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 locked1230 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 test￾ing 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 ther￾apy and a brief, sham exposure to the robot [53.39]. The robot group patients received the additional robotic ther￾apy for an hour each day, five days per week, for several weeks. The robot group recovered more arm move￾ment 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 deliv￾ered 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 pa￾tients would have also improved their movement ability if they had practised additional movements with MIT￾MANUS 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 pa￾tients [53.40]. The device has been used to compare two different types of therapy – assisting movement ver￾sus resisting movement – in chronic stroke subjects, but with inconclusive results: both types of therapy pro￾duced benefits [53.37]. The device has also been used to compare assistive robot therapy with another technolog￾ical approach to rehabilitation – electrical stimulation of finger and wrist muscles [53.41]. Again, significant ben￾efits were found for both therapies, and those benefits were specific to the movements practised, but the ben￾efits 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., inade￾quate 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 al￾lows 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 tar￾get, 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 to￾ward 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 meas￾ured 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 pa￾tients 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 move￾ment 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