A clinical trial of an investigational, non-invasive medical device has shown that trans-spinal direct-current stimulation and peripheral nerve direct-current stimulation significantly reduced upper-limb spasticity in participants who had experienced a stroke.

The treatment involves passing a direct electrical current across the spinal cord with a skin-surface electrode, known as trans-spinal direct-current stimulation (tsDCS), and adding a peripheral direct-current stimulation (pDCS) in the paralyzed upper limb. There are additional benefits to patients when tsDCS is combined with pDCS, according to the study, which was led by researchers at the Feinstein Institutes for Medical Research in Manhasset, N.Y. and was published in Springer Nature’s Bioelectronic Medicine.

The researchers employed PathMaker Neurosystems’ MyoRegulator device to provide simultaneous, non-invasive stimulation intended to suppress hyperexcitable spinal neurons involved with spasticity. In the single-blind cross-over design study, 26 participants were treated with five consecutive days of 20 minutes of active, paired tsDCS+pDCS. The participants received both active and sham stimulation treatments but were not told the order of stimulation.

The results showed that active treatment significantly reduced upper-limb spasticity for up to five weeks and these patient responders saw significant improvements in motor function, according to Feinstein Institutes.

“Spasticity is a persistent and common inhibitor of movement in patients with chronic stroke, and it has been a great hurdle as we continue to use intensive training to assist motor recovery,” said lead author and Feinstein Institutes professor Dr. Bruce T. Volpe. “The surprise in these clinical results was the improved motor functions that apparently occurred with the focused treatment only of spasticity. We are eager to start a trial that couples motor training and anti-spasticity treatment.”

Related: PathMaker gets NIH grant to develop MyoRegulator for spasticity