Abstract
Purpose :
In the present study, we investigated whether deficits in attentional tracking following mild traumatic brain injury (TBI) are associated with neurophysiological measures, particularly eye movements and pupil dilation responses (pupil dilation amplitudes (PDA)), which can be reflective of attentional processes.
Methods :
Fifteen patients with mild TBI and 19 control participants between 19 and 38 years of age participated in the study. Participants performed a multiple object tracking (MOT) task in which they were required to track a number of moving dots for a fixed duration. In different conditions, the number of target dots (3, 4 and 5), noise dots (3, 6 and 9), and tracking duration (5 or 10 seconds) were varied to determine whether these manipulations had an impact on correctly discriminating the target dots. Whilst performing these conditions, eye movements and pupillary responses were measured using Gazepoint eye-tracker (150Hz).
Results :
We find that TBI patients performed poorer on the MOT task (compared to controls), particularly for conditions where the number of target and noise dots were high and for longer durations. Differences in eye movements and pupillary responses were observed between the two groups. TBI patients had comparatively smaller PDA than control participants, particularly for conditions with high target and distractor dots. Eye movement analysis showed that patients with TBI patients tended to scan the target dots continuously and made more and briefer fixations compared to control participants. In contrast, control participants tended not to scan the target dots but instead fixated on a centroid location.
Conclusions :
In conclusion, pupil dilation response and eye movement patterns provided further evidence of visual attention deficits following TBI, particularly deficits in mental effort (which is positively correlated with PDA) and visual span indicated by an increased number of fixations.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.