E-stimulation helps paralyzed spinal cord injury patients walk again

E-Stimulation helps a few paralyzed patients “walk” again / take steps.

 

Picture: Susan Harkema, left, Associate Scientific Director of the Kentucky Spinal Cord Injury Research Center at the University of Louisville, with Kelly Thomas, who was paralyzed in a car accident and is learning to walk with the help of a trainer and a surgically-implanted electric stimulation) device.  The picture above and the videos below are from the Washington Post.

Written by Corinne Jeanmaire – Edited by Beverley Saunders, October 2018.

E-stimulation helps paralyzed spinal cord injury patients walk again

Various news channels covered two American research publications made by, respectively, the University of Louisville and the Mayo Clinic. We definitely cannot ignore those articles, this news is difficult to share without raising high expectations. Hence our attempt to provide some background information.

E-stimulation helps paralyzed spinal cord injury patients walk again

To summarize:  A few patients have made seemingly impressive progress towards taking steps with the help of an implanted e-stimulator and a walker. They received a combination therapy consisting of an intensive rehabilitation regime (including, for example, locomotor therapy) and the transplantation of an e-stimulation device.  According to the Louisville publication, all four patients treated achieved independent standing and trunk stability. One of them (Kelly Thomas, a patient of Dr. Harkema) can actually walk a short distance on her own, with the stimulator on and with the use of a walker (see video below).

A simultaneous case report published in Nature Medicine reported that a single patient with a spinal cord injury at the Mayo Clinic was also able to take steps and walk with trainer assistance thanks to electrical stimulation and intensive physical therapy. See the second video below.

E-stimulation helps paralyzed spinal cord injury patients walk again

E-stimulation helps paralyzed spinal cord injury patients walk again

E-stimulation helps paralyzed spinal cord injury patients walk again

How it works:  A Medtronic electric stimulator (until now regularly used to treat neuropathic pain) is surgically implanted in the lower back of the patient. The electric stimulation gives impulses to the spinal cord. Scientists believe that the e-stim enables a number of dormant but intact spinal cord fibers/nerves to “awaken” and conduct the signal from the brain to the leg muscles again.  In these studies, the e-stim was combined with a lot of physical training (for example loco-motor training on a treadmill: repeating the walking pattern with the help of therapists and of body-weight support).

 

E-stimulation helps paralyzed spinal cord injury patients walk again

The limitations: 

Very limited number: Out of the total of five patients referred to in the publications only a few (three patients) are shown to have booked significant progress: two out of the Louisville study and one out of the Mayo Clinic study.  It is rather frustrating that since the first publication on the e-stim subject in May 2014 (four men were shown moving their legs slightly further to the surgical implant of an electric stimulator), no further information has been shared. A well-known fact is that, since 2014, a number of studies/clinical trials have started treating many more patients. However, the total number of patients treated and their progress/results are still unknown.  A more transparent and integral information flow would help us better understand the real impact of the therapy.

Patient and spinal cord injury profile: the patient with the best outcome (first video below) had a motor-complete, but sensory-incomplete spinal cord injury (she had sensation below the level of her lesion, which is not often the case and does indicate that a number of nerve fibers are actually intact).

(not yet?) functional outcome: the few patients who can indeed take steps thanks to the epidural stimulation do not seem to do that in a functional manner. Some of them still need human assistance. Others are limited in speed and in the walking distance that they are able to cover. This, even after months of very intense and targeted physiotherapy.

Epidural Electric Stimulator: in these studies, the e-stim has to remain on for the subject to take a step. The electric impulse given by the surgically-implanted stimulator is necessary to take the step.

E-stimulation helps paralyzed spinal cord injury patients walk again

University  of Louisville – Video.

In a research study at the University of Louisville, Kelly Thomas and three others had a device surgically implanted on their spinal cords.

E-stimulation helps paralyzed spinal cord injury patients walk again

The advantages:

– Compared to walking with an exoskeleton or with long leg braces, this type of ambulation certainly seems less cumbersome and can be attractive, even if it’s purely for therapeutic walking. If the patient could regulate the e-stim himself in situations outside the lab/ rehab center, being able to stand up in a social gathering could definitely represent an advantage compared to existing solutions. However, we should not forget that this therapy is invasive and requires the surgical implantation of a stimulator as well as months of very intensive rehabilitation. Plus, without a doubt, this procedure is not suitable or effective for all patients. At this stage, we do not have conclusive knowledge of the impact of this line of research. Based on the results so far, it could be regarded as a possible rehabilitation tool for people with an incomplete spinal cord injury but falls short of a stand-alone therapy for patients with a complete lesion. It does not provide any repair or actual regeneration, even though it might help in combination with other (regenerative) therapies.

Possible impact on bowel and bladder, sexual function? Previous anecdotal reports stated that epidural stimulation could lead to (a certain level of) bowel, bladder, and sexual functions. That would absolutely be a fantastic outcome.  However, as to date, this hypothesis has never been supported by actual facts or publications, it remains questionable. Those potential outcomes are not mentioned at all in the two studies described here. Again, we wish more data would be provided by the various teams experimenting with epidural stimulation on various groups of patients.

Mayo Clinic – Video.

This video shows the progression of a patient’s EES (Epidural Electric Stimulation)-enabled stepping performance over ground.

According to the publication (Nature Medicine): “ We have demonstrated that human spinal networks can be transformed years after SCI to reach physiologic states that generate coordinated and robust spinal motor outputs to generate independent stepping and standing. The outcomes we have reported suggest that the MMR (multi-modal rehabilitation) paradigm, which was focused on dynamically training multiple motor tasks in the presence of EES-facilitated spinal network activity, enhanced a synergistic functional reorganization of supraspinal–spinal connectivity. The new outcomes we have reported support the concept that spinal neuromodulation with sensorimotor rehabilitation facilitatefunctional reorganization of the supraspinal–spinal connectome to recover functions lost due to SCI.”

E-stimulation helps paralyzed spinal cord injury patients walk again

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