Revolutionary spinal cord stimulation helps stroke victims regain arm mobility

By Stephen Beech via SWNS

Stroke victims who lost the use of an arm have regained mobility after several years following revolutionary spinal cord stimulation treatment.

Patients say the new technology instantly improves their arm and hand mobility, enabling them to conduct their normal daily activities more easily.

The treatment involves implanting a pair of thin metal electrodes- resembling strands of spaghetti - along the neck to engage intact neural circuits.

It allows stroke patients to fully open and close their fist, lift their arm above their head or use a knife and fork to cut a piece of steak for the first time in years.

In a series of tests adapted to individual patients, stimulation enabled them to perform tasks of different complexity ranging from moving a hollow metal cylinder to grasping common household objects, such as a can of soup and opening a lock.

Clinical assessments by the American research team showed that stimulation targeting cervical nerve roots immediately improves strength, range of movement and function of the arm and hand.

Surprisingly, the effects of stimulation seem to be longer-lasting than scientists originally believed and persisted even after the device was removed, suggesting it could be used both as an assistive and a restorative method for upper limb recovery.

The team said that the immediate effects of the stimulation enable intense physical training that, in turn, could lead to even stronger long-term improvements in the absence of the stimulation.

Study co-senior author Dr. Marco Capogrosso said: “We discovered that electrical stimulation of specific spinal cord regions enables patients to move their arm in ways that they are not able to do without the stimulation.

"Perhaps even more interesting, we found that after a few weeks of use, some of these improvements endure when the stimulation is switched off, indicating exciting avenues for the future of stroke therapies."

Capogrosso, assistant professor of neurological surgery at the University of Pittsburgh, added: “Thanks to years of preclinical research building up to this point, we have developed a practical, easy-to-use stimulation protocol adapting existing clinical technologies that could be easily translated to the hospital and quickly moved from the lab to the clinic.”

Globally, one in four people over the age of 25 will suffer a stroke in their lifetime, and 75 percent of those will suffer lasting reductions in control of their arm and hand.

No treatments are currently effective for treating paralysis in the so-called "chronic" stage, which begins around six months after the stroke.

However, researchers say the new technology has the potential to offer hope for people living with impairments that would otherwise be considered permanent.

Senior co-author Dr. Elvira Pirondini, assistant professor of physical medicine and rehab at the University of Pittsburgh, said: “Creating effective neurorehabilitation solutions for people affected by movement impairment after stroke is becoming ever more urgent.

“Even mild deficits resulting from a stroke can isolate people from social and professional lives and become very debilitating, with motor impairments in the arm and hand being especially taxing and impeding simple daily activities, such as writing, eating and getting dressed.”

Spinal cord stimulation technology uses a set of electrodes placed on the surface of the spinal cord to deliver pulses of electricity that activate nerve cells inside the spinal cord.

The technology is already being used to treat high-grade, persistent pain.

Several research groups around the world have shown that spinal cord stimulation can be used to restore movement to the legs after spinal cord injury.

But the unique dexterity of the human hand, combined with the wide range of motion of the arm at the shoulder and the complexity of the neural signals controlling the arm and hand, add a significantly higher set of challenges.

Following years of extensive preclinical studies involving computer modeling and animal testing in macaque monkeys with partial arm paralysis, researchers were cleared to test this optimized therapy in humans.

Co-senior author Professor Douglas Weber, of Carnegie Mellon University, said: “The sensory nerves from the arm and hand send signals to motor neurons in the spinal cord that control the muscles of the limb.

“By stimulating these sensory nerves, we can amplify the activity of muscles that have been weakened by stroke"

He added: "Importantly, the patient retains full control of their movements:

"The stimulation is assistive and strengthens muscle activation only when patients are trying to move.”

The team are enrolling further trial participants to understand which stroke patients can benefit most from this therapy and how to optimize stimulation protocols for different severity levels.

Scientists are also working to translate the therapy into clinical use.

The findings were published in the journal Nature Medicine.