The story at a glance
- The first permanent brain-computer interface has been implanted in a patient in the United States
- The technology aims to give severely paralyzed people the ability to control a computer using only their thoughts.
- Brain-computer interface developer Synchron has developed a new approach to the procedure that has launched an FDA-cleared preliminary feasibility study.
In recent years, experimental brain-computer interface (BCI) technology has made progress in giving severely paralyzed patients hands-free control of computers using only their thoughts. And now, for the first time in the United States, an ALS patient has successfully received a permanent BCI implant in a landmark study.
Australian start-up Synchron received the green light last year from the Food and Drug Administration (FDA) to conduct a preliminary feasibility study of its flagship BCI product, Stentrode, to assess safety and efficacy of the device in six patients with ALS. severe paralysis, meaning no functional use of the muscles in their arms or legs. The trial is being 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 completed the procedure and said the patient could go home just 48 hours after the operation. The goal is to ensure that the device can be implemented safely, as well as to see if patients can perform simple functions such as pointing and clicking with a computer using only their brain signals.
There have been several iterations of BCI that have enabled study participants in the United States and abroad who have lost the use of their limbs due to strokes, accidents, or illnesses such as multiple sclerosis, to control a mouse cursor, keyboard, mobile device and even a robot. arm that provides sensory feedback to the patient.
But the typical brain-computer interface process is invasive. It requires opening the skull and implanting an implant directly into the brain, a complicated new surgery foreign to most neurosurgeons that comes with its fair share of risk.
But Synchron’s procedure is unique in the field of BCI. The Stentrode is an endovascular stent that enters the body through the jugular vein and winds through an area called the transverse sinus into a secondary area called the superior sagittal sinus – a large vein that travels comfortably between the two hemispheres of the brain – to midway between 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 within the blood vessel walls for several weeks. The electrodes embedded in the stent can then record brain activity in the motor cortex. A small wire from the stent then transmits brain activity to a pacemaker-like unit in the chest, which relays the signals to an external monitoring unit via Bluetooth, which is plugged into a computer.
Months of training then take place using algorithms to decode brain signals into practical functions on a computer, like clicking a mouse.
“These people cannot initiate movements with their own muscles, but when they try, for example, to move their ankle up and down, the stent can identify this signal. And because the stent is hooked up to a computer, it can take that signal and use it for something else, say, a left mouse click,” David Putrino, director of rehabilitation innovation for Mount Sinai Health System and principal investigator of the study, said in an interview.
“And when the patient tries to move his right ankle, same idea. The stent can pick up this signal, decode it and say “Okay, the patient is trying to move his right ankle”. Let’s right click it. And so on as it builds and identifies more signals over time,” Putrino said.
The procedure is advantageous for several reasons. Stents have been widely used in medicine for decades. Fine-mesh tubing is 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 skills are transferable. Putrino said that makes a big difference to the risk profile of the procedure and the long-term feasibility of the technology.
Implants that go directly into the brain also cause scar tissue around the electrodes, making 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 stent electrodes to register brain activity,” Putrino said.
The technology’s first human trials were carried out in Australia and found the device to be generally safe with no serious adverse effects after following participants for a year. The Stentrode also remained in place in the patients and the blood vessel in which the device was placed remained open. Participants successfully used a computer to communicate by text and perform tasks such as online shopping and banking.
In a Ted Talk earlier this year, Synchron CEO Thomas Oxley featured a study participant who tweeted using the device, as well as two others who communicated with him via text. .
“I think the brain-computer interface is an example of a type of tool that’s going to be used to unlock the brain and start treating conditions that were previously incurable and impossible before,” Oxley said in an interview.
“I really have the impression that we are in this period of renaissance that is coming. I think it’s a corollary of what happened with genome sequencing. We first had to figure out how to sequence the genome. There was all this information. Then we started creating tools to interact with the genome, and that spawned the whole industry of new areas of medicine that we can do by manipulating the genome. The same thing happens in the brain.
Posted on July 24, 2022