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The robotic device that has received the most clinical testing is the Massachusetts Institute of Technology (MIT)-Manus (Interactive Motion Technologies Inc, Cambridge, Massachusetts). A technical description was first presented in 1998. MIT-Manus is a 2 degrees-of-freedom robot manipulator that assists shoulder and elbow movement by moving the patients hand in the horizontal plane. A novel impedance control mode allows MIT-Manus to be highly compliant when interacting with the patient's arm, thereby closely matching the human therapist-patient interaction. A series of clinical trials has shown that MIT-Manus provides effective treatment. Acute stroke subjects who received 25 h of MIT-Manus treatment had greater gains in motor function than control subjects who only received a placebo treatment. Recent trials with chronic stroke subjects have demonstrated significant clinical gains with MIT-Manus training as well. If this robotic treatment can be delivered cost-effectively, these results would justify use of MIT-Manus as an adjunct to conventional treatment.
Stroke Inpatient during Therapy at the Burke Rehabilitation Hospital (White Plains, NY). Therapy is being conducted with a commercial version of MIT-MANUS (Interactive Motion Technologies, Inc., Cambridge, MA). [3]
The second key study of robot-assisted therapy for the arm after stroke used the Mirror Image Movement Enabler (MIME) device [4]. The MIME is a 6-degree-of-freedom, industrial robot manipulator (PUMA 560 [Unimation, Inc, Connecticut, no longer in existence]) that applies forces to the paretic limb through a customized forearm splint. The robot moves the forearm through a large range of positions and orientations in three-dimensional space. A six-axis sensor measures the forces and torques between the robot and the paretic limb. Several modes of robot-assisted movement have been implemented with MIME, including passive, active-assisted, and active-constrained, as well as a bimanual mode in which MIME continuously moves the impaired limb to the mirror image position of the unimpaired limb as measured with a digitizing linkage. The initial clinical testing of MIME compared the effectiveness of robot-assisted therapy with equally intensive conventional therapy. At the conclusion of training, the robot group had statistically larger improvements in the Fugl-Meyer score, a common clinical motor impairment scale. The robot group also had larger gains in strength and reach extent. At the 6-month follow-up, the groups no longer differed in Fugl-Meyer score; however, the robot group improved more in the self-care and transfers sections of the Functional Independence Measure. These results suggest that robot-assisted therapy can be comparable with, or perhaps more effective than, conventional rehabilitation therapy.
MIME: A robot servomechanism provides the assistance necessary for left arm movement in trajectories determined by movement of the right arm. [5]
Another highly influential robotic device is the Assisted Rehabilitation and Measurement (ARM) Guide (Rehabilitation Institute of Chicago, University of California–Irvine). A motorized linear constraint provides active-assisted reaching movements in different directions. After 8 weeks of training in the ARM Guide, chronic stroke subjects had functional gains and improvements in reaching kinematics. The most important result from this initial study was that the control group who received a matched amount of unassisted reaching movements had statistically identical gains. This emphasized the fact that highly repetitive active movements have therapeutic value and that the added value of assistance from a robot during active movements remained to be demonstrated. Motivated by these pioneering studies, several less-tested approaches are under development.
Photo of ARM Guide [6]
ARMin is a new device that supports spatial movements of the shoulder and elbow joint. Innovative, cooperative control strategies allow that the patient effort is taken into consideration. Multi-modal displays (visual, acoustic, tactile) further improve the patient- machine interaction and enhance the therapeutical output. More information in Design section.
ARMin [10]
This device is able to mimic a fluid, natural extension of the arm using pneumatic muscles and can be programmed for repetitive exercises specific to the user that improve arm and hand flexibility and strength. RUPERT (Robotic Upper Extremity Repetitive Therapy) I and II are powered by four pneumatic muscles to assist movement at the shoulder, elbow and wrist. The design was based on a kinematics model of the arm, which showed where to locate the pneumatic muscles and how much force was needed for normal reaching and feeding movements. As the individual's motor function improves, RUPERT can adapt to allow the user faster recovery by requiring the muscles to work independently where possible. The availability of a device like RUPERT, which can be used at home with greater frequency and for a longer period of time, may prove to be a more cost-effective approach that could provide better results. [11,12]
- Inflatable exoskeletons These devices are essentially jackets with sensors to detect the muscle movements in the patient's healthy arm and wrist, then use artificial muscles to stimulate that same movement on the damaged side of the body. Researchers hope repeated therapy will bring back the regular functioning of the damaged limb. [13]
Muscle Therapy Jacket Power Jacket - Many others with variety of strategies
Nudelholz mechanical arm trainer for practicing bilateral shoulder, elbow, and wrist movement. Nonaffected limb drives affected limb. [7]
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