Absolutely none of this review should have been necessary. We should have a database of all stroke protocols and research constantly updated so survivors can use it to get the best rehab out there.
A review of technological and clinical aspects of robot- aided rehabilitation of upper-extremity after stroke
Mahdieh Babaiasl 1,
Seyyed Hamed Mahdioun 1,
Poorya Jaryani 2,
and Mojtaba Yazdani 3
1 School of Engineering Emerging Technologies, University of Tabriz, Tabriz, Iran,
2 Department of Mechanical Engineering, Islamshahr Branch,Islamic Azad University, Islamshahr, Iran, and
3 Control Department, Electronics Faculty, Semnan University, Semnan, Iran
1 School of Engineering Emerging Technologies, University of Tabriz, Tabriz, Iran,
2 Department of Mechanical Engineering, Islamshahr Branch,Islamic Azad University, Islamshahr, Iran, and
3 Control Department, Electronics Faculty, Semnan University, Semnan, Iran
Abstract
Cerebrovascular accident (CVA) or stroke is one of the leading causes of disability and loss of motor function. Millions of people around the world are effected by it each year. Stroke results in disabled arm function. Restoration of arm function is essential to regaining activities of daily living (ADL). Along with traditional rehabilitation methods, robot-aided therapy has emerged in recent years. Robot-aided rehabilitation is more intensive, of longer duration and more repetitive. Using robots, repetitive dull exercises can turn into a more challenging and motivating tasks such as games. Besides, robots can provide a quantitative measure of the rehabilitation progress. This article overviews the terms used in robot-aided upper limb rehabilitation. It continues by investigating the requirements for rehabilitation robots. Then the most outstanding works in robot-aided upper-limb rehabilitation and their control schemes have been investigated. The clinical outcomes of the built robots are also given that demonstrates the usability of these robots in real-life applications and their acceptance.This article summarizes a review done along with a research on the design, simulation andcontrol of a robot for use in upper-limb rehabilitation after stroke.
Implications for Rehabilitation
Implications for Rehabilitation
- Reviewing common terms in rehabilitation of upper limb using robots
- Reviewing rehabilitation robots built up to date
- Reviewing clinical outcomes of the mentioned rehabilitation robots
Introduction
Cerebrovascular accident (CVA) or stroke is one of the leading reasons of disability and loss of motor function, especially ingrowing population of old people. It affects more than one million people in European Union each year [1,2]. In the United States more than 0.7 million people are affected by stroke each year [3]. Stroke can be defined as ischemic or hemorrhagic disturbance in the blood supply to brain tissue. In the first type the blood supply to the brain is interrupted by a blood clot and in the latter by internal bleeding. The result is partial destruction of cortical tissue that leads to disturbed neural commands from the sensorimotor areas of the cortex which results in reduced or even absent ability to selectively activate muscles which in turn affects motor task performance, leading to impaired arm and hand motor function. According to the study by Rossini et al. [4],degrees of recovery depend on two factors: (1) location of the lesion and (2) severity of the lesion. According to the study by Nakayama et al. [5], only 18% of stroke survivors regain full motor function after 6 months. Considering the mentioned issues,using different therapy approaches is necessary to regain motor function and improve functional outcomes. According to literature [6–8], sensorimotor arm therapy has positive effects on the rehabilitation progress of stroke patients. Relevant factors for successful training are training intensity [9–11], duration [12,13]and repetition [14]. High-intensity and task-specific upper limb treatment consists of active and highly repetitive movements,which is considered to be one of the most effective approaches to arm and hand function restoration. In fact, the type of therapy matters less than the exercise intensity. Optimal restoration of arm and hand function is essential to independently perform activities of daily living (ADL). The most common approach in stroke rehabilitation is one-to-one manually-assisted training or physio-therapy. This approach is labor-intensive, time-consuming and expensive. Besides, training sessions are often shorter thanrequired for an optimal therapeutic outcome, the therapy varies from one therapist to another and from one hospital to another and is based on theories and therapist’s experience. Furthermore,manually-assisted training lacks repeatability and objective measures of patient performance and progress. Taking all these constraints into consideration, robots can help to improve rehabilitation and become an important tool in stroke rehabilitation. Robot-aided arm therapy is more intensive, of longer duration and more repetitive. Using robots, number and duration of training sessions can be increased, while reducing the number of therapists required per patient, which in turn yields to reduced personnel costs. Furthermore, robot-aided therapy provides quantitative measures and supports objective observation and evaluation of the rehabilitation progress. Most robotic devices provide a means for ADL training. The reason for incorporating ADL training in robotic devices is that according to literature[8,15], functional and task-oriented training shows good results in stroke patients. Constrained induced movement therapy, which is a common approach in stroke rehabilitation, involves intensive and repetitive exercise of the most affected limb coupled with constraint of the opposite limb, proved to result in a positive cortical reorganization in the motor cortex. In fact, forcing the affected limb to perform ADL yields functional gains, increases patient motivation and allows the stroke patient to increase the use of the affected arm in the real-world environment [16–19]. Therapy that focuses on ADL training is also called motor relearning program. Several studies showed that robot aided therapy indeed improves motor function more than the conventional therapy [20–22]. According to the traditional assumption,most recovery occurs within the first 3–6 months post-stroke with no further improvements later on. But in more recent publications it is stated that the chronic patients, i.e. more than 6 months post-stroke, can also improve upper limb function. In robot aided therapy, moderately-affected patients are more responsive to therapy than severely affected patients. It is better that severely affected patients go on some conventional therapy before exposing to robot-aided therapy. It is worth noting that in robotic rehabilitation, the aim is not to replace human therapist by the robot, but the aim of robotics and automation technology is to assist, enhance, evaluate and document the rehabilitation movements. Finally, it is worth considering that upper limb recovery is more difficult than lower-limb recovery due to upper limb’s anatomical complexity and the fact that in the case of stroke, the parts of the brain that are responsible for upper-limb movement are more prone to injury.
Rehabilitation robots
Classification of rehabilitation robots
Rehabilitation robots can be categorized in several ways. They can be categorized based on their mechanical structure, number and type of actuated joints, actuation principle and place of setup.From mechanical structure point of view, rehabilitation robots canbe categorized as end effector based robots and exoskeleton type robots. End effector based robots (Figure 1a) are connected to patient’s hand or forearm at one point. Depending on the degrees of freedom (DOFs) of the robot, human arm can be positioned and oriented in space. Robot’s axes generally do not correspond to the human joint rotation axes. From mechanical point of view, end effector based robots are easier to build and use. The robot is body or wall-grounded and feedback forces can be applied only to the human hand. End effector based robots cannot influence human arm redundancy and are mostly not redundant themselves.In rehabilitation, this class of robots cannot induce joint trajectories exactly matching the human joints. The advantageous features of these robots are that they can easily adjust to different arm lengths; they are simple, usable and cost-effective. The disadvantageous feature is that in general the arm posture or the individual joint interaction torques, are not fully determined by the robot, because the patient and the robot interact just through one point, i.e. the robot’s end effector. Figure 1 [24] depicts types of rehabilitation robots. A typical example of end effector based robots that is also commercialized and used in several rehabilitation centers is MIT-MANUS.Exoskeleton-type robots can be further categorized into two groups: (1) exoskeletons that are kinematically equivalent to human limb (Figure 1b) and (2) exoskeletons that are kinematically different with respect to the human limb (Figure 1c). First group of exoskeletons has exactly the same degrees of redundant mobility as the human arm, excluding shoulder girdle, i.e. seven DOFs. This class of robots is body or wall-grounded and is attached at several locations along the limb. In order to induce exact joint trajectories and to match natural redundancy, the robot’s joints must be aligned to coincide with the human joints.This feature is important because in the case of mismatch undesired reaction forces can be created in the human joints. The term dynamic manipulability which is defined as the relationship between joint torque and end effector acceleration has an important role in this type of exoskeletons. In the case of kinematical mismatch, manipulability ellipsoids of both exoskeleton and human limb will not be the same and this will rise to dynamic interaction forces that will be felt by the patient as resistance to motion. The second group of exoskeletons possesses multiple degrees of redundancy to cope with the interaction, not only with the human arm but also with the human shoulder and shoulder girdle. As human shoulder girdle is a complex joint, it requires advanced mechanical solutions. Compared to exoskeletons of the first group, these exoskeletons feature a greater working range and no exact alignment is required between the exoskeleton and the patient. In the case of mismatch and rising reaction forces, the additional DOFs can be exploited until those
Figure 1. Types of rehabilitation robots:(a) end effector based robot, (b) exoskeleton kinematically equivalent to human limb,(c) exoskeleton kinematically not equivalent to human limb [24].
Cerebrovascular accident (CVA) or stroke is one of the leading reasons of disability and loss of motor function, especially ingrowing population of old people. It affects more than one million people in European Union each year [1,2]. In the United States more than 0.7 million people are affected by stroke each year [3]. Stroke can be defined as ischemic or hemorrhagic disturbance in the blood supply to brain tissue. In the first type the blood supply to the brain is interrupted by a blood clot and in the latter by internal bleeding. The result is partial destruction of cortical tissue that leads to disturbed neural commands from the sensorimotor areas of the cortex which results in reduced or even absent ability to selectively activate muscles which in turn affects motor task performance, leading to impaired arm and hand motor function. According to the study by Rossini et al. [4],degrees of recovery depend on two factors: (1) location of the lesion and (2) severity of the lesion. According to the study by Nakayama et al. [5], only 18% of stroke survivors regain full motor function after 6 months. Considering the mentioned issues,using different therapy approaches is necessary to regain motor function and improve functional outcomes. According to literature [6–8], sensorimotor arm therapy has positive effects on the rehabilitation progress of stroke patients. Relevant factors for successful training are training intensity [9–11], duration [12,13]and repetition [14]. High-intensity and task-specific upper limb treatment consists of active and highly repetitive movements,which is considered to be one of the most effective approaches to arm and hand function restoration. In fact, the type of therapy matters less than the exercise intensity. Optimal restoration of arm and hand function is essential to independently perform activities of daily living (ADL). The most common approach in stroke rehabilitation is one-to-one manually-assisted training or physio-therapy. This approach is labor-intensive, time-consuming and expensive. Besides, training sessions are often shorter thanrequired for an optimal therapeutic outcome, the therapy varies from one therapist to another and from one hospital to another and is based on theories and therapist’s experience. Furthermore,manually-assisted training lacks repeatability and objective measures of patient performance and progress. Taking all these constraints into consideration, robots can help to improve rehabilitation and become an important tool in stroke rehabilitation. Robot-aided arm therapy is more intensive, of longer duration and more repetitive. Using robots, number and duration of training sessions can be increased, while reducing the number of therapists required per patient, which in turn yields to reduced personnel costs. Furthermore, robot-aided therapy provides quantitative measures and supports objective observation and evaluation of the rehabilitation progress. Most robotic devices provide a means for ADL training. The reason for incorporating ADL training in robotic devices is that according to literature[8,15], functional and task-oriented training shows good results in stroke patients. Constrained induced movement therapy, which is a common approach in stroke rehabilitation, involves intensive and repetitive exercise of the most affected limb coupled with constraint of the opposite limb, proved to result in a positive cortical reorganization in the motor cortex. In fact, forcing the affected limb to perform ADL yields functional gains, increases patient motivation and allows the stroke patient to increase the use of the affected arm in the real-world environment [16–19]. Therapy that focuses on ADL training is also called motor relearning program. Several studies showed that robot aided therapy indeed improves motor function more than the conventional therapy [20–22]. According to the traditional assumption,most recovery occurs within the first 3–6 months post-stroke with no further improvements later on. But in more recent publications it is stated that the chronic patients, i.e. more than 6 months post-stroke, can also improve upper limb function. In robot aided therapy, moderately-affected patients are more responsive to therapy than severely affected patients. It is better that severely affected patients go on some conventional therapy before exposing to robot-aided therapy. It is worth noting that in robotic rehabilitation, the aim is not to replace human therapist by the robot, but the aim of robotics and automation technology is to assist, enhance, evaluate and document the rehabilitation movements. Finally, it is worth considering that upper limb recovery is more difficult than lower-limb recovery due to upper limb’s anatomical complexity and the fact that in the case of stroke, the parts of the brain that are responsible for upper-limb movement are more prone to injury.
Rehabilitation robots
Classification of rehabilitation robots
Rehabilitation robots can be categorized in several ways. They can be categorized based on their mechanical structure, number and type of actuated joints, actuation principle and place of setup.From mechanical structure point of view, rehabilitation robots canbe categorized as end effector based robots and exoskeleton type robots. End effector based robots (Figure 1a) are connected to patient’s hand or forearm at one point. Depending on the degrees of freedom (DOFs) of the robot, human arm can be positioned and oriented in space. Robot’s axes generally do not correspond to the human joint rotation axes. From mechanical point of view, end effector based robots are easier to build and use. The robot is body or wall-grounded and feedback forces can be applied only to the human hand. End effector based robots cannot influence human arm redundancy and are mostly not redundant themselves.In rehabilitation, this class of robots cannot induce joint trajectories exactly matching the human joints. The advantageous features of these robots are that they can easily adjust to different arm lengths; they are simple, usable and cost-effective. The disadvantageous feature is that in general the arm posture or the individual joint interaction torques, are not fully determined by the robot, because the patient and the robot interact just through one point, i.e. the robot’s end effector. Figure 1 [24] depicts types of rehabilitation robots. A typical example of end effector based robots that is also commercialized and used in several rehabilitation centers is MIT-MANUS.Exoskeleton-type robots can be further categorized into two groups: (1) exoskeletons that are kinematically equivalent to human limb (Figure 1b) and (2) exoskeletons that are kinematically different with respect to the human limb (Figure 1c). First group of exoskeletons has exactly the same degrees of redundant mobility as the human arm, excluding shoulder girdle, i.e. seven DOFs. This class of robots is body or wall-grounded and is attached at several locations along the limb. In order to induce exact joint trajectories and to match natural redundancy, the robot’s joints must be aligned to coincide with the human joints.This feature is important because in the case of mismatch undesired reaction forces can be created in the human joints. The term dynamic manipulability which is defined as the relationship between joint torque and end effector acceleration has an important role in this type of exoskeletons. In the case of kinematical mismatch, manipulability ellipsoids of both exoskeleton and human limb will not be the same and this will rise to dynamic interaction forces that will be felt by the patient as resistance to motion. The second group of exoskeletons possesses multiple degrees of redundancy to cope with the interaction, not only with the human arm but also with the human shoulder and shoulder girdle. As human shoulder girdle is a complex joint, it requires advanced mechanical solutions. Compared to exoskeletons of the first group, these exoskeletons feature a greater working range and no exact alignment is required between the exoskeleton and the patient. In the case of mismatch and rising reaction forces, the additional DOFs can be exploited until those
Figure 1. Types of rehabilitation robots:(a) end effector based robot, (b) exoskeleton kinematically equivalent to human limb,(c) exoskeleton kinematically not equivalent to human limb [24].
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