Heather Rendulic had been unable to use her left hand for almost ten years, preventing her from feeding herself or holding lightweight objects such as a can of soup. However, her situation improved after participating in a clinical trial that has the potential to significantly enhance the quality of life of individuals who have suffered paralysis due to a stroke. On Monday, the outcomes of this trial were made public in the journal Nature Medicine.
Rendulic suffers from a rare neurological disorder known as cavernous angioma, a type of blood vessel abnormality that can result in a stroke. At 22, she experienced five strokes over 11 months, which caused paralysis on the left side of her body. According to the Pittsburgh resident, the most challenging aspect of her condition is navigating in a world designed for individuals with two functional hands while limited to using only one hand, as reported by Wired.
When a stroke occurs, the blood supply to the brain is disrupted, which can lead to the death of brain cells within minutes. Depending on the brain area affected by the stroke, a person may experience paralysis if the region responsible for sending signals to activate the muscles is damaged. Despite regaining some movement on her left side, Rendulic could not perform tasks such as using a fork or making a fist with her left hand, as per CDC.
Spinal Cord Stimulation Technology
As part of a collaborative initiative between the University of Pittsburgh and Carnegie Mellon University in 2021, researchers inserted two thin metallic electrodes along Rendulic's neck. Physicians currently utilize spinal cord stimulation to alleviate chronic pain. Previous studies have demonstrated that this technique may help individuals recover leg function following spinal cord damage. However, the complexity of hand movement poses unique challenges since manual dexterity and a broad range of motion are essential for proper hand function.
To conduct the trial, the research team implanted thin, spaghetti-like electrodes along the surface of the spinal cord. These electrodes provide tiny impulses that stimulate specific areas and activate nerve cells within the spinal cord. As stated by Dr. Douglas Weber, a co-author of the study and a mechanical engineering professor at the Neuroscience Institute at Carnegie Mellon University, "Sensory nerves from the arm and hand transmit signals to motor neurons in the spinal cord that regulate the muscles of the limb. By stimulating these sensory nerves, we can enhance the activity of muscles weakened by a stroke. It is essential to note that the patient maintains complete control over their movements, as the stimulation only strengthens muscle activation when patients attempt to move."
The researchers suggest that this technology has the potential to benefit a broad spectrum of patients. Rendulic has reported that the stimulation feels akin to a tickling sensation and is never painful but requires some acclimation. CNN mentioned that the device allows for previously unattainable movements, and the tiny black plastic boxes containing flashing green lights travel up and down her arm. On the first day of using the device, Rendulic experienced a more extensive range of motion. The researchers noted that she did not require assistance opening her hand or extending her arm, but some training was necessary for more intricate movements.
Stroke Promising Technological Treatment
Rendulic expressed her delight with the results, stating, "When the stimulation is activated, I feel as though I now have control over my arm and hand, which I haven't had in over nine years." She can now raise her arm over her head, use a fork to feed herself, and fully open and close her hand. The other trial participant also experienced similarly encouraging outcomes. During the trial, Rendulic successfully picked up a soup can and dropped it onto a designated spot on a board. The laboratory erupted in applause, and Rendulic enthusiastically pumped her other arm in triumph.
The researchers were also pleased to discover 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," according to study co-author Dr. Marco Capogrosso, an assistant professor of neurological surgery at the University of Pittsburgh. This suggests that, with intense physical training, patients may experience long-term improvements even after removing the device, the researchers explained. According to doctors, no treatments are deemed adequate for treating paralysis six months or more after a stroke, which they refer to as the chronic stage. While the stimulation technology needs to undergo further testing, the researchers believe it has enormous potential and may address an increasing need.
The World Stroke Organization reports that one in every four individuals over 25 will have a stroke in their lifetime, and many will experience some form of paralysis. The study co-author Dr. Elvira Pirondini, an assistant professor of physical medicine and rehabilitation at Pitt, says developing effective neurorehabilitation solutions for individuals with movement impairment following a stroke is becoming increasingly urgent. Even minor deficits resulting from a stroke can isolate people from their social and professional lives and become very debilitating, with motor impairments in the arm and hand particularly challenging and hindering basic daily activities such as writing, eating, and dressing.
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