Head knocks and food system shocks

Plus, what a liquid biopsy from the eye can reveal about your general health...
20 October 2023
Presented by Chris Smith


Rugby match


In the news pod, we speak to World Rugby's Chief Medical Officer to hear how they're making the professional game as safe as possible. Also, we explore the potential consequences of climate change on the world's stock of farmland, and hear why an increasing number of satellites means our atmosphere is filling up with potentially harmful chemicals. Then, we send a member of the team for an eye test, and find out whether swatting mosquitoes could impact selection pressures on the species...

In this episode


00:59 - On tooth technology signals head injuries in contact sport

Fitted mouth guards provide more accurate data for pitch side medics seeking to treat traumatic knocks...

On tooth technology signals head injuries in contact sport
Eanna Falvey, World Rugby

Could cutting-edge technology be about to dramatically reduce the devastating impact of concussion in sport? Repeated head knocks in collision sports like rugby can cause traumatic brain injuries, and enough of those TBIs might add up to dementia later in life. This is what the former Wales rugby international, Alix Popham, who was diagnosed with dementia at the age of 40, had to tell us about his own experience recently...

Alix - I didn't know a lot about concussion or traumatic brain injury. I thought that I had two big KO's that were my concussion, so I didn't think I was that unlucky. I started talking to players that I played with, players I played against, my mum and dad, people I knew, and they were saying, 'What about this one? What about that one?' I had no recollection. The big one in all of this is the silent killer, and that's the sub-concussive hits, and that is literally every contact that you're involved in which is causing a small amount of damage. And the amount of contact we did as players during my career was insane.

That was Alix Popham speaking to us earlier this year.

Now, many contact sports are attempting to manage the risk of serious brain damage by  trialling the use of new technology, including impact-sensing smart mouth guards, and AI. I’ve been speaking to World Rugby’s chief medical officer, Dr Eanna Falvey. I began by asking him to explain how rugby is using science to help tackle concussion:

Eanna - We started this journey three years ago. We went to New Zealand in the middle of Covid because New Zealand were the only country playing rugby at that point in time. We looked at under thirteens, under fifteens, under eighteens and adult players in the community and we put an instrumented mouth guard in over 600 athletes' mouths and we measured what it looked like to be a rugby player. Following on from that journey, we went and looked at this in the adult elite game and what we've been able to deduce from this information is that we can accurately measure head acceleration events. That is how your head reacts to a head impact. The first thing we're going to be able to do is use this to identify those big impact events that we need to be having a look at. Right now, we have a process for diagnosing concussion in rugby where the person, if they have a suspected concussion, comes off in the match, they have an assessment performed, they either go back or they stay off after the game, they're assessed again, and at 36 hours they're assessed again. At the moment, about one in six of our concussions actually present either after the game or at 36 hours. So there are events that have occurred in the match, but the player didn't show an obvious sign or symptom and then came up after the game and said, 'I don't feel well' or, at 36 hours had symptoms. We want to know about this earlier. Just the weekend gone by, we have used this in the WXV, which is a women's international tournament. One of our Italian players, who had an event, nothing was noticed by the doctor or the independent match day doctor, but the mouth guard alerted, the player was removed, and has actually subsequently been confirmed as having had a concussion event. So that's exactly what we're after. There's a second role for this and that role is looking at what we call chronic load, which is how often you hit your head over the course of a week, a month, a season, or a career. We now know that we can accurately measure it. So to reduce something you first have to measure, you have to understand why it's happening, what the causes are, what are the types of activities in the game that cause the big events? Most often we know this is the tackle followed by the ruck. So what can we do with the tackle in the ruck to make them safer and to reduce the head impact events that occur?

Chris - How does the technology actually work?

Eanna - There are two distinct technologies. There are basically gyroscopes and accelerometers which measure the movement, and there's a second technology in there which measures whether the mouth guard is on your tooth or not. It's called on tooth technology. When it's on tooth, it measures the impact events and then it has a Bluetooth capacity. So it can send a message to our independent doctor on the sideline and that doctor will get the alert and remove the player. When this started out, what would happen is an impact or a head acceleration event was measured, it sent the message to the cloud, was then filtered on the company's portal and sent back out to the iPad or the computer of the person looking at the information. This technology is filtered on tooth, so it's ready to go within a second or two of the event. And then, via Bluetooth, the message is sent to the match day doctor. So the match day doctor then can be aware that they need to have a look at the player and remove them.

Chris - And how do you know that that data recorded from that player is an accurate representation of the experience of that player's brain when they're succumbing to those knocks?

Eanna - We looked at, for example, putting sensors in helmets, but that's notoriously inaccurate because the helmet moves independently of the head so you get a lot of artificial movement and noise from the technology. The reason we use an instrumented mouth guard is that the player has a 3D intraoral scan performed, the mouth guard is made to that scan and it fits snugly onto their teeth. The teeth are attached to the skull, the skull surrounds the brain, that's as close as we can get to measuring brain movement and brain response. The technology then centres to the centre of the head so players' age and size have a bearing on how that's filtered, but that information is a proxy. The next step on this is some really clever engineering. We've been in discussion with Stanford University and with the NFL who have what are called finite element models, so they'll take the information about the head acceleration events, about the direction of force, about the clinical outcome, and they can then understand what's called 'brain strain.' But again, even that is hypothesis driven because there's no way of measuring what's actually happening in the brain.

Chris - Does it take into account the fact that different people are different shapes and different sizes? Because a person whose brain anatomy, as in the structure of their head and neck and so on, they might be subjecting their nervous system to a different set of shocks from the same movement than someone who's a totally different shape and size.

Eanna - So if you're a female rugby player, by virtue of the type of game you play, you will have less and lower magnitude impact events, yet the concussion rate is very similar. So we think there's a susceptibility difference between men and women, which may be related to head size, neck strength tolerance, neuromuscular control, which is basically how well your nervous system responds to movement and your ability to cope with that. So, for example, when you fall on the ground, if you have very good neuromuscular control in your neck, you hold your head steady and you don't bang your head to the ground. Whereas a mechanism that we sometimes see in the women's game that we don't see in men is that when the player falls, they subsequently bang their head on the ground. And the hypothesis there is that neck strength and neuromuscular control of the neck is a factor in that.

Chris - So is this a reflection on match fitness as well? In the sense that if you know someone is very fit, they're very strong, they've got really good muscular control, that they're going to be less susceptible. And so that's one of the metrics that perhaps you'll be arguing makes some knocks safer for some people, but once you've got this data, it reinforces your ability to make those sorts of judgements.

Eanna - I would turn it around ever so slightly, and I would say that we understand that playing age is a significant factor in injury risk. So your level of experience and your level of physical training and preparation are in some ways protective. But the other edge of that sword is the fact that as you get better and bigger and stronger, you move faster, you generate higher forces. So there's probably a tipping point, there. Lots to learn in that space, and we're just tipping the iceberg on it at the moment.

A satellite over Earth

08:52 - Scrapped satellites cause atmospheric metal pollution

Scientists ask what harm we could be doing by introducing foreign chemicals into this environment...

Scrapped satellites cause atmospheric metal pollution
Daniel Murphy

A new study has found that space junk is a polluting presence in Earth’s upper atmosphere. When satellites become defunct, those who are responsible for them have three options: leave them up there as junk; let them fall down in bits; or, as is becoming increasingly popular, let them burn up on reentry. But the study’s author, Daniel Murphy, says that this process leaves traces of metal particles lingering in our planet's atmosphere. They’re building up, and the consequences are unknown. He’s been speaking to Will Tingle…

Daniel - You have these satellites reentering and we know they burn up and they produce metals: aluminium, copper, these other metals, and those aren't going to disappear out of the atmosphere. And what's really new here is we have measurements showing that they end up in the stratospheric particles. And that was not necessarily obvious. Now we know where they go, they go into the stratospheric particles. And there's also a background of what's called meteoric smoke, and it's little tiny nanoparticles that are left behind after meteors vaporise. And there's a constant drizzle of these incredibly small particles, tens of nanometers in size. And one of the things we're finding is that the metals from the spacecraft are either condensing on or coagulating with these meteoric smoke particles. So instead of having the composition you'd expect from meteors, which is things like iron, silicon, magnesium, they also have these other metals like aluminium, copper, and other metals like that. The concern is that it's different material, it's now metals that weren't previously there.

Will - When this stuff burns up, it's not gone. It remains up in the stratosphere. But, as we say, it's tiny, it's very difficult to detect. So how did you detect the various metal constituents if they were so small?

Daniel - So they're actually burning up at much higher levels than the stratosphere. The satellites burn up between 40 and 80 kilometres. In the atmosphere, that air descends at some point down into the stratosphere. And as these particles come down, they pick up sulfuric acid, which is a natural process. And we have a mass spectrometer on a NASA aeroplane, and we sampled these particles and blasted them with a pulse of laser light and looked at what comes off. And we can very sensitively tell what the sulfuric acid particles are made of. And in many of those sulfuric acid particles, we see small amounts of metals, either from meteors or now from reentering satellites. Our measurements were showing, we estimate, that right now we can detect aluminium in about 10% of the particles in the stratosphere.

Will - That does sound like a lot of stuff that I personally wouldn't want hanging around in the upper atmosphere.

Daniel - Well, I think right now, on the one hand we don't have concrete evidence that it's causing harm. On the other hand, these are new things we're putting in the atmosphere and we really don't know what they're going to do to the atmosphere. And that's an uncomfortable situation to have. There are plans to put a lot of material in the atmosphere and you don't quite know what's going to happen.

Will - That's a very unnerving concept then, isn't it? That 10% of the stratosphere has this particle and we have no idea what it does?

Daniel - I have to say personally, yes, I find it uncomfortable. And again, it's kind of the trite call for more research. Much of which, incidentally, will probably be in the laboratory. People looking at what aluminium does in a sulfuric acid particle. And a lot of the stratosphere is quite cold, and what's the chemistry and how do the chemicals in the stratosphere then react with that particle? So there's actually a lot of laboratory work as well as measurements in the atmosphere.

Will - Within this decade, we've got Jeff Bezos planning to launch over 3000 satellites to keep up with Starlink. Starlink is aiming for 12,000 satellites. Each of them only have, as a rough estimate, a five year orbit time. So with this exponential rise in satellites and therefore a rise in stuff burning up, are we looking at an increase in these sorts of particles in the atmosphere that we don't really know what are going to do?

Daniel - I think you put it very well. That's exactly what you're looking at. And I just saw an article in Science magazine that, at least on paper, there's plans for up to a million satellites in orbit.

Farmer fertilising wheat

13:52 - Climate change to convert wilderness to farmland

As temperatures rise, currently protected regions may be more suitable for crops...

Climate change to convert wilderness to farmland
Alexandra Gardner, Exeter University

Researchers at the University of Exeter have been attempting to find out how the world’s agricultural landscape might change over the next 40 years. By pulling together information on seventeen hundred crops from a database created by the Food and Agricultural Organization, they predict that, as global temperatures rise, wilderness areas closer to the Earth’s poles will become suitable for growing crops. At the same time, current agricultural areas will become less productive. As a consequence, farming may have to move, placing valuable wilderness ecosystems at risk. The study’s lead author, Alexandra Gardner, has been telling me about the research...

Alexandra - We wanted to look at what will climate change mean for agriculture and how might it change where we're able to grow crops? And we were particularly interested in high latitude areas currently classified as wilderness, so they're untouched by humans. These are really important areas for global biodiversity. They've got huge cultural value and they also have huge value as carbon stores. Are these areas going to be under threat from changes to agriculture?

Chris - So in order to feed a growing population, and an ever hungry world, because some areas, because of climate change, are going to be less good at growing crops, we're going to have to exploit areas that at the moment we regard as pristine wilderness?

Alexandra - Yeah, exactly. We've got a growing population we need to feed, so we need more food, but potentially on less land if some areas are becoming less suitable for growing crops. So we might be looking to areas where crops currently aren't grown and considering their conversion to agriculture.

Chris - How does one go about doing a study like that? How did you approach it?

Alexandra - We used a model called Ecocrop. Essentially, it looks at what the crop needs to grow and considers whether the temperature and the amount of rainfall that falls in the area over that season is going to be sufficient to allow it to grow. It was nearly 2000 crops. We modelled the climate suitability globally, 2008 to 2019, and then we made projections into the future and looked at, under two different climate scenarios, what might happen in terms of crop suitability for those crops. So we've just looked at climate, we've just looked at temperature and precipitation, how those are going to change and whether that will make it an area more suitable or less suitable for a crop.

Chris - And what picture emerges?

Alexandra - What we've seen globally is that large areas of land that are currently suitable for crops will no longer be suitable for crops in the future, or fewer crops will be able to be grown in those areas in the future. Whereas some places where cold temperatures currently limit crop reduction, they're going to become suitable for growing crops in the future.

Chris - Does this mean then that we're basically going to move farming from where it currently is to places that look much more promising just to sustain output and possibly augment output? Because we do have more people, we anticipate more people as we go into the future, and we've got to feed them.

Alexandra - That is the threat that we wanted to highlight. If we don't increase production or maintain production in some places on the land that is currently agricultural land, we will have to look elsewhere to meet the needs of a growing population.

Chris - Does your work give you any insight into how much new land we might have to open up and therefore how much wilderness might be under threat under these sorts of situations?

Alexandra - The area of land that becomes newly suitable for agriculture in the future, so that is an area where at present no crops can be grown but in the future at least one, possibly more crops, could be suitable to grow. This area is equivalent to 7% of the total wilderness areas. So 7% of wilderness becomes newly suitable for agriculture in the future.

Chris - So that means, given our track record for when an opportunity exists, we tend to find people exploiting it, up to 7% of the world's wilderness could be at risk?

Alexandra - Yes, if all of the areas that become newly suitable for agriculture in wilderness areas get converted to farmland, then up to 7% of total wilderness could be lost.

Chris - How bad did you assume climate change was going to have to get in order for the effects in your simulations to play out and therefore is it potentially preventable from that standpoint?

Alexandra - We looked at two scenarios of climate change, an intermediate scenario where we are able to cut our emissions of greenhouse gases, but still it results in a certain level of warming. And then we looked at a high emission scenario whereby essentially we do nothing, greenhouse gas emissions continue to rise and it's kind of the worst case scenario. Even with that intermediate scenario, there's still a lot of the wilderness at risk from being converted to agriculture, really just underscoring the fact that we need to do as much as we can to reduce those greenhouse gas emissions.


Liquid biopsy from the eye gives new health insights
Kez Latham, Anglia Ruskin University & Vinit Mahajan

We’ve long used eye tests as a way of checking the health of our vision, but increasingly the medical community is finding ways of using our eyes as a way of examining the health of the rest of our body. Will Tingle has been taking a look…

Will - As a keen bird spotter and cameraman, I pride myself on having tip top vision. And so any research into maintaining healthy vision is very important. In a minute, we'll hear how researchers at Stanford University have used fluid in the eye to age the eye and even spot the early onset of certain diseases. But before that, back in the here and now, what can you or I learn about our own body's health from our eyes? Well, that's why I went to Anglia Ruskin University to have a checkup.

Kez - Hello, I'm Kez Latham. I am Professor of Optometry here at Anglia Ruskin University.

Will - How would you be able to tell about any kind of general health condition by looking at my eye?

Kez - The eye is composed of lots of different components, each of which can be affected by systemic diseases that affect the rest of the body. And the particular thing that we are definitely looking for is the blood vessels. When we look at the back of the eye, we can see the blood vessels spread across the retina, and it's the only place in the body that you can see blood vessels and visualise them directly without having to open the skin.

Will - Where do I get started?

Kez - What we're going to do to start with is I'm going to do some tests of your visual function, just to see how your eyes are doing at the moment in terms of how they're performing. So what we'll do is I'll get you to look over at that letter chart in the mirror there, and I will get you to start on a line that's comfortable and then carry on reading down the letters as far as you can go.

Will - H, E, P, R, V.

Kez - Lovely. How about the ones below that?

Will - D, N, O, H, N, E.

Kez - So you have got exceptionally good vision there. In an ideal world, what I would like is another line underneath that you can't see, just so that I can tell I've got to threshold, but you are reading the smallest line of letters that I've got there, which is excellent.

Will - You can see listeners why I can't afford to lose this.

Will - Now, I've been put into a booster seat.

Kez - Okay. Now I'm just going to adjust the height of the chair a little bit here. This looks like quite an intimidating machine, but basically all it is is a bright light and a microscope that will allow me to look at your eye under magnification. So what I'm going to do first is I'm going to have a look at the front of the eyes and just check the structures at the front of the eye to see if there is anything we need to comment on, there. Next, I'm going to do the same again looking at the eyes now, but this time I'm going to hold up a lens as well and that lets me look through to the back of the eyes, here. That's really super. So looking at the health of the eyes both front and back, I'm not seeing any problems there either in terms of issues that relate to the eye or issues that relate to other things that are going on in the body. So I can give you a clean bill of health, but hopefully that hasn't put you off from having an eye exam. We generally recommend for most people that you would have an eye exam every two years as part of your routine health checks. For some people it does need to be more frequent. Often children, if their vision is changing quicker, or older people where there's more likelihood of things changing with time.

Will - Always good to have a clean bill of health, but say there was something wrong: what are your options? Well, to get a better look at your eye, there's two ways of doing things. The first is you can take a tissue sample from the eye. The issue with that, of course, is that your eye is non regenerative, so won't grow back. The other way of doing things is to take a sample of the eye's liquid. It's called a liquid biopsy. And that plays very heavily into what Vinit Mahajan and his team at Stanford University have been doing. Thanks to some remarkable advancements in protein mapping, they have been making some very interesting findings about our eyes.

Vinit - When patients come in for regular eye surgery, let's say cataract surgery, fluid is removed from the eye and frequently just thrown away. But we collected that fluid and used newer proteomics techniques. So proteomics means, instead of just measuring one protein, we can actually measure several hundred or even thousand different proteins.

Will - Is that the idea then, that you are less likely to damage the eye, but is the trade off there that you don't really get as clear a picture, if you'll pardon the pun, as if you use samples directly?

Vinit - So that's a great question. When we take a liquid biopsy, it means we're taking some fluid, almost like taking the blood, and our hypothesis was that the fluid inside the eye is going to be really enriched with lots of proteins coming from the retina and different kinds of tissues within the eye. All these proteins would collect in there like a bunch of proteins or little molecules in the ocean. But the real challenge is where did those proteins come from of the million different cells and different cell types? We don't know where those proteins came from, they're just a big collection. And so a postdoctoral fellow in the lab, Julian Wolf, worked out a computer method that combined proteins and gene expression maps, and he connected the proteins to this DNA map. And what that allowed us to do was actually figure out which cells the proteins had come from.

Will - That in and of itself is remarkable, but I guess the question is what's the use of that? What's the use of knowing what came from where?

Vinit - With so many proteins, and mapping them back to the cells, we could actually see which cells were involved in different kinds of diseases and in specific diseases. The types of proteins they leaked were different between diseases.

Will - Ah, so you can tell which diseases are prevalent by looking in the eye. This is almost like an early diagnosis system?

Vinit - Very much so. And we had some different kinds of surprises. In the case of diabetes, for example, we could see that in advanced diabetes there was a different kind of immune cell that really hadn't been implicated in the disease. That cell was starting to show up in the eye and cause damage. One of the really interesting things that we were able to do, because there's so much data here, is we were able to use artificial intelligence to create a biological clock for the eye. So we know that different parts of our body seem to age at different rates. So a lot of our patients are super healthy except for their eyes: it's as if their eyes had aged more than their muscles or their heart or their brain. And we found using the artificial intelligence algorithm that if we measured 26 proteins, we could predict the chronic logical age, the actual birthdate of our patient, just by measuring those proteins in the eye. But what was really interesting was, we all have this question that, if we have a disease, does that actually accelerate ageing? And what we found is that in diabetes and inflammatory eye disease, this biological clock was accelerated. So it was as if a patient's eye was as much as 30 years older than their chronological age.

Female Aedes albopictus mosquito on skin

26:38 - Am I breeding a master race of mosquitoes?

Would survival of the fittest cause chaos down the line..

Am I breeding a master race of mosquitoes?

James Tytko took on this question with the help of Laurence Hurst from the University of Bath...

James -  A thought to make your skin crawl. But could whittling away the measliest mosquitos be having an effect on the population? To help us find the answer, I got in touch with Laurence Hurst, Professor of evolutionary biology at the University of Bath.)

Laurence - Thanks James. In short, the answer to Sarah’s question is no: the notion that swatting a few mosquitoes will result in a master race of mosquitoes is not a problem I would worry about.
It is known that broad scale measures in which a sizeable proportion of a population are affected can cause rapid evolution. For example hunting for prized specimens of several species with large tusks or horns has led to selection favouring shorter horns or tusks. 
Likewise, broadscale administration of insecticides has led to the evolution of insecticide resistance (including in mosquitoes). 
The difference between these situations and the mosquito whacking by Sarah is the scale of the enterprise, meaning the proportion of the population affected.

James - So you’re right to deduce, Sarah, that swatting the weakest and least cunning mosquitos might mean the mutations associated with these characteristics are not inherited by as many future generations.

Laurence - However, the reason that this case is different from the others is that a minuscule proportion of the population is affected so the strength of selection operating on the average mosquito to be more cunning is itself miniscule. In a way, Sarah, you’ve answered your own question - if there are a huge number of mosquitoes where you live, the proportion that you’re likely to whack is tiny!


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