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Action possibility judgments of people with varying motor abilities due to spinal cord injury.

Manson GA, Sayenko DG, Masani K, Goodman R, Wong L, Popovic MR, Tremblay L, Welsh TN - PLoS ONE (2014)

Bottom Line: Participants also performed the task.However, there were no between-group differences in judged MTs for the young adult.Although it is unclear how the judgments were adjusted (altered simulation vs. threshold modification), the data reveal that people with different motor capabilities due to SCI are not completely biased by their present capabilities and can effectively adjust their judgments to estimate the actions of others.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Kinesiology & Physical Education, University of Toronto, Toronto, Ontario, Canada; Centre for Motor Control, University of Toronto, Toronto, Ontario, Canada.

ABSTRACT
Predictions about one's own action capabilities as well as the action capabilities of others are thought to be based on a simulation process involving linked perceptual and motor networks. Given the central role of motor experience in the formation of these networks, one's present motor capabilities are thought to be the basis of their perceptual judgments about actions. However, it remains unknown whether the ability to form these action possibility judgments is affected by performance related changes in the motor system. To determine if judgments of action capabilities are affected by long-term changes in one's own motor capabilities, participants with different degrees of upper-limb function due to their level (cervical vs. below cervical) of spinal cord injury (SCI) were tested on a perceptual-motor judgment task. Participants observed apparent motion videos of reciprocal aiming movements with varying levels of difficulty. For each movement, participants determined the shortest movement time (MT) at which they themselves and a young adult could perform the task while maintaining accuracy. Participants also performed the task. Analyses of MTs revealed that perceptual judgments for participant's own movement capabilities were consistent with their actual performance- people with cervical SCI had longer judged and actual MTs than people with below cervical SCI. However, there were no between-group differences in judged MTs for the young adult. Although it is unclear how the judgments were adjusted (altered simulation vs. threshold modification), the data reveal that people with different motor capabilities due to SCI are not completely biased by their present capabilities and can effectively adjust their judgments to estimate the actions of others.

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Related in: MedlinePlus

Mean movement times (ms) as a function of Group and Index of Difficulty for the execution task.Open symbols with dashed connecting lines represent data from the group with cervical SCI. Closed symbols with solid connecting lines represent data from the group with below cervical SCI. SEM bars are shown.
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pone-0110250-g002: Mean movement times (ms) as a function of Group and Index of Difficulty for the execution task.Open symbols with dashed connecting lines represent data from the group with cervical SCI. Closed symbols with solid connecting lines represent data from the group with below cervical SCI. SEM bars are shown.

Mentions: The analysis of MTs from the execution task revealed main effects of ID, F(2, 38)  = 79.76, p<.05, and Group, F(1, 19)  = 8.08, p<.05. The Group by ID interaction approached but did not reach significance, F(2, 38)  = 2.81, p>.05. Overall, MTs increased with increases in movement difficulty as predicted by Fitts's Law (ID 2 = 272 ms; ID 3 = 312 ms; ID 4 = 380 ms). Further, the mean overall MTs for the group with cervical level injuries (369 ms) were longer than those for the group with below cervical SCI injuries (273 ms) (see Figure 2). For the correlation analyses, the categories of perceived arm function (see Table 1) were converted into a 1–4 Likert scale (1 =  Below Functional to 4 =  Very Good). Each participants' (i.e., participants in both the cervical and below cervical groups) assessment of their general capabilities were then correlated with movement times in the execution task. As expected, perceived arm function was significantly negatively correlated with movement times in the performance task, r = −.57, p<.01. The results of this analysis indicate that mean MTs decreased as the participants reported arm function increased. Although the observed between-group differences in MTs on the actual movement task is the most theoretically-relevant index of motor capability for the present purposes, it is reassuring to observe that the participant's assessment of their own capabilities on a 1–4 scale is consistent with their actual performance on the present movement task.


Action possibility judgments of people with varying motor abilities due to spinal cord injury.

Manson GA, Sayenko DG, Masani K, Goodman R, Wong L, Popovic MR, Tremblay L, Welsh TN - PLoS ONE (2014)

Mean movement times (ms) as a function of Group and Index of Difficulty for the execution task.Open symbols with dashed connecting lines represent data from the group with cervical SCI. Closed symbols with solid connecting lines represent data from the group with below cervical SCI. SEM bars are shown.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4215910&req=5

pone-0110250-g002: Mean movement times (ms) as a function of Group and Index of Difficulty for the execution task.Open symbols with dashed connecting lines represent data from the group with cervical SCI. Closed symbols with solid connecting lines represent data from the group with below cervical SCI. SEM bars are shown.
Mentions: The analysis of MTs from the execution task revealed main effects of ID, F(2, 38)  = 79.76, p<.05, and Group, F(1, 19)  = 8.08, p<.05. The Group by ID interaction approached but did not reach significance, F(2, 38)  = 2.81, p>.05. Overall, MTs increased with increases in movement difficulty as predicted by Fitts's Law (ID 2 = 272 ms; ID 3 = 312 ms; ID 4 = 380 ms). Further, the mean overall MTs for the group with cervical level injuries (369 ms) were longer than those for the group with below cervical SCI injuries (273 ms) (see Figure 2). For the correlation analyses, the categories of perceived arm function (see Table 1) were converted into a 1–4 Likert scale (1 =  Below Functional to 4 =  Very Good). Each participants' (i.e., participants in both the cervical and below cervical groups) assessment of their general capabilities were then correlated with movement times in the execution task. As expected, perceived arm function was significantly negatively correlated with movement times in the performance task, r = −.57, p<.01. The results of this analysis indicate that mean MTs decreased as the participants reported arm function increased. Although the observed between-group differences in MTs on the actual movement task is the most theoretically-relevant index of motor capability for the present purposes, it is reassuring to observe that the participant's assessment of their own capabilities on a 1–4 scale is consistent with their actual performance on the present movement task.

Bottom Line: Participants also performed the task.However, there were no between-group differences in judged MTs for the young adult.Although it is unclear how the judgments were adjusted (altered simulation vs. threshold modification), the data reveal that people with different motor capabilities due to SCI are not completely biased by their present capabilities and can effectively adjust their judgments to estimate the actions of others.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Kinesiology & Physical Education, University of Toronto, Toronto, Ontario, Canada; Centre for Motor Control, University of Toronto, Toronto, Ontario, Canada.

ABSTRACT
Predictions about one's own action capabilities as well as the action capabilities of others are thought to be based on a simulation process involving linked perceptual and motor networks. Given the central role of motor experience in the formation of these networks, one's present motor capabilities are thought to be the basis of their perceptual judgments about actions. However, it remains unknown whether the ability to form these action possibility judgments is affected by performance related changes in the motor system. To determine if judgments of action capabilities are affected by long-term changes in one's own motor capabilities, participants with different degrees of upper-limb function due to their level (cervical vs. below cervical) of spinal cord injury (SCI) were tested on a perceptual-motor judgment task. Participants observed apparent motion videos of reciprocal aiming movements with varying levels of difficulty. For each movement, participants determined the shortest movement time (MT) at which they themselves and a young adult could perform the task while maintaining accuracy. Participants also performed the task. Analyses of MTs revealed that perceptual judgments for participant's own movement capabilities were consistent with their actual performance- people with cervical SCI had longer judged and actual MTs than people with below cervical SCI. However, there were no between-group differences in judged MTs for the young adult. Although it is unclear how the judgments were adjusted (altered simulation vs. threshold modification), the data reveal that people with different motor capabilities due to SCI are not completely biased by their present capabilities and can effectively adjust their judgments to estimate the actions of others.

Show MeSH
Related in: MedlinePlus