Story at a glance
- The first permanent brain-computer interface was implanted in a patient in the US
- The technology is intended to give paralyzed people the extreme ability to control a computer using only their thoughts.
- Brain-computer interface developer Synchron has developed a new approach to the procedure that began with an FDA-approved early feasibility study.
In recent years, experimental brain-computer interface (BCI) technology has advanced to give severely paralyzed patients hands-free control of computers using only their thoughts. And now for the first time in the US, a patient suffering from ALS has successfully received a permanent BCI implant as part of a landmark study.
Australian-based startup Synchron was given the green light last year by the Food and Drug Administration (FDA) to conduct an early feasibility study of its flagship BCI product, the Stentrode, to assess the safety and efficacy of the device in six ALS patients have severe paralysis, meaning they have no use of the muscles in their arms or their legs. The trial was conducted with support from the National Institutes of Health (NIH) Neural Interfaces Program.
Earlier this month, doctors at Mount Sinai West in New York successfully stopped the procedure and said the patient was able to go home just 48 hours after the operation. The goal is to ensure that the device can be safely implemented, as well as to see if patients can perform simple functions such as point and click on a computer using only their brain signals.
There are many iterations of BCIs that have enabled study participants in the US and abroad who have lost the use of their arms due to strokes, accidents or diseases such as multiple sclerosis, to control the cursor. of mouse, keyboard, mobile device and even a robotic. arm that provides sensory feedback to the patient.
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But the typical brain-computer interface process is invasive. It requires opening the skull and embedding an implant directly into the brain, a complicated new operation foreign to most neurosurgeons that comes with its fair share of risks.
But Synchron’s approach is unique in the field of BCI. The Stentrode is an endovascular stent that enters the body through the jugular vein and snakes through an area called the transverse sinus into a secondary area called the superior sagittal sinus – a large vein that travels well between in both hemispheres of the brain – almost half in half. the back and front of the head near the primary motor cortex, the target of the stent and the area of the brain responsible for voluntary movement.
Once in the right place, the stent opens like a flower and heals the walls of the blood vessels over several weeks. Electrodes embedded in the stent can then record brain activity from the motor cortex. A small wire from the stent then transmits the brain activity to a pacemaker-like unit that sits on the chest that relays the signals to an external monitoring unit via Bluetooth, which is plugged into the a computer.
Months of training then take place using algorithms to decode brain signals into practical functions on a computer, such as clicking a mouse.
“These individuals can’t initiate movement with their own muscles, but when they try to, say, move their ankle up and down, the stent recognizes that signal. And because the stent is connected to a computer, can take that signal and use it for something, say, a left mouse click,” said David Putrino, director of rehabilitation change for the Mount Sinai Health System and principal investigator of the study, said in an interview.
“And if the patient tries to move their right ankle, same idea. The stent can take the signal and decode it and say ‘OK, the patient is trying to move their right ankle. Let’s do that right click.’ And so on and so forth as it builds and recognizes more signals over time,” Putrino said.
The method is useful for several reasons. Stents have been widely used in medicine for decades. Small eye tubes are used to hold open passages in the body, such as weak or narrowed arteries. Many neurosurgeons and cardiologists are familiar with the technique so the skill is transferable. Putrino said that it makes a big difference in the risk profile for the procedure and the long-term feasibility of the technology.
Implants that go directly into the brain also cause scar tissue around the electrodes that make it difficult to record brain activity over time, which is not the case with the Stentrode.
“Over time as the stent becomes more and more continuous with the blood vessel, it becomes easier for the electrodes of the stent to record brain activity,” Putrino said.
The first human trials of the technology were conducted in Australia and found the device to be generally safe with no serious adverse events after following participants for a year. The Stentrode also remains in place in patients and the blood vessel where the device is placed remains open. Participants successfully used a computer to communicate via text and perform tasks such as online shopping and banking.
In a Ted Talk earlier this year, Synchron’s CEO Thomas Oxley showed a study participant sending a tweet using the device, as well as two others communicating with him via text.
“I think the brain-computer interface is an example of a type of tool that will be used as we open up the brain and start treating conditions that were previously untreatable and impossible before,” Oxley said in an interview.
“I really feel like we’re in this renaissance time that’s emerging. I think this is a consequence of what happened with the genome sequence. We first need to know how to sequence the genome. There is all this information. Then we started to develop tools to interact with the genome, and it spawned a whole industry of new areas of medicine that we could do by manipulating the genome. The same thing happens in the brain. “
Published on July 24, 2022