I was a lab rat in a sleep deprivation study
Norman Swan: Now, here on the Health Report we don't like to take important things like sleep lying down. Which is why we sent our producer and relatively new first-time father, Joel Werner, to experience what really happens when you don't sleep.
Joel Werner: Any number of things might keep you awake at night. Cramming for an exam, a party so good that no one wants to leave, sleep-training a baby or, in my case, Andrew Vakulin.
Andrew Vakulin: You'll arrive at the Woolcock Institute of Medical Research at roughly 6pm in the evening. You'll be greeted there by the research staff and the sleep technicians.
Joel Werner: Andrew's a sleep scientist, and tonight I'm going to be a lab-rat in one of his sleep deprivation studies.
I'm taken to my room for the night; double bed, camera on the ceiling, cameras on the wall, a couple of PA speakers. In one corner there's a desktop PC with a driving simulator steering wheel and pedals attached. I change into my pyjamas and before long I'm greeted by a woman pushing a trolley with a technicolour of wires draped over the top.
Eliza: My name is Eliza. I'm a sleep technician.
Joel Werner: I sit in a chair and Eliza stands behind me. She carefully parts my hair, feeling out different regions of my skull which from time to time she marks in crayon. These crayon Xs mark the spot where electrodes will be attached—16 in all.
Eliza: I'm putting all the electrodes needed to pick up signals from the brainwaves and from the other parts of the body. According to them we can score your sleep stages and obviously periods of awakeness.
Joel Werner: These electrodes are attached to my head and either side of my eyes, my jaw and my chest. They're held in place by this horrible conductive paste that takes days to completely wash off, but guarantees a good signal, which is important because these wires play a crucial role in sleep research.
Andrew Vakulin: It's the only way that we have to know when a person is actually asleep. The way we tell when a person is in different stages of sleep is through the different pattern of brainwave activity, essentially getting slower, followed by fast EEG and rapid eye movements when a person is in a dreamlike sleep stage.
Joel Werner: Most sleep research involves monitoring people while they sleep. But tonight's different. For this study I have to stay awake. And the team don't make it easy for you. You're not allowed caffeine or any other stimulants, and the lighting in the room is kept really dim to control the build-up of melatonin, a hormone naturally produced by your brain at night that helps trigger sleep.
So they're setting me up to feel sleepy. For this study they want me to be as tired as possible without actually falling asleep. But what happens if I do start to fall asleep? How do you keep someone awake in a sleep deprivation study?
Eliza: I can talk to you through the speaker, and if this one doesn't work, I might just sing…trust me, you're not going to sleep when I'm singing.
Joel Werner: What's your favourite song to sing to keep someone awake?
Eliza: 'Wake Me Up When September Ends.'
Joel Werner: I should have guessed!
Okay, so the idea is that I'll do a bunch of experiments now, while I'm fresh, and then I'll repeat the same experiments throughout the night as I'm getting more and more tired. The brainwave data gives a good indication of how tired I'm getting, and that'll be matched to what I imagine will be the serious decline in my performance throughout the night.
Andrew Vakulin: So the cognitive test battery begins with a subjective assessment of how sleepy you might be feeling. It's a simple one to nine scale asking you how sleepy you feel.
Joel Werner: Okay, so it's coming up to half-past eight. I'm feeling kind of all right, by the way, which you'd probably expect me to feel at half-past eight at night, being a human adult.
Andrew Vakulin: It then follows with a test called the PVT.
Joel Werner: I kind of like this next test, because it's not on the computer.
Andrew Vakulin: The psychomotor vigilance task, which is a fancy way of saying a simple reaction time test.
Joel Werner: I'm holding a piece of hardware and it's kind of like the size of an old VHS videotape and on this box there's a numeric display that randomly starts counting upwards in milliseconds. Your job is to pay attention to that display and press the button as quickly as you can as soon as the numbers start counting. My quickest was 190 milliseconds. Pretty proud of that. What I liked about the PVT was this immediate feedback on your performance.
Andrew Vakulin: Yeah, and I think by design it's the feedback you receive when you're pressing the buttons in order to continually monitor your performance and motivate the person to keep going. So if there is actual slowing of reaction time during sleepiness, at least the motivation is high to continue performing.
Joel Werner: But that can't be said for all of the tests, or indeed any of the other tests. Like denying participants coffee and keeping the lighting dim, these tests are designed to be boring. They're meant to be tedious to drain your concentration. As you get more and more sleep-deprived, this means that these simple tests of attention become really difficult. Like this working memory test.
Andrew Vakulin: That's a fairly tricky task. A lot of people find it difficult and it's basically asking you to remember the location of letters that appear on the screen.
Joel Werner: But if the task itself is difficult, then the instructions ore impossible.
Andrew Vakulin: If a letter A appears in a position on a screen…
Joel Werner: Remember the position of the first letter. Compare it to the position of all other letters…
Andrew Vakulin: You need to wait for another two letters before you have to respond…
Joel Werner: Press M on the keyboard for 'match'…
Andrew Vakulin: To where the letter A appeared, or 'no match'. So essentially you have to keep online the memory of where a letter appeared, but two letters behind, and you have to continuously update that information as the letters appear.
Joel Werner: Reading those instructions I got this wave of tiredness.
Andrew Vakulin: It's a complicated way to explain it, but…
Joel Werner: Can I just say, I read the instructions on the night, like two or three times. You just tried to explain it then. I still don't really know what was going on in that test. If it was what I think it was, it's so hard. It's like one of the hardest things I've ever done.
Andrew Vakulin: It is very hard. And that's the reaction we get from most people when we first introduce the test, and then they actually do it.
Joel Werner: And remember, you're trying to get your head around these super-difficult instructions in the middle of the night.
[Recorded during test] Okay, so this is one of those really difficult…keep a thing…I don't even understand the rules at this point. I was on track before, like I made mistakes but I kind of could follow the game. And this time, oh, I'm just guessing. If someone came in here now and said we'd offer you chance, I'd take that in a heartbeat, because I'd be struggling to get a pass.
Andrew Vakulin: You'll be surprised if we pull out your results, you would definitely be getting more than 50% except you're not actually realising that.
Joel Werner: Is it so hard though that you risk having a flaw effect in the data, that there's not enough variation downwards to see a difference between the person when they're not sleepy and the person when they're really sleepy?
Andrew Vakulin: Look, for the third sub task, yes, I think it's the most difficult one. But in the literature we mostly use the second one, so that's the most useful test and the most informative one. But we do the whole lot just to get the full spectrum of the test.
Joel Werner: Not only are you doing this really hard test, and not only is it the middle of the night, but you've got to remember they're doing everything they can to maximise your sleepiness, which is a fact not at all lost on me just before 2am.
[Recorded during the test] So one thing…I reckon if I could have a cup of coffee I would be so good at all of these tests. I live off coffee. I'd settle for like, instant and lukewarm water. I would drink a muddy puddle of lukewarm coffee out of the sink and I reckon I would be so good at these tests. [Laughs] But they're not going to let me have any coffee.
Andrew Vakulin: Following all of those brief attention vigilance tasks, you would have started a driving simulator test.
Joel Werner: This is the worst.
Andrew Vakulin: And that's a non-stop, one-hour driving test and it's trying to simulate night-time country driving.
Joel Werner: You have to keep the speed between 60 and 80 kilometres an hour, which given how sensitive the pedals are is kind of tricky, and you have to keep the car within the lane, which given how non-responsive the steering wheel is is also kind of tricky. Occasionally you come up behind a truck, but instead of looking to see if it's clear and overtaking like you might in real life, whenever you see the back of a truck, as soon as you see it you've got to slam on the brake. And your reaction time to do that is measured. If you go off the road, you crash. And you do that for an hour. For a whole hour.
Andrew Vakulin: By design it's quite monotonous, and mostly involves a rural highway, mostly straight, with only a few bends in it every now and then.
Joel Werner: [Recorded during test] That's the engine sound…and I crashed straight away. I'm not this bad in real life, promise.
Andrew Vakulin: It's really a challenging test, and most participants don't enjoy the experience.
Joel Werner: It was horrible. It was so bad, and doing that at two and three in the morning…Andrew! What are you doing to me?
Andrew Vakulin: That's right. You're lucky. Most people get an hour and a half versions.
Joel Werner: [Recorded during test] I think a big thing with this driving simulator is motivation, that's what I keep coming back to it. If I'm on a road at night I have this intrinsic motivation to not crash the car because I might seriously injure or kill myself. But here it's just like…what, okay. The worst that's going to happen is a red screen flashes up with 'Crash' and I have to start again.
Andrew Vakulin: Motivation is a big challenge when you're trying to do this type of experiments, when using any simulator. What we're trying to do is come up with tests that can be used clinically to assess people's alertness and vigilance. And in those type of settings I believe the motivation becomes less of a problem, because when people come to sleep clinics and they are assessed for daytime sleepiness they have much higher motivation to keep awake. These are clinical assessments and a lot of the time there's often motivation to do well because not doing well would possibly mean driving restrictions or it would dictate how the person is clinically managed. But you're right, it is a challenge, and it's something that we can't really safely overcome by sleep-depriving people or having people with severe obstructive sleep apnoea doing this type of work out in the real world.
Joel Werner: [Recorded during test] The thing that's been really been playing on my mind during the last ten minutes of this driving simulator is I don't even think there's a destination. I've got this fear that we're not going to get anywhere, that there's not going to be an end screen where you pull in to a nice motel or a roadside diner or something and music plays and they're like, 'Congratulations! You've reached your destination. That hour of your life was meaningful.' I've got a feeling it's just going to go back to the instruction screen or something. That's the kind of monotony that we're dealing with here. Literally on a road to nowhere.
Andrew Vakulin: It would have been the worst possible time in terms of your body clock and your drive for sleep. So that period between 1am to 5am is when your drive for sleep is the highest.
Joel Werner: [Recorded during test] Okay, so it's 3am, I've been awake for 21 hours. I'm feeling really tired now. I can feel my performance just dropping away, and I didn't think my performance was particularly good to start with. You can check the data but, you know, I can just tell you, it's had a huge impact on my attention and my capacity to think and yeah, I'm just really tired.
Andrew Vakulin: So at that point you have complete inattention, you have lack of concentration, and lack of ability to maintain vigilance for a prolonged period of time, which things like driving or operating any sort of machinery in a monotonous situation is quite dangerous. So really it's not that a person can't maintain vigilance for a short period of time but it's just that the risk of having a micro-sleep becomes a lot higher, and the number of times you have the lapses where essentially parts of your brain are starting to fall asleep becomes a lot more frequent.
Joel Werner: But this study isn't just about torturing me. You see, in this experiment I played the part of the healthy control. I don't have a sleep disorder, so by quantifying how sleep deprivation affects my performance, the research team have a yardstick to assess the group they're actually interested in; people with obstructive sleep apnoea.
Andrew Vakulin: Obstructive sleep apnoea is a common condition which is characterised by the collapse of the airway during sleep.
Joel Werner: Which means that people stop breathing on and off throughout the night.
Andrew Vakulin: A person with moderate to severe sleep apnoea would stop breathing more than 30 times every hour. If you're sleeping for seven hours you can see that's hundreds of times that a person has been woken up. Big fluctuations in their blood pressure, their heart rate and their oxygen levels, so it puts a lot of strain on the body and on the brain every night for years on end. And what we're trying to do with this particular study is we want to find out how patients with already existing sleep disorder like sleep apnoea, how they're affected by additional sleep deprivation. Because this type of sleep deprivation is not unrealistic whereby somebody might have to stay awake and perform things like driving a few hours beyond their normal bedtime.
Joel Werner: From research already done, we know that in general people with sleep apnoea really feel the effects of sleep loss. But there are exceptions. So some people with severe sleep apnoea might easily maintain alertness throughout the night. They might perform better than I did. There's more to it than just how severe someone's sleep apnoea is. And what else might be at play is something that this study hopes to tease out.
Andrew Vakulin: Just because somebody might have severe obstructive sleep apnoea it doesn't mean that they would have severe cognitive abnormalities as a result of that. We don't currently know just from a sleep study how bad somebody might be in terms of their performance and how sleepy someone might be if they are in a sleep-deprived situation. So that's why we are searching for new methods to try to assess patients clinically and be able to have more confidence in determining how sleepiness might impact sleep apnoea patients.
Norman Swan: Dr Andrew Vakulin is a Postdoctoral Research Fellow at Flinders University's Adelaide Institute of Sleep Health. And our victim was Health Report producer Joel Werner. And if you'd like to follow in Joel's sleepy footsteps and volunteer to be a control in Andrew Vakulin's sleep deprivation experiment, follow the link at the Health Report's website to see if you're eligible. I'm Norman Swan, and there's lots more that you can get on the Health Report's website, including podcasts. I'll see you next week.