Development and validation of a high-speed video system for measuring saccadic eye movement

Abstract

Laboratory-based retroreflective and magnetic scleral search-coil technologies are the current standards for collecting saccadometric data, but such equipment is costly and cumbersome. We have validated a novel, portable, high-speed video camera-based system (Exilim EX-FH20, Casio, Tokyo, Japan) for measuring saccade reaction time (RT) and error rate in a well-lit environment. This system would enable measurements of pro-and antisaccades in athletes, which is important because antisaccade metrics provide a valid tool for concussion diagnosis and determining an athlete's safe return to play. A total of 529 trials collected from 15 participants were used to compare saccade RT and error rate measurements of the high-speed camera system to a retroreflective video-based eye tracker (Eye-Trac 6: Applied Sciences Laboratories, Bedford, MA). Bland-Altman analysis revealed that the RT measurements made by the highspeed video system were 11 ms slower than those made by the retroreflective system. Error rate measurements were identical between the two systems. An excellent degree of reliability was found between the system measurements and in the ratings of independent researchers examining the video data. A strong association (r = .97) between the RTs determined via the retroreflective and high-speed camera systems was observed across all trials. Our high-speed camera system is portable and easily set up, does not require extensive equipment calibration, and can be used in a well-lit environment. Accordingly, the camera-based capture of saccadometric data may provide a valuable tool for neurological assessment following a concussive event and for the continued monitoring of recovery.

Tracking gaze position from EEG: Exploring the possibility of an EEG‐based virtual eye‐tracker

“…Based on the sample size used in previous related works (Brooks et al., 2019; Niehorster et al., 2020), 25 healthy adults were initially included in the present study, 7 participants were excluded due to poor behavioral performance (fixation duration of 10% trials below than 300 ms, which follow the calibration procedure of commercialized eye‐trackers; n = 3), problems with eye‐tracking (missing trials >10%; n = 2), and EEG data quality (impedances of 1/3 electrodes >20 kΩ; n = 2). The final sample consisted of 18 participants (11 females) with a mean age of 20.71 years (SD = 1.83).…”

Effect of Repetitive Head Impacts on Saccade Performance in Canadian University Football Players

“…Fiber optic cables (Simplex 1.0 mm Industrial Fiberoptics, Tempe, AZ), in series with the light board, were secured in the camera field of view to record the timing of the target light on the video system. 36 In the second season, electro-oculography (EOG) was used to capture participants' saccade latency and direction. [38][39][40][41] Participants were fitted with three disposable surface electrodes (AM-N00S/E, AMBU Blue Sensor Adhesive Snap Electrode; Ambu Inc, Glen Burnie, MD) placed at the outer canthi of each eye and the center of the forehead.…”

A Framework to Advance Biomarker Development in the Diagnosis, Outcome Prediction, and Treatment of Traumatic Brain Injury

“… 93–99 This method correlates with concussion symptoms in children and adults and has promising utility as a rapid, objective, and non-invasive aid for diagnosis. Several oculomotor measures have been investigated for use as potential biomarkers of altered brain function after TBI, including metrics of fixation, smooth pursuit, saccades, 100 and convergence. 101 One study demonstrated that oculomotor assessment may be an indicator of decreased integrity of frontal white matter tracts and of altered attention and working memory functioning.…”