Revolutionary Neurotechnology Restores Sensation After Spinal Wire Harm in Rodents

A nerve stimulation therapy developed at Columbia University’s Vagelos College of Physicians and Surgeons is showing promise in animal studies and could eventually allow people with spinal cord injuries to regain function in their arms.

“The stimulation technique targets those nervous system connections spared by injury,” says Jason Carmel, MD, PhD, a Columbia University neurologist and New York Presbyterian who is leading the research, “and allows them to regain some of the lost.” to take over the function.”

The results were published in the journal Brain in December.

A personal endeavor to develop treatments for people with paralysis

In 1999, while Carmel was a sophomore in medicine at Columbia, his identical twin brother suffered a spinal cord injury that left him paralyzed from the chest down and limited the use of his hands.

Carmel’s life also changed that day. Eventually, his brother’s injury led Carmel to become a neurologist and neuroscientist with the goal of developing new treatments to restore movement to people with paralysis.

In recent years, some high-profile studies of electrical stimulation of the spinal cord have enabled some people with incomplete paralysis to get back up and take steps.

Carmel’s approach is different because it targets the arm and hand and because it combines brain and spinal cord stimulation with electrical stimulation of the brain followed by stimulation of the spinal cord. “When the two signals converge at the spinal cord level within about 10 milliseconds, we get the most powerful effect,” he says, “and the combination seems to allow the remaining connections in the spinal cord to take control.” ”

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In his latest study, Carmel tested his technique — called associative spinal cord plasticity (SCAP) — on rats with moderate spinal cord injuries. Ten days after injury, rats were randomized to receive 30 minutes of SCAP or sham stimulation for 10 days. At the end of the study period, rats receiving SCAP targeted to their arms were significantly better at handling food and had near-normal reflexes compared to those in the control group.

“The improvements in both function and physiology lasted as long as they were measured, up to 50 days,” says Carmel.

The results indicate that SCAP permanently changes the synapses (connections between neurons) or the neurons themselves. “The paired signals essentially mimic the normal sensorimotor integration that must come together to perform a skilled movement,” says Carmel.

From mice to humans

If the same technique works for people with spinal cord injuries, patients could regain something else they lost when they were injured: independence. Many spinal cord stimulation studies focus on walking, but “if you ask people with cervical spinal cord injury, which is the majority, what movement they want back, they say hand and arm function,” says Carmel. “Hand and arm function allows people to be more independent, e.g. E.g. moving from bed to wheelchair or dressing and eating yourself.”

Carmel is now testing SCAP in spinal cord injury patients at Columbia, Weill Cornell and the VA Bronx Healthcare System in a clinical trial sponsored by the National Institute of Neurological Disorders and Stroke. Stimulation is provided either during a clinically indicated surgical procedure or non-invasively by magnetically stimulating the brain and stimulating the skin on the front and back of the neck. Both techniques are routinely performed in clinical settings and are known to be safe.

In the study, the researchers hope to learn more about how SCAP works and how the timing and strength of the signals affect motor responses in the fingers and hands. This would lay the groundwork for future trials to test the technique’s ability to meaningfully improve hand and arm function.

Looking ahead, the researchers believe the approach could be used to improve movement and sensation in patients with lower body paralysis.

Meanwhile, Jason Carmel’s twin is working, marrying and raising twins of his own. “He has a fulfilling life, but I hope we can give him and other people with similar injuries more function back,” says Carmel.

Relation: Pal A, Park H, Ramamurthy A, et al. Spinal cord associative plasticity improves sensorimotor function of the forelimbs after cervical injury. Brain. 2022;145(12):4531-4544. doi: 10.1093/brain/awac235

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