A Japanese university professor has developed the "Tail-wrist-II," a device that induces wrist movement, for the use of rehabilitation at home.
Hideyuki Tsukakoshi, an assistant professor of Mechanical Control Systems at the Graduate School of Science and Engineering of the Tokyo Institute of Technology, developed the device to prevent contracture (loss of retractility) of patients who are paralyzed on one side of the body due to strokes and the disuse syndrome suffered by the elderly.
The patient operates the joystick using the unaffected hand to adjust the air pressure inside the flat helical tube in order to induce movement of joints via the actuator unit attached to the paralyzed side.
When hemiplegic or bedridden patients or the elderly who can not move the joints as intended stay in bed for a long period, they could suffer from secondary symptoms such as contracture of muscles and the economy-class syndrome. To prevent these symptoms, hospitals offer programs that include a range of motion exercises by physical therapists and employ CPM (Continuous Passive Motion) devices.
However, going to the hospital is a burden for some patients, and the CPM devices are not appropriate for some patients with brain disorders because of the following reasons. (1) They are heavy and expensive. (2) The moving area of them could be displaced from the proper position on the patient. (3) Their fitting procedure is complicated. (4) They use a position control method.
For these reasons, it is not easy to use the CPM devices at home, and post-discharge cares have been a big issue for patients.
Therefore, Tsukakoshi and his team developed the "helical and flat wearable actuator" (WTA) using resin tubes so that the patients can continue to move their joints at home. The device is lighter than existing ones because the number of metal components was decreased, and it can be used outside of the hospital.
The WTA features a mechanism for pulling a string inward responding to the elongation movement of the device and has a 100° range of outward movement. The moving directions can be controlled by the patient's uninjured hand.
Even if the device is used by a patient who has a brain disorder and could move the joint toward unintended directions, there is little risk of damaging the joint because the device absorbs the patient's force directed against the movement of the device.
In addition, the "Fit-band," a fitting band that automatically grasps and fixes the patient's body to the device with a push of a button, enables paralyzed patients to wear the device without difficulty. This was made possible by using the characteristics of a flat tube: Its cross section shape changes to a circular shape when its inner pressure is increased.
A number of flat tubes are positioned in a given direction on the band, and the band changes its shape from a belt to a cylinder when it is inflated. If the patient shifts his/her weight while moving the joints, the grasping force will be controlled by a valve attached with a sensor, which is incorporated in the band so as to keep a constant grasping force.
This research is intended for treating wrist joints, but similar drive principles can be used for leg joints to develop a rehabilitation assisting device for home use that can replace existing CPM devices. Tsukakoshi said he would collaborate with hospitals and carry out the necessary clinical tests, aiming at the commercialization of the device. Furthermore, he plans to enhance the technology so that it can be used for rehabilitation at home in combination with remote operations by hospitals via the Internet.
The research is part of the Industrial Technology Research Grant Program of the New Energy and Industrial Technology Development Organization (NEDO).
Nikkei Electronics Asia magazine is available each month free of charge to engineers, managers and other qualified readers.
Nikkei Electronics |
Nikkei Monozukuri |
Nikkei Microdevices |
Nikkei Automotive Technology |
|---|---|---|---|
 |
 |
 |
 |
| The magazine for electronics designers and managers. | Design You Won't Regret - How to Reduce the Risk of Accidents | The most comprehensive technical journal for makers and users of LSIs and LCDs. | The comprehensive automotive technology magazine. |
Copyright © 1995-2009 Nikkei Business Publications, Inc. All rights reserved.
All editorial content and graphics on this Web site may not be reproduced in whole or in part without the express permission of the copyright owner.
November 2009
October 2009
September 2009