Posts Tagged End-effector

[ARTICLE] Comparisons between end-effector and exoskeleton rehabilitation robots regarding upper extremity function among chronic stroke patients with moderate-to-severe upper limb impairment – Full Text


End-effector (EE) and exoskeleton (Exo) robots have not been directly compared previously. The present study aimed to directly compare EE and Exo robots in chronic stroke patients with moderate-to-severe upper limb impairment. This single-blinded, randomised controlled trial included 38 patients with stroke who were admitted to the rehabilitation hospital. The patients were equally divided into EE and Exo groups. Baseline characteristics, including sex, age, stroke type, brain lesion side (left/right), stroke duration, Fugl–Meyer Assessment (FMA)–Upper Extremity score, and Wolf Motor Function Test (WMFT) score, were assessed. Additionally, impairment level (FMA, motor status score), activity (WMFT), and participation (stroke impact scale [SIS]) were evaluated. There were no significant differences in baseline characteristics between the groups. After the intervention, improvements were significantly better in the EE group with regard to activity and participation (WMFT–Functional ability rating scale, WMFT–Time, and SIS–Participation). There was no intervention-related adverse event. The EE robot intervention is better than the Exo robot intervention with regard to activity and participation among chronic stroke patients with moderate-to-severe upper limb impairment. Further research is needed to confirm this novel finding.


Upper extremity dysfunction is a common complication after stroke, and it has been reported to affect approximately 85% of stroke survivors in the early stage1 and 50% in the chronic stage2. Impaired upper extremity function limits performance of activities of daily living (ADLs) and decreases social participation3. Novel therapeutic techniques have been introduced to promote upper extremity function, and one such technique is robotic rehabilitation.

Rehabilitation robots are capable of reducing the burden on therapists by substituting human intervention and providing ideal therapies that fulfil the following main principles of stroke rehabilitation: repetition, high intensity, and task specificity4. Thus, robotic intervention has been highlighted as a promising therapy. A recent multicentre randomised controlled trial showed better improvements in FMA scores with robot-assisted training on comparing robot-assisted training with usual care, but showed no significant difference in scores on comparing robot-assisted training with enhanced upper limb therapy. These findings indicate that robot-assisted training can reduce the burden for therapists but is not a definite superior option5. Many systematic reviews and meta-analyses on rehabilitation robots have been published in the last two decades. In 2012, Norouzi-Gheidari et al. summarised 10 trials that compared robotic therapy with dose-matched conventional therapy and reported no significant differences in Fugl–Meyer Assessment (FMA) of the upper extremity and Functional Independence Measure scores between the therapies6. However, with an increase in the number of randomised controlled trials, a recent review involving 38 trials reported a significant difference in the FMA–Upper Extremity score between robotic therapy and conventional therapy, with a better score for robotic therapy7.

Many rehabilitation robots for the upper extremity have been released and are available for clinical use. These robots have shown positive clinical results. Thus, healthcare professionals and patients have multiple choices among many kinds of robots; however, there is limited evidence to guide their choices. Physicians tend to prescribe ‘robot intervention’ rather than specify a particular robot, unlike medication prescription, when selecting robotic rehabilitation. So far, different rehabilitation robots have been considered broadly as rehabilitation robots per se, despite some differences in effectiveness.

Rehabilitation robots are generally categorised into end-effector (EE) and exoskeleton (Exo) types according to their mechanical structures8. EE robots are connected to patients at one distal point, and their joints do not match with human joints. Force generated at the distal interface changes the positions of other joints simultaneously, making isolated movement of a single joint difficult8,9. Exo robots resemble human limbs as they are connected to patients at multiple points and their joint axes match with human joint axes. Training of specific muscles by controlling joint movements at calculated torques is possible8,9. Recent systematic reviews have performed indirect comparisons by subgroup analysis and have demonstrated contradictory results for EE and Exo robots. Veerbeek et al. reported significant favourable results with regard to FMA–Upper Extremity for EE robots but not for Exo robots7. On the other hand, Bertani et al. reported significant favourable results with regard to arm function for Exo robots but not for EE robots; however, the risk of bias should be considered owing to the smaller sample size of Exo robots when compared with that of EE robots10. Although these indirect comparisons are helpful, they are limited by the heterogeneity in clinical studies, including design, population, outcomes, and intervention protocols.

Many new robotic devices have been developed; however, there are no guidelines or standard requirements with regard to the most appropriate robot subtype, extent of degrees of freedom, and approach (functionality based or impairment based) for favourable outcomes. To our knowledge, no head-to-head clinical trial comparing different types of rehabilitation robots has been performed. Such a comparison may help in the decision making of healthcare professionals with regard to rehabilitation robots and may ultimately offer more optimal rehabilitation for patients. In particular, there is a great need for a direct comparison study to clarify effects according to the types of robots, as robots are expensive.

Therefore, we performed a randomised controlled trial to directly compare EE and Exo robots in a selected population of chronic stroke patients with moderate-to-severe upper limb impairment. The InMotion2 (Interactive Motion Technologies, Watertown, MA, USA) and Armeo Power (Hocoma, Volketswil, Switzerland) robots were selected as representative EE and Exo robots, respectively, among commercially available robots for their proven efficacy and safety, as well as accessibility around hospitals11,12,13,14.


Study design

This single-blinded, randomised controlled trial was conducted at a single rehabilitation hospital. Participants were randomly allocated to an EE group and Exo group (1:1 ratio) by using concealed envelopes with a card representing the group assignment. Occupational therapists who carried out assessments were blinded to group allocation. The study was approved by the Ethics Committee of the National Rehabilitation Center, Korea and was carried out in accordance with the approved guidelines. Written informed consent was provided by all participants. The study was registered at (NCT03104881).


For enrolment, the study considered 92 patients with stroke who were admitted to the rehabilitation hospital between March 2015 and August 2016. The inclusion criteria were as follows: (1) unilateral hemiplegic upper extremity dysfunction secondary to a unilateral ischaemic or haemorrhagic brain lesion; (2) stroke duration > 3 months; (3) FMA–Upper Extremity score of 8–30 for the affected upper extremity; and (4) ability to follow simple instructions. The exclusion criteria were as follows: (1) age < 20 years or > 80 years; (2) previous ischaemic or haemorrhagic stroke; (3) shoulder or elbow spasticity with a modified Ashworth scale (MAS) score ≥ 2; (4) severe upper extremity pain that could interfere with rehabilitation therapy; (5) neurological disorders other than stroke that can cause motor deficits, such as Parkinson’s disease, spinal cord injury, traumatic brain lesion, brain tumour, and peripheral neuropathy; and (4) uncontrolled severe medical conditions. Of the 92 patients, 53 did not meet the inclusion criteria or declined to participate. Thus, 39 patients were finally enrolled.


All participants received robot-assisted therapy with InMotion2 (EE group) or Armeo Power (Exo group) (30 minutes of active therapy 5 days a week for 4 weeks [total 20 sessions]) along with conventional occupational therapy (30 minutes of therapy [total 20 sessions]). Both robot-assisted therapies were managed by the same experienced research physical therapist. The therapy period was quantified by considering the active intervention time and not the time for preparations, such as attaching the robot to the patient and aligning the axis of the robot to that of the patient. Conventional occupational therapy involved range of motion exercises, strengthening exercises for the affected upper extremity, and basic ADL training. Overall, the same dosing parameters, including frequency and duration, were applied in the EE and Exo groups.

EE group

The EE robot InMotion2 was used in the EE group. In the seated position, each participant held the handle attached to an arm support and performed goal-directed reaching movements in the gravity-compensated horizontal plane with two degrees of freedom, including the shoulder and elbow joints. From the starting point in the centre, the participant was instructed to move the handle toward eight targets positioned 45 degrees apart in circular arrangements, and the position of the handle was marked on the screen for real-time visual feedback (Fig. 1A). Reaching movements were supported through an assist-as-needed control system when targets could not be reached independently.

Figure 1

Two types of rehabilitation robots used for the robot-assisted therapy (A) InMotion2 for the EE group and (B) Armeo Power for the Exo group. EE, end-effector; Exo, exoskeleton.


via Comparisons between end-effector and exoskeleton rehabilitation robots regarding upper extremity function among chronic stroke patients with moderate-to-severe upper limb impairment | Scientific Reports

, , , , , , , , , ,

Leave a comment

[ARTICLE] Robotics for rehabilitation of hand movement in stroke survivors – Full Text

This article aims to give an overall review of research status in hand rehabilitation robotic technology, evaluating a number of devices. The main scope is to explore the current state of art to help and support designers and clinicians make better choices among varied devices and components. The review also focuses on both mechanical design, usability and training paradigms since these parts are interconnected for an effective hand recovery. In order to study the rehabilitation robotic technology status, the devices have been divided in two categories: end-effector robots and exoskeleton devices. The end-effector robots are more flexible than exoskeleton devices in fitting the different size of hands, reducing the setup time and increasing the usability for new patients. They suffer from the control of distal joints and haptic aspects of object manipulation. In this way, exoskeleton devices may represent a new opportunity. Nevertheless their design is complex and a deep investigation of hand biomechanics and physical human–robot interaction is required. The main hand exoskeletons have been developed in the last decade and the results are promising demonstrated by the growth of the commercialized devices. Finally, a discussion on the complexity to define which design is better and more effective than the other one is summarized for future investigations.

Over the past years, rehabilitation engineering has played a crucial role in improving the hand and finger function after stroke. The applications of robotics and mechatronic devices have rapidly expanded from the industrial environment to human assistance in rehabilitation and functional improvements. Rehabilitation engineering has increased the quality lives of individuals with disabilities, offering dedicated training that performs better than conventional methods.

In this way, there are many challenges and opportunities to integrate engineering concepts into hand rehabilitation, and increasing population wellbeing and wealth as well as reducing healthcare costs. This motivates researchers to study, design, and develop novel rehabilitative and assistive technologies and devices to help people to motor functions. Specifically, the current challenge is to transfer the research results and new knowledge to stakeholders creating a general awareness of the importance of rehabilitation engineering.

This review aims to present and discuss the main robotic technologies for hand recovery rehabilitation in stroke survivors, evaluating and comparing previous and current works and researches. This study explores the current state of art to help and support designers and clinicians make better choices among varied devices and components. The review also focuses on both mechanical design (e.g. concept), usability (e.g. setup, lightness, portability) and training paradigms (e.g. hand, hand/wrist or entire arm) since these parts are interconnected for an effective hand recovery. An overview of the main advantages and drawbacks in applying robotics to hand motor impairments is provided in order to give a general view of the relationship between hand rehabilitation devices, rehabilitation theories and results. The challenge is to restore the hand movements such as opening, closing, grasping and releasing movements. Second, a discussion on the application and new challenges of rehabilitation robotic devices is summarized for future investigations. In particular, the main challenges are to develop safe devices with less complex designs, increasing potential for portability and efficacy. In fact, future development for patient treatment should include the device portability to increase the potential applications. The preliminary results have highlighted the robot-assisted therapy currently works hand in hand rather than a replacement of traditional therapy. Therapies and rehabilitation strategies should be not only more effective but also more cost-efficient.

Stroke is one of the leading causes of long-term disability, affecting approximately 14% of world’s population.1,2 33% of survivors reports very limited or no functional use of the upper limb.3 Rehabilitation activities based on repeated exercises have been identified suitable in recovering some degree of motion, in particular, a simple flexion and extension of fingers has demonstrated improvements in hand functionality.4,5 In this way, medical devices and robot-assisted strategies may provide a number of advantages guaranteeing the range of motion (ROM) and avoiding inappropriate movements. Nevertheless, only a limited part of the proposed devices by the literature has been clinically tested, highlighting as the design complexity and development costs may negatively impact the system implementation. The previous and current robots and devices are often too complex to be used by patients limiting any testing on the real users.

Note that the hand functional improvement may be the result of a set of compensatory strategies based on an initial support assisted by the physiotherapist. Usually, these approaches may be suggested during the first months after stroke, when the impairment reduction may be preferred to extensive functional training. In this phase of impairment, the patients show a loss of control and a decreased tactile sensation and proprioception, reducing the physical independence and social integration. The patient’s motivation associated with verbal encouragement may significantly impact the therapy efficacy.

Over the last decades, a set of studies has evaluated the influence of the robot-assisted therapies on arm motor improvement and impairment reduction using randomized clinical controlled trials.612 The obtained results have not shown a complete consensus; nevertheless, the therapy assisted by robotics seems to obtain results beyond what is done by conventional methods.1317 In particular, researchers have been slow to investigate the hand function due to the complexity of this limb.11,12,1820

In any case, a number of studies observed that the rehabilitation training can improve the hand motor in terms of pull, push, and grip strengths, confirming that robotic training is at least as effective as conventional training.13,2124 A significant part of the obtained outcomes have been also proved by Fugl-Meyer Assessment (FMA) and Functional Independence Measure (FIM) tests, performed after the robot treatment.2527

Despite these promising results, the literature review shows also researches that did not observed significant difference between conventional and robotic training groups, highlighting as the conventional therapies are more effective in decreasing levels of impairment and disability.2,8,28,29 Mazzoleni et al.29 and Colombo et al.30 have underlined that there are other significant factors that may impact the efficacy of the training outcome, such as recovery stage, intensity, or duration of the rehabilitation therapy. This point needs to be considered to evaluate and compare different therapy treatments. In the light of these considerations, there are not evident conclusions that sustain the robot-therapy efficacy, suggesting further investigations.31,32


Robot-based methods may be used independently by patients in different levels of impairment. Robots permit to obtain a quantifiable measure of subjective performance, repeating treatment protocols without the need of continuous involvement of therapists saving a significant amount of the human labor that may lead to high cost.8,10 In fact, traditional therapist–based methods require several sessions of rehabilitation training, inducing impractical and unaffordable therapies for many patients. Robotic therapy techniques guarantee a safe, intensive, and task-oriented rehabilitation at relatively moderate costs.14,1533 They may apply forces with precision, improving accuracy and reducing variance. These actions are potentially effective to strengthen muscle, ROM, and motor coordination. Advanced robots provide also tactile feedback that may correct the impaired movements. In addition, robot-assisted therapies may be quantified easily and collect a number of parameters useful to track the patient’s status (e.g. spasticity or level of voluntary control).34

A further advantage of robotic rehabilitation consists of the possibility to be combined with other technologies (e.g. virtual reality (VR), brain computer interface (BCI) technology or haptic stimuli).3537 This combination allows to motivate the patients to perform the rehabilitation tasks without the constant supervision, guaranteeing repetitive movements and informative feedback. On the other hand, robot-assisted therapy permits the therapist to conduct rehabilitation tasks for two or more patients at the same time, improving the service efficiency.

Finally, it has been noted that robotics may improve the accessibility to rehabilitation. In fact, a patient prefers to use the unaffected limb in daily activities, damaging the recovery of the impaired limb.38 The possibility to perform rehabilitation in remote locations (e.g. home) using robotics devices may involve better the patient in the recovery process.

Despite these noted advantages, a number of limits and constraints of rehabilitation robot-based cannot be ignored. First, there is a significant gap between the outcomes of rehabilitation robots and people’s expectations. This element may negatively impact patient’s motivations during the therapy. In particular, the personalization is still difficult due to the design complexity of devices. Another further issue is the determination of the most efficient dosage of rehabilitation training.

Although the literature has demonstrated the main advantages and benefits of robot applications, more studies involving a large participant size are required to confirm whether robotic-assisted therapy performs better than conventional methods, evaluating and comparing the treatment dosage. In particular, a lack of robust methods to evaluate the efficacy of the robot-assisted therapy making difficult to define which design is better and more effective than the other one. A deep investigation is needed to explore whether the obtained results on the patient can be maintained in the long term and how the potential improvements can be transformed into the motor skills in performing the activities of daily living (ADL). The user’s safety needs to be guaranteed during the training, avoiding the nonlinear movement of the patient. Further limits are noted on the current robotic devices regarding their design, often complex and unconvinced for the user, or the high costs for the treatment access.3941 The ratio between the price and performance is rather dissatisfactory due to the high cost of development combined with a relatively benefit for patients and clinics.4244 These drawbacks need to be considered in the overall evaluation of robotic application. They represent an open challenge to improve the integration of engineering concepts into hand rehabilitation, increasing population wealth, as well as reducing healthcare costs. These issues justify the low penetration of robotics in the market and the requirements of new investigations. Only a limited number of stroke patients (5%–15%) who requires assistive devices and technologies may access to this service. On the other hand, the studies and researches on rehabilitation robots are becoming strategic for the society due to the fact that the costs of excluding people with disabilities are high and borne by community.45

A primary categorization of rehabilitation robotic technologies is based on the design concepts of the device: end-effector or exoskeleton.

An end-effector device (also called endpoint control) recreates dynamic environments corresponding to ADL, determining the movements at the joint level. Usually, the patient’s joint rotation is distally executed using a support (e.g. a table or a tripod) to facilitate the training and avoiding muscle fatigue. It means that the more proximal joints are not directly controlled by the robot. End-effector devices may be dedicated to hand rehabilitation or to be integrated in more complex structures for the arm recovery.

The second main logic to design a rehabilitation robotic device is the exoskeleton. An exoskeleton, from Greek “exo” = outer and “skeletos” = skeleton, is a wearable robot attached to the user’s limbs, in order to enhance their movements. It focuses on the anatomy of the subject’s hand following the limb segments, each degree of freedom is aligned with the corresponding human joint. Figure 1 illustrates a number of examples. An exoskeleton should be compliant with the user’s movements and delivers at least part of the power required by the movements. In order to guarantee the natural motor of the hand joints, their design is more complex than end-effector devices. For example, a set of components (e.g. rings, hinges, external linkages, or structures) is embedded to accomplish the alignment between the forearm axial rotation of the forearm located along an axis between the ulna and the radius50,51 to support in forearm pronation and supination.


Figure 1. Examples of rehabilitation robotic devices: (a) Gloreha,46 (b) CyberGrasp,47 (c) Hand of Hope,48 and (d) Reha-Digit.49


Continue —> Robotics for rehabilitation of hand movement in stroke survivors – Francesco Aggogeri, Tadeusz Mikolajczyk, James O’Kane, 2019

, , , , , , ,

Leave a comment

[Abstract] What does best evidence tell us about robotic gait rehabilitation in stroke patients: A systematic review and meta-analysis


  • Recovery of walking function is one of the main goals of patients after stroke.
  • RAGT may be considered a valuable tool in improving gait abnormalities.
  • The earlier the gait training starts, the better the motor recovery.



Studies about electromechanical-assisted devices proved the validity and effectiveness of these tools in gait rehabilitation, especially if used in association with conventional physiotherapy in stroke patients.


The aim of this study was to compare the effects of different robotic devices in improving post-stroke gait abnormalities.


A computerized literature research of articles was conducted in the databases MEDLINE, PEDro, COCHRANE, besides a search for the same items in the Library System of the University of Parma (Italy). We selected 13 randomized controlled trials, and the results were divided into sub-acute stroke patients and chronic stroke patients. We selected studies including at least one of the following test: 10-Meter Walking Test, 6-Minute Walk Test, Timed-Up-and-Go, 5-Meter Walk Test, and Functional Ambulation Categories.


Stroke patients who received physiotherapy treatment in combination with robotic devices, such as Lokomat or Gait Trainer, were more likely to reach better results, compared to patients who receive conventional gait training alone. Moreover, electromechanical-assisted gait training in association with Functional Electrical Stimulations produced more benefits than the only robotic treatment (−0.80 [−1.14; −0.46], p > .05).


The evaluation of the results confirm that the use of robotics can positively affect the outcome of a gait rehabilitation in patients with stroke. The effects of different devices seems to be similar on the most commonly outcome evaluated by this review.


via What does best evidence tell us about robotic gait rehabilitation in stroke patients: A systematic review and meta-analysis – Journal of Clinical Neuroscience

, , , , ,

Leave a comment

%d bloggers like this: