In the future, implantable devices that interface with the brain could help people with severe neurodegenerative movement disorders communicate again through a computer or tablet device.
The pages of cyberpunk science fiction describe fantastical technology that enhances the human brain — what we now call brain-computer interfaces (BCIs). Perhaps the most famous of these fictional devices is described in William Gibson’s Neuromancer, the simstim. The simstim BCI projects a person’s body and thoughts into virtual reality, fitting the modern definition of a BCI as it reads brain activity, processes it, and translates their thoughts into a virtual world.
As scientists developed more technology to understand and decode the brain’s signals, this sci-fi technology is becoming a science. With the company Synchron taking their BCI to clinical trials — aiming to allow paralyzed patients to connect to their electronic devices — these devices have the potential to translate into new treatments for neurodegenerative disease in the coming decades.
Across neurodegenerative disorders like Parkinson’s disease (PD) and Amyotrophic Lateral Sclerosis (ALS), neurons in the aging brain begin dying off progressively, affecting a person’s motor abilities. The characteristics of PD include posture instability, an inability to initiate quick movements and involuntary tremors. Hallmarks of ALS also include slowness of movement as well as muscle degeneration. Eventually, ALS and PD make it very difficult for someone to do everyday activities.
We take our cellphones, laptops, and tablets for granted, but they require an immense amount of coordination. Already, BCIs can help translate a paralyzed person’s thoughts into text on a computer screen. Engineers are also developing efficient ways to translate these signals to an external device without any wires.
However, while they can improve the quality of life, non-invasive BCIs cannot reliably detect signals from individual brain cells and cannot send signals back to the brain. More invasive approaches will be needed to restore some of the abilities lost through disease progression.
Ambitious well-funded startups are now aiming at a much tougher therapeutic target — restoring motor activity. There are a few different approaches for interfacing with the brain, the most common of which involve inserting small devices directly into the brain.
Elon Musk’s biotechnology venture Neuralink is the most well-known company — with flashy demonstrations featuring pigs with devices implanted in their brains and monkeys playing Pong with their mind. Neuralink’s strategy involves an invasive surgery to implant their device on the brain allowing it to record activity from 1024 individual neurons, with wires as thin as human hair.
These electrodes detect specific brain activity which is transmitted and analyzed by an implanted interface. The interface then sends signals to an electronic device or stimulates cells within the brain. While Musk himself has claimed that these devices will act like a “Fitbit in your skull,” the company has not yet received approval for clinical trials, as of September 2021.
Synchron went for a less-invasive approach allowing them to secure the first-ever BCI clinical trial for improving communication and quality of life in paralysis. The device called the Stentrode is inserted into the jugular vein, with electrodes and sensors interfacing with the vasculature to record brain activity.
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“The Stentrode device’s biocompatibility allows it to be accepted by the walls of a blood vessel in the same way the skin accepts the ink of a tattoo user or a pacemaker is accepted by the body,” a spokesperson from Synchron’s team told Being Patient over email. “Because Stentrode remains in the blood vessel and does not penetrate the brain, patients are at reduced risk of rejection of the device.”
This approach separates the Stentrode from other BCI-ventures, which must perform invasive surgeries to insert electrodes into the brain. Synchron explained that “patients are at reduced risk of brain tissue inflammation and rejection of the device, which have been issues for techniques that require direct brain penetration.”
The stentrode allows people to do everything from online shopping, texting, banking, and even sending emails. Within the next two decades, the stentrode may allow people with severe ALS and perhaps even PD to communicate and control other types of electronic devices.
Future development may even allow for minimally-invasive neuromodulation, which would be significantly cheaper than current approaches that involve implanting a pacemaker into the brain to ameliorate tremors.
Could these devices one day allow people with ALS and PD to restore movement through neuromodulation or by controlling artificial limbs? Researchers are already studying applications for PD that help rehabilitate movement while simple brain-controlled prosthetics have been around for more than a decade. Other promising approaches in development involve millimeter-sized devices that can measure and stimulate individual brain cells.
Nonetheless, even though these devices aren’t widely available, it is important to ensure that the devices and any data collected are properly secured. According to neuroethics expert Marcello Ienca at ETH Zurich, there are legitimate concerns about data collected by these devices and the need for mental privacy. “We already have consumer neurotech, with people trading their brain data for services from private companies,” Ienca told Vox.
While these devices are still in their infancy, many studies show how they help people with neurodegenerative diseases communicate through a computer or even use a tablet device. But restoring movement or enhancing memory and reflexes remains as science fiction, at least for now.
In a 2020 article for The Conversation, Andrew Jackson, professor of neural interfaces at Newcastle University explained that “decades of research have shown that the brain does not yield its secrets easily and is likely to resist our attempts at mind hacking for some decades yet.”