title: The impact of aging on the spatial accuracy of quick corrective arm movements in response to sudden target displacement during reaching.
abstract: Age-related declines in visuomotor processing speed can have a large impact on motor performance in elderly individuals. Contrary to previous findings, however, recent studies revealed that elderly individuals are able to quickly react to displacement of a visual target during reaching. Here, we investigated the influence of aging on quick, corrective responses to perturbations during reaching in the terms of their functional contribution to accuracy. Elderly and young adults performed reaching movements to a visual target that could be displaced during reaching, and they were requested to move their hand to reach the final target location as quickly as possible. Results showed that, for the younger group, the variance in the directional error of the corrective response correlated with the variance in the reaching trajectory at the halfway point of the reach, but the correlation decreased at the end of the reaching. On the other hand, such correlations were not significant in elderly participants, although the variance of the directional error did not show a significant difference between age groups. Thus, the quick, corrective response seems to play an important role in decreasing variability, especially before the end of reaching, and aging can impair this process.
authors.affiliation: Biomechanics and Motor Control Laboratory, Graduate School of Medicine, Osaka University Toyonaka, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Kimura
authors.affiliation: Biomechanics and Motor Control Laboratory, Graduate School of Medicine, Osaka University Toyonaka, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Kadota
authors.affiliation: Biomechanics and Motor Control Laboratory, Graduate School of Medicine, Osaka University Toyonaka, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kinoshita
keywords: implicit motor control; online feedback control; reaching accuracy; reflexive correction; response latency