1228 Part F Field and Service Robotics mechanical inputs are known.The scientific basis for 53.2.2 Movement Therapy neuro-rehabilitation remains ill-defined,with competing after Neurologic Injury schools of thought.The number of large,randomized, controlled trials that have rigorously compared different At present,much of the activity in physical therapy and therapy techniques is still small,in part because these tri- training robots has been focused on retraining movement als are expensive and difficult to control well.Therefore, ability for individuals who have had a stroke or spinal the first problem that a robotics engineer will encounter cord injury(SCI).The main reasons for this emphasis are when setting out to build a robotic therapy device is that that there are a relatively large number of patients with there is still substantial uncertainty as to what exactly these conditions.the rehabilitation costs associated with the device should do. them are high,and because these patients can sometimes This uncertainty corresponds to an opportunity to use experience large gains with intensive rehabilitation be- robotic therapy devices as scientific tools themselves. cause of use-dependent plasticity.Some systems have Robotic therapy devices have the potential to help iden- also been targeted at assisting in cognitive rehabilitation tify what exactly provokes plasticity during movement of persons with neurologic injury,as reviewed below. rehabilitation,because they can provide well-controlled A stroke refers to an obstruction or breakage of patterns of therapy.They can also simultaneously mea-a blood vessel supplying oxygen and nutrients to the sure the results of that therapy.Better control over brain.Approximately 800000 people suffer a stroke therapy delivery and improved quantitative assessment each year in the USA alone,and about 80%of these peo- of patient improvement are two desirable features for ple experience acute movement deficits [53.32].There clinical trials that have often been lacking in the past.are over 3000000 survivors of stroke in the USA, 驾 Recent work with robotic movement training devices with over half of these individuals experiencing per- is leading,for example,to the characterization of com-sistent,disabling,movement impairments.The number 53.2 putations that underlie motor adaptation,and then to of people who have experienced and survived a stroke is strategies for enhancing adaptation based on optimiza- expected to increase substantially in the USA and other tion approaches [53.5,31]. industrialized countries in the next two decades.because The second roadblock is a technological one:robotic age is a risk factor for stroke and the mean age of peo- therapy devices often have as their goal to assist in ther- ple in industrialized countries is rapidly increasing due apy of many body degrees of freedom (e.g.,the arms and to the baby boom of the 1950s. torso for reaching,or the pelvis and legs for walking). Common motor impairments that result from stroke The devices also require a wide dynamic bandwidth such are hemiparesis,which refers to weakness on one side of that they can,for example,impose a desired movement the body:abnormal tone,which refers to an increase in on a patient who is paralyzed,but also fade-to-nothing the felt resistance to passive movement a limb;impaired as the patient recovers.Furthermore,making the devices coordination,which can manifest itself as an appar- light enough to be wearable is desirable,so that the pa- ent loss in control degrees of freedom and decreased tient can participate in rehabilitation in a natural setting smoothness of movement;and impaired somatosensa- (for example,by walking over ground or working at tion,which refers to a decreased ability to sense the a counter in a kitchen),or even throughout the course movement of body parts.Secondary impairments in- of normal activities of daily living.The development clude muscle atrophy and disuse-related shortening and of high-degree-of-freedom,wearable,high-bandwidth stiffening of soft tissue,resulting in decreased passive robotic exoskeletons is an unsolved problem in robotics. range of motion of joints.Often the ability to open the No device at present comes close to matching the flex- hand,and to a slightly lesser extent close the hand,is ibility of a human therapist,in terms of assisting in dramatically decreased. moving different body degrees of freedom in a vari- The number of people who experience a SCI in the ety of settings (e.g.,walking,reaching,grasping,neck USA each year is relatively smaller-about 15 000,with movement),or the intelligence of a human therapist,in about 200000 people alive who have survived a SCI terms of providing different forms of mechanical input -but the consequences can be even more costly than (e.g.,stretching,assisting,resisting,perturbing)based stroke [53.32].The most common causes of SCI are au- on a real-time assessment of the patient's response.tomobile accidents and falls.These accidents crush the Meeting the grand challenge of robotic therapy there- spinal column and contuse the spinal cord,damaging or fore will require substantial,interrelated advances in destroying neurons within the spinal cord.The resulting both clinical neuroscience and robot engineering. pattern of movement impairment depends strongly on
1228 Part F Field and Service Robotics mechanical inputs are known. The scientific basis for neuro-rehabilitation remains ill-defined, with competing schools of thought. The number of large, randomized, controlled trials that have rigorously compared different therapy techniques is still small, in part because these trials are expensive and difficult to control well. Therefore, the first problem that a robotics engineer will encounter when setting out to build a robotic therapy device is that there is still substantial uncertainty as to what exactly the device should do. This uncertainty corresponds to an opportunity to use robotic therapy devices as scientific tools themselves. Robotic therapy devices have the potential to help identify what exactly provokes plasticity during movement rehabilitation, because they can provide well-controlled patterns of therapy. They can also simultaneously measure the results of that therapy. Better control over therapy delivery and improved quantitative assessment of patient improvement are two desirable features for clinical trials that have often been lacking in the past. Recent work with robotic movement training devices is leading, for example, to the characterization of computations that underlie motor adaptation, and then to strategies for enhancing adaptation based on optimization approaches [53.5, 31]. The second roadblock is a technological one: robotic therapy devices often have as their goal to assist in therapy of many body degrees of freedom (e.g., the arms and torso for reaching, or the pelvis and legs for walking). The devices also require a wide dynamic bandwidth such that they can, for example, impose a desired movement on a patient who is paralyzed, but also fade-to-nothing as the patient recovers. Furthermore, making the devices light enough to be wearable is desirable, so that the patient can participate in rehabilitation in a natural setting (for example, by walking over ground or working at a counter in a kitchen), or even throughout the course of normal activities of daily living. The development of high-degree-of-freedom, wearable, high-bandwidth robotic exoskeletons is an unsolved problem in robotics. No device at present comes close to matching the flexibility of a human therapist, in terms of assisting in moving different body degrees of freedom in a variety of settings (e.g., walking, reaching, grasping, neck movement), or the intelligence of a human therapist, in terms of providing different forms of mechanical input (e.g., stretching, assisting, resisting, perturbing) based on a real-time assessment of the patient’s response. Meeting the grand challenge of robotic therapy therefore will require substantial, interrelated advances in both clinical neuroscience and robot engineering. 53.2.2 Movement Therapy after Neurologic Injury At present, much of the activity in physical therapy and training robots has been focused on retraining movement ability for individuals who have had a stroke or spinal cord injury (SCI). The main reasons for this emphasis are that there are a relatively large number of patients with these conditions, the rehabilitation costs associated with them are high, and because these patients can sometimes experience large gains with intensive rehabilitation because of use-dependent plasticity. Some systems have also been targeted at assisting in cognitive rehabilitation of persons with neurologic injury, as reviewed below. A stroke refers to an obstruction or breakage of a blood vessel supplying oxygen and nutrients to the brain. Approximately 800 000 people suffer a stroke each year in the USA alone, and about 80% of these people experience acute movement deficits [53.32]. There are over 3 000 000 survivors of stroke in the USA, with over half of these individuals experiencing persistent, disabling, movement impairments. The number of people who have experienced and survived a stroke is expected to increase substantially in the USA and other industrialized countries in the next two decades, because age is a risk factor for stroke and the mean age of people in industrialized countries is rapidly increasing due to the baby boom of the 1950s. Common motor impairments that result from stroke are hemiparesis, which refers to weakness on one side of the body; abnormal tone, which refers to an increase in the felt resistance to passive movement a limb; impaired coordination, which can manifest itself as an apparent loss in control degrees of freedom and decreased smoothness of movement; and impaired somatosensation, which refers to a decreased ability to sense the movement of body parts. Secondary impairments include muscle atrophy and disuse-related shortening and stiffening of soft tissue, resulting in decreased passive range of motion of joints. Often the ability to open the hand, and to a slightly lesser extent close the hand, is dramatically decreased. The number of people who experience a SCI in the USA each year is relatively smaller – about 15 000, with about 200 000 people alive who have survived a SCI – but the consequences can be even more costly than stroke [53.32]. The most common causes of SCI are automobile accidents and falls. These accidents crush the spinal column and contuse the spinal cord, damaging or destroying neurons within the spinal cord. The resulting pattern of movement impairment depends strongly on Part F 53.2
Rehabilitation and Health Care Robotics 53.2 Physical Therapy and Training Robots 1229 the vertebrae at which the spinal cord is injured,since MIT-MANUS nerves branch out to the head,arms,legs,and bladder The first robotic therapy device to undergo extensive and bowel at different vertebrae.About 50%of spinal clinical testing,and now to achieve some commercial cord injuries are incomplete,meaning that some sensa- success,is the MIT-MANUS,sold as the InMotion2 tion or motor function is preserved below the level of the by Interactive Motion,Inc.[53.33].MIT-MANUS is injury.Spinal cord injuries are commonly bilateral and a planar two-joint arm that makes use of the selective thus are often more functionally devastating in compar-compliant assembly robot arm (SCARA)configura- ison to strokes,which at least leave a person with one tion,allowing two large,mechanically grounded motors side of their body that is relatively normal(which we to drive a lightweight linkage.The patient sits across will refer to as the less impaired side).Individuals ex- from the device,with the weaker hand attached to the perience especially severe disability if the lesion is high end-effecter,and the arm supported on a table with a low- enough to involve the arms as well as the legs. friction support.By virtue of the use of the SCARA configuration,the MIT-MANUS is perhaps the simplest 53.2.3 Robotic Therapy possible mechanical design that allows planar move- for the Upper Extremity ments while also allowing a large range of forces to be applied to the arm without requiring force feedback The following sections describe the best-known clini- control. cally tested upper-limb therapy robot systems that have MIT-MANUS assists the patient in moving the arm been developed since the 1980s(Fig.53.1). across the tabletop as the patient plays simple video Part F 53.2 Fig.53.1a-e Arm-therapy robotic systems that have undergone extensive clinical testing;(a)MIT-MANUS,developed by Hogan,Krebs,and colleagues at the Massachusetts Institute of Technology (USA);(b)MIME,developed at the Department of Veterans Affairs in Palo Alto in collaboration with Stanford University (USA);(c)GENTLE/s developed in the EU,(d)ARM-Guide,developed at the Rehabilitation Institute of Chicago and the University of California,Irvine (USA),and (e)Bi-Manu-Track,developed by Reha-Stim(Germany)
Rehabilitation and Health Care Robotics 53.2 Physical Therapy and Training Robots 1229 the vertebrae at which the spinal cord is injured, since nerves branch out to the head, arms, legs, and bladder and bowel at different vertebrae. About 50% of spinal cord injuries are incomplete, meaning that some sensation or motor function is preserved below the level of the injury. Spinal cord injuries are commonly bilateral and thus are often more functionally devastating in comparison to strokes, which at least leave a person with one side of their body that is relatively normal (which we will refer to as the less impaired side). Individuals experience especially severe disability if the lesion is high enough to involve the arms as well as the legs. 53.2.3 Robotic Therapy for the Upper Extremity The following sections describe the best-known clinically tested upper-limb therapy robot systems that have been developed since the 1980s (Fig. 53.1). a) b) c) d) e) Fig. 53.1a–e Arm-therapy robotic systems that have undergone extensive clinical testing; (a) MIT-MANUS, developed by Hogan, Krebs, and colleagues at the Massachusetts Institute of Technology (USA); (b) MIME, developed at the Department of Veterans Affairs in Palo Alto in collaboration with Stanford University (USA); (c) GENTLE/s developed in the EU, (d) ARM-Guide, developed at the Rehabilitation Institute of Chicago and the University of California, Irvine (USA), and (e) Bi-Manu-Track, developed by Reha-Stim (Germany) MIT-MANUS The first robotic therapy device to undergo extensive clinical testing, and now to achieve some commercial success, is the MIT-MANUS, sold as the InMotion2 by Interactive Motion, Inc. [53.33]. MIT-MANUS is a planar two-joint arm that makes use of the selective compliant assembly robot arm (SCARA) configuration, allowing two large, mechanically grounded motors to drive a lightweight linkage. The patient sits across from the device, with the weaker hand attached to the end-effecter, and the arm supported on a table with a lowfriction support. By virtue of the use of the SCARA configuration, the MIT-MANUS is perhaps the simplest possible mechanical design that allows planar movements while also allowing a large range of forces to be applied to the arm without requiring force feedback control. MIT-MANUS assists the patient in moving the arm across the tabletop as the patient plays simple video Part F 53.2
1230 Part F Field and Service Robotics games,such as moving a cursor into a target that finger and wrist muscles [53.41].Again,significant ben- changes locations on a computer screen.Assistance is efits were found for both therapies,and those benefits achieved using a position controller with an adjustable were specific to the movements practised,but the ben- impedance.Additional modules have been developed for efits were not significantly different between therapies. the device for allowing vertical motion [53.34],wrist We note that the lack of a significant difference in these motion [53.35],and hand grasp [53.36].Software has studies may simply be due to the limited number of been developed for providing graded resistance as well patients who participated in these studies (i.e.,inade- as assistance to movement [53.37],and for varying the quate study power),rather than a close similarity of the firmness and timing of assistance based on real-time effectiveness of the therapies. measurements of the patient's performance on the video games [53.38]. MIME MIT-MANUS has undergone extensive clinical test- Several other systems have undergone clinical testing. ing in several studies,summarized as follows.The first The mirror image movement enhancer(MIME)system clinical test of the device compared the motor recovery uses a Puma-560 robot arm to assist in movement of of acute stroke patients who received an additional dose the patient's arm [53.42].The device is attached to the of robot therapy on top of their conventional therapy,to hand through a customized splint and a connector that that of a control group,who received conventional ther- is designed to break away if interaction forces become apy and a brief,sham exposure to the robot [53.39].The too large.Compared to MIT-MANUS,the device al- robot group patients received the additional robotic ther-lows more naturalistic motion of the arm because of apy for an hour each day,five days per week,for several its six degrees of freedom(DOFs),but must rely on 驾 weeks.The robot group recovered more arm move- force feedback so that the patient can drive the robot ment ability than the control group according to clinical arm.Four control modes were developed for MIME. 53.2 scales,without any increase in adverse effects such as In the passive mode,the patient relaxes and the robot shoulder pain.The improvements might subjectively be moves the arm through a desired pattern.In the active characterized as small but somewhat meaningful to the assist mode,the patient initiates a reach toward a tar- patient.The improvements were sustained at three-year get,indicated by physical cones on a table top,which follow-up. then triggers a smooth movement of the robot toward This first study with MIT-MANUS demonstrated the target.In the active constrained mode,the device that acute stroke patients who received more therapy acts as a sort of virtual ratchet,allowing movement to- recover better,and that this extra therapy can be deliv- ward the target,but preventing the patient from moving ered by a robotic device.It did not answer the question away from the target.Finally,in mirror-image mode, as to whether the robotic features of the robotic device the motion of the patient's less impaired arm is meas- were necessary.In other words,it may have been that pa- ured with a digitizing linkage,and the impaired arm is tients would have also improved their movement ability controlled to follow along in a mirror-symmetric path. if they had practised additional movements with MIT- The initial clinical test of MIME found that chronic MANUS with the motors off(thus making it equivalent stroke patients who received therapy with the device to a computer mouse),simply by virtue of the increased improved their movement ability about as much as pa- dose of movement practice stimulating use-dependent tients who received conventional tabletop exercises with plasticity.Thus,while this study indicated the promise an occupational therapist [53.42].The robot group even of robots for rehabilitation therapy,it did not close the surpassed the gains from human-delivered therapy for gap of knowledge as to how external mechanical forces the outcome measures of reaching range of motion and provoke use-dependent plasticity. strength at key joints of the arm.A follow-on study Subsequent studies with MIT-MANUS confirmed is being undertaken to elucidate which of the control that robotic therapy can also benefit chronic stroke pa-modes or what combination of MIME exercises caused tients [53.40].The device has been used to compare the gains [53.43]. two different types of therapy-assisting movement ver- sus resisting movement-in chronic stroke subjects,but ARM Guide with inconclusive results:both types of therapy pro- The question of the effect of robot forces on move- duced benefits [53.37].The device has also been used to ment recovery was also left unresolved by a study with compare assistive robot therapy with another technolog- another device,the ARM guide.The ARM guide is ical approach to rehabilitation-electrical stimulation of a trombone-like device that can be oriented then locked
1230 Part F Field and Service Robotics games, such as moving a cursor into a target that changes locations on a computer screen. Assistance is achieved using a position controller with an adjustable impedance. Additional modules have been developed for the device for allowing vertical motion [53.34], wrist motion [53.35], and hand grasp [53.36]. Software has been developed for providing graded resistance as well as assistance to movement [53.37], and for varying the firmness and timing of assistance based on real-time measurements of the patient’s performance on the video games [53.38]. MIT-MANUS has undergone extensive clinical testing in several studies, summarized as follows. The first clinical test of the device compared the motor recovery of acute stroke patients who received an additional dose of robot therapy on top of their conventional therapy, to that of a control group, who received conventional therapy and a brief, sham exposure to the robot [53.39]. The robot group patients received the additional robotic therapy for an hour each day, five days per week, for several weeks. The robot group recovered more arm movement ability than the control group according to clinical scales, without any increase in adverse effects such as shoulder pain. The improvements might subjectively be characterized as small but somewhat meaningful to the patient. The improvements were sustained at three-year follow-up. This first study with MIT-MANUS demonstrated that acute stroke patients who received more therapy recover better, and that this extra therapy can be delivered by a robotic device. It did not answer the question as to whether the robotic features of the robotic device were necessary. In other words, it may have been that patients would have also improved their movement ability if they had practised additional movements with MITMANUS with the motors off (thus making it equivalent to a computer mouse), simply by virtue of the increased dose of movement practice stimulating use-dependent plasticity. Thus, while this study indicated the promise of robots for rehabilitation therapy, it did not close the gap of knowledge as to how external mechanical forces provoke use-dependent plasticity. Subsequent studies with MIT-MANUS confirmed that robotic therapy can also benefit chronic stroke patients [53.40]. The device has been used to compare two different types of therapy – assisting movement versus resisting movement – in chronic stroke subjects, but with inconclusive results: both types of therapy produced benefits [53.37]. The device has also been used to compare assistive robot therapy with another technological approach to rehabilitation – electrical stimulation of finger and wrist muscles [53.41]. Again, significant benefits were found for both therapies, and those benefits were specific to the movements practised, but the benefits were not significantly different between therapies. We note that the lack of a significant difference in these studies may simply be due to the limited number of patients who participated in these studies (i. e., inadequate study power), rather than a close similarity of the effectiveness of the therapies. MIME Several other systems have undergone clinical testing. The mirror image movement enhancer (MIME) system uses a Puma-560 robot arm to assist in movement of the patient’s arm [53.42]. The device is attached to the hand through a customized splint and a connector that is designed to break away if interaction forces become too large. Compared to MIT-MANUS, the device allows more naturalistic motion of the arm because of its six degrees of freedom (DOFs), but must rely on force feedback so that the patient can drive the robot arm. Four control modes were developed for MIME. In the passive mode, the patient relaxes and the robot moves the arm through a desired pattern. In the active assist mode, the patient initiates a reach toward a target, indicated by physical cones on a table top, which then triggers a smooth movement of the robot toward the target. In the active constrained mode, the device acts as a sort of virtual ratchet, allowing movement toward the target, but preventing the patient from moving away from the target. Finally, in mirror-image mode, the motion of the patient’s less impaired arm is measured with a digitizing linkage, and the impaired arm is controlled to follow along in a mirror-symmetric path. The initial clinical test of MIME found that chronic stroke patients who received therapy with the device improved their movement ability about as much as patients who received conventional tabletop exercises with an occupational therapist [53.42]. The robot group even surpassed the gains from human-delivered therapy for the outcome measures of reaching range of motion and strength at key joints of the arm. A follow-on study is being undertaken to elucidate which of the control modes or what combination of MIME exercises caused the gains [53.43]. ARM Guide The question of the effect of robot forces on movement recovery was also left unresolved by a study with another device, the ARM guide. The ARM guide is a trombone-like device that can be oriented then locked Part F 53.2
Rehabilitation and Health Care Robotics 53.2 Physical Therapy and Training Robots 1231 in different directions and assist in reaching in a straight cylinders to help extend or flex the fingers,and has been line.Chronic stroke patients who received assistance shown to improve hand movement ability of chronic during reaching with the robot improved their move- stroke subjects [53.50].Simple force-feedback con- ment ability [53.44].However,they improved about as trolled devices,including a one-DOF wrist manipulator much as a control group that simply practised a matched and a two-DOF elbow-shoulder manipulator,were also number of reaches without assistance from the robot. recently shown to improve movement ability of chronic This suggests that movement effort by the patient is stroke subjects who exercised with the devices [53.51]. a key factor for recovery,although the small sample size A passive exoskeleton,the T-WREX arm orthosis,pro- of this study limited its ability to resolve the size of the vides support to the arm against gravity using elastic difference between guided and unguided therapy. bands,while still allowing a large range of motion of the arm [53.52].By incorporating a simple hand-grasp Bi-Manu-Track sensor,this device allows substantially weakened pa- Perhaps the most striking clinical results generated so tients to practise simple virtual reality exercises that far have come from one of the simplest devices built.simulate functional tasks such as shopping and cooking. Similar to a design proposed previously [53.45],the Chronic stroke patients who practised exercising with Bi-Manu-Track uses two motors,one for each hand,to this non-robotic device recovered significant amounts allow bimanual wrist-flexion extension [53.46].The de-of movement ability,comparable with the Fugl-Meyer vice can also assist in forearm pronation/supination if it gains seen with MIT-MANUS and MIME.NeReBot is tilted downward and the handles are changed.In an is a three-DOF wire-based robot that can slowly move extensive clinical test of the device,22 subacute patients a stroke patient's arm in spatial paths.Acute stroke (i.e.,4-6 weeks after stroke)practised 800 movements patients who received additional movement therapy art with the device for 20 min per day,five days per week beyond their conventional rehabilitation therapy with for six weeks [53.461.For half of the movements,the de-NeReBot recovered significantly more movement ability vice drove both arms,and for the other half,the patient's than patients who received just conventional rehabilita- stronger arm drove the motion of the more-impaired arm.tion therapy [53.53].RehaRob uses an industrial robot A control group received a matched duration of electri- arm to mobilize patients'arms along arbitrary trajecto- cal stimulation(ES)of their wrist extensor muscles,with ries following stroke [53.54]. the stimulation triggered by voluntary activation of their muscles when possible,as measured by electromyo- Other Systems Currently under Development graphy (EMG).The number of movements performed Several other robotic therapy devices are currently under with EMG-triggered ES was 60-80 per session.The development.For example,at the high end of cost and robot-trained group improved by 15 points more on the complexity are the ARM-In [53.55]and Pneu-WREX Fugl-Meyer scale,a standard clinical scale of movement systems [53.56],which are exoskeletons that accommo- ability with a range from 0 to 66 points in upper extrem- date nearly naturalistic movement of the arm while still ity function.It assigns a score of 0(cannot complete),I achieving a wide range of force control.A system that (completes partially),or 2(completes normally)for 33 couples a immersive virtual-reality display with a haptic test movements,such as lifting the arm without flexing robot arm is described in [53.571.A wearable exoskele- the elbow.For comparison,reported gains in Fugl-Meyer ton driven by pneumatic muscles is described in [53.58]. score after therapy with the MIT-MANUS and MIME At the lower end of cost/complexity are devices that use devices ranged from 0-5 points [53.47]. force feedback joysticks and steering wheels with a view toward implementation in the home [53.59-62].Exam- Other Devices to Undergo Clinical Testing ples of recent,novel robotic devices for the hand are Other devices to undergo clinical testing are as fol-given in [53.63-65]:these devices typically follow an lows.The GENTLE/s system uses a commercial robot,active assist therapy paradigm in that they are designed the HapticMaster,to assist in patient movement as the to help open and close the hand.One robotic therapy patient plays video games.The HapticMaster allows system for the hand incorporates the idea of using visual four degrees of freedom of movement and achieves feedback distortion to enhance motivation of patients a high bandwidth of force control using force feedback. during movement therapy [53.66].Using robotic force Chronic stroke patients who exercised with GENTLE/s fields to amplify the kinematic errors of stroke patients improved their movement ability [53.48,49].The Rut- during reaching may provoke novel forms of adaptation gers hand robotic device uses low-friction pneumatic of those patterns [53.4,67]
Rehabilitation and Health Care Robotics 53.2 Physical Therapy and Training Robots 1231 in different directions and assist in reaching in a straight line. Chronic stroke patients who received assistance during reaching with the robot improved their movement ability [53.44]. However, they improved about as much as a control group that simply practised a matched number of reaches without assistance from the robot. This suggests that movement effort by the patient is a key factor for recovery, although the small sample size of this study limited its ability to resolve the size of the difference between guided and unguided therapy. Bi-Manu-Track Perhaps the most striking clinical results generated so far have come from one of the simplest devices built. Similar to a design proposed previously [53.45], the Bi-Manu-Track uses two motors, one for each hand, to allow bimanual wrist-flexion extension [53.46]. The device can also assist in forearm pronation/supination if it is tilted downward and the handles are changed. In an extensive clinical test of the device, 22 subacute patients (i. e., 4–6 weeks after stroke) practised 800 movements with the device for 20 min per day, five days per week for six weeks [53.46]. For half of the movements, the device drove both arms, and for the other half, the patient’s stronger arm drove the motion of the more-impaired arm. A control group received a matched duration of electrical stimulation (ES) of their wrist extensor muscles, with the stimulation triggered by voluntary activation of their muscles when possible, as measured by electromyography (EMG). The number of movements performed with EMG-triggered ES was 60–80 per session. The robot-trained group improved by 15 points more on the Fugl-Meyer scale, a standard clinical scale of movement ability with a range from 0 to 66 points in upper extremity function. It assigns a score of 0 (cannot complete), 1 (completes partially), or 2 (completes normally) for 33 test movements, such as lifting the arm without flexing the elbow. For comparison, reported gains in Fugl-Meyer score after therapy with the MIT-MANUS and MIME devices ranged from 0–5 points [53.47]. Other Devices to Undergo Clinical Testing Other devices to undergo clinical testing are as follows. The GENTLE/s system uses a commercial robot, the HapticMaster, to assist in patient movement as the patient plays video games. The HapticMaster allows four degrees of freedom of movement and achieves a high bandwidth of force control using force feedback. Chronic stroke patients who exercised with GENTLE/s improved their movement ability [53.48, 49]. The Rutgers hand robotic device uses low-friction pneumatic cylinders to help extend or flex the fingers, and has been shown to improve hand movement ability of chronic stroke subjects [53.50]. Simple force-feedback controlled devices, including a one-DOF wrist manipulator and a two-DOF elbow–shoulder manipulator, were also recently shown to improve movement ability of chronic stroke subjects who exercised with the devices [53.51]. A passive exoskeleton, the T-WREX arm orthosis, provides support to the arm against gravity using elastic bands, while still allowing a large range of motion of the arm [53.52]. By incorporating a simple hand-grasp sensor, this device allows substantially weakened patients to practise simple virtual reality exercises that simulate functional tasks such as shopping and cooking. Chronic stroke patients who practised exercising with this non-robotic device recovered significant amounts of movement ability, comparable with the Fugl-Meyer gains seen with MIT-MANUS and MIME. NeReBot is a three-DOF wire-based robot that can slowly move a stroke patient’s arm in spatial paths. Acute stroke patients who received additional movement therapy beyond their conventional rehabilitation therapy with NeReBot recovered significantly more movement ability than patients who received just conventional rehabilitation therapy [53.53]. RehaRob uses an industrial robot arm to mobilize patients’ arms along arbitrary trajectories following stroke [53.54]. Other Systems Currently under Development Several other robotic therapy devices are currently under development. For example, at the high end of cost and complexity are the ARM-In [53.55] and Pneu-WREX systems [53.56], which are exoskeletons that accommodate nearly naturalistic movement of the arm while still achieving a wide range of force control. A system that couples a immersive virtual-reality display with a haptic robot arm is described in [53.57]. A wearable exoskeleton driven by pneumatic muscles is described in [53.58]. At the lower end of cost/complexity are devices that use force feedback joysticks and steering wheels with a view toward implementation in the home [53.59–62]. Examples of recent, novel robotic devices for the hand are given in [53.63–65]: these devices typically follow an active assist therapy paradigm in that they are designed to help open and close the hand. One robotic therapy system for the hand incorporates the idea of using visual feedback distortion to enhance motivation of patients during movement therapy [53.66]. Using robotic force fields to amplify the kinematic errors of stroke patients during reaching may provoke novel forms of adaptation of those patterns [53.4, 67]. Part F 53.2
1232 Part F Field and Service Robotics 53.2.4 Robotic Therapy for Walking automation.The efforts of roboticists have been espe- cially focused on BWSTT rather than overground gait Background training because BWSTT is done on a stationary setup Scientific evidence that gait training improves recovery in a well-defined manner and thus can be more easily of mobility after neurologic injury started to accumu- automated than overground gait training.Randomized, late in the 1980s through studies with cats.Cats with controlled clinical trials have shown that BWSTT is SCI can be trained to step with their hind limbs on comparable in effectiveness to conventional physical a treadmill with partial support of the body weight therapy for various gait-impairing diseases [53.75-80]. and assistance of leg movements [53.68,69].Follow-These trials support the efforts towards automation of ing the animal studies,various laboratories developed BWSTT,as the working conditions of physical thera- a rehabilitation approach in which the patient steps on pists will improve if the robots do much of the physical a treadmill with the body weight partially supported by work,which in the case of BWSTT actually leads to an overhead harness and assistance from up to three occasional back injuries to therapists.Usually,only therapists [53.70-73].Depending on the patient's im-one therapist is needed in robot-assisted training,for pairment level,from one to three therapists are needed the tasks of helping the patient into and out of the for body-weight supported treadmill training(BWSTT),robot and monitoring the therapy.In the case of SCI with one therapist assisting in stabilizing and moving patients,a small randomized,controlled trial [53.76] the pelvis,while two additional therapists sit next to reported that robotic-assisted BWSTT with a first- the treadmill and assist the patient's legs in swing and generation robot required significantly less labor than stance.This type of training is based on the principle both conventional overground training and therapist- Part FI of generating normative,locomotor-like sensory input assisted BWSTT,with no significant difference found that promotes functional reorganization and recovery in effectiveness. 53.2 of the injured neural circuitry [53.74].In the 1990s, several independent studies indicated that BWSTT im- Gait-Training Robots in Current Clinical Use proves stepping in people with SCI or hemiplegia after Three gait-training robot systems are already in use stroke[53.70-721. for therapy in several clinics worldwide:the gait Gait training is particularly labor-intensive and trainer GT-I[53.81],the LokomatR [53.82],and the strenuous for therapists,so it is an important target for AutoAmbulatorTM [53.83](Fig.53.2). b) Fig.53.2a-c Gait-training robotic systems currently in use in clinics;(a)the gait trainer GT-I,developed by Hesse's group and commercialized by Reha-Stim (Germany):(b)the Lokomat,developed by Colombo and colleagues and commercialized by Hocoma AG(Switzerland),and(c)AutoAmbulatorTM,developed by the HealthSouth Corporation (USA)
1232 Part F Field and Service Robotics 53.2.4 Robotic Therapy for Walking Background Scientific evidence that gait training improves recovery of mobility after neurologic injury started to accumulate in the 1980s through studies with cats. Cats with SCI can be trained to step with their hind limbs on a treadmill with partial support of the body weight and assistance of leg movements [53.68, 69]. Following the animal studies, various laboratories developed a rehabilitation approach in which the patient steps on a treadmill with the body weight partially supported by an overhead harness and assistance from up to three therapists [53.70–73]. Depending on the patient’s impairment level, from one to three therapists are needed for body-weight supported treadmill training (BWSTT), with one therapist assisting in stabilizing and moving the pelvis, while two additional therapists sit next to the treadmill and assist the patient’s legs in swing and stance. This type of training is based on the principle of generating normative, locomotor-like sensory input that promotes functional reorganization and recovery of the injured neural circuitry [53.74]. In the 1990s, several independent studies indicated that BWSTT improves stepping in people with SCI or hemiplegia after stroke [53.70–72]. Gait training is particularly labor-intensive and strenuous for therapists, so it is an important target for a) b) c) Fig. 53.2a–c Gait-training robotic systems currently in use in clinics; (a) the gait trainer GT-I, developed by Hesse’s group and commercialized by Reha-Stim (Germany); (b) the Lokomatr , developed by Colombo and colleagues and commercialized by Hocoma AG (Switzerland), and (c) AutoAmbulatorTM, developed by the HealthSouth Corporation (USA) automation. The efforts of roboticists have been especially focused on BWSTT rather than overground gait training because BWSTT is done on a stationary setup in a well-defined manner and thus can be more easily automated than overground gait training. Randomized, controlled clinical trials have shown that BWSTT is comparable in effectiveness to conventional physical therapy for various gait-impairing diseases [53.75–80]. These trials support the efforts towards automation of BWSTT, as the working conditions of physical therapists will improve if the robots do much of the physical work, which in the case of BWSTT actually leads to occasional back injuries to therapists. Usually, only one therapist is needed in robot-assisted training, for the tasks of helping the patient into and out of the robot and monitoring the therapy. In the case of SCI patients, a small randomized, controlled trial [53.76] reported that robotic-assisted BWSTT with a firstgeneration robot required significantly less labor than both conventional overground training and therapistassisted BWSTT, with no significant difference found in effectiveness. Gait-Training Robots in Current Clinical Use Three gait-training robot systems are already in use for therapy in several clinics worldwide: the gait trainer GT-I [53.81], the Lokomatr [53.82], and the AutoAmbulatorTM [53.83] (Fig. 53.2). Part F 53.2