Robotic Mirror Therapy System for Functional Recovery of Hemiplegic Arms

We developed a real-time mirror robot system for functional recovery of hemiplegic arms using automatic control technology, conducted a clinical study on healthy subjects, and determined tasks through feedback from rehabilitation doctors. This simple mirror robot can be applied effectively to occupational therapy in stroke patients with a hemiplegic arm.

Transcript

The overall goal of this procedure is to introduce a real-time robotic mirror therapy system for functional recovery of hemiplegic arms. This method can help answer key questions in translationary neurorehab biomedical engineering research by showing that functional recovery of hemiplegic arms with advanced occupational therapy is achievable. The main advantage of this robotic mirror therapy is that it can enhance proprioceptive input to the sensory cortex, which is very important in brain neuroplasticity for stroke patients.

Individuals new to this method may struggle, as it was complicated to develop the software protocol, and assemble frames and motors. We first had the idea for this method when we observed conventional neurotherapy, which was limited in that the hemiplegic arm was not actually moving. Visual demonstration of this method is critical, as the sensor settings, assembly, and setup for robotic mirror therapy are difficult to learn.

Begin by obtaining a three attitude and heading reference system, or AHRS sensors, and connect them to a computer, one at a time, with a USB connector. Use communications software to configure the general sensor settings on the computer. Set each sensor to RS 232.

And select the COM port. Then, set the baud rate to 115, 200 bits per second. Data bits to eight.

Parity to none. Stop bits to one. And the flow control to none.

To check the COM port, click the home button on the bottom-left corner. Right-click on the computer, select properties, device manager, and click on the port tab to expand it. Once the communication has been established, the hyperterminal will display sensor readings.

Then, set the channels and assign different IDs for each sensor. Repeat the configuration, COM port check, and channel and ID assignment for each sensor. Finally, set the output format as quaternions.

And set the sensors to display the battery reserve. Begin assembling the elbow-joint motor by putting one of the coupling bodies with a keyway on the motor shaft. And securing it using an M5 hex-socket screw.

Secure the elbow coupling hollow cylinder cover to the elbow motor by using four 10 millimeter M5 socket-head screws. And place a second buffer coupling body on top of the first coupling body. Then, plug the ball bearing into the elbow rooftop frame, and secure it with four eight millimeter M4 socket-head screws.

Next, plug the elbow motor force dispersion shaft into the lower elbow support, and secure it with four six millimeter M3 socket-head screws. Then, place the upper elbow support on top of the lower elbow support and secure it using eight 12 millimeter M3 socket-head screws. Place part C on top, part B in the middle, and another coupling body at the bottom.

Join them together and secure the coupling body with one 10 millimeter M5 hex-socket screw. Then, attach part A to the bottom of this assembly with four 15 millimeter M5 socket-head screws. Next, secure a lower-wrist coupling hollow cylinder cover with the wrist motor, using four 10 millimeter M4 socket-head screws.

Then, place a coupling body on the motor shaft. Secure it with one M4 hex-socket screw, and follow that with a buffer coupling body on top. Attach a friction-reduction ring on top of the wrist rooftop frame with double-sided tape.

Then, plug the wrist motor force dispersion shaft into the handle, and secure it using four M2.5 socket-head screws. Join part F on top, part E in the middle, and a coupling body on the bottom. Fix the coupling body with a 10 millimeter M4 hex-socket screw.

Add an upper-wrist coupling hollow cylinder cover to the bottom of this assembly, using four 10 millimeter M3 socket-head screws. Then, secure part D to the bottom of the upper-wrist coupling hollow cylinder cover using four 15 millimeter socket-head screws. Next, secure two join-movement limiters, wrapped with sponges for safety reasons, and two shaft collars with levers, using four 15 millimeter M4 socket-head screws.

Then, slide the shaft collars in part G into the shafts, and use two normal shaft collars to secure the shafts and the wrist rooftop frame together, using eight eight millimeter M3 socket-head screws. Secure additional shaft collars with the lower-elbow support using four 15 millimeter M4 socket-head screws. Then, join the two parts and secure with a lever.

Finally, attach a support wall to the assembly using six 15 millimeter M4 socket-head screws, and secure a table stand using six 15 millimeter M6 socket-head screws. Begin by placing the AHRS sensors on the handle, the wrist frame, and the edge of the platform on the participant's healthy side, making sure to align them in parallel with the robot's orientation. Then, start the therapy software on the computer.

Choose the hemiplegic side by clicking the patient side switch button. Set the following joint angle limits:Elbow flexion at less than 50 degrees, elbow extension at more than minus 70 degrees, wrist flexion at less than 80 degrees, and wrist extension at more than minus 60 degrees. Then, set the velocity value between zero and 22.5 RPM for the elbow motor.

Use a velocity value between zero and 33 RPM for the wrist motor, and set the maximum acceleration and deceleration values as well. Next, turn on all the AHRS sensors. Then, run the program by clicking the arrow button in the upper-left corner of the program.

When the Save As"prompt pops up, write the file name for the results data and press OK.Finally, while the robot and healthy arm are at the initial position, where both hands are away from the body and parallel to each other, press the calibration button to initiate sensor values to zero. Begin by informing the participant that they will use their healthy arm to complete a set of mirror therapy tasks. The ball in holes, soccer game, dots tracing, and moving a cup task.

For the ball in holes task, place a small ball into the chosen hole, similar to the game of billiards. Likewise, for the soccer game, dribble and place a small ball into a goal, much like in a real game of soccer. Next, for the dots tracing task, use numbered stickers placed on a table as a guide to repeatedly move a handle in numerical order.

And then return it in the reverse direction. Finally, for the moving a cup task, take a cup with the handle and push it to a chosen location. Repeat until five minutes have elapsed.

Here, results are shown from a patient who suffered a right basal ganglia hemorrhage 19 months ago and received robotic mirror therapy for two weeks. The Fugl-Meyer assessment of the hemiplegic arm improved from 12 to 17 after ten sessions. Furthermore, the modified Ashworth scale of elbow flexors, measuring spasticity, was reduced from grade two, to one plus.

And the left-lateral pinch power was increased from zero to three pounds. Once mastered, the robotic mirror therapy can be completed in 40 minutes, if it is performed properly. While performing this procedure, it's important to know that the illusion of sychronicity between both arms is essential for the mirror therapy.

After its development, this procedure will pave the way for the research in the field of neuro-rehabilitation to explore the effects of advanced occupational therapy to enhance proprioception in patients with brain legions, such as stroke. After watching this video, you should have a good understanding of how to make and conduct a real-time robotic mirror therapy system for functional recovery of hemiplegic arms.

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Journal (Bioengineering)

Journal (Bioengineering)

Robotic Mirror Therapy System for Functional Recovery of Hemiplegic Arms

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