In another major clinical breakthrough of the Walk Again Project, a non-profit international consortium aimed at developing new neuro-rehabilitation protocols, technologies and therapies for spinal cord injury, two patients with paraplegia regained the ability to walk with minimal assistance, through the employment of a fully non-invasive brain-machine interface that does not require the use of any invasive spinal cord surgical procedure. The results of this study appeared on the May 1 issue of the journal Scientific Reports.
The two patients with paraplegia (AIS C) used their own brain activity to control the non-invasive delivery of electrical pulses to a total of 16 muscles (eight in each leg), allowing them to produce a more physiological walk than previously reported, requiring only a conventional walker and a body weight support system as assistive devices. Overall, the two patients were able to produce more than 4,500 steps using this new technology, which combines a non-invasive brain-machine interface, based on a 16-channel EEG, to control a multi-channel functional electrical stimulation system (FES), tailored to produce a much smoother gait pattern than the state of the art of this technique.
“What surprised us was that, in addition to allowing these patients to walk with little help, one of them displayed a clear motor improvement by practicing with this new approach. Patients required approximatively 25 sessions to master the training before they were able to walk using this apparatus,” said Solaiman Shokur one of the authors of the study.
The two patients that used this new rehabilitation approach had previously participated in the long-term neurorehabilitation study carried out using the Walk Again Project Neurorehabilitation (WANR) protocol. As reported in a recent publication from the same team (Shokur et al., PLoS One, Nov. 2018), all seven patients who participated in that protocol for a period of 28 months improved their clinical status, from complete paraplegia (AIS A or B, meaning no motor functions below the level of the injury, according to the ASIA classification) to partial paraplegia (AIS C, meaning partial recovery of sensory and motor function below the injury level). This significant neurological recovery included major clinical improvements in sensory discrimination (tactile, nociception, vibration, and pressure), voluntary motor control of abdomen and leg muscles, and important gains in autonomic control, such as bladder, bowel, and sexual functions.
“The last two studies published by the Walk Again Project clearly indicate that partial neurological and functional recovery can be induced in chronic spinal cord injury patients by combining multiple non-invasive technologies that are based around the concept of using a brain-machine interface to control different types of actuators, like virtual avatars, robotic walkers, or muscle stimulating devices, to allow the total involvement of patients in their own rehabilitation routine,” said Miguel Nicolelis, scientific director of the Walk Again Project and one of the authors of the study.
In a recent report by another group, one AIS C and two AIS D patients were able to walk thanks to the employment of an invasive method for spinal cord electrical stimulation, which required a spinal surgical procedure. In contrast, in the present study two AIS C patients – which originally were AIS A (see Supplemental Material below)- and a third AIS B subject, who recently achieved similar results, were able to regain a significant degree of autonomous walking without the need for such invasive treatments. Instead, these patients only received electrical stimulation patterns delivered to the skin surface of their legs, so that a total of eight muscles in each limb could be electrically stimulated in a physiologically accurate sequence. This was done in order to produce a smoother and more natural pattern of locomotion.