Development and evaluation of a non-invasive brain-spine interface using transcutaneous spinal cord stimulation.

The participants were unimpaired adults, not people with spinal cord injury, so the study does not show that the system helps patients recover movement. The sample was small and variable across analyses: 17 participants were recruited, 2 were excluded for noisy EEG channels, and different analyses used 7, 9, 4, or 2 participants. The system decoded only a single right knee extension, not bilateral or multi-joint walking movements. Real-time timing was imperfect: with a 0.8-second tolerance window, stimulation onset was within 0.8 seconds of true onset 56% of the time for cued movement and 41% for uncued movement. Uncued movement, which is closer to natural rehabilitation practice, had lower performance, and training on uncued movement did not significantly improve it. The young university-based age range may not reflect older people with spinal cord injury. The topographical R-squared analysis included 32 channels and 7 participants and was not corrected for multiple comparisons.

The work was funded by the National Institute of Neurological Disorders and Stroke, the National Institute of Child Health and Human Development, the National Institutes of Health, and the National Institute of Biomedical Imaging and Bioengineering. No commercial funding or author conflicts are reported in the supplied text.

Do not read this as evidence that brain-controlled spinal cord stimulation improves walking or recovery in spinal cord injury. It was tested only in unimpaired participants and reported no clinical outcomes.