Limits...
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.

Show MeSH

Related in: MedlinePlus

Hand-velocity variables.Effects of recall-delay and cognitive-task on hand velocity (peak resultant velocity in the transverse plane, time-to-peak-velocity and time-after-peak-velocity) are shown in (A) and (B), respectively. Means and standard deviations are shown for young adults (gray) and older adults (black). Note that older adults tended to achieve lower peak velocity, as well as spending significantly longer time on deceleration (i.e. larger time-after-peak-velocity). § indicates a significant difference due to age (main effect); * indicates a significant difference due to cognitive-task in (B) (α=0.05); whiskers indicate standard deviations.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3818305&req=5

pone-0079401-g005: Hand-velocity variables.Effects of recall-delay and cognitive-task on hand velocity (peak resultant velocity in the transverse plane, time-to-peak-velocity and time-after-peak-velocity) are shown in (A) and (B), respectively. Means and standard deviations are shown for young adults (gray) and older adults (black). Note that older adults tended to achieve lower peak velocity, as well as spending significantly longer time on deceleration (i.e. larger time-after-peak-velocity). § indicates a significant difference due to age (main effect); * indicates a significant difference due to cognitive-task in (B) (α=0.05); whiskers indicate standard deviations.

Mentions: The recall-delay analyses, in trials with no secondary cognitive task, indicated that older adults tended to have slower responses than the young adults, across all recall-delay times, in terms of EMG latency, movement-time, time to handhold-contact and time-after-peak-velocity [mean differences of 17-69ms; F’s(1,18)≥7.04, p’s≤0.016; Figure 4A and 5A]. There was, however, no statistical evidence that older adults were more likely to sustain hand-handhold collision (4-5% of trials in each age group; p=0.63) or less likely to achieve a complete grasp (60% of trials vs. 71% in young adults; p=0.51). Analyses of reach trajectory and endpoint error (systematic or variable) also revealed no statistically significant main effects due to age (p's>0.14; Figure 6C, 7A, 8A), although there was an apparent (but not significant, p’s>0.07) tendency for the older adults to transport the hand with a more lateral trajectory; see Figure 6A and 6C.


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)

Hand-velocity variables.Effects of recall-delay and cognitive-task on hand velocity (peak resultant velocity in the transverse plane, time-to-peak-velocity and time-after-peak-velocity) are shown in (A) and (B), respectively. Means and standard deviations are shown for young adults (gray) and older adults (black). Note that older adults tended to achieve lower peak velocity, as well as spending significantly longer time on deceleration (i.e. larger time-after-peak-velocity). § indicates a significant difference due to age (main effect); * indicates a significant difference due to cognitive-task in (B) (α=0.05); whiskers indicate standard deviations.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0079401-g005: Hand-velocity variables.Effects of recall-delay and cognitive-task on hand velocity (peak resultant velocity in the transverse plane, time-to-peak-velocity and time-after-peak-velocity) are shown in (A) and (B), respectively. Means and standard deviations are shown for young adults (gray) and older adults (black). Note that older adults tended to achieve lower peak velocity, as well as spending significantly longer time on deceleration (i.e. larger time-after-peak-velocity). § indicates a significant difference due to age (main effect); * indicates a significant difference due to cognitive-task in (B) (α=0.05); whiskers indicate standard deviations.
Mentions: The recall-delay analyses, in trials with no secondary cognitive task, indicated that older adults tended to have slower responses than the young adults, across all recall-delay times, in terms of EMG latency, movement-time, time to handhold-contact and time-after-peak-velocity [mean differences of 17-69ms; F’s(1,18)≥7.04, p’s≤0.016; Figure 4A and 5A]. There was, however, no statistical evidence that older adults were more likely to sustain hand-handhold collision (4-5% of trials in each age group; p=0.63) or less likely to achieve a complete grasp (60% of trials vs. 71% in young adults; p=0.51). Analyses of reach trajectory and endpoint error (systematic or variable) also revealed no statistically significant main effects due to age (p's>0.14; Figure 6C, 7A, 8A), although there was an apparent (but not significant, p’s>0.07) tendency for the older adults to transport the hand with a more lateral trajectory; see Figure 6A and 6C.

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