Long Term Effects of Concussion on Eye Tracking Patterns

Abstract

PURPOSE: The purpose of this study is to investigate long-term changes in eye-tracking patterns in previously concussed individuals (>1-year post-injury) compared to non-concussed controls. METHODS: This case control study will include 40 total participants, but currently includes 12 participants with (n=5 concussed, 3.00±1.79 concussions, 4.92±2.43 years post-injury, 22.80+2.23 years, 170.18+6.62 cm, 71.49+9.19 kg) and without (n=7; 27.00+4.96 years, 177.8+9.40 cm, 77.69+12.83 kg) a concussion history were evaluated. Participants were excluded if they only had a previously undiagnosed concussion, were currently playing contact sports, did not have normal or corrected to normal vision without glasses. Participants completed two eye-tracking tasks: an anti-saccade task consisting of 5 test blocks, 40 trials each and a circle tracking task consisting of 3 trials. The anti-saccade task measured saccadic and anti-saccadic movements, while the circle tracking task measured smooth pursuit eye movements. In both groups, results were analyzed using independent T-tests. RESULTS: The mean reaction and processing times in the saccade task in formerly concussed subjects was significantly different from controls (p=0.02 and p<0.01). The control group had a 7.41% slower reaction time and 12.64% slower processing time than the concussed group. Other anti-saccade task variables (i.e. movement time, number of correct saccades, number of trials where saccade ended outside of the target zone, percent of accurate saccades, distance from target block, distance from target block for correct trials) and circle tracking (i.e. horizontal root mean squared error (RMSE), vertical RMSE, horizontal delay, mean vertical delay) were not significant (p’s>0.05). CONCLUSIONS: Counter to work on the acute effects of concussion, the preliminary findings of this study indicate that concussion may not have a long-term effect on eye-tracking reaction and processing time. Additional work in this area with larger samples is warranted.