A third arm of breathing control was tested on humans

Neuroengineer Silvestro Micera develops advanced technological solutions that help people regain sensory and motor functions lost due to traumatic events or neurological disorders. So far, he has never worked on improving the human body and intellect with the help of technology.

A study has now been published Scientific RoboticsMicera and his team report how diaphragmatic movement can be monitored for successful control of an extra arm, essentially augmenting a healthy person with a third – robotic – arm.

„This study opens up new and exciting possibilities, showing that additional arms can be controlled in detail and that simultaneous control with both natural hands is possible,” says Micera, Chair of the Bertarelli Foundation in Translational Neuroengineering at EPFL and Professor of Bioelectronics at the Scuola Superiore Sant. 'elder brother.

Research is a part of Third hand plan, previously funded by the Swiss National Science Foundation (NCCR Robotics), aims to provide a wearable robotic arm to aid in daily tasks or assist in search and rescue. Micera believes that exploring the cognitive limits of third-hand control may actually provide gateways to a better understanding of the human brain.

Mysera continues, „The main thrust of this third hand control is to understand the nervous system. If you challenge the brain to do something completely new, you can learn whether the brain has the ability to do it and whether it is possible to facilitate this learning. To build on this knowledge, for example, assistive devices for people with disabilities or stroke Then we can change to develop rehabilitation protocols.”

„We want to understand whether our brains are hardwired to control what nature has given us, and we have shown that the human brain can adapt to integrate new organs together with our biological organs,” explains Solaiman Shokur. Research at the Neuro-X Institute and EPFL Senior Scientist. „It’s about acquiring new motor functions, improving them beyond the current functions of a given user, whether it’s a healthy person or a disabled person. From a neurological perspective, it’s a continuum between rehabilitation and augmentation.

To investigate the cognitive controls of augmentation, the researchers first created a virtual environment and tested a healthy user’s ability to control a virtual hand using movement of the diaphragm. They found that diaphragmatic control does not interfere with actions such as controlling one’s physical hands, one’s speech, or vision.

In this virtual reality system, the user is fitted with a belt that measures the movement of the diaphragm. Wearing a virtual reality headset, the user sees three hands: a right hand and hand, a left hand and hand, and a third hand between the two with a symmetrical, six-fingered hand.

„We designed the arm symmetrically to avoid any left- or right-handed bias,” explains Giulia Dominijani, a PhD student at EPFL’s Neuro-X Institute.

In the virtual environment, the user is asked to reach with either the left hand, the right hand, or a symmetrical hand in the middle. In the real environment, the user holds an exoskeleton with both hands, allowing control of the virtual left and right hands. Motion detected by a belt around the diaphragm is used to control a virtual middle, symmetrical arm. The system was tested on 61 healthy subjects in 150 sessions.

„The diaphragmatic control of the third arm is actually very intuitive, and participants learn to control the extra limb very quickly,” Dominijani explains. „Furthermore, our control strategy is inherently independent of biological components, and we show that diaphragm control does not affect the user’s ability to speak coherently.”

The researchers successfully tested diaphragm control with a real robotic arm, which can extend a simplified single wire, and pin inside. As the user contracts the diaphragm, the rod extends outward. In an experiment similar to a VR environment, the user is asked to reach and hover over target circles with their left or right hand or a robotic arm.

In addition to the diaphragm, but not reported in the study, vestigial ear muscles have also been tested for their potential to perform new tasks. In this approach, a user is equipped with ear sensors and trained to use better ear muscle movement to control the displacement of a computer mouse.

„Users can use these ear muscles to control additional limbs,” says Shokur, emphasizing that these alternative control strategies may one day help develop rehabilitation protocols for people with motor disabilities.

Part of the third-hand project, previous studies related to this Control of robotic arms They are focusing on helping the differently abled. The latest scientific robotics research is a step beyond repairing the human body.

„Our next step is to explore the use of more complex robotic devices using our various control strategies, performing real-life tasks in and out of the lab. Only then can we understand the true potential of this approach,” concludes Micera.

Note: Dominijanni G, Pinheiro DL, Pollina L, et al. Human motor augmentation with an additional robotic arm without functional interference. Scientific robot. 2023;8(85):eadh1438. doi: 10.1126/scirobotics.adh1438

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