1.1 Background and Purpose
Stroke remains a leading cause of permanent disability and is a large source of disease burden in the world. Upper limb (UL) paralysis is one of the most common and persistent disabilities after stroke. UL paresis can lead to deficits in motor control, motor
dysfunction, and in participating in activities of daily. Therefore, developing and
providing effective therapeutic techniques to improve UE motor control and recovery is crucial. The goal of neurorehabilitation is to restore and maximize physiological function, activities of daily living (ADL), and quality of life for patients with neurological
disorders. Current evidence indicates that robot-aided therapy, mirror therapy (MT), and bilateral arm training (BAT) are prominent approaches to improve upper extremity motor function and daily function in patients with stroke. These approaches are bilateral
approaches to intensive practice based on theories of neuroplasticity.
Bilateral arm training (BAT) is provided in different forms, such as symmetric or alternating patterns, task-oriented or non–task-oriented practice, robots, or auditory cueing (Coupar et al., 2010). Bilateral upper limb training has been shown to activate the central nervous system (McCombe Waller & Whitall, 2008) and activate similar neural networks in both hemispheres of the brain, promoting neural plasticity and cortical repair that may result in improved motor control of the affected arm. Previous studies
demonstrated that BAT reduced motor impairment, increase grip strength, and improve motor control (Lin et al., 2010). However, BAT may not provide enough practice
relevant to bilateral complementary tasks, such as opening a jam jar, occurring in daily living situations that require a differentiated role for each hand (Lin et al., 2010). Recent research has explored the effects of BAT in improving upper limb function and ADL performance in hemiplegic stroke patients and found that BAT combined with
conventional occupational therapy is more effective than occupational therapy alone for improving upper limb function and ADL performance (Lee et al., 2017).
Mirror therapy (MT) is a rehabilitation therapy in which a mirror is placed between the arms so that the mirror box blocks the vision of the paretic arm, and the individual can only see the actual movements of the non-paretic arm and its mirror reflection. The image of the non-affected limb gives the illusion of normal movements in the affected limb. At the same time, the participant is encouraged to move the paretic arm along with the mirror reflection. MT could induce greater improvements in motor functions movement control strategies, and activities of daily compared with conventional occupational therapy (Lin et al., 2014; Wu, Huang, et al., 2013). In addition to MT treatment alone, MT combined with afferent stimulation improved manual dexterity, ambulation function and daily function, and led to reduced motor impairment and synergistic shoulder
abduction (Lee et al., 2015; Lin et al., 2014; Lin et al., 2014). The findings support the benefit of MT as an alternative regimen to BAT. Both MT and BAT are functionally based and task-specific in the nature of their practice. As a restriction, the number of repetitions in these formats of practice is limited. A priming procedure that may be implemented prior to functional task practice may augment the treatment effect. Robotic therapy is technology-based and relevant to serve the purpose of movement priming.
Robot-assisted therapy (RT) is an emerging intervention approach that provides high-intensity, high-repetition, and task-specific training to enhance motor learning and control in patients with stroke (Hsieh et al., 2016). Previous studies demonstrated that RT
provides better or different improvement for patients with stroke compared with dose-matched therapist-based rehabilitation (Liao et al., 2012), and higher intensity of RT could lead to greater improvements in motor ability and functional performance than lower intensity of RT (Hsieh et al., 2011). However, because of the limitation of RT devices that focusing on specific joint movements, RT lack functional practice and linkage to daily life (Hung et al., 2016). In order to optimize the effect of RT treatment, several studies combined RT with different therapies.
Combining RT with the constraint-induced therapy (CIT) in a sequential manner and found that the combined group addictively improved motor control strategies, motor function, and functional independence of instrumental activities of daily living compared with the monotherapy (Hsieh et al., 2016). Also, patients who received the task-oriented intervention immediately after RT had greater improvement in self-reported strength and disability degrees than patients who received task-oriented intervention alone (Hsieh et al., 2017). However, the evidence of RT on QOL improvement is insufficient. RT
protocols should be modified, such as combining RT with bilateral arm training or mirror therapy to intensify the treatment and enhance the benefits on functional outcomes pertaining to the trained task activities. Moreover,the BRT training in con-junction with a 10-minute sensorimotor stimulation program can have benefits for motor restoration in the affected upper extremities of chronic stroke patients. The experience of normal
proprioceptive feedback and neuro-physiological adaptation through repetitive- and- intensive bilateral movement practice can help restore patients’ motor capability in affected upper limbs. (Hsu et al., 2019)
Motor priming in neurorehabilitation can be defined as a change in behavior on the basis of previous stimuli and is an emerging strategy to facilitate motor relearning
(Stoykov & Madhavan, 2015). Various types of priming techniques have been developed, including movement- or stimulation-based priming. Bilateral priming is a type of
movement-based priming technique which involves bimanual, repetitive, and mirror-symmetric movement training before functionally-based rehabilitative therapy. Bilateral priming may promote brain plastic change after stroke for improved functional recovery (Stinear et al., 2008). Bilateral priming of conventional rehabilitation therapy may facilitate or accelerate improvements in upper-limb motor function for chronic stroke (Stinear et al., 2008) and subacute stroke (Stoykov & Stinear, 2010) at follow-up assessments. Previous research indicated that bilateral robotic training can be used as a priming technique that in which both arms can be passively or actively moved in a progressive manner to improve upper limb motor function, affected arm use, and reduce compensatory movements (Wu, Yang, et al., 2013). As a therapeutic possibility, bilateral robotic therapy may be used in combination with different task-oriented therapies (Hsieh et al., 2017) such as MT and BAT and may yield differential benefits. This project aims to investigate the comparative efficacy of these different combinatory approaches based on the tenet of bilateral movement practice approach
Mirror therapy (MT) and bilateral arm training (BAT) are both task-oriented and bilateral movement practice, but mirror therapy provides additional mirror visual feedback. Whether the mirror visual feedback in MT may lead to differential benefits comparing with the BAT is unclear. In addition, bilateral robotic priming of MT versus BAT may lead to differing effects, depending on the domain of treatment outcome. To address these issues, the purpose of this study is to examine the treatment effects of bilateral robotic priming combined with bilateral arm training approach versus bilateral robotic priming combined with mirror therapy on sensorimotor function, daily function, self-efficacyand quality of life in patients with stroke.
1.2 Study Hypotheses
The hypotheses of this study described as follows: (1) we hypothesized that the RMT and RBT will lead to improvements on the study outcomes immediately after the
intervention and at 3-month follow-up.; (2) we hypothesized that the RMT and RBAT will lead to differential effects on the study outcomes.