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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.


Related in: MedlinePlus

Mean time course for reaching finger displacement and velocity in one young (left panels) and one elderly (right panels) participant during the pro- and anti-tasks. Displacement (A) and velocity (C) for the mediolateral direction with right- and left-ward displacements. Displacement (B) and velocity (D) for the vertical direction with up- and down-ward displacements. Bottom panels are horizontal reaching movement velocities (y-direction) (E). A time of 0 s corresponds to the onset of the target displacement to a new position. Gray triangles represent TJR onset, and vertical dots lines show peak TJR time for each participant. Orange shaded areas show a period for calculating the directional differences of TJR.
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Figure 3: Mean time course for reaching finger displacement and velocity in one young (left panels) and one elderly (right panels) participant during the pro- and anti-tasks. Displacement (A) and velocity (C) for the mediolateral direction with right- and left-ward displacements. Displacement (B) and velocity (D) for the vertical direction with up- and down-ward displacements. Bottom panels are horizontal reaching movement velocities (y-direction) (E). A time of 0 s corresponds to the onset of the target displacement to a new position. Gray triangles represent TJR onset, and vertical dots lines show peak TJR time for each participant. Orange shaded areas show a period for calculating the directional differences of TJR.

Mentions: Figures 3A,C show the mean curves of mediolateral displacement and velocity for young and elderly participants when responding to right and left target displacement during the pro- and anti-tasks. Figures 3B,D show the corresponding vertical displacement and velocity for upward and downward target displacements. Figure 3E shows horizontal reaching movement velocities (y-direction). The TJR was not evident in any of the displacement trajectories for either young or elderly participants. In contrast, the velocity trajectories showed a notable early response, indicating a TJR at around 150 ms during the pro- and anti-tasks for the four directions. Note that during the anti-task, a TJR occurred in the direction of the target displacement, indicating that this early movement modulation was not under volitional control. The corrective movements shown in these displacement and velocity curves were quite similar for the different target-displacement directions.


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)

Mean time course for reaching finger displacement and velocity in one young (left panels) and one elderly (right panels) participant during the pro- and anti-tasks. Displacement (A) and velocity (C) for the mediolateral direction with right- and left-ward displacements. Displacement (B) and velocity (D) for the vertical direction with up- and down-ward displacements. Bottom panels are horizontal reaching movement velocities (y-direction) (E). A time of 0 s corresponds to the onset of the target displacement to a new position. Gray triangles represent TJR onset, and vertical dots lines show peak TJR time for each participant. Orange shaded areas show a period for calculating the directional differences of TJR.
© Copyright Policy
Related In: Results  -  Collection

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

Figure 3: Mean time course for reaching finger displacement and velocity in one young (left panels) and one elderly (right panels) participant during the pro- and anti-tasks. Displacement (A) and velocity (C) for the mediolateral direction with right- and left-ward displacements. Displacement (B) and velocity (D) for the vertical direction with up- and down-ward displacements. Bottom panels are horizontal reaching movement velocities (y-direction) (E). A time of 0 s corresponds to the onset of the target displacement to a new position. Gray triangles represent TJR onset, and vertical dots lines show peak TJR time for each participant. Orange shaded areas show a period for calculating the directional differences of TJR.
Mentions: Figures 3A,C show the mean curves of mediolateral displacement and velocity for young and elderly participants when responding to right and left target displacement during the pro- and anti-tasks. Figures 3B,D show the corresponding vertical displacement and velocity for upward and downward target displacements. Figure 3E shows horizontal reaching movement velocities (y-direction). The TJR was not evident in any of the displacement trajectories for either young or elderly participants. In contrast, the velocity trajectories showed a notable early response, indicating a TJR at around 150 ms during the pro- and anti-tasks for the four directions. Note that during the anti-task, a TJR occurred in the direction of the target displacement, indicating that this early movement modulation was not under volitional control. The corrective movements shown in these displacement and velocity curves were quite similar for the different target-displacement directions.

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.


Related in: MedlinePlus