4.1 Summary of the Study Results
Our findings were partially consistent with our hypotheses. The objectives of this study were to compare the differential efficiency among the RMT and RBAT group. All two groups have improved on sensorimotor function, daily function, self-efficacy and quality of life in patients after the interventions. No severe adverse effect was found and both groups had significantly decreased muscle tone in the upper limb. The results indicated that the different hybrid therapies may lead to different treatment effects, and that the robotic priming was applicable, safe, and promising interventions on chronic stroke rehabilitation.
The within-group results showed that both two groups led to the improvements on motor ability, muscle power, functional ability, self-perceived arm use, functional goal achievement, instrumental activities of daily living, quality of life and the ratio of affect arm activity counts. Form posttreatment to follow-up test, both two groups had no change on FMA, MAL, and SIS (both p>0.05) however there are only 9 participants finished the follow-up test, the result should be interpreted with caution. The correlation between self-perceived arm use and the ratio of affect arm activity counts change score was no
relevance, some participants did not wear enough amount of time in posttreatment test, the large difference of wearing time may affect the reliability of the evaluation. On the order hand, the daily routine of the participants in wearing days may be reason is also reason that affect the reliability of the evaluation.
For the between-group analyses, the participants receiving the RMT improved their motor ability more than those receiving the RBAT. Even though RMT group didn’t reach the statistically significant level on most of measure outcome, a positive tendency was observed in the FMA-UE proximal, rNSA-temperature, NEADL, SIS-overall, SIS-ADL, SIS-mobility and SIS-physical function compared to the RBAT group. In contrast, the RBAT group revealed a positive trend in the GAS and SIS-hand function compared to the RMT group.
4.2 The Benefits of RMT group
RMT group showed a significantly increase on the FMA-UE scale and a trend of more improvement on proximal UE. Previous study demonstrated that mirror therapy might be more associated with motor recovery in the distal part of the body (Wu et al.,2013).
Conversely, bilateral robotic training mainly led to improvement on proximal segments (Yang et al.,2012). In addition, the change scores were 5-11 point, most of the participant reached minimal clinically meaningful values. It seems that the bilateral robotic priming combined with mirror therapy would enchase the treatment effect of bilateral robotic training compared with the RBAT group. The effects might result from cortical reorganization. MT could provide “proper visual input” and, perhaps, “substitutes” for absent or reduced proprioceptive input from the affected body side. MT might also facilitate self-awareness and spatial attention by activating the superior temporal gyrus, precuneus, and the posterior cingulate cortex. Consequently, the experience during MT might help recruit the premotor cortex or balance the neural activation within the primary motor cortex toward the affected hemisphere to facilitate motor improvements.
The visual illusion of mirror could provide sensory inputs that might modulate the somatosensory cortex network and contribute to the recovery of somatosensation (Wu et al.,2013). RMT group shows tend to get more improvement than the RBAT group on rNSA- temperature sensation. This finding is also consistent with previous study that mirror therapy may get more benefits on temperature sensation (Wu et al.,2013).The benefits could relate to multi-modal neurons. Multimodal neurons in the posterior parietal and premotor cortical areas respond to sensory stimuli, such as visual input, as well as movement stimuli. The visual illusion of MT could provide sensory inputs that might modulate the somatosensory cortex network and contribute to the recovery of
somatosensation.
For quality of life, RMT group shows trend to get more improvement than the RBAT group on NEADL, SIS-overall, SIS-ADL, SIS-mobility and SIS-physical function although the previous study demonstrated that mirror therapy might not significantly get better effects on ADL (Wu et al.,2013) and bilateral robotic priming gets better
improvement on the Stroke Impact Scale strength (Hsieh et al.,2017). These slight positive trends might be the result of the reaction between bilateral robotic priming and mirror therapy which provides additional mirror visual feedback.
4.3 The Benefits of RBAT group
The RBAT group showed significantly improvements on motor ability, muscle power, functional ability, self-perceived arm use, functional goal achievement, instrumental activities of daily living and quality of life after six weeks intervention.
There was a trend in RBAT group that more improvements could be found on GAS.
This may be explained in part by the nature of functional task practice involved in this regimen. Since the participant could practice their self-preserved task directly without the mirror box, it might help them achieve their own expectation more easily.
4.4 Study Implication
To our best knowledge, this study was the first study compared the bilateral robotic priming combined with different types of bilateral arm training to chronic stroke with moderate to severe motor impairments.
The bilateral robotic priming combined with mirror therapy can be optimal intervent ion to improving the motor ability and positive trends on sensorimotor function, daily function and quality of life. Moreover, the bilateral robotic priming combined with bilateral arm training has a positive trend on the achievement of self-expectation, it can provide an individualized intervention focused on functional goals and can connect to the real-life environment.
The robotic priming was applicable, safe, and promising interventions on chronic stroke rehabilitation.
4.5 Study Limitation
There are several limitations in this study should be mentioned. Due to the small sample size, the findings should be interpreted with caution and difficult to generalize the results to all stroke patients. Also, the wearing time of accelerometers were not equal
during pretest and posttest, it affected the reliability of the objective measure the amount affected arm used in real-life situation. Furthermore, the ratio of side brain hemisphere lesion of participants was large in this study, there were 13 participants with left
hemisphere lesion but only 4 participants with right hemisphere lesion, it would make a sampling bias in this study.
Further researches should expand the sample size. The sample size calculation resulted in 56 participants pre group with an overall effect size of 0.48, a power set at 0.80, and alpha of 0.05. Also, the wearing time of accelerometers during pretest and posttest should be confirmed as equally., the number of side brain hemisphere lesion of participants should be balance. Last but not least, a control group should be set to clarifiy the treatment effect of two groups in the future.