Reliability of smooth pursuit, fixation, and saccadic eye movements

The present study investigated the reliability and susceptibility to practice effects of oculomotor tasks. Smooth pursuit, fixation. antisaccade, and prosaccade tasks were administered to 31 healthy participants to assess internal consistency (Cronbach's alpha') and within-session practice effects. Twenty-one of these participants were retested after an average interval of 57.86 days to assess temporal stability and between-session practice effects. Internal consistencies were high for most measures. with few within-session performance changes. Test-retest reliabilities of most measures were good. Between-session practice effects were most consistently observed on the antisaccade task, indicated by reduced error rate and improved spatial accuracy at retest. Magnitude of improvement on these measures was related to performance, indicating that poor performers benefited most from repeated assessment. These findings support the trait nature of oculomotor function and point to the need to take into consideration between-session practice effects on the antisaccade task in longitudinal studies.