Trunk-controlled spinal stimulation helps four people walk with a walker

Four people with chronic, functionally motor-complete thoracic spinal cord injuries learned to stand and walk with a walker after receiving epidural spinal stimulation and four months of intensive rehabilitation. None could voluntarily contract their leg muscles before or during the study. Yet all walked without hands-on assistance or systems supporting their body weight.

The Italian team used a commercially available spinal stimulator and turned a movement each participant retained into a control signal. A slight voluntary extension of the torso, averaging about nine degrees, altered how the stimulation affected the nerves. This helped switch the legs from the extension needed for support to coordinated flexion at the hip, knee and ankle for a step. Researchers call the method trunk-mediated control.

Training was daily, progressive and individualized, moving from torso control and stimulated leg activation to standing, weight transfer and walking. All four participants improved from 0 to 9 on the WISCI II walking scale. One covered 132 metres in 42 minutes, and all navigated turns, slopes and uneven outdoor ground. Three could stand with one hand for support while using the other for simple tasks.

The study, published in Med, involved only four participants, so larger studies are needed. It did not restore natural voluntary control of the legs: electrical stimulation generated the contractions. Its advance is a simpler way for users to participate actively in producing steps, without a brain implant, external sensors or real-time neural decoding.