Timing-Dependent Paired Stimulation Study from Movement Recovery Lab Published in Clinical Neurophysiology

The Movement Recovery Laboratory and colleagues have shown that a carefully timed combination of brain and spinal cord stimulation can help muscles respond better in people living with spinal cord injury. The study is published in Clinical Neurophysiology. Precise movement depends on communication between motor pathways in the brain and sensory networks in the spinal cord. The new study demonstrates that when non-invasive stimulation to the motor cortex and cervical spinal cord is timed to arrive simultaneously in the spinal cord, responses in arm and hand muscles are significantly augmented. This suggests that residual circuits after spinal cord injury can still support enhanced motor output when carefully targeted.

The team combined experiments in 16 people living with chronic cervical spinal cord injury and 15 uninjured participants. Compared to their previous intraoperative work in elective spine surgeries, they found that non-invasive pairing of transcranial magnetic stimulation with transcutaneous spinal cord stimulation produced a smaller effect than transcranial electrical stimulation combined with epidural stimulation. However, both approaches depend on precisely timed interactions in the spinal cord.

These results build on foundational work from Jason B. Carmel, MD, PhD, demonstrating that precisely timed epidural spinal stimulation can interact with cortical inputs to activate spared motor pathways. The current study extends those findings to a fully non-invasive approach, which may lead to new therapeutic strategies for strengthening movement in people with paralysis.

The authors note that the strength of the effect increased with higher spinal stimulation levels and was seen in participants with different injury levels and severity. Importantly, the study focused on immediate physiological effects, providing guidance for future rehabilitation approaches that could support longer-term recovery.