Abstract
Purpose :
Traumatic brain injury (TBI) leads to cognitive, attentional and sensorimotor disturbances. Memory-guided antisaccades, where saccades are made in the direction opposite to remembered target location, have been used to investigate working memory and response inhibition capacity. Here, we investigated the performance on a memory-guided antisaccade task by systematically varying the delay between target onset and cue for eye-movement (thereby affecting working memory and response inhibition processing capacity) in individuals with and without TBI.
Methods :
Twenty-six subjects ((mean age= 22.4yr±6.6), 14 females) with TBI and thirty-three ((mean age= 23.4yr±6.7), 19 females) controls participated. At each trial, subjects fixated a central target and made an antisaccade in response to a peripheral target which was cued for 100ms. The antisaccade was made after a time delay indicated by a central visual cue that appeared after a variable delay period of 0, 0.125, 0.250, 0.500, 1 or 2s. Eye movements were measured using GazepointGP3 eye tracker. The antisaccade latency, disinhibition errors (saccades during delay) and directional errors (incorrect saccades to target location after the delay), primary gain and gain of final eye position were determined.
Results :
A 6 (delay) x 2 (group) repeated measures ANOVA using mixed model with delay period as within-subject and group as between-subject variables was conducted for antisaccade latency, disinhibition errors, directional errors, primary gain and gain of final eye position. None of the outcome measures demonstrated two-way interaction effect. However, there was a main effect for delay for latency (F (4, 212) = 39, p<0.001) and directional errors (F (4, 197) = 3, p=0.042). Only directional errors (F (1, 57) = 6, p=0.017) demonstrated significant main effect for group; no other outcome measures showed main effect for group. Saccade latency and directional error rates decreased for both groups with delay durations. However, the TBI group made significantly more directional errors compared to controls.
Conclusions :
Our results suggest that the TBI group are similarly affected by the delay period as controls in saccade initiation and inhibition of reflexive saccades during delay period. However, the TBI group generated more incorrect saccades than controls, to the target direction after the delay, suggesting impaired working memory and/or decision-making capacity.
This is a 2020 ARVO Annual Meeting abstract.