Abstract
Purpose :
Deficits in cognitive function (particularly to attention, memory and processing speed), commonly manifesting as ‘brain fog’, have increasingly been recognised as sequelae of COVID-19 infection. However, the full extent of cognitive impairment post-infection and whether such deficits are temporary or permanent remains largely unclear. In the present study, we report an exploratory study that indicates post-COVID-19 infection is associated with deficits in executing a memory-guided anti-saccade task which engages the working memory and inhibition processes.
Methods :
A modified saccadic task was employed in which participants were required to make an anti-saccade, that is, eye movement in the opposite direction to a cued location after a variable delay period of 0.5, 1 or 2s. Six participants (mean age =19.67±1.03 yr, 4 females) with post-COVID-19 infection period of 8.16 months and 6 healthy controls (mean age =18.5±1.4 yr, 4 females) participated in the study. Outcome measures such as saccadic latency (the time taken to make a correct antisaccade) and error rates (incorrect eye movements made during and after delay period) were obtained from eye movement data measured using GazepointGP3 eye tracker and compared between the study groups.
Results :
A 3 (delay) x 2 (group) two-way repeated measures ANOVA using mixed effect model was performed for saccadic latency and error rates. For saccadic latency, there was no significant interaction effect (F (2, 30) = 1.991, p= 0.15) but a main effect of delay (F (2, 30) = 4.022, p =0.028) and group (F (1, 30) = 7.328, p=0.01). Notably, increasing the delay period decreased saccadic latency for both groups; overall, participants with post-COVID-19 infections had comparatively longer latencies (~ 50-100ms), particularly at shorter delay periods than controls. For error rates, there was neither a significant interaction effect (F (2, 27) = 0.71 p =0.49) nor a main effect of delay (F (2,27) = 1.37, p =0.27) but a significant main effect of group (F (1, 27) = 6.15, p =0.02). Participants with post-COVID infection made more incorrect saccades during and after delay period than controls.
Conclusions :
Our findings suggest that COVID-19 can lead to slower processing speeds and poor inhibition, as indicated by longer saccadic latencies and more saccadic errors. Our study shows a broader impact of COVID-19 infection beyond respiratory health and to brain function and cognition.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.