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Do aging and dual-tasking impair the capacity to store and retrieve visuospatial information needed to guide perturbation-evoked reach-to-grasp reactions?

Cheng KC, Pratt J, Maki BE - PLoS ONE (2013)

Bottom Line: Ten healthy older adults were tested with the previous protocol and compared with the previously-tested young adults.Both age groups showed similar reduction in medio-lateral end-point accuracy when recall-delay was longest (10 s), but differed in the effect of recall delay on vertical hand elevation.For both age groups, engaging in either the non-spatial or spatial-memory task had similar (slowing) effects on the arm reactions; however, the older adults also showed a dual-task interference effect (poorer cognitive-task performance) that was specific to the spatial-memory task.

View Article: PubMed Central - PubMed

Affiliation: Toronto Rehabilitation Institute, University Health Network, Toronto, Ontario, Canada ; Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada ; Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.

ABSTRACT
A recent study involving young adults showed that rapid perturbation-evoked reach-to-grasp balance-recovery reactions can be guided successfully with visuospatial-information (VSI) retained in memory despite: 1) a reduction in endpoint accuracy due to recall-delay (time between visual occlusion and perturbation-onset, PO) and 2) slowing of the reaction when performing a concurrent cognitive task during the recall-delay interval. The present study aimed to determine whether this capacity is compromised by effects of aging. Ten healthy older adults were tested with the previous protocol and compared with the previously-tested young adults. Reactions to recover balance by grasping a small handhold were evoked by unpredictable antero-posterior platform-translation (barriers deterred stepping reactions), while using liquid-crystal goggles to occlude vision post-PO and for varying recall-delay times (0-10 s) prior to PO (the handhold was moved unpredictably to one of four locations 2 s prior to vision-occlusion). Subjects also performed a spatial- or non-spatial-memory cognitive task during the delay-time in a subset of trials. Results showed that older adults had slower reactions than the young across all experimental conditions. Both age groups showed similar reduction in medio-lateral end-point accuracy when recall-delay was longest (10 s), but differed in the effect of recall delay on vertical hand elevation. For both age groups, engaging in either the non-spatial or spatial-memory task had similar (slowing) effects on the arm reactions; however, the older adults also showed a dual-task interference effect (poorer cognitive-task performance) that was specific to the spatial-memory task. This provides new evidence that spatial working memory plays a role in the control of perturbation-evoked balance-recovery reactions. The delays in completing the reaction that occurred when performing either cognitive task suggest that such dual-task situations in daily life could increase risk of falling in seniors, particularly when combined with the general age-related slowing that was observed across all experimental conditions.

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Related in: MedlinePlus

Motion platform and moveable handhold systems.Dashed lines in the insert indicate the four handhold positions that were tested. Analysis focused on the highlighted handhold position (33% shoulder-width*) and anterior platform translations (backward falling motion).
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pone-0079401-g001: Motion platform and moveable handhold systems.Dashed lines in the insert indicate the four handhold positions that were tested. Analysis focused on the highlighted handhold position (33% shoulder-width*) and anterior platform translations (backward falling motion).

Mentions: The protocol was identical to an earlier study involving only healthy young adults [8]. Balance-recovery reach-to-grasp reactions were evoked by sudden forward (0.12m, 0.41m/s, 1.4m/s2) or backward (0.18m, 0.6m/s, 2.0m/s2) translation of a 2m×2m computer-controlled motion-platform [20]. In each trial, a motor-driven device [21] mounted on the platform controlled a cylindrical handhold to move along a transverse axis in front of the subject (distance from handhold to back of heels=33% of body height; handhold height=60% of body height) and to stop unpredictably at one of four locations [0%, 33%, 67% or 100% of shoulder-width (SW) to the right of the mid-sagittal plane; Figure 1]. The focus of the study was on the grasping reactions evoked by forward platform translation (backward falling motion), in trials where the handhold was positioned at 33% of shoulder-width from the mid-sagittal plane; however, other combinations of handhold position and perturbation direction were also included to increase unpredictability and deter anticipatory reactions or other proactive strategies (see Table 2). For safety, subjects wore a harness designed to prevent impact between body and floor, as well as padded gloves and wrist guards to reduce impact to the hands and wrist if and when collision to the back of hand or wrist occurred. The padding was only on the dorsal side of the hand and did not interfere with grasping.


Do aging and dual-tasking impair the capacity to store and retrieve visuospatial information needed to guide perturbation-evoked reach-to-grasp reactions?

Cheng KC, Pratt J, Maki BE - PLoS ONE (2013)

Motion platform and moveable handhold systems.Dashed lines in the insert indicate the four handhold positions that were tested. Analysis focused on the highlighted handhold position (33% shoulder-width*) and anterior platform translations (backward falling motion).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3818305&req=5

pone-0079401-g001: Motion platform and moveable handhold systems.Dashed lines in the insert indicate the four handhold positions that were tested. Analysis focused on the highlighted handhold position (33% shoulder-width*) and anterior platform translations (backward falling motion).
Mentions: The protocol was identical to an earlier study involving only healthy young adults [8]. Balance-recovery reach-to-grasp reactions were evoked by sudden forward (0.12m, 0.41m/s, 1.4m/s2) or backward (0.18m, 0.6m/s, 2.0m/s2) translation of a 2m×2m computer-controlled motion-platform [20]. In each trial, a motor-driven device [21] mounted on the platform controlled a cylindrical handhold to move along a transverse axis in front of the subject (distance from handhold to back of heels=33% of body height; handhold height=60% of body height) and to stop unpredictably at one of four locations [0%, 33%, 67% or 100% of shoulder-width (SW) to the right of the mid-sagittal plane; Figure 1]. The focus of the study was on the grasping reactions evoked by forward platform translation (backward falling motion), in trials where the handhold was positioned at 33% of shoulder-width from the mid-sagittal plane; however, other combinations of handhold position and perturbation direction were also included to increase unpredictability and deter anticipatory reactions or other proactive strategies (see Table 2). For safety, subjects wore a harness designed to prevent impact between body and floor, as well as padded gloves and wrist guards to reduce impact to the hands and wrist if and when collision to the back of hand or wrist occurred. The padding was only on the dorsal side of the hand and did not interfere with grasping.

Bottom Line: Ten healthy older adults were tested with the previous protocol and compared with the previously-tested young adults.Both age groups showed similar reduction in medio-lateral end-point accuracy when recall-delay was longest (10 s), but differed in the effect of recall delay on vertical hand elevation.For both age groups, engaging in either the non-spatial or spatial-memory task had similar (slowing) effects on the arm reactions; however, the older adults also showed a dual-task interference effect (poorer cognitive-task performance) that was specific to the spatial-memory task.

View Article: PubMed Central - PubMed

Affiliation: Toronto Rehabilitation Institute, University Health Network, Toronto, Ontario, Canada ; Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada ; Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.

ABSTRACT
A recent study involving young adults showed that rapid perturbation-evoked reach-to-grasp balance-recovery reactions can be guided successfully with visuospatial-information (VSI) retained in memory despite: 1) a reduction in endpoint accuracy due to recall-delay (time between visual occlusion and perturbation-onset, PO) and 2) slowing of the reaction when performing a concurrent cognitive task during the recall-delay interval. The present study aimed to determine whether this capacity is compromised by effects of aging. Ten healthy older adults were tested with the previous protocol and compared with the previously-tested young adults. Reactions to recover balance by grasping a small handhold were evoked by unpredictable antero-posterior platform-translation (barriers deterred stepping reactions), while using liquid-crystal goggles to occlude vision post-PO and for varying recall-delay times (0-10 s) prior to PO (the handhold was moved unpredictably to one of four locations 2 s prior to vision-occlusion). Subjects also performed a spatial- or non-spatial-memory cognitive task during the delay-time in a subset of trials. Results showed that older adults had slower reactions than the young across all experimental conditions. Both age groups showed similar reduction in medio-lateral end-point accuracy when recall-delay was longest (10 s), but differed in the effect of recall delay on vertical hand elevation. For both age groups, engaging in either the non-spatial or spatial-memory task had similar (slowing) effects on the arm reactions; however, the older adults also showed a dual-task interference effect (poorer cognitive-task performance) that was specific to the spatial-memory task. This provides new evidence that spatial working memory plays a role in the control of perturbation-evoked balance-recovery reactions. The delays in completing the reaction that occurred when performing either cognitive task suggest that such dual-task situations in daily life could increase risk of falling in seniors, particularly when combined with the general age-related slowing that was observed across all experimental conditions.

Show MeSH
Related in: MedlinePlus