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The impact of aging on the spatial accuracy of quick corrective arm movements in response to sudden target displacement during reaching.

Kimura D, Kadota K, Kinoshita H - Front Aging Neurosci (2015)

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Biomechanics and Motor Control Laboratory, Graduate School of Medicine, Osaka University Toyonaka, Japan.

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.

No MeSH data available.


Typical examples of mean reaching trajectories during the pro-task (A,B) and anti-task (C,D) performed by young (A,C) and elderly (B,D) participants. Squares and triangles indicate the starting hand position and the mean hand position at the moment of target displacement, respectively. Red triangles indicate TJR onset, and filled, black triangles indicate peak TJR time. Circles represent endpoints in the pro-task for each target displacement direction.
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Figure 2: Typical examples of mean reaching trajectories during the pro-task (A,B) and anti-task (C,D) performed by young (A,C) and elderly (B,D) participants. Squares and triangles indicate the starting hand position and the mean hand position at the moment of target displacement, respectively. Red triangles indicate TJR onset, and filled, black triangles indicate peak TJR time. Circles represent endpoints in the pro-task for each target displacement direction.

Mentions: Figure 2 shows representative mean reaching trajectories during the pro- and anti-tasks performed by young and elderly participants. For the TJR trials, the corrective reaching movement of the finger during the pro-task commonly occurred relatively close to the screen (Figures 2A,B). During the anti-task, the hand first moved towards the opposite side and then switched direction; thus, the corrective reaching movement occurred even closer to the screen compared to the pro-task (Figures 2C,D). For any of these trajectories, the early part of the TJR was hardly discernible due to a small magnitude. Furthermore, differences between young and elderly participants regarding reaching trajectories were not evident.


The impact of aging on the spatial accuracy of quick corrective arm movements in response to sudden target displacement during reaching.

Kimura D, Kadota K, Kinoshita H - Front Aging Neurosci (2015)

Typical examples of mean reaching trajectories during the pro-task (A,B) and anti-task (C,D) performed by young (A,C) and elderly (B,D) participants. Squares and triangles indicate the starting hand position and the mean hand position at the moment of target displacement, respectively. Red triangles indicate TJR onset, and filled, black triangles indicate peak TJR time. Circles represent endpoints in the pro-task for each target displacement direction.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4585039&req=5

Figure 2: Typical examples of mean reaching trajectories during the pro-task (A,B) and anti-task (C,D) performed by young (A,C) and elderly (B,D) participants. Squares and triangles indicate the starting hand position and the mean hand position at the moment of target displacement, respectively. Red triangles indicate TJR onset, and filled, black triangles indicate peak TJR time. Circles represent endpoints in the pro-task for each target displacement direction.
Mentions: Figure 2 shows representative mean reaching trajectories during the pro- and anti-tasks performed by young and elderly participants. For the TJR trials, the corrective reaching movement of the finger during the pro-task commonly occurred relatively close to the screen (Figures 2A,B). During the anti-task, the hand first moved towards the opposite side and then switched direction; thus, the corrective reaching movement occurred even closer to the screen compared to the pro-task (Figures 2C,D). For any of these trajectories, the early part of the TJR was hardly discernible due to a small magnitude. Furthermore, differences between young and elderly participants regarding reaching trajectories were not evident.

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Biomechanics and Motor Control Laboratory, Graduate School of Medicine, Osaka University Toyonaka, Japan.

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.

No MeSH data available.