Two stroke patients were able to move their hands again after an experimental procedure that resembles tickling, temporarily restoring weakened connections between their upper limbs, brain and spinal cord.
Heather Rendulic is one of these two women. For a month, in a pioneering study by researchers at the University of Pittsburgh, she was able to maneuver her disabled arm more easily when electrical impulses zapped her upper spinal cord.
Rendulic had a stroke in his early twenties that paralyzed the left side of his body. Like many stroke survivors, she regained stilted movements, but her recovery quickly plateaued and many daily tasks like tying shoelaces or chopping vegetables were beyond her reach.
For years, Rendulic has “lived with one hand in a two-handed world” – but has now glimpsed what could be possible for some stroke patients, years from now, if spinal cord stimulation s proves to be safe and effective.
“When the stimulation is on, I feel like I have control of my arm and hand again, which I haven’t had in over nine years,” says Rendulic.
“The stimulation feels a bit like a tickle, and it’s never painful, but it does take some getting used to, I would say.”
While only two cases are reported in the study, Rendulic and the other participant both showed marked improvements in grip strength, arm movement, and hand dexterity almost immediately after switching on the device. ‘device.
The device consisted of a pair of thin metal electrical implants – flexible like strands of spaghetti – inserted into the upper part of the spinal cord where it joins sensory inputs from the arm and hand.
When turned on, the electrodes delivered electrical impulses to spinal circuits that had been weakened by a stroke but remained intact. Rather than forcing muscles to move, the pulsed current amplifies messages in neural circuits in the spine to facilitate movement.
“We wanted to pick up those weak signals and essentially turn them into functional outputs so that a person could control their own hand voluntarily,” Marco Capogrosso, a biomedical engineer and lead author from the University of Pittsburgh, told NPR.
The two women in this study suffered from different types of strokes, but both showed improvement in hand and arm movement to varying degrees. They received the experimental form of stimulation for four hours a day, five days a week, over a trial period of one month.
In a series of tests captured on video and with wireless sensors detecting muscle contraction, Rendulic can be seen raising an arm, grabbing a can of soup, grabbing bits of food with a fork, opening a lock and drawing shapes of base.
These skillful movements, combined with the wide range of motion of the arm and shoulder, posed a greater challenge than stimulating the movement of the legs, according to the researchers – although both are remarkable feats.
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Just last year, researchers reported that nine people were able to walk again with help after five months of spinal cord stimulation and rehabilitation.
Previously, a 2016 study showed that electrical stimulation can also improve upper limb movement after spinal cord injury. And with further animal testing and computer modelling, the researchers behind this latest study were encouraged to believe that stroke survivors could also benefit.
To the researchers’ surprise, some of the mobility improvements lasted up to four weeks after the implants were removed — but those gains have since dissipated, Rendulic says.
“We found that after a few weeks of use, some of these improvements persist when stimulation is turned off, which points to exciting avenues for the future of stroke therapies,” says Capogrosso. This raises the possibility that spinal cord stimulation may not only help arm function, but potentially restore some of it if the therapy is used over longer periods of time.
Researchers not involved in the study are also delighted that the promising results first seen with spinal cord injury appear to be replicable for stroke.
“However, the small numbers of patients and the results need to be validated in a larger study,” tweeted Euan McCaughey, a biomedical engineer studying electrical stimulation for spinal cord injury.
These studies may take years to come to fruition, but the results will be key to understanding what types of stroke patients may benefit from the therapy, at what stage of recovery, and whether there are any safety issues or limitations to its efficiency.
“It’s for research purposes, it’s very early days,” Eellan Sivanesan, director of neuromodulation at Johns Hopkins University, told STAT News.
“There is promise. It’s good to have hope, but I don’t want to mislead patients by telling them that this is something that will be available to them tomorrow.”
The hope is indeed what the researchers have, that when combined with ongoing physical therapy, the approach can bring lasting benefits to stroke patients. But the cost of surgery to implant electrodes can still be a barrier for many.
Rendulic also hopes that her participation in the study has helped the researchers and that someday in the future she can get a permanent stimulator to tickle her nerves once again.
The research has been published in Natural medicine.