Every year, around the world, between 250,000 and 500,000 people suffer a spinal cord injury (SCI). People with a spinal cord injury are two to five times more likely to die prematurely than people without a spinal cord injury, with worse survival rates in low- and middle-income countries.
At our Neurosurgery department at Bhagwan Mahavir Medica Superspecialty Hospital in Ranchi, I was discussing with my colleagues, Dr. Amar and Ms. Shayanti on how to apply neuroprosthetics in treatment of impaired brains. We discussed many futuristic options, which would revolutionize the management of impaired brains and SCI cases.
The impaired brain is often difficult to restore, owing to our limited knowledge of the complex nervous system. Accumulating knowledge in systems neuroscience, combined with the development of innovative technologies, may enable brain restoration in patients with nervous system disorders that are currently untreatable.
Where once prosthetics were crude and simplistic, now they’re carefully engineered works of art. In fact, with breakthroughs such as neuroprosthetic limbs, there’s even the potential for prosthetics to interface with the human brain.
As the name suggests, neuroprosthetics combines neural processing with prosthetics. Neuroprosthetics, also known as brain-computer interfaces, are devices that help people with motor or sensory disabilities to regain control of their senses and movements by creating a connection between the brain and a computer. In other words, this technology enables people to move, hear, see, and touch using the power of thought alone.
Although some neuroprosthetics, such as cochlear implants and visual prosthetics, have been around since the 1950s, they are just beginning to emerge as viable interventions in the field of brain injury. Neuroprosthetics encompass a variety of artificial devices or systems that can be used to enhance the motor, sensory, cognitive, visual, auditory, and communicative deficits that arise from acquired brain injuries. These include assistive technology, functional electrical stimulation, myoelectric prostheses, robotics, virtual reality gaming, and brain stimulation.
Implanted neuroprosthetics and neuroelectrode systems have been under investigation for a number of decades and have been proven to be safe and efficacious as treatments for several neurological disorders as well as for biosensor systems. Neuroelectrode technologies are typically fabricated from metallic conductors, such as platinum, gold, iridium, and their oxides, materials that while chemically inert and excellent electrical conductors are often not intrinsically cytocompatible and do not promote integration with neural tissues.
A brain-computer interface (BCI) relies either on a chip implanted in the user’s brain or electrodes placed upon the scalp. That way signals from the brain may be read by the prosthetic device itself. The BCI is an input/output device that bridges the brain and prosthetic devices. The same signals that would control an organic limb fire, and thus perform the desired function. The signals may be sent via electrodes on the scalp, the brain’s surface, peripheral nerves, and embedded within the brain. Depending on the type of electrodes used, it’s a pretty simple procedure or rather invasive implantation.
But it’s not as simple as hooking up a BCI and connecting everything. Rather, brain imaging is first necessary. Mapping the brain provides intent into what a brain signal means, and how the body is supposed to respond accordingly. Artificial intelligence can expedite this process. Still, there’s definitely a learning period wherein calibration is required.
Moe Long has aptly said prosthetics, both neuroprosthetics and otherwise, have evolved greatly. Even a prosthesis that allows for running is a massive improvement from where the field began. Yet now brain-computer interfaces have been successfully implemented. A paraplegic man, for example, pulled off the first World Cup kick with a neuroprosthesis. Similarly, a Roman woman began using a BCI-powered hand that even senses touch. Once the subject of science fiction, neuroprosthetics have seeped into the mainstream with field-tested hardware. Expect the accuracy and ease of implementation to only improve.