include visual components such as visual latencies and visual speed, and can identify if the person was looking at the target area when a stimulus is presented. The aim of this paper was to examine the reliability of the simple reaction time, choice reaction time, and discriminate reaction time tests measured using eye tracking technology. Additionally, we sought to establish performance norms and examine gender differences in reaction time in the general population. A final objective was to conduct a preliminary comparison of reaction time measures across different populations including non-athletes, athletes, and individuals that had sustained a traumatic brain injury. Methods: A sample of 125 participants were recruited to undertake test-retest reliability, analysed using Cronbach’s alpha and intraclass correlation coefficients. A different data set of 1893 individuals, including athletes (n = 635), non-athletes (n = 627) and people with traumatic brain injury (n = 631) were compared using MANOVA to explore group differences in reaction time. Results: Results demonstrated that overall, the tests had good test-retest reliability. No significant differences were found for gender. Significant differences were found between groups with athletes performing best overall. Reaction times of people with traumatic brain injury were overall much more variable, showing very large standard deviations, than those of the non-athletes and athletes. Conclusions: Future research should consider the accuracy of eye movements and various demographic variables within groups

Horizontal and vertical self-paced saccades as a diagnostic marker of traumatic brain injury

Aim: Eye tracking tests to measure horizontal and vertical saccades as a proxy for neural deficits associated with traumatic brain injury (TBI) were evaluated in the present study. Methodology: A total of 287 participants reporting either no TBI, mild, moderate or severe TBI participated in a suite of eye tracking tests to measure horizontal and vertical saccadic performance. Results: The horizontal saccades test offered a sensitivity of 0.77 and a specificity of 0.78, similarly the vertical saccades tests offered a sensitivity of 0.64 and a specificity of 0.65. Conclusion: The results indicated that using eye-tracking technology to measure these metrics offers an objective, reliable and quantifiable way of differentiating between individuals with different severities of TBI, and those without a TBI

An examination of the oculomotor behavior metrics within a suite of digitized eye tracking tests

Eye tracking has recently been used to examine oculomotor behavior (OMB) for visual and neurological health and wellness with promise in determining characteristics of healthy eyes and in turn a healthy brain. Recent research has demonstrated that human eye movements reflect individual and group differences, however, clinical evaluations of eye movements often lack test-retest reliability. The purpose of this study was to examine the reliability of oculomotor behavior metrics in healthy individuals, to determine the normative values through cluster analysis, and to compare oculomotor behavior metrics by age groups in a suite of digitized eye tracking tests. A large sample of 2993 participants completed RightEye tests. These tests demonstrated acceptable or higher reliability on 85% of the eye movement metrics and the clustering analysis distinguished 5 distinct age groups. Furthermore, group differences were found between age clusters. Overall, the findings represent the reliability of a computerized oculomotor behavior measure and the importance to consider individual and group characteristics for clinical applications as well as applied settings

Vertical smooth pursuit as a diagnostic marker of traumatic brain injury.

AIM: Neural deficits were measured via the eye tracking of vertical smooth pursuit (VSP) as markers of traumatic brain injury (TBI). The present study evaluated the ability of the eye tracking tests to differentiate between different levels of TBI severity and healthy controls. METHODOLOGY: Ninety-two individuals divided into four groups (those with mild, moderate or severe TBI and healthy controls) participated in a computerized test of VSP eye movement using a remote eye tracker. RESULTS: The VSP eye tracking test was able to distinguish between severe and moderate levels of TBI but unable to detect differences in the performance of participants with mild TBI and healthy controls. CONCLUSION: The eye-tracking technology used to measure VSP eye movements is able to provide a timely and objective method of differentiating between individuals with moderate and severe levels of TBI