How to Build BCIs That Last

How to Build BCIs That Last

How to Build BCIs That Last

May 14, 2024

At Paradromics, we’re committed to building devices that last and that enhance people’s lives. 

To do that, we have built an implantable device that can access brain-activity data and uses artificial intelligence to translate that activity into actions, like texting, typing or even speaking. As with any AI-enabled application, the more high-quality data, the better. But this is more than just a software/data problem. To meet our goals, we also have to overcome biological hurdles–ensuring that our device interacts safely and reliably with the body.

The Connexus® Cortical Module

There are two big challenges in developing next generation brain computer interfaces, or BCIs. They have to record a lot of data AND they have to perform reliably for years after they’re implanted in the brain. To access the highest resolution brain data, you need lots and lots of sensors called electrodes to collect brain-activity data. To be more precise, these electrodes have to listen in on the conversations individual brain cells, or neurons, are having with each other. These “conversations” are the building blocks of everything we do, from speaking and typing to tasting our food and walking around. The more of that neural conversation the sensors are able to record, the better. The electrodes then have to connect to advanced computer chips that can process that data efficiently, and with the help of AI, get it translated into meaningful, real-world actions.

It sounds relatively straightforward, but it’s not. The body is simultaneously a harsh and delicate environment. The components have to survive in it for years without hurting it.

Here’s what we’ve done to ensure the Paradromics Connexus® BCI does that.

What are some design decisions Paradromics made to overcome these challenges?

When we designed our system, we had three important things in mind.

1. The electrode materials.

Everything interfacing with the brain should be made of materials that last for many, many years in the body without degrading. That’s why we chose to build our device with metals and ceramics that are known to last a long time in the body. Neuralink, by contrast, is building thin polymer threads that have an expected lifetime in the body of less than two years.

2. Waterproofing.

BCIs are electronic devices that need to survive in the body for years or even decades. The waterproofing used for your iPhone isn’t sufficient to provide that level of protection. In fact, BCIs need to be sealed up using airtight packaging methods that are also used in spaceships. That is especially challenging when the device is tiny and it has hundreds of electrical connections. A lot of medical device companies can build reliable implantable electronics with a few electrical connections, and a few labs can build high data rate neural interfaces with hundreds of connections, but only Paradromics is building high data-rate BCIs that are reliable.

3. The arrangement of the electrodes and the recording electronics.

The form factor should ensure that everything stays where it's supposed to be for as long as you need it to stay there. Our device looks like a tiny metal disk. It’s about a centimeter in diameter. It's designed to sit right on the surface of the brain so that when the brain moves, it can move with it, like an untethered boat bobbing on the ocean. That’s extremely important for durability. The Neuralink N1 Implant is tethered to the skull. If the brain moves relative to the skull, that can tug at the electrodes and pull them out.

This is a cross section of the brain. It is not to scale.

How do you know that these design choices were the right call?

We have the benefit of 20 years of successful human clinical BCI work using a similar, but older, device called the Utah Array, which is made by Blackrock Neurotech. The Utah Array looks like a tiny hairbrush with 96 tiny bristles. Those are the electrodes that record brain activity. In research studies, these devices sometimes have lasted for years, allowing patients to do exciting things like imagining handwriting and turning thoughts into computer-generated words. So we know that this kind of device can work and we have leveraged and improved upon that in designing our own device.

The Utah Array by Blackrock Neurotech

What are some of the improvements over that older technology?

The Utah Array sensors are made of silicon. We built ours out of platinum iridium. It was more challenging to fabricate, but it is a superior electrode material. We also shrank the size of each individual sensor. That allows us to balance getting more data out of the brain while minimizing damage. Each individual electrode is thinner than a human hair and a bit longer than a poppy seed.

Electrodes in the brain capturing signals from neurons firing.

What future applications do those capabilities enable?

We're focused on being able to restore computer control and speech for individuals who have lost the ability to communicate. That patient population has a really dire unmet medical need, and they're relying on us to provide them with something that's going to allow them to communicate with their family, not for six months, but for years. And so the design choices that we've made are with that purpose in mind: to enable a therapeutic outcome that can last for many years.

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