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L.A. Abel, R. Fraser; The Effects of Ageing and Learning on Antisaccade and Memory–Guided Saccade Performance . Invest. Ophthalmol. Vis. Sci. 2006;47(13):2661.
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To evaluate the effects of normal ageing on antisaccades and memory–guided saccades and to determine whether with practice older subjects' performance approached that of younger subjects.
Eye movements were recorded in 16 young (23.2 ± 3.07 years) and 14 older subjects (65.9 ± 5.88 years) as they carried out 10 blocks of 15 trials each for the tasks. The antisaccade requires subjects to look oppositely from a target flash; the memory–guide task requires them to remember a flash's location but not look there until the fixation light goes off. Two memory–guided tasks, both the conventional version and one where the peripheral flash occurred during a 200 msec gap in the fixation light, were used.
Older subjects made significantly more errors on the antisaccade (41.93 vs 14.5, p< .001), memory–guided (30.6 vs 12.7, p<.05) and gap memory–guided (25.1 vs 10.3, p <.06) tasks. Latencies significantly increased with age for all tasks. Error rates declined with increasing trial number for both age groups on the conventional memory–guided task (young: r2 = 0.29, p=.11; older: r2 =0.38, p=.058) but not when a gap was present. In contrast, antisaccade errors significantly increased across trial number for both ages (young: r2 = 0.41, p < .05; older: r2 = 0.52, p < .02). Slopes on the conventional memory–guided and antisaccade tasks were similar between age groups. On the memory gap task, older subjects maintained a higher error rate, whilst younger subjects made fewer errors but their number significantly increased across trials. Latency showed very modest differences across trials for any task. Analysis of error latencies showed, surprisingly, that the presence of a gap during the occurrence of the target flash increased the proportion of long, not short, latency errors.
As many, but not all, authors have previously reported, age appears to impair performance on the antisaccade task. This also is the case on the much less studied memory–guided saccade task. Both age groups showed modest declines in errors across blocks of trials, but the performance of the older subjects did not approach that of the younger. Thus, practice over the course of a single session improves performance on these volitional saccade tasks but does so similarly for both age groups. Introduction of a gap before and during target presentation in the memory–guided task appears to disengage fixation for the duration of the trial.
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