Pairing targeted vagus nerve stimulation with physical therapy seems to help people who are partially paralysed from spinal cord injuries regain the ability to perform some everyday activities, like putting on a necklace or doing up a zipper.
The treatment is already approved by the US Food and Drug Administration (FDA) for treating some motor impairments after stroke. This prompted at the University of Texas at Dallas and his colleagues to wonder if it may also benefit people with incomplete cervical spinal cord injuries. This is when damage to the spinal cord in the neck blocks some nerve signals between the brain and upper extremities, reducing hand and arm function.
To learn more, the researchers surgically implanted a device that electrically stimulates the vagus nerve into 19 people with the condition, who were between 21 and 65 years old and had been injured for more than a year. The participants also underwent 18 physical rehabilitation sessions, usually three per week, that involved exercises such as finger pinching, hand gripping and wrist twisting to target their muscles with limited function.
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Vagus nerve stimulation was delivered to 10 of the participants within 1 second of them completing an above-average movement for them, in terms of its force, speed, accuracy or fluidity. The rest received this stimulation at random intervals. Hand and arm function was assessed using a standardised test that measures sensation, strength and grip.
Eight of those receiving the targeted stimulation saw significant improvement 鈥� an average 23 per cent reduction in movement limitations from their initial scores 鈥� while no one in the control group did. The targeted stimulation probably worked better because of its mechanism, says Kilgard, which involves the release of neurochemicals that help strengthen and form neural pathways. Having that release after an above-average movement may then reinforce it, he says.
All the participants then received an additional 18 sessions of targeted stimulation, after which average pinch force and wrist torque improved by almost 400 per cent and 152 per cent, respectively, compared with their initial scores.
鈥淭hese people didn鈥檛 just make gains on metrics we used for the clinical trial, they made gains on things they wanted to do in everyday life,鈥� such as putting on a necklace or doing up a zipper, says team member , also at the University of Texas at Dallas.
at the Feinstein Institutes for Medical Research in New York state says that while these findings are promising, they must be replicated in larger clinical trials before the treatment can be made available to people with incomplete cervical spinal cord injuries. Kilgard says he and his team are planning a large, late-stage trial 鈥� the final step before submitting a therapy for regulatory approval.
鈥淭here are no FDA-approved treatments for spinal cord injury,鈥� says Kilgard. 鈥淣ow, there could be one in only three to four years.鈥�
Nature
