A Comparative Efficacy Study of Robotic Priming of Bilateral Approach in Stroke Rehabilitation

Good luck in trying to get your hospital to have this robotic priming device. When you ask for it all you are going to get is the deer in the headlights look. 

A Comparative Efficacy Study of Robotic Priming of Bilateral Approach in Stroke Rehabilitation

Yi-chun Li¹, Keh-chung Lin^1,2*, Chia-ling Chen^3,4, Grace Yao⁵, Ya-ju Chang^6,7,8, Ya-yun Lee⁹ and Chien-ting Liu¹⁰

• ¹School of Occupational Therapy, College of Medicine, National Taiwan University, Taipei, Taiwan
• ²Division of Occupational Therapy, Department of Physical Medicine and Rehabilitation, National Taiwan University Hospital, Taipei, Taiwan
• ³Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan
• ⁴Graduate Institute of Early Intervention, College of Medicine, Chang Gung University, Taoyuan, Taiwan
• ⁵Department of Psychology, National Taiwan University, Taipei, Taiwan
• ⁶Neuroscience Research Center, Chang Gung Memorial Hospital, Taoyuan, Taiwan
• ⁷School of Physical Therapy and Graduate Institute of Rehabilitation Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan
• ⁸Healthy Aging Research Center, Chang Gung University, Taoyuan, Taiwan
• ⁹School and Graduate Institute of Physical Therapy, College of Medicine, National Taiwan University, Taipei, Taiwan
• ¹⁰Department of Physical Medicine and Rehabilitation, Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Taipei, Taiwan

Background: Stroke survivors can remain impaired in body functions, activity, and participation. A novel rehabilitation regimen is required to obtain scientific evidence and to help clinicians determine effective interventions for stroke. Mirror therapy (MT) and bilateral upper limb training (BULT) are based on the tenet of bilateral movement practice; however, the additional effect of bilateral robotic priming combined with these two therapies is unclear.

Objectives: This study examined the effects of two hybrid therapies, robotic priming combined with MT and robotic priming combined with BULT, in stroke survivors.

Methodology: The study randomized 31 participants to groups that received robotic priming combined with MT (n = 15) or robotic priming combined with BULT (n = 16). Outcome measures included the Fugl–Meyer Assessment (FMA), the revised Nottingham Sensory Assessment (rNSA), the Chedoke Arm and Hand Activity Inventory (CAHAI), and accelerometer data.

Results: Both groups showed statistically significant within-group improvements in most outcome measures. Significant between-group differences and medium-to-large effect sizes were found in favor of the group that received robotic priming combined with MT based on the FMA distal part subscale scores, FMA total scores, and accelerometer data.

Conclusion: Robotic priming combined with MT may have beneficial effects for patients in the improvements of overall and distal arm motor impairment as well as affected arm use in real life. Additional follow-up, a larger sample size, and consideration of the effect of lesion location or different levels of cognitive impairment are warranted to validate our findings in future studies.

Clinical trial registration: www.ClinicalTrials.gov, identifier NCT03773653.

Introduction

Rehabilitation of stroke patients is a long process that takes several months or even years. More than 30% of stroke patients admitted to the hospital remain impaired in autonomy, engagement, and fulfillment of societal roles (1). Rehabilitation methods are needed to allow individuals to continue to maximize gains in arm impairment and function more than 3 months after stroke. Priming, an implicit learning technique, can be used to prepare the brain for a more plastic response before task-based rehabilitative therapy, thereby leading to improved functional outcomes (2). Bilateral robotic priming, an extended application of robotic therapy involving bimanual, repetitive, mirror-symmetric movement practice, is a type of movement-based priming with a low-tech robot device (3). It can normalize cortical inhibition, prepare the brain for subsequent rehabilitative therapies, and facilitate recovery through a task-oriented approach (2, 4, 5).

In recent years, reports on task-oriented approaches have increased. Mirror therapy (MT) and bilateral upper limb training (BULT) are bimanual strategies for stroke recovery and can be applied as task-oriented approaches (3, 6). BULT is performed intensively and simultaneously with both arms in a symmetrical or alternating pattern. According to the classical definition, BULT is typically symmetrical, both temporally and spatially, and can exploit the coupling effect of both arms to improve movement of the affected arm, for example, in simultaneously lifting two soft drink bottles (3, 7–11). Asymmetrical movement with different temporal and spatial relationships for the achievement of common goals, such as opening a jar of coffee or drying one's own back with a towel, has also been viewed as a kind of BULT in recent studies. BULT focuses on facilitating the coordination of a variety of different real-world tasks (12–14). For comprehensive effects, rehabilitation regimens should include not only classical definitive bilateral arm training but also the bilateral synergy framework.

MT is a promising approach in which a mirror is positioned vertically between the two arms so that the reflected image of the less affected arm gives the appearance of normal movement in the affected arm (15). The possible mechanism for the success of this therapy is that it could induce primary motor cortex cortical activations (16). Compared with BULT, MT has been proposed to provide significant benefits to distal hand function and superior improvements in sensory deficits, quality of life, and the amount of use of the affected arm (6, 17). A previous study found that BULT integrated with bilateral robotic priming was more effective than unilateral hybrid therapy for improving motor function. The efficacy was believed to result from inter limb coupling and the priming effects of bilateral symmetric practice (18). MT and BULT are both bimanual strategies for stroke; however, the distinct effect of bilateral robotic priming combined with MT and BULT is unclear.

In summary, bilateral robotic priming, MT, and BULT have been considered to be types of bilateral approaches (3, 6) and are based on the tenet of bilateral movement practice. MT and BULT can be provided as task-oriented approaches involving both arms. When combined with bilateral robotic priming, the effects of MT and BULT may be increased and differentiated. Bilateral hybrid therapy (bilateral robotic priming plus BULT) yielded a better effect on motor improvement (18). However, if bilateral robotic priming is followed by MT, which is also a type of bilateral approach but involves mirror visual feedback, the regimen may enhance the recovery effect.

This study compared the efficacy of these two different hybrid approaches that are both based on the tenet of bilateral movement practice. We hypothesized that within-group differences in the robotic primed MT (RMT) and robotic primed BULT (RBULT) groups would be found after the intervention. Furthermore, we hypothesized that sensorimotor function recovery would be better in the RMT group than in the RBULT group.

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