The brain is an incredibly complex organ and comprises about 86 billion nerve cells and more than a trillion connections among brain and nerve cells throughout the human body. Our brains are what give us personality and emotions, allow us to communicate and feel. In fact, we are who we are to a large extent because of our brains.
In the majority of people the brain works remarkably well. But when problems occur with the brain, these can have a profound and debilitating impact. Brain diseases affect one in six people worldwide and include a wide spectrum of diseases and disorders – from stroke and Alzheimer’s to multiple sclerosis, epilepsy, traumatic brain injury, and many more.
Among these are neuromuscular diseases that attack the nerves cells in the brain and the muscles they control. Probably the best-known of the neuromuscular diseases is amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig’s disease. Lou Gehrig was a New York Yankees baseball player who was the first person to be diagnosed with this disease in 1939. This life-changing illness is a progressive and fatal illness and recently also took the life of the scientist Stephen Hawking.
When motor neurons in the brain can no longer communicate with muscles due to amyotrophic lateral sclerosis, the person suffers from muscle weakening, twitching, and an inability to move their arms, legs and body.
Except for medications to slow the disease’s progression and manage symptoms, equipment to prolong mobility and independence is limited.
But in 1992 researchers from the University of Utah developed the Utah array ‒ a micro-electrode array technology that is a small, silicone square with a hundred needles that are pushed into the brain when implanted.
Up to 2021, the Utah array has been the standard for relaying electrical signals from the brain to a computer since it was the only brain-computer interface (BCI) approved by the US Food and Drug Administration (FDA). The technology allowed several paraplegics to control robot arms with great success.
Unfortunately, the Utah array is based on 1990s technology and can only cover a small fraction of the brain’s 86 billion neurons and offers limited assistance to people suffering from neuromuscular diseases. It was generally only used under supervision at a hospital and the brain formed scar tissue around it, which degraded the signals over time.
In 2016, innovative entrepreneur Elon Musk founded Neuralink with the main aim to develop a small, disc-shaped device that, after being implanted in a human brain by a surgical robot, would allow a computer to translate a person’s thoughts into action.
Musk’s objective is not only to treat brain diseases and disorders, but cure them. Musk promised that human trials would start in 2020 and later changed the date to 2022. However, despite successful animal trials, Neuralink has still not conducted human trials or received approval from the FDA to implant its technology in humans.
Unfortunately, Neuralink experienced some management issues and employee conflict. Eventually its former president and biomedical engineer, Max Hodak, left abruptly and became an investor in the Australian start-up, Synchron.
Synchron, a brain-computer interface start-up, developed a 38mm Stentrode endovascular device that unlike Neuralink’s technology or the Utah array, can be inserted into any part of the brain without cutting through the patient’s skull or damaging their tissue.
A neurointerventional surgeon makes an incision in the patient’s neck to reach the jugular vein, from where the Stentrode, with the help of a catheter, is placed into a blood vessel within the brain. As the catheter is removed, the Stentrode (a cylindrical, hollow wire mesh with 16 electrodes) opens up and begins to fuse with the outer edges of the blood vessel almost like a tattoo. The process is thus very similar to implanting a coronary stent and takes only a few minutes.
After the implantation of the device, a second procedure connects it to a computing device implanted in the patient’s chest. The surgeon creates a tunnel for the wire and a pocket for the device underneath the patient’s skin, as in the case of a pacemakers. The Stentrode reads the signal produced by neurons firing in the brain and then sends the signal to the receiver device, which amplifies the signals and transmits them via Bluetooth to a decoder (computer or smartphone with the brain interface software). The decoder then uses a machine learning algorithm to translate the signals into specific digital commands.
Synchron and Neuralink implants have very similar immediate applications. They are both designed to translate human thoughts into computer commands to assist patients with neurological diseases like Parkinson's or amyotrophic lateral sclerosis to communicate.
But since the development of artificial intelligence is considered as a threat by Musk, he is more ambitious and claimed that the Neuralink device could give people telepathic powers and make humans symbiotic with artificial intelligence.
After implanting its devices in four patients in Australia since 2019, Synchron in July 2022 implanted its first device into the brain of a US patient — in this case a patient suffering from amyotrophic lateral sclerosis.
As in the case of the four patients in Australia, the device was placed in the motor cortex, an area involved in the planning, control and execution of voluntary movements.
Synchron believes that just as the device allowed the Australian patients to send messages through WhatsApp and make online purchases, it would also enable the six severely paralysed US patients to browse the web, communicate through email and text, and control digital devices just by thinking. The implanted device translates the patient’s thoughts into action through commands sent to a computer after they have lost the ability to move or speak.
Although the Stentrode device has wonderful possibilities for people who have debilitating illnesses, the current trial is focused more on the reaction of the human body and the clarity of the brain signals than on the functions that can be performed by the person.
However, Synchron focuses on several broad therapeutic applications of their technology. Currently, they are busy with the clinical trial phase in the restoration of neuroprosthetics, with a focus on paralysis and pre-clinical trials of the treatment via neuromodulation of epilepsy.
The plan is to extend future neuroprosthetic implants to people debilitated by strokes, spinal cord injuries and multiple sclerosis. Similarly, they plan to extend their neuromodulation treatment to depression and hypertension. The third application of the technology is to map the neurodiagnostics of brain injuries, which is already in a pre-clinical phase.
Currently the Stentrode’s computing power is limited, which means the device cannot translate whole sentences yet. The patient with the implant can only pick letters one-by-one on a screen with a hands-free point-and-click, and the technology converts those “yes or no” thoughts into commands. But it allowed the Australian patients to continue with their day-to-day lives in their own homes.
The technology is thus still in its early stages of development, but this minimally invasive technology certainly introduces a new era of restoring the lives of people with severe disabilities by deciphering the neural code of the brain.
Professor Louis C H Fourie is an Extraordinary Professor at the University of the Western Cape.
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