Authors: Nicolas Kon Kam King, FRCS Ed, PhD; Tzy Harn Chua; Julian Han; Thevapriya Selvaratnam, MSc; Angela See (Singapore, Singapore)
Visual dysfunction is a common sequala following mild traumatic brain injury (mTBI). Impaired eye movements may not be easily detected on examination. Eye tracking tools have been increasingly utilised in recent years to detect these subtle changes in ocular motility. The purpose of this study was to assess the impact of mTBI on oculomotor movements using an eye tracking tool.
Patients with mTBI (n = 25) and healthy controls (n = 25) were recruited and assessed for oculomotor performance in clockwise smooth pursuit and horizontal anti-saccades tasks using an eye tracking tool. In three trials of smooth pursuit task, participants were instructed to trace a stimulus (red dot) as it moved in a clockwise direction. In the horizontal anti-saccades task, participants were asked to look in the opposite direction of the stimulus (red dot) with reference to a fixation cross.
In the smooth pursuit task, mTBI patients made more eye position errors than healthy controls (Z-scoremTBI -0.37 ± 0.47 versus Z-scoreHC 0.15 ± 0.76, p = 0.006). The minimum bounding circle radius was larger in patients than healthy controls (16.1 ± 1.7cm versus 15.1 ± 1.3 cm, p = 0.025). In the horizontal anti-saccades task, there were no differences in the number of directional errors and anti-saccades latency. However, the directional error latency in response time (0.30 ± 0.09 secs versus 0.21 ± 0.11 secs, p = 0.005) and correction time were longer in mTBI patients (0.28 ± 0.26 secs versus 0.15 ± 0.09 secs, p = 0.032).
Compared to healthy controls, patients with mTBI demonstrated impaired performance in smooth pursuit and longer directional error latency and correction time in executing horizontal anti-saccades. These abnormalities were detected with an eye tracking tool, which may have clinical applications in the future.