Paraplegia: moving muscles using electrical impulses

Interview with Dr. Ronny Grunert, Fraunhofer Institute for Machine Tools and Forming Technology IWU, Medical Technology


It happens about 1,800 times per year: after a sporting or traffic-related accident, a person's spinal cord is injured to where nerve tracts are severed and he becomes paralyzed. Researchers now want to develop software that measures the brain signals of paralyzed patients and sends out electrical impulses via a system to stimulate muscles, causing them to move again.

Image: Dr. Ronny Grunert; Copyright: private

Dr. Ronny Grunert; © private

With this research project, a team of scientists from the West Saxon University of Applied Sciences of Zwickau, the University Hospital Leipzig, and the Fraunhofer IWU tries to reduce the effects of paraplegia. In this interview, Dr. Ronny Grunert explains the technologies designed to implement this goal.

Dr. Grunert, what are the most common causes of paraplegia?
Dr. Ronny Grunert: Most of our patients are paraplegics due to an accident or spinal cord injuries. Our technology primarily aims to help newly injured patients.

Your project intends to reduce the effects of paraplegia. How do you want to achieve this?
Grunert: The project just started in August. Our research has been approved for three years. During this time, we want to be able to generate first functional models with which we can subsequently obtain conclusive evidence of muscle control. We will use electroencephalography (EEG) for this. Our long-term goal is for a paraplegic patient to be able to get up and stand again. But first, we need to conduct extensive research.

We are also closely collaborating with Dr. Winkler of the Department of Neurosurgery at the University of Leipzig, who co-developed this project idea with us. He is an expert in placing electrodes in the brain and stimulating it with electrical impulses to help patients with Parkinson's disease to reduce their tremors for example.

Image: Eileen Stark prepares Dominik Wetzel for a measurement; Copyright: WHZ/Helge Gerischer

Eileen Stark prepares Dominik Wetzel for a measurement; © WHZ/Helge Gerischer

How exactly is the EEG method used?
Grunert: We record brain potential and conduct studies on which brain areas are active during certain thought patterns to determine the thoughts that are actually suited to read signals. We read brain potential with the EEG; these signals are transmitted to an electrical system that is being developed within the scope of this project. The EEG then detects a start signal, for example, if the test person wants to carry out a voluntary movement. This signal subsequently triggers an electrical impulse using electrodes, thereby carrying out the desired movement.

What challenges are you currently still facing?
Grunert: The initial technical difficulties are in getting accurate EEG signals. We then need to decide whether the surface EEG is sufficient or whether we have to use invasive electrodes. We also want to find out whether patients are able to handle this system. That’s why we want to provide a self- learning program with artificial intelligence.

What are your long-term objectives with this project?
Ideally, we want to enable patients to perform fluid movements and to make them easier and more natural and not machine-like, as is currently the case with exoskeletons. Our goal is to forego exoprosthetics in the future and instead use the system to manipulate the muscles to bypass the injury and have patients use their muscles without aids. Many research groups around the world are committed to this objective but so far, none of them have succeeded in helping patients to walk normally. During the three years of this project, we first conduct basic research. Our first goal is to get patients to stand up on their own with the help of electrical impulses. The intention is to then fine-tune this basic principle during follow-up projects.

The project is scheduled for three years and is funded at 1.2 million Euros by the European Social Fund. The Sächsische Aufbaubank (Development Bank of Saxony) is the project sponsor.
Image: Lorraine Dindas; © B. Frommann

© B. Frommann

This interview was conducted by Lorraine Dindas and translated from German by Elena O'Meara.