New Technology Helps Two Patients With Stroke Paralysis Regain Movement in Their Hands

According to a report in Nature Medicine, two stroke patients were able to regain the use of a paralyzed arm and hand after receiving electrical pulses to a specific area of their spinal cords.

One of the patients, Heather Rendulic, previously could not carry out routine tasks involving her left hand, such as holding a fork or making a fist.

Rendulic had a series of five strokes over a period of 11 months when she was 22 years old due to a rare brain disease called cavernous angioma, which left her paralyzed on her left side.

After volunteering for and undergoing a clinical study in 2021 to improve the lives of people like her, Rendulic opened her hand for the first time in nine years.

“I live one-handed in a two-handed world, and you don’t realize how many things you need two hands for until you only have one good one.”

During the clinical trial, researchers from the University of Pittsburgh and Carnegie Mellon University implanted a pair of thin metal electrodes along the surface of Rendulic’s spinal cord. The electrodes sent tiny electrical pulses to stimulate specific regions and activate nerve cells.

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Study co-author and assistant professor of neurological surgery at the University of Pittsburgh, Dr. Marco Capogrosso, shared how everyone in the room was stunned when Rendulic could “move her hand and arm after nine years from day one.”

“The whole lab was crying because…we didn’t really expect that this could work as fast.”

Rendulic described the stimulation as “kind of like a tickle.” The process did not hurt her, but it initially felt a bit uncomfortable.

“When the stimulation is on, I feel like I now have control of my arm and my hand again that I haven’t had.”

Rendulic can now carry out several mobility tasks, including drawing a spiral, opening a lock, and gripping and lifting a soup can while the device is still on. At the end of the four-week trial, she was even able to cut her own steak. The other patient in the trial saw the same newfound range of motion.

Researchers hope this new technology, paired with targeted physical training, can improve outcomes even further.

Spinal cord stimulation has long been used to treat chronic pain. Prior research has shown that the same technology could restore leg movement after a spinal cord injury. However, upper limb paralysis has always been more challenging to restore since multiple nerves are involved in the movement of shoulders, wrists and arms.

Dr. Capogrosso says that while people still retain some of these neural connections, “They’re just not enough to enable movement.” The messages are weaker than normal.

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Dr. Douglas Weber, another of the study’s co-authors and professor of mechanical engineering at the Neuroscience Institute at Carnegie Mellon University, described how electrical pulses could strengthen those connections.

“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. Importantly, the patient retains full control of their movements: The stimulation is assistive and strengthens muscle activation only when patients are trying to move.”

Dr. Capogrosso looks forward to what these results mean for future stroke treatment.

“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.”

As of right now, the chronic stage of paralysis, which occurs six months or later after a stroke, cannot be treated effectively. However, this new simulation technology has promising potential, given that the benefits of the simulation persisted for up to four weeks after the end of the procedure with no serious side effects.

Study co-author Dr. Elvira Pirondini, an assistant professor of physical medicine and rehabilitation at the University of Pittsburgh, states, “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.”

In the meantime, Rendulic has hope for the future. “I really hope and pray that this becomes widely available,” she says, “because I know it’s going to change so many lives.”