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Age-Specific Effects of Mirror-Muscle Activity on Cross-Limb Adaptations Under Mirror and Non-Mirror Visual Feedback Conditions.

Reissig P, Stöckel T, Garry MI, Summers JJ, Hinder MR - Front Aging Neurosci (2015)

Bottom Line: Training resulted in significant bilateral performance gains that did not differ as a result of age or visual feedback (both p > 0.1).For younger adults, CLT was significantly predicted by performance gains in the trained hand (β = 0.47), whereas for older adults it was significantly predicted by mirror activity in the untrained hand during training (β = 0.60).In this particular task, MVF did not facilitate the extent of CLT.

View Article: PubMed Central - PubMed

Affiliation: Human Motor Control Laboratory, School of Medicine, Faculty of Health, University of Tasmania Hobart, TAS, Australia ; Faculty of Health Graduate Research Program, University of Tasmania Hobart, TAS, Australia.

ABSTRACT
Cross-limb transfer (CLT) describes the observation of bilateral performance gains due to unilateral motor practice. Previous research has suggested that CLT may be reduced, or absent, in older adults, possibly due to age-related structural and functional brain changes. Based on research showing increases in CLT due to the provision of mirror visual feedback (MVF) during task execution in young adults, our study aimed to investigate whether MVF can facilitate CLT in older adults, who are known to be more reliant on visual feedback for accurate motor performance. Participants (N = 53) engaged in a short-term training regime (300 movements) involving a ballistic finger task using their dominant hand, while being provided with either visual feedback of their active limb, or a mirror reflection of their active limb (superimposed over the quiescent limb). Performance in both limbs was examined before, during and following the unilateral training. Furthermore, we measured corticospinal excitability (using TMS) at these time points, and assessed muscle activity bilaterally during the task via EMG; these parameters were used to investigate the mechanisms mediating and predicting CLT. Training resulted in significant bilateral performance gains that did not differ as a result of age or visual feedback (both p > 0.1). Training also elicited bilateral increases in corticospinal excitability (p < 0.05). For younger adults, CLT was significantly predicted by performance gains in the trained hand (β = 0.47), whereas for older adults it was significantly predicted by mirror activity in the untrained hand during training (β = 0.60). The present study suggests that older adults are capable of exhibiting CLT to a similar degree to younger adults. The prominent role of mirror activity in the untrained hand for CLT in older adults indicates that bilateral cortical activity during unilateral motor tasks is a compensatory mechanism. In this particular task, MVF did not facilitate the extent of CLT.

No MeSH data available.


Related in: MedlinePlus

Normalized (n) performance of the untrained (left column) and the trained (right column) hand in the pre-, mid-, and post-test for the young (top row) and the older (bottom row) groups. Error bars denote SEM.
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Figure 3: Normalized (n) performance of the untrained (left column) and the trained (right column) hand in the pre-, mid-, and post-test for the young (top row) and the older (bottom row) groups. Error bars denote SEM.

Mentions: A subsequent analysis on nACC revealed a significant main effect of time, F(1,49) = 29.27, p < 0.001, = 0.374. Post hoc comparisons showed that acceleration was greater at post-test (M = 1.46 [1.36, 1.57]) when compared to mid-test (M = 1.28 [1.20, 1.36]), p < 0.001. Furthermore, an interpretation of 95% CI’s indicated that acceleration was greater at mid-test than at pre-test for both the trained hand (M = 1.33 [1.23, 1.43]) and the untrained hand (M = 1.23 [1.14, 1.32]). A significant main effect of hand revealed greater acceleration in the trained hand (M = 1.48 [1.36, 1.60]) compared to the untrained hand (M = 1.27 [1.17, 1.36]), F(1,49) = 14.96, p < 0.001, = 0.234. In addition, the time × hand interaction was also found to be significant, F(1,49) = 13.33, p = 0.001, = 0.214. Post hoc comparisons revealed that acceleration at mid-test did not differ between the trained hand (M = 1.33 [1.23, 1.43]) and the untrained hand (M = 1.23 [1.14, 1.32]; p = 0.081, d = 0.285), while at post-test it was significantly higher in the trained hand (M = 1.63 [1.48, 1.78]) than the untrained hand (M = 1.30 [1.19, 1.41]; p < 0.001, d = 0.705). The main effects of age, F(1,49) = 2.54, p = 0.117, = 0.049, and feedback, F(1,49) = 1.12, p = 0.295, = 0.022, were not significant. No other significant interactions were found (all F < 2.19, all p > 0.146; Figure 3).


Age-Specific Effects of Mirror-Muscle Activity on Cross-Limb Adaptations Under Mirror and Non-Mirror Visual Feedback Conditions.

Reissig P, Stöckel T, Garry MI, Summers JJ, Hinder MR - Front Aging Neurosci (2015)

Normalized (n) performance of the untrained (left column) and the trained (right column) hand in the pre-, mid-, and post-test for the young (top row) and the older (bottom row) groups. Error bars denote SEM.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4664666&req=5

Figure 3: Normalized (n) performance of the untrained (left column) and the trained (right column) hand in the pre-, mid-, and post-test for the young (top row) and the older (bottom row) groups. Error bars denote SEM.
Mentions: A subsequent analysis on nACC revealed a significant main effect of time, F(1,49) = 29.27, p < 0.001, = 0.374. Post hoc comparisons showed that acceleration was greater at post-test (M = 1.46 [1.36, 1.57]) when compared to mid-test (M = 1.28 [1.20, 1.36]), p < 0.001. Furthermore, an interpretation of 95% CI’s indicated that acceleration was greater at mid-test than at pre-test for both the trained hand (M = 1.33 [1.23, 1.43]) and the untrained hand (M = 1.23 [1.14, 1.32]). A significant main effect of hand revealed greater acceleration in the trained hand (M = 1.48 [1.36, 1.60]) compared to the untrained hand (M = 1.27 [1.17, 1.36]), F(1,49) = 14.96, p < 0.001, = 0.234. In addition, the time × hand interaction was also found to be significant, F(1,49) = 13.33, p = 0.001, = 0.214. Post hoc comparisons revealed that acceleration at mid-test did not differ between the trained hand (M = 1.33 [1.23, 1.43]) and the untrained hand (M = 1.23 [1.14, 1.32]; p = 0.081, d = 0.285), while at post-test it was significantly higher in the trained hand (M = 1.63 [1.48, 1.78]) than the untrained hand (M = 1.30 [1.19, 1.41]; p < 0.001, d = 0.705). The main effects of age, F(1,49) = 2.54, p = 0.117, = 0.049, and feedback, F(1,49) = 1.12, p = 0.295, = 0.022, were not significant. No other significant interactions were found (all F < 2.19, all p > 0.146; Figure 3).

Bottom Line: Training resulted in significant bilateral performance gains that did not differ as a result of age or visual feedback (both p > 0.1).For younger adults, CLT was significantly predicted by performance gains in the trained hand (β = 0.47), whereas for older adults it was significantly predicted by mirror activity in the untrained hand during training (β = 0.60).In this particular task, MVF did not facilitate the extent of CLT.

View Article: PubMed Central - PubMed

Affiliation: Human Motor Control Laboratory, School of Medicine, Faculty of Health, University of Tasmania Hobart, TAS, Australia ; Faculty of Health Graduate Research Program, University of Tasmania Hobart, TAS, Australia.

ABSTRACT
Cross-limb transfer (CLT) describes the observation of bilateral performance gains due to unilateral motor practice. Previous research has suggested that CLT may be reduced, or absent, in older adults, possibly due to age-related structural and functional brain changes. Based on research showing increases in CLT due to the provision of mirror visual feedback (MVF) during task execution in young adults, our study aimed to investigate whether MVF can facilitate CLT in older adults, who are known to be more reliant on visual feedback for accurate motor performance. Participants (N = 53) engaged in a short-term training regime (300 movements) involving a ballistic finger task using their dominant hand, while being provided with either visual feedback of their active limb, or a mirror reflection of their active limb (superimposed over the quiescent limb). Performance in both limbs was examined before, during and following the unilateral training. Furthermore, we measured corticospinal excitability (using TMS) at these time points, and assessed muscle activity bilaterally during the task via EMG; these parameters were used to investigate the mechanisms mediating and predicting CLT. Training resulted in significant bilateral performance gains that did not differ as a result of age or visual feedback (both p > 0.1). Training also elicited bilateral increases in corticospinal excitability (p < 0.05). For younger adults, CLT was significantly predicted by performance gains in the trained hand (β = 0.47), whereas for older adults it was significantly predicted by mirror activity in the untrained hand during training (β = 0.60). The present study suggests that older adults are capable of exhibiting CLT to a similar degree to younger adults. The prominent role of mirror activity in the untrained hand for CLT in older adults indicates that bilateral cortical activity during unilateral motor tasks is a compensatory mechanism. In this particular task, MVF did not facilitate the extent of CLT.

No MeSH data available.


Related in: MedlinePlus