Next EEG — new human interface
It was the beginning of 2014 and I was in Hallstatt, Austria, on BNCI Horizon 2020 Retreat, the event aimed to discuss the future of BCIs (brain-computer interfaces) with over 60 experts from the field. Among the hot topics was the state of brainwave reading by means of electroencephalography (EEG). The special thing about this event is that I had a “secret agenda”: without announcing it, I brought up with me the just assembled first working small Smarting mobile EEG device AND the Android phone with the (first beta version of) application able to display signals in real-time! It may not sound impressive — but believe me, it was. No one had such ability (!) and it is still rather unique today. While mounting the system I had an unexpected observer, a professor from the UK…her words still resonate in my mind “that is not EEG” … Yes, the demo failed. The unit was soldered manually and the loose connector was damaged on the way. But this was minor (although very embarrassing at the time) and we had it fixed soon and many successful demos followed since and, more importantly, many great scientific outputs came out of it.
With me, then (also as a subject in a demo attempt) was my friend and advisor prof. Maarten De Vos from Oxford University. He also co-authored arguably the first paper showing the proof of concept for truly mobile, event-related potential (ERP) ready EEG (How about taking a low‐cost, small, and wireless EEG for a walk? ).
It was an immense work that preceded the device I showcased (also assisted by our partners from EasyCap GmbH), and I was a bit edgy and annoyed when he asked me, “So ok, now we have mobile EEG on the phone, so what’s next?” and I don’t know exactly how I put it but it was on the line “hold on for a second, we are not yet done here, this is a demonstrator, we will need more time to make this work and give it to other people” (which we did in the years that followed).
But the essence is the following: Maarten did ask the correct question as we all were looking to the future. Milestone 1 was crossed though — we brought scientific excellence outside of the lab. It was now possible to do some really neat stuff (tracking athletes while they perform, demonstrate home-based stroke rehab, optimize workplaces for mental fitness, and many others).
Milestone 2 was not upfront planned but became self-evident once Smarting (and other mobile EEG devices) came to use. You are wondering what it was, right? :) Ok, EEG is mobile and we can do all this neat stuff, but hey, how do you feel with it on your head knowing that the other people around are looking? (check the picture below).
People didn’t really like three things: 1) wearing a cap 2) having to wash hair and 3) other people looking at them strangely. We knew what we had to deal with, but had an additional constraint: whatever we do, we had to ensure that we still record (good) EEG.
Oldenburg University group run by prof. Stefan Debener (also our scientific advisor) decided to use Smarting and its high mobility and mobile phone compatibility to try out a new EEG modality. Instead of classical 10–20 montage used in cap setups, and with the help of Dutch TMSi company developed the around the ear, printed electrodes termed cEEGrids. They still needed a tiny amount of gel but had recording contacts in places without hair. This aimed to solve two of the problems — easy to apply system and, more importantly, the unobtrusive character of the recordings. With cEEGrids (that are still in their infancy) and the headband to hold the amplifier, people could walk out of the lab and be less noticeable on the street.
cEEGrids also enabled some really cool research — with many ongoing studies.
Milestone 2 was, therefore, almost reached. Almost. Subjects still had something strange on their head and the residual gel present…. not so easy to mount as well, as testified by some users.
Milestone 3 was again in sight. We needed a scientific system that is being mounted in a seamless way, without washing hair AND that looked more natural.
This was a tough one to reach. I have a whole story about this one, but I will keep it for a later time. Let’s just say it was a life-changing experience, with lots of mistakes, and it took a few years, tears, pain and who knows what. It was worth it though.
So, what is the Milestone 3? Let's make a bullet list where each starts with the expectations and goes towards the solution.
· We wanted to avoid hair washing.
What every researcher thinks at this moment is — dry electrodes. Sometimes they are referred to as the wet dream of every EEG researcher (also confirmed by our recent twitter poll). Again, long story short, this was out of reach, at least if one wanted to have a valid, research-grade EEG. Solution came with the so-called semi-dry electrodes. Sponge-based system that relied on saline solution (salty water). Special credits here go to Greentek company, our collaborator and distributor for China. Together, we first made a Smarting-compatible cap, that also didn’t call for hair washing.
· We wanted unobtrusive looks.
So, how do we measure EEG and not get noticed? cEEGrids were the first step, but still — not the final solution. How do we conceal the EEG? By nice cap design? Nope. Didn’t work.
The only plausible solution was — lets fit it in something that people ALREADY wear and that comes naturally. What do we wear on the head that is not strange? List was not too large:
1) Headband
2) Winter cap
3) Glasses
4) Headphones
Headband was too sporty and out of fashion. Winter cap could be worn during winter times. Glasses — too tight, with little space for electrodes. Which leaves us with headphones.
Is there a natural connection between EEG and headphones, or did we just go with the only possible option?
Yes, it turns out there is. Music and the brain are very much connected. Music can drive our mental states. Lots of EEG research is music and auditory-in-general oriented.
· Easy mounting.
I am guessing you are already bored of “it’s a tough one” statements. So I will skip them. On a more technical side, EEG signals are in the mV range. That is tiny. Every single movement, adherence imperfection, touch, very much everything that causes micromovements causes EEG signals to go wild. This is mechanical noise which is very dangerous for recordings to say the least. You need to ensure stable contact, proper pressure, just enough but not too much (no pain or discomfort after longer use). Besides, human heads are vastly different, and unless you wish to make super-expensive 1000 versions of headphones for each head you really have to be smart and careful with the geometry.
But we did it. All of the above. And we have just released our EEG-enabled research headphones — Smartfones.
Is this the end of the road? By no means. Is it super-exciting? Oh yes! So much so, that I am going to get one pair for myself, taking huge advantage of being one of the mbt founders and getting a huge personal discount :)
What is then the end game?
You might have noticed that the headphones I previously described still have the “research” prefix or suffix. In reality, that means that they will have sponges soaked in saline, inserted manually in each electrode cup. In each recording. Great for research but not for everyday people.
But imagine if we all had our EEG screened during our normal day. We could get first-hand information on how our brain reacts during normal everyday activities. Often times we can only remember our past events and our related feelings but we cannot KNOW what they were at the time of the event. We can often RECALL someday as being productive, us being stressed out, and so forth. But is this really a true feeling or are we just super-subjective as we are? If we had our brains screened regularly, we could also detect early biomarkers of upcoming medical conditions. We could have home-based epilepsy screening. We could have a better gaming experience, the one that considers our mental states when adjusting the game difficulty. We could have a smart music recommender. And the list goes on.
Milestone 4 is just this. Making an EEG as seamless as drinking water, as sitting on a work desk, as answering a phone call. Getting rid of the sponges, salty water, and any other consideration — we don’t have to worry about a piece of hardware — it takes care of us.
If you think this is far-fetched, just go a few years back when the only way to measure EEG was to sit in an electrically isolated room (Faraday cage), not moving, looking straight ahead surrounded by wires and cumbersome devices. And of course, all the while “feeling relaxed” as many scientific papers describe their subjects in the above conditions.
Yes, there is work to do. But I am confident we are in reach. And hey, hard work has never been more interesting and motivating.
