Armin stands directly on the window front of the open-plan office. This robust, silver silver machine with its long, articulated gripper arm looks like it came from a factory hall for car assembly. But it is located in a research building on several floors opposite Inselspital Bern.
"This is our therapy robot," says Laura Marchal-Crespo, striking her arm through the trails for the demonstration. A few years ago, Armin was developed at ETH Zurich by Robert Riener and Tobias Nef to train hand and arm movements in patients with paralysis following a stroke. Now the 39-year-old professor at the Competence Center at the University of Berne for Biomedical Engineering (Artorg) is working on adapting the control of the rehabilitation robot to individual needs.
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"The longer a patient is inactive, the harder it is for him to regain mobility later," Marchal-Crespo says. It is also important to constantly repeat the exercises so that the brain structures can organize themselves. However, rehabilitation robots are not intended at all to replace conventional therapies, but rather as a useful complement.
Learning by mistake
Spanish Laura Marchal-Crespo was already researching the interface between ETH Zurich and Zurich Man and machine using robotic assistance and virtual reality. She was particularly interested in helping paralyzed people after a stroke. Prior to ETH, she studied and earned a doctorate at the University of California at Irvine. In 2017, she was appointed professor at the Swiss National Science Foundation (SNSF) and has since worked at the University of Bern. In October she gave her inaugural lecture at the faculty of medicine .
During training with Armin, the patient's affected arm is strapped to the external skeleton of the mobile robotic arm and follows the movements dictated by the robot. In this way, everyday situations, such as pouring water into a glass, can be practically practiced in front of the screen.
"We improve the ability to move by amplifying the faults," the engineer says. This sounds strange. But if a stroke patient, for example, wants to grab something but not do it exactly, the rehabilitation robot reinforces this inaccuracy by creating a little resistance. In this way, the patient must work harder. The learning algorithm developed by Marchal-Crespo independently determines which patient complicates the task and which makes it easier.
During training, the robot decides whether to help or resist. Photo: Adrian Moser
In addition to Armin, there is also a horizontal walking machine in Bern's open plan office. Marchal-Crespo can then examine a patient even during training in a magnetic resonance tomograph. Lying, he either actively or passively moves his legs with a knee-jack robot. The researcher wants to find out which areas of the brain are stimulated by such specific exercises and how the neurons reconnect after a stroke. She is currently trying to simulate the feeling of walking as accurately as possible so that the pressure on the soles feels.
Originally, she came from the suburbs to Barcelona, so to speak, laughing. She was very lucky to receive a scholarship for the United States at that time. Because her parents were not academics and her father made money as a taxi driver. Her mother has always supported her and her two sisters in every way, she adds. One is now a mechanical engineer in Australia, the other a chemist in Barcelona.
Since Marchal-Crespos also comes from the capital of Catalonia, he speaks Catalan with three children aged three to seven while she speaks Spanish with them. Everyday life with family and work is a challenge, but it is also exciting and a privilege, she thinks. Her husband works as an engineer at ABB in Zurich. When the family lives there, she commutes to Bern four days a week. "If possible, we do all outdoor activities together on the weekend and either go hiking or cycling."
Virtual Reality Therapy
Marchal-Crespo is also particularly fascinated by the unnecessary opportunities in the virtual world. So one of her doctoral students now produces a VR glasses. If you open it, you're in a virtual room where suddenly an apple, then a pear or another apple hangs in the air. With a control unit you now have to control a ball exactly for these fruits and at the same time count the fruits.
"It sounds like it's very easy," the researcher says. But for patients after a stroke, the combination of motor activity and a cognitive task is difficult. Because they have to focus on both and just regain those abilities.
Also use games
Marchal-Crespo has other gadgets in his test lab. For example, a special joystick that lets you run a small ball over various rough, smooth, soft, hilly or canyon-like surfaces and feel the special material on the hand you just touch in the virtual world. "We try to activate as many senses as possible to achieve the greatest possible training success," she says.
Her goal is to motivate patients to exercise longer and more intensively. Of course, this is exhausting and often frustrating, she stresses. When a child learns to walk, let go, but rise again, try again and again. But it comes from the inner driving force. Those who need to practice walking again after a stroke need much more strength and endurance.
She is currently investigating if she can increase the patient's motivation with special games. "I also want to make boring workouts exciting," says the researcher.
Created: 09.11.2019, 21:04