Researchers at the University of Glasgow implanted a vagus nerve stimulator in 108 chronic stroke patients with arm weakness, then had every patient complete the same six-week rehab program, pairing the device's pulses with rehab for half and a sham signal for the rest.
Patients who received real stimulation during their rehab sessions improved on standard arm and hand function scores by two to three times as much as those who did the identical exercises with sham stimulation. The gains appeared in patients whose strokes had happened long before enrollment, a group not expected to improve much from rehab alone.
The pairing appears to work by using a brief nerve pulse to make the brain more receptive to rewiring itself during a specific movement, rather than by strengthening muscle directly. The trial led to regulatory approval of the device for stroke rehabilitation, though it still requires a minor implant procedure and the same weeks of supervised therapy sessions used in the study.
Read the original study
Dawson et al., The Lancet, 2021 · doi.org/10.1016/S0140-6736(21)00475-X
A nerve pulse reopened a closed recovery window.
Source
- Dawson, J., Liu, C. Y., Francisco, G. E., Cramer, S. C., Wolf, S. L., Dixit, A., Alexander, J., Ali, R., Brown, B. L., Feng, W., DeMark, L., Hochberg, L. R., Kautz, S. A., Majid, A., O'Dell, M. W., Pierce, D., Prudente, C. N., Redgrave, J., Turner, D. L., . . . Kimberley, T. J. (2021). Vagus nerve stimulation paired with rehabilitation for upper limb motor function after ischaemic stroke (VNS-REHAB): a randomised, blinded, pivotal, device trial. The Lancet, 397(10284), 1545–1553. https://doi.org/10.1016/S0140-6736(21)00475-X