Non-invasive closed-loop spinal stimulation enables paraplegic patients to regain stepping control

Spinal cord injury (SCI) rostral to the lumbar locomotor center disrupts communication between the brain and the spinal circuits that control leg movements, leading to paraplegia. A research team led by Dr. Yukio Nishimura of the Tokyo Metropolitan Institute of Medical Science, in collaboration with Dr. Toshiki Tazoe and colleagues, has now demonstrated a novel noninvasive closed-loop spinal stimulation paradigm that restores stepping control in humans with paraplegia. 

The system records electrical activity from hand muscles and converts these signals into trigger pulses for magnetic stimulation delivered to the lumbar spinal cord. By performing rhythmic hand grips, participants with SCI were able to initiate and terminate bilateral leg stepping, and also control step length and cadence. 

Ten individuals with chronic SCI participated in the study. Repeated application of the closed-loop stimulation led to progressive improvements: 

• Stimulus-induced stepping became stronger over time, particularly in participants with thoracic SCI. 

• Volitional stepping without stimulation improved in participants with incomplete SCI, suggesting strengthening of residual descending pathways. 

This noninvasive approach bypasses the lesion site and strengthens preserved spinal and descending circuits, thereby enabling recovery of bilateral stepping control. Because the technique does not require surgery, it represents a safe and promising alternative for patients with contraindications to invasive procedures.