Robotic therapy methods being used so far consist of two primary components: repetitive, yet voluntary movement by the patient, and mechanical assistance by the robot [14]. Repetitive active movement allows the patient to activate damaged and/or alternate motor pathways while repetitive passive movements help to maintain soft tissue health [15]. Robots can now quantify forces and movements that used to be judged by “touch and feel.”

The Tools

Device	Capabilities	Uses	Limitations
Lokomat [click name for picture/movie]	Motorized exoskeleton brace with four rotary joints. Precision ball-screws connected to DC motors to drive hip and knee flexion/extension for each leg.	Provides repetitive training for moving legs and walking over a treadmill. Cost and labor efficient therapy for SCI patients. Being used for stroke research.	Lacks backdriveability due to its high-advantage, ball-screw actuators. Needs mechanical adjustments to suit the size of the patient.
ARThur -Ambulation-assisting Robotic Tool for Human Rehabilitation [click name for picture/movie]	Can reduce amount of assistance as patient recovers. Provides direct and natural kinematic feedback of movement control errors. Quantifies motion. Controlled using MATLAB’s Real Time WindowsTarget.	Enables adaptation studies–how the nervous system uses internal models of the body and environment to compensate for force-fields. Used for step training and eventually will incorporate robot-patient attachments for spinal cord injury patients.	Provides backdriveability, but is limited to gross motor skills. Unknown if it will eventually provide virtual experience, otherwise could be repetitious, boring.
MIT-Manus [click name for picture/slideshow]	A video screen prompts the person to perform arm movement tasks. If movement does not occur, the robotic device moves the arm for the person and adjusts levels of guidance needed for the patient. Capable of assisting planar motion.	Provided to increase therapists productivity for upper limb rehabilitation, and for ongoing research. Is helping to determine post-stroke central nervous system reorganization.	Limited to arm movements. Additional robots in progress for therapy of legs and wrist/hand. Heavy, large.
ARM Guide -Assisted Rehabilitation Measurement [click name for diagrams/movie]	Singly-actuated. Provides 4 degrees-of-freedom. Handpiece is attached to an orientable linear track. DC servo motor assists arm movement. Optical encoders record positions. Six-axis force sensor records forces and torques.	Provides robotic active assistive therapy to improve arm movement recovery. Quantifies spasticity, limb stiffness, and muscle synergies. Reaching is the goal. Relatively inexpensive.	Limited to a linear path unlike the MIT-MANUS which can assist planar motion.
MIME, 3rd Generation [click name for diagrams]	Uses a PUMA-560. Offers 6 degrees-of-freedom. Two unilateral modes, one bimanual mode. Can assist in 3D and mirror-image movements.	Provides active assist therapy towards more sensitive, objective measures of rehabilitation.	Master/slave mode adds significant cost. Heavy, large.

Table sources: [11], [14], [15], [16]

Future Applications for Current Technology

   Quantitative data produced by robots during therapy will help doctors prescribe therapy for new patients, repeat medical procedures done by skilled neurologists for training therapists, and data recorded by robots can be sent through the internet to areas lacking specialists [17].