Premature eye movements (fixation breaks)
Young adults generally exhibited fewer antisaccade trials with fixation breaks (mean = 4.2 ± 9.4%) than elderly (mean = 8.4 ± 7.4) and patients (mean = 9.0 ± 13.7%), although this trend did not reach significance (F(1,36) = 2.20, p < 0.145). Reward anticipation did not affect fixation breaks in any of the groups. Adding specific cues led to a significant increase in fixation breaks in elderly (non-specific mean = 4.4 ± 5.3%; specific mean = 12.4 ± 10.7% (F(1,17) = 19.084, p < 0.0001) and patients (non-specific mean = 7.0 ± 12.2%; specific mean = 10.9 ± 16.0% (F(1,19) = 5.238, p < 0.034), and a marginal increase in young (non-specific mean = 1.9 ± 4.7%; specific mean = 6.5 ± 14.3% (F(1,17) = 3.841, p < 0.068). No significant effects of cue-target intervals on fixation breaks were found in any of the groups.