Taking steps after paralyzing injury

A patient with complete lower limb paralysis can independently step again following a combination of electronic spinal cord stimulation and rehabilitation therapy, reports a paper published online this week in Nature Medicine.

Severe spinal cord injuries can functionally disconnect the higher brain centers that guide movement from the spinal cord circuitry, located below the injury, that directly interacts with skeletal muscle—causing chronic paralysis. Electrical stimulation of the spinal cord has been shown to have therapeutic potential in humans, facilitating voluntary muscle contractions and even enabling patients to stand.

Kristin Zhao and Kendall Lee report the first case of independent stepping in a human patient experiencing complete lower limb paralysis following spinal cord injury. Their results are the culmination of a 43-week-long study in which the subject was implanted with an electrical spinal stimulation device and underwent task-specific, multimodal rehabilitation training in a research setting. The authors find that at the end of this period, the patient was able to produce intentional contraction of the leg muscles that could support not only standing, but also stepping. The patient was able to step, with both legs, using a front-wheeled walker and on a treadmill. Successful stepping required activation of the stimulator.

While this is the first case of successful reactivation of chronically dormant human spinal cord circuits such that they can support locomotion, trainer assistance was still required to maintain balance while stepping over ground with a walker. The authors conclude that additional research is required to investigate how the rehabilitation training interacts with the electrical stimulation to recover lost motor functions and to confirm whether this approach could be successful in patients with different types or durations of injury.