This experimental protocol outlines the use of a dual upper limb task-oriented robotic system for stroke patients with upper limb dysfunction. The findings indicate that this system can significantly improve stroke patients’ upper limb function and daily living activities.
Highly repetitive and task-oriented training has been shown to promote the recovery of limb function in stroke patients. Additionally, bilateral arm training can help stroke survivors regain their upper limb function and improve their daily activities. The dual upper limb task-oriented robotic system is designed to assist the healthy side of the stroke patient in driving the affected side to perform bilateral arm training through the use of a robotic device. It can also guide the patient in carrying out dual upper limb coordinated movements and engage them in a task-oriented virtual game using force feedback and human-computer interaction technology. This study aimed to assess the efficacy of the system in enhancing upper limb function and activities of daily living in stroke patients. The assessment methods used included motor evoked potential (MEP), functional test for the hemiplegic upper extremity-Hong Kong (FTHUE-HK), Fugl-Meyer Assessment Upper Extremity Scale (FMA-UE), and modified Barthel index (MBI). The results of the study indicate that the dual upper limb task-oriented robotic system can significantly improve the corticospinal pathway, upper limb function, and activities of daily living in stroke patients after 6 weeks of treatment. This system can serve as an effective adjunct to upper limb functional rehabilitation in stroke survivors, reducing the dependence on rehabilitation therapists. In conclusion, the dual upper limb task-oriented robotic system provides a new strategy for post-stroke limb functional rehabilitation and holds great potential for application, as it offers certain social and financial benefits.
Stroke is one of the major causes of disability and the second leading cause of death globally1,2. Stroke patients often face various challenges, such as motor, sensory, and cognitive deficits3. Upper limb dysfunction is a common problem after stroke, characterized by muscle weakness, spasticity, and reduced motor ability of the upper limb on the hemiplegic side4. It is reported to be present in more than 70% of stroke patients, and only around 5% recover to normal, while 20% regain some upper limb capabilities5. More than half of human life requires the participation of the upper limbs6, and upper limb dysfunction after a stroke severely affects patients’ activities of daily living7, significantly decreasing their quality of life8 and increasing their financial burden9. Therefore, it is particularly important to explore effective methods of upper limb functional rehabilitation.
Various clinical upper limb rehabilitation treatments, such as mirror therapy, constraint-induced movement therapy, functional electrical stimulation, and other active or passive training, are commonly utilized for stroke patients3,10. In recent years, bilateral arm training has garnered increased attention6,11,12. It has been demonstrated to enhance neural connectivity between the sensorimotor areas of both ipsilateral and contralateral hemispheres12. This type of training helps correct abnormalities in interhemispheric inhibition, facilitates reorganization of brain functional networks, and ultimately leads to improvements in upper limb function12,13. Furthermore, robot-assisted training has also been shown to assist patients in consistently executing accurate limb movements and engaging in task-specific training14. This process provides the brain with substantial feedback stimulation, ultimately boosting neuroplasticity and aiding in the restoration of upper limb function in individuals with hemiplegia14,15. There is currently limited research on strategies utilizing robot-assisted dual upper limb training for stroke patients. This study employed a dual upper limb task-oriented robotic system to combine robot-assisted training with bilateral upper limb training. The robotic device was utilized to aid stroke patients in conducting dual upper limb task-oriented training with high repetitions in a proper movement pattern. The objective of the research was to evaluate the effects of this method on the corticospinal pathway, upper-limb function, and activities of daily living in stroke survivors, with the aim of discovering innovative strategies for upper limb functional rehabilitation.
This study (Approval No. JXEY-2020SW038) was approved by the Medical Ethics Committee of the Second Hospital of Jiaxing, with all participants providing informed consent. It aimed to assess the feasibility and effectiveness of a protocol through a randomized, single-blind, controlled trial. Between January and December 2021, 60 stroke patients admitted to the Second Hospital of Jiaxing were enrolled.
NOTE: Inclusion criteria comprised: 1) confirmed diagnosis of cerebral infarction or hemorrhage via computed tomography (CT) or magnetic resonance imaging (MRI), 2) first-onset and unilateral lesion with a disease duration of 2 weeks to 3 months and a stable condition, 3) age 25-75 years, 4) absence of hemianopsia or unilateral spatial neglect, as well as no visual or auditory deficits, 5) conscious, compliant, and able to participate in rehabilitation treatment, 6) clear unilateral upper limb dysfunction with a modified Ashworth scale (MAS) grade ≤ 216. Exclusion criteria included: 1) previous craniocerebral injury or other intracranial diseases, 2) severe myocardial infarction, angina pectoris, liver, kidney, lung, or other important organ diseases, malignant tumors, etc., 3) previous history of psychiatric disorders and epilepsy, 4) severe pain, numbness, or other sensory deficits on the hemiplegic side of the limbs, 5) significant limitation of movement in the bilateral upper limbs.
1. Study design
2. Dual upper limb task-oriented robotic system training session
NOTE: Only the stroke patients in the experimental group received these training sessions.
3. Follow-up procedure
A total of 60 stroke patients were divided into a control group (n = 30) and an experimental group (n = 30) for this study. Upon comparing age, gender, stroke type, disease duration, side of hemiplegia, and other general information between the two groups, no statistically significant differences were found (P > 0.05), indicating their comparability (Table 1). Patients in the experimental group, who underwent training with a dual upper limb task-oriented robotic system, showed greater improvements in MEPs, FMA-UE, FTHUE-HK, and MBI compared to those receiving conventional treatment.
After 6 weeks of training, the detection ratio of motor evoked potentials (MEPs) in the experimental group surpassed that of the control group (P < 0.05) (Table 2). Following the training period, both groups of patients exhibited improvements in FTHUE-HK compared to pre-treatment levels (P < 0.05), with the experimental group showing more pronounced improvement than the control group (P < 0.05) (Table 3). Moreover, improvements in FMA-UE and MBI scores were observed in both groups of patients compared to pre-treatment levels (P < 0.05), with the experimental group experiencing more significant enhancements than the control group (P < 0.05) (Table 4). These findings highlight the effectiveness of the dual upper limb task-oriented robotic system in promoting the recovery of upper limb function in stroke patients.
Statistical analysis was conducted using appropriate software, with a significance level set at P < 0.05 for a two-tailed test. The measurement data were verified to adhere to a normal distribution and display homogeneous variances. Paired t-tests were utilized for comparisons within groups before and after treatment for normally distributed continuous variables, while two independent samples t-tests were employed for comparisons between groups. Count data were assessed using the χ2 test, ranking variables within groups were evaluated using the Wilcoxon signed-rank test, and between-group analysis was performed using the Mann-Whitney test.
Figure 1: Dual upper limb task-oriented robotic system. This system assists stroke patients with bilateral upper limb training to promote the recovery of upper limb function. Please click here to view a larger version of this figure.
Figure 2: Air Flying game. With the robot's assistance, the patient is guided to control the virtual airplane on the computer screen to make the virtual airplane fly along the set flight path. At the same time, the virtual airplane captures the virtual gold coins. Please click here to view a larger version of this figure.
Figure 3: Ping-Pong game. With the robot's assistance, the patient is instructed to control the virtual table tennis racket and move the racket to catch the flying ping pong. Please click here to view a larger version of this figure.
Figure 4: Bridge & Road game. The patient is guided to control the two ends of the wooden bridge on the screen and move it at different distances. The two ladders with different heights should be connected and maintained for a certain period of time so that the virtual villain can pass smoothly. Please click here to view a larger version of this figure.
Figure 5: Weight-Lifting game. The patient should control the two ends of the weight-lifting barbell on the screen, move it to different distances, press the barbell to the target position, and hold it for the specified time. Please click here to view a larger version of this figure.
Figure 6: Pop Matching game. The patient should control the two virtual fingers on the left and right ends of the screen through the healthy side and the affected side. The upper limbs need to use virtual fingers to select the same items in the left and right columns of pictures and maintain this position for the specified time. Please click here to view a larger version of this figure.
Group | n | Sex (n) | Age (x ± s, y ) | Course of the disease (x ± s, d) | Type of stroke (n) | Hemiplegic side (n) | |||
Male | Female | Ischemic | Hemorrhagic | Left | Right | ||||
Control group (n=30) |
30 | 16 | 14 | 56.70±7.60 | 38.77±15.71 | 14 | 16 | 14 | 16 |
Experimental group (n=30) |
30 | 17 | 13 | 57.17±6.93 | 39.47±16.23 | 17 | 13 | 17 | 13 |
P | >0.05 | >0.05 | >0.05 | >0.05 | >0.05 |
Table 1. Baseline characteristics between the two groups. It comprehensively compares the baseline characteristics of the control and experimental groups. This includes demographic and clinical data, ensuring comparability between groups.
Group | n | Pre-treatment | Post-treatment | ||
response | no-response | response | no-response | ||
Control group (n = 30) |
30 | 8 | 22 | 10 | 20 |
Experimental group (n = 30) |
30 | 7 | 23 | 18 | 12 |
P | >0.05 | <0.05 |
Table 2. Comparison of MEPs response between the two groups. It demonstrates the effect of a dual upper limb task-oriented robotic system on corticospinal pathways in stroke patients.
Group | FTHUE-HK (M(P25, P75)) | |
Control group (n = 30) |
Pre-treatment | 3(2,3) |
Post-treatment | 3(3,4)* | |
Experimental group (n = 30) |
Pre-treatment | 3(2,3) |
Post-treatment | 4(3,5)*# | |
*P < 0.05, compared to pre-treatment; #P < 0.05, compared to the control group |
Table 3. Comparison of FTHUE-HK between the two groups. It describes the impact of the dual upper limb task-oriented robotic system on upper limb function in stroke patients.
Group | FMA-UE (x ± s) |
MBI (x ± s) |
|
Control group (n=30) |
pre-treatment | 25.33±11.72 | 44.27±13.21 |
Post-treatment | 34.63±13.06* | 51.03±12.55* | |
Experimental group (n=30) |
pre-treatment | 25.93±11.87 | 44.93±14.10 |
Post-treatment | 42.37±15.20*# | 59.73±14.63*# | |
*P < 0.05, compared to pre-treatment; #P < 0.05, compared to the control group |
Table 4. Comparison of FMA-UE and MBI between the two groups. It illustrates the impact of the dual upper limb task-oriented robotic system on upper limb function and activities of daily living in stroke patients.
Bilateral training has been shown to normalize intercortical inhibition in stroke patients, facilitate brain functional network reorganization, and ultimately enhance upper limb function21. This study presents a program for upper limb functional training in stroke patients utilizing a dual upper limb task-oriented robotic system. The program integrates bilateral upper limb movement, task-oriented activities, and robot-assisted training to enhance the rehabilitation of upper limb function in stroke patients.
Several key steps warrant attention in implementing the dual upper limb task-oriented robotic system training. First, the therapist should promptly adjust the tilt angle of the robotic arm and the angle between the two arms based on the functional status of the patient’s upper limb and the therapeutic goals. Second, the level of assistance or resistance provided by the system must be accurately selected in accordance with the patient’s upper limb muscle strength. When the patient’s training score reaches the maximum, it should be adjusted to the next level without delay. Third, in the resistance training mode, the therapist should establish the resistance levels for both the healthy and affected sides, as well as the direction of resistance (including push and pull), depending on the muscle strength of the patient’s upper limbs on each side.
The dual upper limb task-oriented robotic system training involves movements of the upper limbs across various planes and directions. However, random switching between these planes and directions during training is not feasible, as each switch necessitates halting the current training session to recondition the system. Some researchers have employed two identical robots to assist patients in bilateral upper extremity training across three dimensions4. While this approach enables patients to engage in multiple directions of motion during training, it poses challenges in effectively transferring forces between the healthy and affected limbs. As the dual upper limb task-oriented robotic system is refined in subsequent stages, it is essential to enhance the degrees of freedom of movement of the robotic arm to accommodate the multi-directional movement training of the upper limb. Additionally, it is crucial to address the issue of compensatory trunk movements that some patients exhibit during training with the dual upper limb task-oriented robotic system. Such compensatory movements can diminish the range of motion of the upper extremities and may lead to the development of faulty movement patterns. To mitigate the impact of this issue, therapists should promptly remind patients to maintain proper sitting posture and adhere to correct movement patterns during training.
Most traditional bilateral upper limb training methods involve the healthy hand holding the affected hand or connecting the two hands with a device (e.g., a wooden stick). In contrast, the dual upper limb task-oriented robotic system training utilized in this study offers significant advantages. Research indicates that recovery of limb function in stroke patients is enhanced by precise and highly repetitive rehabilitation training22. However, following a stroke, patients often exhibit diminished muscle strength in the affected limb and reduced motor function in the healthy limb23,24. Consequently, during traditional bilateral upper limb training, it becomes challenging for patients to maintain normal movement patterns continuously and repetitively over extended periods. Furthermore, to perform a specific movement, the healthy upper limb may exert considerable force while the affected upper limb applies minimal force, thereby compromising the full engagement of the affected limb. The dual upper limb task-oriented robotic system training can modulate the force transmitted from the healthy upper limb to the affected limb based on the muscle strength of the patient’s affected upper limb, thereby facilitating gradual and structured participation of the affected limb. This training also employs robotic assistance to enable patients to execute highly repetitive and precise movements, which has been shown to provide constant feedback to the brain, which promotes functional reorganization and ultimately enhances limb function14,22. Additionally, the virtual games incorporated into the dual upper limb task-oriented robotic system training are task-oriented, and studies have demonstrated that such training can improve upper limb function and the ability to perform activities of daily living in stroke patients25,26.
In this study, the MEPs in patients were based solely on the presence or absence of detectable MEP. This decision was made because a comprehensive comparative analysis of MEP latency and amplitude was not possible, as MEP could not be detected in some patients. The study included patients with varying disease durations ranging from 2 weeks to 3 months, potentially impacting the results due to differences in spontaneous recovery. Patient selection criteria focused solely on stroke type and hemiplegic lateral condition without considering the specific brain lesion areas, thus affecting the comparative analysis of efficacy. Additionally, there are other limitations identified in this study. Firstly, patients with high muscle tone (MAS > 2) were excluded from the experiment, as their condition could potentially impact the training outcomes. Secondly, the evaluation of the experiment’s efficacy was only conducted up to 6 weeks post-intervention, lacking long-term follow-up data. Thirdly, all participants were within 3 months of disease onset, leaving uncertainty regarding the effectiveness of this training approach for patients beyond the 3-month mark. Moreover, the study’s sample size was small, highlighting the necessity for future research with a larger and more diverse sample. In response to the issues mentioned above, we will implement further enhancements and optimizations during the subsequent stages of the study.
In conclusion, the dual upper limb task-oriented robotic system has shown promise in enhancing upper limb function and activities of daily living for stroke patients. This approach warrants broader adoption in clinical settings for upper limb functional rehabilitation post-stroke.
The authors have nothing to disclose.
We express gratitude to the patients and medical staff of the Second Hospital of Jiaxing for their support and cooperation during the research process.
Dual upper limb task-oriented robotic system | Auckland Tongji Rehabilitation Medical Equipment Research Center, Tongji Zhejiang College | N/A | The dual upper limb task-oriented robotic system can aid stroke patients in bilateral upper limb virtual game training by regulating force transmission between the healthy and affected upper limbs. |
Magnetic stimulation therapy system | Sichuan Junjian Wanfeng Medical Equipment Co.,Ltd. | http://www.jjwf-med.com | This system can be used to measure the Motor evoked potential (MEP) |
SPSS 25.0 | IBM | Version 25.0 | https://www.ibm.com/support/pages/downloading-ibm-spss-statistics-25 |