Exploring the Future of Brain Imaging: OPM-MEG - Zelekha Seedat, Young Epilepsy, UK
Post-doc researcher Zelekha Seedat discusses her work as a postdoctoral researcher at Young Epilepsy, focusing on Magnetoencephalography (MEG) and the innovative Optically Pumped Magnetometers (OPM) technology. She explains the differences between MEG and EEG, the advantages of OPM technology, and the challenges faced in interpreting data. The conversation also covers the importance of combining EEG with OPM-MEG for better data accuracy, the future potential of OPM-MEG in clinical settings, and how to get involved in her research!
Reported by Torie Robinson | Edited and produced by Carrot Cruncher Media.
Podcast
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00:00 Zelekha Seedat
“You can wear the helmet and that means you can move your head while the scan's happening and that's great, especially for children who really struggle to sit still for any length of time.”
00:09 Torie Robinson
Fellow homo sapiens! My name is Torie Robinson, and welcome to, or welcome back to: Epilepsy Sparks Insights.
In part 2 of 2, this week, about OPM-MEG brain scans (check out part 1 with Christine Embury if you haven’t yet seen it!), we have guest star researcher (also from Young Epilepsy), Zelekha Seedat, who will elaborate further for us on the research that they are doing into childhood epilepsy - and indeed, how clinicians and patients can be involved.
00:36 Zelekha Seedat
So I'm a postdoctoral researcher and trainee physiologist at Young Epilepsy. So, I originally did my degree and my PhD at Nottingham, at the University of Nottingham, and that was in MEG - so the physics of MEG - and then also applying machine learning algorithms to MEG data to look at healthy brain activity but also activity from kids with epilepsy.
01:02 Torie Robinson
And could you just confirm for those who aren't familiar, what is an MEG? Because most people have heard of EEG, MRI, etc.. But what does MEG stand for?
01:11 Zelekha Seedat
So, MEG stands for Magnetoencephalography and it means that we're measuring the tiny magnetic fields produced by your brain. So, in EEG you're measuring the electric fields produced by your brain, in MEG you're measuring the magnetic fields. And the difference is that the magnetic fields pass straight through the skull which means that you can then pinpoint where that activity is coming from, whereas in EEG the electric fields get sort of smeared out by the presence of the skull (which is not a good electrical conductor) and that means you can't really tell where that activity is coming from - except, to say, you know, “It's coming from the left frontal lobe” rather than, you know, within millimetre accuracy “This is where it's coming from”.
01:54 Torie Robinson
And compared to an MRI?
01:57 Zelekha Seedat
So, MRI measures structural brain, like, what the brain “looks like”, essentially. Whereas MEG and EEG measure brain function, so what the brain is “doing”. So, the activity that's passing from one part of the brain to another part of the brain rather than what it looks like.
02:16 Torie Robinson
So, we have that… we're relatively new, right? Fancy “opium” - which I really like saying because I'm so mature…but tell us what the OPM-MEG is.
02:27 Zelekha Seedat
So OPM…
Torie Robinson (02:05.268)
OPM!!
02:31 Zelekha Seedat
…yeah, Optically Pumped Magnetometers. So, all they are, are tiny little sensors that can measure these magnetic fields from your brain. But the difference is that they measure it using a combination of, like, a little cell of gases and lasers. So, it uses lasers to work, essentially. So, there are different magnetic field sensors that have been used to measure MEG in the past. But the OPMs use lasers to work. It means they can be smaller and they can be placed on the head. They don't need to be kept in a big bat of liquid helium.
03:03 Torie Robinson
I've seen pictures of OPM-MEGs and they look quite bulky, there's loads of wires everywhere. Can you tell us the pros and cons, please, of using it, and, well, the complexities of the OPM-MEGs, please?
03:18 Zelekha Seedat
Yeah, so one of the good things about OPM-MEG (compared to Cryogenic MEG) is that it's wearable. So, the sensors, like I said, they don't need to be kept really cold in a big vat of liquid helium. They can just be mounted in a bike helmet kind of thing on the head. So, it's just like a 3D printed lattice structure…
03:40 Torie Robinson
And the way that you hold it, looks quite light!
03:42 Zelekha Seedat
Yeah, it is, I mean, this doesn't really weigh a lot. Once you've got all the sensors in it, it's a little bit heavier, maybe sort of, a kilo. So, it's quite heavy to have on your head. For adults it's completely fine. We've scanned… we can comfortably scan, like, a 4-year-old child with it on for a while. But any younger than that and I think they do start to feel the weight; they get a little bit uncomfortable and maybe they'll rest their head on the back of the chair. So, this is not the final solution. So, there are lots of things we're still trying to work out. OPM-MEG is a brand-new technology. So, we're still trying to work out the best way to mount them in a helmet or in a flexible cap or different things like that. Also, the sensors themselves are changing all the time; the cables from the sensors to the electronics change, the electronics themselves change, so bits are changing all the time and none of it is the final solution just yet. So, trying to record MEG in a system that's brand new - but also changing - is really quite difficult and to interpret it and to know exactly what you're looking at. So, for example you can, like I said, you can wear the helmet and that means you can move your head while the scan's happening - and that's great, especially for children who really struggle to sit still for any length of time - they can be wearing their helmet, they can be watching Bluey, their favourite TV programme, anything they want to watch. They can just chill, can watch whatever they want to watch or we can be doing MEG tasks with them. And while they're doing that, they're moving their heads ever so slightly. So, the cables will be moving behind them…
05:22 Torie Robinson
Yep.
05:23 Zelekha Seedat
…so we can get things like cable artifacts. But, also, they're moving their heads through a magnetic field which also produces an artifact. And none of this is recorded in EEG or in cryogenic MEGs so we need to be able to recognise those artifacts, and also, with confidence, understand exactly what we're recording from the OPM-MEG.
05:43 Torie Robinson
That does sound rather complex and challenging.
05:47 Zelekha Seedat
Yeah, it is!
05:47 Torie Robinson
So, how are you going to learn how to, like, do that and I guess, interpret the data to get what we need?
05:55 Zelekha Seedat
Yeah, so our solution is to record EEG and OPM-MEG at the same time. So, clinicians and physiologists working in the field of, like, epilepsy imaging, I guess, are used to looking at EEG.
06:16 Torie Robinson
Mm-hmm.
06:17 Zelekha Seedat
And that means that that's the space that they're comfortable with, that's how they're trained. So, if we record EEG - so we stick all the wires on like normal and then put the OPM-MEG helmet on top and then record them both at the same time, we can use the EEG as, kind of, a roadmap; to help us understand what we're looking at in the OPM-MEG. So, if we see some, like, epileptiform activity in the EEG, then we can look in the OPM-MEG and say “Well, okay, this is exactly what it looks like. These are the similarities and differences.”. And then, similarly, if we have, like, weird cable artifact at the back of the head and we want to know if that's genuine brain activity or just cable artifact…
06:56 Torie Robinson
Like a wiggle!
06:57 Zelekha Seedat
Yeah, exactly! We can look in the EEG and see is that “wiggle” brain activity or is it just the cables moving? And then, being able to share that with doctors and say, you know “We're confident that what we're looking at is this” or “We're confident that actually it's artifact”. So that's our solution: is to record them both at the same time to start with.
07:17 Torie Robinson
So, you'll be able to identify correlations between both sets of data to clarify what is real and useful and what is just, like, a wiggle in the background.
07:28 Zelekha Seedat
Yeah, exactly, and, you know; we can have all the fanciest, newest, cutting-edge brain technology in the world, but if there isn't a clinician who understands how to use that data, or a training pathway to upskill clinicians and physiologists to be able to record and interpret that data, then it's never gonna be used. Like, we need the workforce to be in place alongside the new cutting-edge technology as well.
07:57 Torie Robinson
When does your study finish actually, this particular study?
08:00 Zelekha Seedat
So, we've got another couple of years, and so the study that we're doing at the moment: we are recruiting children with focal epilepsies who are candidates for epilepsy surgery
08:13 Torie Robinson
So not generalised, must be focal.
08:15 Zelekha Seedat
Focal, yep so that's one part of the study. And then we've got another part of the study which is actually anybody that comes to Young Epilepsy to have, like, a clinical EEG so they could have generalised seizures…
08:29 Torie Robinson
“Anybody” meaning children, sorry?
08:31 Zelekha Seedat
Yeah children, so at Young Epilepsy we see kids and young adults up to the age of 25. So, for some of those patients, we're recruiting them to be recorded in the OPM-MEG as well. And that's because we want to understand - at a population level - like, who this study is useful for. So, we already know that it's probably useful for surgical candidates, but for other people… a lot of kids have like sensory challenges or other extra complicated needs. They really struggle to sit still and have an EEG put on their head. And if we could show that OPM-MEG shows you exactly the same thing as EEG - plus a little bit more - and it's less difficult to do (because you can just put a hat on them), then that could be really valuable for some of those patients. So, it's trying to work out exactly the patient populations that will benefit from it now and in the long run as well.
09:30 Torie Robinson
I imagine if we can find out that it benefits kids, well, those kids will grow up and it could benefit them in the future too…
09:37 Zelekha Seedat
Yeah, yep.
09:38 Torie Robinson
…you know, so it sounds quite exciting. And I believe it's all, like, silky in the middle as well, isn't it? So, it's not, like, rough on your face. Because, stereotypically, if you have an EEG, you've got the grit, right? Which goes in your face and the glue and stuff like that. And lots of people hate that, right? And so, I imagine; this device, you don't have to go through any of that because it's all slippy and you just plonk it on, right?
10:02 Zelekha Seedat
Yeah, so we've actually got, like, a wool insert. So, the sensors (the OPMs) get a little bit warm. So, we have a wool insert, like a little hat that goes underneath the helmet so it's nice and soft. Obviously, some of the people we're recording, we're also recording EEG at the same time. So, right now, we're still using the paste…
10:22 Torie Robinson
Okay.
10:22 Zelekha Seedat
…and the grit. But for kids who aren't having EEG at the same time, then yeah, it's just a comfy warm hat.
10:32 Torie Robinson
But for this study they will be having both at the same time - but, it's like, you know, two in one I guess! And it’s…
10:38 Zelekha Seedat
Yeah, and it will help us for the future as well. I mean, I don't think we should be aiming to always do EEG and OPM-MEG at the same time. It's just for the next few years to help us build up that database of “This is what OPM-MEG data looks like and we can confidently interpret it”. So, in, you know, in 10 years’ time, I don't know, we might not need to do EEG and OPM-MEG together.
11:40 Torie Robinson
Interesting. Where do you think we'll be in 10 years’ time?!
11:08 Zelekha Seedat
Ohhh, that's such a question!
11:10 Torie Robinson
Isn't it! It's like it's like the question from telly “So, tell us about the future!”.
11:17 Zelekha Seedat
I'd hope that we've moved from… so at the moment we're definitely a research system. I would hope that there would be an OPM-MEG system somewhere in the world that is clinically approved; so, it's gone through the medical device approval and somebody has said “Yes, it does what it says on the tin and it's safe and you can put it in any hospital”. So, I'm hoping in 10 years’ time that commercially available medical device approved systems will start to appear in hospitals so that we can use it in the clinic rather than just for research. That's where I hope we'll be!
11:56 Torie Robinson
And then hopefully as a result of that, can collect more data simultaneously, people need to spend less time in the hospital, and [we’ll] get the results that we need earlier to get people in surgery earlier (if they need it) right, which could potentially reduce the number of people who have cognitive regression or, you know “insults” to the brain as a result of the seizures. Instead… gosh, I'm promoting it already. But yeah, yeah!
12:20 Zelekha Seedat
Haha!
12:20 Torie Robinson
To everyone listening and watching; we have the study on the Epilepsy Sparks page as well for research that you can check out. And if you can propose that to either your patients or to your clinicians, and hopefully we'll get more people on this cool study.
12:40 Zelekha Seedat
Thanks so much.
12:40 Torie Robinson
Thank you so much to Zelekha for elaborating on what a OPM-MEG is, for reconfirming that it has nothing to do with opiUM, and for getting us all excited about - and sharing how families and clinicians can get involved too! Check out Zelekha’s papers and more about her work via the website torierobinson.com (where you can also access the podcast, the video, and the transcription of this entire episode, and, if you haven’t already, don’t forget to like, comment, and subscribe to our channel, share this episode with your friends/your colleagues/your family members(!) and see you next week!
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Zelekha is a post-doctoral researcher in the clinical applications of OPM-MEG and is currently also training to become a clinical physiologist at Young Epilepsy in Surrey, England. She is a specialist in analysing both EEG and MEG data from children with epilepsy.
During her PhD, Zelekha applied hidden Markov models to MEG data to provide insight into both healthy brain function and epileptiform activity. Her research is focused on:
Interpreting clinical OPM-MEG data through combined EEG and OPM-MEG in children with epilepsy
Using machine learning methods to detect epileptiform activity, unique to each patient, in both time and space
Detecting functional brain networks
She hopes to change the way that MEG is used in the UK by bridging the gap between the clinical world and research, so that cutting edge brain imaging techniques are accessible to the patients who would benefit the most.
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LinkedIn: zelekha-seedat
Google Scholar: yUx_QdEAAAAJ&hl=en&oi=ao
Young Epilepsy: ResearchProjectsSupplementReport2023.pdf