Optomotor and neuropsychological performance in old age

While a delayed initiation of visually guided saccades with increasing age has been documented in a number of studies, little research has been done on the control of antisaccades. The present study investigates aging effects on the control of visually guided saccades (prosaccades) and antisaccades as well as a selection of neuropsychological functions by the cross-sectional comparison of 14, 22, and 16 participants aged 20-35 years, 59-73 years, and 74-88 years, respectively. The geriatric and neurological status of the elder participants (including evidence from computed tomography, electroencephalography, and neurological soft signs) was assessed. In four task blocks of 200 trials each, pro- and antisaccades were elicited under the 200-ms-gap and overlap conditions. Left- and right-sided stimuli were presented in random order at 4 degrees, and the order of the task blocks was varied within each age group. In addition, the Wisconsin card-sorting test (WCST) and working memory, go-nogo discrimination, alertness, and stimulus-response incompatibility tests were administered. Participants aged 59-73 years exhibited widespread reductions of optomotor and neuropsychological performance, with greatest effect sizes of age differences in the optomotor parameters and the WCST measures. A further decay after the age of 73 years was discernible in those optomotor functions reflecting saccade disinhibition (in particular, directional errors during the antisaccade task and premature responses) and the performance in some neuropsychological tests. In line with previously published reports, variance in optomotor performance could be explained by two factors, accounting for a total of 76% of the age variance. Our results suggest that the investigation of saccade control may be a highly sensitive tool for neurodevelopmental aging research.