Scientists at the Swiss Federal Institute of Technology Lausanne (EPFL) and Lausanne University Hospital (CHUV) have refined their STIMO (STImulation Movement Overground) targeted neurotechnology system that they previously used to restore the ability to walk in three paraplegic patients with cervical spinal cord injuries. The enhanced system restored independent motor movements within a few hours of starting therapy.
The previous system they developed involved implanting an array of 16 electrodes in the lumbar region of the spinal cord outside the dura mater with stimulation provided using an implanted pulse generator controlled with a voice-controlled watch, which allowed the patient to control their movements when trying to walk. The system allowed patients to walk with body weight support within a week, with locomotor performance improving during rehabilitation. Within a few months of rehabilitation, patients regained voluntary control of their previously paralyzed muscles without stimulation and were able to walk or cycle during spatiotemporal stimulation.
Previous systems that used electrostimulation of the nerves provided continuous electrical stimulation of the spinal cord but failed to stimulate all of the nerves, which limited the recovery of motor functions. The system developed by the researchers is personalized for each patient, with the electrodes precisely positioned to target all nerves associated with leg and trunk movements in the spinal cord.
The researchers have now enhanced their system to significantly improve the speed of recovery thanks to the use of new AI software. The AI software has set protocols for different activities, which the patients activate using a tablet. “All three patients were able to stand, walk, pedal, swim, and control their torso movements in just one day, after their implants were activated!” said Grégoire Courtine, Ph.D., associate professor at EPFL. “That’s thanks to the specific stimulation programs we wrote for each type of activity. Patients can select the desired activity on the tablet, and the corresponding protocols are relayed to the pacemaker in the abdomen.”
The new system could be adapted to allow patients with a wide range of spinal cord injuries and severities to regain meaningful motor activities.
You can read more about the study in the paper – Activity-dependent spinal cord neuromodulation rapidly restores trunk and leg motor functions after complete paralysis – which was recently published in Nature Medicine. DOI: 10.1038/s41591-021-01663-5