Thanks to the recent developments in the field of electrical stimulation, the possibility for paraplegics to walk again is always less utopian than we might think. We are talking about a few steps or partial recovery of muscular control, but the perspectives in the next few look really hopeful. The last important results come from the Walk Again Project, an international no-profit consortium whose objective is to show the potential of Brain-Computer interfaces in the clinical employment for motor rehabilitation.
Two paraplegic patients started moving again their legs and making few steps, with a minimum sustain, thanks to a completely non-invasive BMI, that does not require spinal surgery to implant electrodes. The results of the study had been published on Scientific Reports journal.
The two patients had previously attended a long-term neurorehabilitation that lasted 28 months, which consisted of the combined use of a BCI that controlled a robotic exoskeleton, Virtual Reality, and sensor feedbacks. All the 7 subjects that attended the therapy, passed from a complete paraplegia to a partial recovery of the sensitivity and of the motor function.
Despite the previous long-term rehabilitation, the new protocol consists of controlling the electrical stimulation of 16 leg muscles (8 per leg). This happens through brain activity, recorded with a 16 channel EEG. The stimulation, that follows the precise physiological sequence, takes place through electrodes placed on the skin.
“Crucial for this implementation was the development of a closed-loop controller that allowed real-time correction of the patients’ walking pattern, taking into account muscle fatigue and external perturbations, in order to produce a predefined gait trajectory. Another major component of our approach was the use of a wearable haptic display to deliver tactile feedback to the patients´ forearms in order to provide them with a continuous source of proprioceptive feedback related to their walking,”
said Solaiman Shokur, one of the authors of the study.
After a training session that allowed the patients to control their brain signals, related to the imagination of the movement itself, they were able to make about 4500 steps, with a sustain of 65/70% of their body weight. The researcher also highlighted improvements both on a cardiovascular and neurological level, with a minor dependence from external assistive systems.
The next step is to merge all the available instruments to create a unique non-invasive protocol for the treatment of patients with spinal injuries.