This is a very well designed and high quality work, carried out by a multinational team of researchers coordinated by Dr. Grégoire Courtine, Dr. Jocelyne Bloch and Dr. Joachim von Zitzewitz. The main objective is the development of new therapeutic strategies to help restore mobility in people with spinal cord injuries. 

Gait rehabilitation therapy plays a crucial role in the recovery of people who have suffered spinal cord injury. This therapy focuses on helping patients regain, to the extent possible, the ability to walk. Through a combination of specific exercises, the use of assistive devices and, in some cases, technologies involving exoskeletons and advanced robotic systems, it seeks to stimulate muscles, improve balance and coordination and promote plasticity.  

However, these techniques often fail to activate all muscles sufficiently, limiting recovery. Epidural electrical stimulation of the spinal cord can activate, in a very specific way, the motor neurons that move the legs. It does this by sending small electrical currents to the spinal cord that mimic the natural pattern of activation during movement, but unfortunately this is also not sufficient in more severe injuries. This is where rehabilitation robots come into play. Researchers combine robot-assisted gait rehabilitation and muscle activation coordinated with an epidural electrical stimulation device to maximize muscle activation during gait rehabilitation. 

For this approach to work, the two systems need to be perfectly synchronized. The spinal cord stimulation system must be able to send electrical signals at the exact moment the robot needs them, and adapt to different types of robots and rehabilitation environments. The researchers are testing it on nine people with spinal cord injuries, and the results suggest that this new approach is capable of accelerating rehabilitation outcomes. 

This is a preliminary proof-of-concept study. Although the results are promising, it is important to note that there is no control group and it is not a randomized trial. We have to be aware that more clinical studies still need to be performed and with a sufficient number of participants. These studies will allow us to confirm the validity of the results, evaluate the long-term impact of this type of therapeutic approach and determine which groups of patients could benefit most from this new strategy. In addition, we must develop technologies that simplify communication between the two systems and be able to precisely adjust the characteristics of electrical stimulation for each patient, personalizing the treatment and maximizing the benefits. 

The future is bright and we must be prepared to use the results of this research to improve the quality of life of patients with spinal cord injuries. However, it is necessary to advance little by little and not to raise false expectations.