I want you to meet Casey Harrell.
He’s a climate activist, a father, and a husband. He also has ALS, a devastating disease that has left him paralyzed and unable to speak clearly. For many, that would be the end of the story. But for Casey, it was the beginning of a new chapter. He’s what the researchers he works with call the first “power user” of a brain implant.
For nearly three years, Casey has been living with a brain-computer interface, or BCI. It’s a piece of technology that, frankly, feels like it’s pulled straight from a science fiction novel. It allows him to "speak," browse the internet, and even do his job. It has, in his own words, been "nothing short of revolutionary!"
His story isn’t just about one man. It’s a window into a field of technology that is absolutely exploding right now. Casey is one of a growing wave of volunteers who are, as he puts it, helping to “pay it forward” by advancing the science while also getting some incredible personal benefit.
So, let's talk about what’s really going on with these brain implants. Because this isn't just a far-off future concept anymore. It's happening right now.
First Off, What Exactly Are We Talking About?
When you hear "brain-computer interface," it’s easy to picture a single, futuristic device. But the reality is a bit more varied. Think of it like microphones. You can have a tiny lapel mic clipped right to your shirt for a super clear signal, or you can have a big boom mic hanging over a whole room. They both pick up sound, but they do it in very different ways.
BCIs are kind of like that.
The Deep Dive: Casey’s device is the lapel mic. It involves a set of electrodes placed directly on his brain, picking up the faint electrical whispers of his neurons as he thinks about speaking. These electrodes are physically connected to ports on his head, which plug into a computer running some seriously smart software. That software has been trained to translate his brain signals into sounds, or phonemes, and predict the words he wants to say. It's an incredibly direct connection.
The Less Invasive Options: On the other end of the spectrum, you have BCIs that don't require such intense surgery. Some involve placing electrodes on the surface of the brain, not deep inside it. Others are completely non-invasive, like a cap you wear that’s studded with electrodes.
There's a trade-off here, and it's a big one. The closer you get to the neurons, the cleaner and more powerful your signal is. But, as you can imagine, the more invasive the surgery, the higher the potential risks. It's a constant balancing act for researchers and volunteers.
This Isn't Just a Handful of Labs Anymore
For the longest time, BCI research was a slow, steady burn happening in a few dedicated academic centers. But in the last couple of years, things have hit an inflection point.
A study published in early 2024 looked back at all the BCI trials between 1998 and the end of 2023. They found a total of 67 volunteers across 21 research groups. That’s over a 25-year span.
Now, hold onto your hat. A researcher I follow, Mariska Vansteensel, estimates that since that paper was published, the number of people with these implants has more than doubled. Her current guess? We’re probably looking at around 150 people.
That’s a massive acceleration, and it’s being driven by a mix of academic pioneers and a new wave of ambitious companies. You’ve probably heard of some of them:
- Neuralink: Yes, Elon Musk’s company. They announced they’ve implanted their device in 21 people in just the last two years.
- Synchron: Another major player, currently running trials in both North America and Australia.
- Precision Neuroscience: This one was co-founded by someone who helped start Neuralink, and they’re focused on that less-invasive, on-the-surface-of-the-brain approach.
- Neuracle: A Shanghai-based company that recently got approval in China to use its device outside of clinical trials—a huge step forward.
And all the while, the academic efforts that started it all, like the BrainGate consortium that works with Casey Harrell, are still pushing the boundaries.
From Simple Clicks to Full-Blown Conversations
The technology itself is also evolving at a dizzying pace.
For the better part of two decades, a primary goal for many BCI trials was what you might call "point-and-click" communication. The idea was to let a user control a computer cursor with their thoughts—to move it around a screen and click on letters or icons. It's an amazing feat, but it can be slow.
But lately, the focus has shifted to something far more ambitious: decoding speech directly from the brain.
This is what Casey’s team at UC Davis is focused on. Instead of just decoding movement intentions, they’re decoding the neural signals associated with the very act of speaking. And to make it even more personal, the voice that comes out of the computer is a clone of Casey's own voice, built from recordings made before he lost his ability to speak.
They've even added thoughtful features you might not think of, like a privacy mode and, get this, a "profanity filter" so he can talk to his daughter without any accidental slips of the tongue. It's these human-centered details that show how mature the thinking around this technology is becoming.
The Big Questions We Still Need to Answer
Okay, as exciting as all this is, let's take a breath. We are still very much in the experimental phase. This isn't an off-the-shelf solution just yet, and there are some huge questions that scientists are still grappling with.
For one, how long do these devices last? The brain is a complex and dynamic environment, and ensuring an implant works reliably for years, or even decades, is a massive engineering challenge.
We also don't fully understand who will benefit most. Most trials so far have focused on people with spinal cord injuries, who often have paralysis but can still speak. For people with conditions like ALS, like Casey, the situation can be different. There have been cases where a BCI that initially worked wonders for someone with ALS eventually stopped working, and researchers aren't entirely sure why.
The only way we'll find answers is through more research—and through the courage of volunteers like Casey Harrell, who are willing to be pioneers. Seeing this field truly start to take off, with more funding, more companies, and more brilliant minds focused on the problem, is incredibly exciting. It feels like we're on the cusp of something that will fundamentally change what's possible. I’ll be watching closely, and I promise you, I’ll keep you posted on where we stand a few years from now.
