Bimanual coordination and spinal cord neuromodulation: how neural substrates of bimanual movements are altered by transcutaneous spinal cord stimulation.

The study included only 12 neurologically intact adults, so it cannot show that transcutaneous cervical spinal cord stimulation improves hand function in people with spinal cord injury or stroke. Effects were measured only while stimulation was on, and the authors did not test whether any change remains after stimulation stops. The participants were not blinded because they reported strong buzzing, vibration, neck muscle contraction, or skin irritation at the stimulation sites. The study tested many kinematic and EEG outcomes, and significant results appeared only in some tasks and bands, while other results were null. The EEG results depended on removing stimulation artifacts, and about 28 to 45 percent of EEG data were replaced with an average value, which may alter the original signal. The stimulation intensity was close to each participant's maximum tolerance, and discomfort itself may have affected cortical activity. The participants were young adults aged 19 to 36 years, recruited from students and staff during the pandemic, so older adults and clinical populations were not represented. Brief intervals between tasks may have caused carry-over effects from stimulation into the no-stimulation condition.

The supplied text lists research support from the Faculty of Medicine and Dentistry Doctoral Award, University of Alberta Graduate Fellowship, Canadian Institutes of Health Research Post-doctoral Fellowship, Alberta Innovates – Health Solutions Post-doctoral Fellowship, Craig H. Neilsen Foundation Post-doctoral Fellowship, Government of Canada Work Integrated Learning Digital Placement Program, Natural Science and Engineering Research Council of Canada, Canada Foundation for Innovation, and Canada Research Chairs. It does not report author conflicts of interest.

Do not conclude that transcutaneous cervical spinal cord stimulation improves hand function in patients with spinal cord injury or stroke. The only significant movement finding was lower movement error during a bimanual common-goal task in 12 healthy adults, movement time was not significant, and no patient outcomes or effects after stimulation were tested.