UNIVERSO POBLACIÓN
Taller 5 RECONOCE Y AMA TU CUERPO EN TCHOUKBALL Fecha: 8 de octubre de
For the tapping task we compared the number of taps made pre – and post-intervention (within-subjects factor: time), with the healthy vs. the impaired hand (within-subjects factor:
0 5 10 15 20 25 30 35 40 45
Before Intervention After Intervention Before Intervention After Intervention
Exprimental Controls A R A T Pe rfor m an ce ARAT TEST
71
hand), for unimanual and bimanual movements (within-subjects factor: action) and across experimental and control groups (between-subjects factors: group). There was no overall effect of group ( F (1, 14) = 1.219, p = 0.288). There were reliable main effects of hand ( F (1, 14) = 15.880, p = 0.001), action ( F (1, 14) = 29.646, p < 0.001) and time ( F (1, 14) = 239.471, p < 0.001). There were also two 2-way significant interactions between hand and group ( F (1, 14) = 10.163, p = 0.007) and hand and time ( F (1, 14) = 13.339, p = 0.003). There were also two 3- way interactions between hand, time and group ( F (1, 14) = 9.603, p = 0.008) and between hand, action and time ( F (1, 14) = 3.279, p = 0.034). Figures 14-16.
Figure 14a and 14b: Pre and Post mirror therapy tapping performance (in terms of N(Taps) for control participants a) Healthy Hand and b) Impaired Hand. Error bars depict 1 SE on each side of the mean
Figure 15a and 15b: Pre and Post mirror therapy tapping performance (in terms of N(Taps) for experimental participants a) Healthy Hand and b) Impaired Hand. Error bars depict 1 SE on each side of the mean
5 25 45 65 85
Pre Post Pre Post Unimanual Bimanual
Tap
p
in
g
Healthy Hand - Controls
5 25 45 65 85
Pre Post Pre Post Unimanual Bimanual
Tap
p
in
g
Impaired Hand - Controls
5 25 45 65 85
Pre Post Pre Post Unimanual Bimanual
Tap
p
in
g
Healthy Hand - MT Group
5 25 45 65 85
Pre Post Pre Post Unimanual Bimanual
Tap
p
in
g
72
Figure 16: Pre and Post mirror therapy tapping performance (in terms of N(Taps) for all participants per group following average of time and task. Error bars depict 1 SE on each side of the mean
The 3-way interaction between hand, time and group was broken down by running two 2- way ANOVAs, one for each group. For the control group, the ANOVA returned a significant main effect of time ( F (1, 7) = 93.659, p < 0.001) and no significant effect of hand and no hand x time interaction (Figure 16). For the MT group there were significant effects of hand ( F (1, 7) = 18.481 p = 0.004) and time ( F (1, 7) = 174.335, p < 0.001). Also, there was a significant interaction between hand and time ( F (1, 7) = 13.803, p = 0.008). In order to identify significant changes per time for the healthy and impaired hand separate t-tests were ran. There was a significant effect for the impaired hand per time ( t (7) = -6.517), p < 0.001). The same t-test for the intact hand was not significant ( t (7) = .720, p = 0.495).
The 3-way interaction between hand, action and time, was assessed by means of two 2x2 ANOVA’s, one for each hand. For the healthy hand there was only a significant effect of time ( F (1, 7) = 20.896, p = 0.003) revealing more taps post intervention. For the impaired hand there were significant main effects of action ( F (1, 7) = 30.822, p = 0.001) and time ( F (1, 7) = 13.445, p = 0.008). There were more taps post- relative to pre-intervention, and there were more
5 55
Healthy Impaired Healthy Impaired Controls MT Group
Tap
p
in
g
Tapping Performance following averaged across time and task
73
taps with uni- relative to bimanual actions. There was no significant interaction of action and time for the impaired hand ( F (1, 7) = 3.294, p = 0.112).
3.4. DISCUSSION
The present study reports on the use of mirror therapy (MT) in chronic stroke subjects following a 4 weeks course of home based intervention. We demonstrated that MT generated functional improvements in motor performance. First, the data demonstrate chronic stroke participants may benefit from MT based on a clinical outcome measure, the Action Research Arm Test (ARAT). The change itself was relatively small in magnitude; specifically it was an averaged across the participants’ change of 24 to 33 (increase of 37.5%) for the experimental group and no significant change for the control group. Similar results of improvements have been noted in mirror therapy research papers such as: in Thieme et al. (2013) a change of 3.2 to 8.2 had been found in the experimental group (increase of 156%); in Dohle et al. (2012) no significant improvement found; in Lin et al. (2012) an increase of ARAT score from 8.5 to 12 has been argued (change of 41%). Similarly in other intervention such as Functional Electrical Stimulation (FES) similar functional improvements have been reported: Powell et al. (1999) argued an increase from 6 to 10 in ARAT performance which is equal to 67% and Sullivan and Hedman (2004) found an increase of 27 to 42 which can be translated in 55.5% improvement.
74
Therefore our findings represent a significant result both functional and clinical given the short term rehabilitation protocol.
Second, MT improved both unimanual and bimanual taps, though it did not change the ratio of tapping actions for the uni- and bimanual actions (there was no interaction between action and time). More specifically the lack of interaction between unimanual and bimanual task indicates that MT had an effect on limb use but not necessarily on attention to the limb as there remained a drop under bimanual condition, though tapping improved in both the uni- and the bimanual conditions.
The evidence that tapping improved for both the uni- and bimanual conditions is consistent with the general motor improvement in the patients trained using MT. If MT had also improved attention to the affected limb, we might have expected to see a differential improvement under the more attentionally demanding condition of bimanual movements. We did not. We conclude that MT improved motor function without differentially generating improved attention to the affected limb.
The argument for an effect of MT on motor output is supported by Fukumura et al. (2007). The authors proposed that MT as motor imagery enables increase of activation of the motor cortex and that motor imagery combined with observation of the moving hand in the mirror could have beneficial implication during the rehabilitation process. Brain imaging studies have shown that MT can induce enhanced visual activation in the superior occipital gyrus and the posterior parietal cortex (Matthys et al., 2009). This suggests that, by generating illusory visual feedback, MT increases the functional ability of the hand and maybe even further to promote bimanual tasks that are crucial for activities of daily living. There was no evidence here however that any sensory-associated activation in relation to MT had an impact on attention (differential
75
improvement under bimanual action) as opposed to movement alone. Rather the data are consistent with an effect on motor activity, perhaps operating through the mirror neuron system (Rizzolatti and Craighero, 2004). The functional and neural mechanisms through which MT operates is clearly a question that requires additional research.
Limitations. The present study had some limitations. The number of experimental participants’ (n=8) was relatively small and this constrains generalization for clinical use. Also, it would be useful to document the neural mechanisms of motor improvement using fMRI recorded prior to and post the intervention (see Michielsen et al, 2011). It should also be noted that the home-based approach adopted in this intervention applies is not clinically feasible in relation to the demands on monitoring the patient by the clinician.
76