Category Archives: General Interest

“Is Anyone Even Listening?” Can Journalism Make a Difference to Public Opinion?

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Flickr @Mick Baker(rooster)

How do journalists gauge the impact of their work?  More importantly, does their work have a positive impact on people’s perceptions of important societal issues such as climate change? Well people have to read the article for a start but let’s assume people do move past the title for now. You can look at comments, page views, discussions on a topic to assess a given article’s impact. However, it is very hard to say whether an article, or group of articles, were responsible for those changes observed. This is where an interesting new study by Dr Gary King at the University of Harvard comes in. Published in Science, the study attempted something rather impressive: a randomised controlled trial of journalism.

Randomised controlled trials (or RCTs) are typically run in medicine to ascertain whether a particular treatment has an effect on a studied illness. They have the advantage of being less biased than if researchers were to assign people to either the treatment or control group based on a whim. The randomisation process reduces the impact the experimenter, or clinician, may have on the efficacy of the treatment in question. This is exactly the approach this study took to understand whether writing on one of 11 key policy topics (race, climate, abortion, etc.) stimulated conversations on these topics. However, instead of a treatment they looked at whether the impact of writing an article on a societal issue (treatment) could lead to an increase in conversations about this topic on social media.

The researchers recruited 48 media outlets, of generally small size, to take part in their study to assess the impact of journalism on public conversations. To deal with journalists trying to ‘scoop’ one another and get the best story out there the quickest they used a process known as pack journalism. This also had the advantage of maximising the chance people would be speaking about their policy area on social media. Pack journalism is where multiple media outlets will collaborate and share sources and even quotes to ensure a story is reported and, importantly for political stories, reported in the same way. This is the approach the experimenters took, and they organised their recruited media outlets into packs of 2-5.  Each ‘pack’ wrote about the same policy area that was assigned based on their expertise and confidence in the chosen area.

The researchers then took two consecutively quiet news weeks. They randomised each pack to write about the specific policy area on one week and to produce their normal content on the other. This allowed the researchers to compare Twitter activity surrounding the chosen policy area (e.g. climate change) on both weeks. This was not a quick experiment to set up. As the authors state in the paper, it took almost five years to source, organise and oversee the news outlets involved.

When all packs had been randomised and completed their two-week experiment, the researchers assessed the number of Twitter posts across the two weeks. This, broadly speaking, allowed them to assess the impact of the policy-relevant article. Upon examining all of the packs together, it was found that in the first day after publication of the policy article the number of Twitter posts on this area increased by about 20% compared to the control condition. Over the course of the following week the increase in posts on the policy area was just over 10%. These effects are not big but, unlike previous estimates of the impact of journalism, we can be more convinced by their providence. It’s important to note that the media outlets included were small. Therefore, it shouldn’t be too surprising that the effects on Twitter would also be small as presumably these outlets have limited impact on global conversations. It’s also important to note that particularly quiet news weeks were chosen and, although this was practical, it likely influenced the effect.

To assess what the impact of a heavy-hitting media outlet, the researchers examined the change in Twitter posting following a story by the New York Times about fracking influencing drinking water. In this instance, although considerably less controlled, they found that the first day following the article publication, there was a 300% increase in Twitter posts concerning water quality and related topics. This suggests that with larger institutions the impact would be more impressive.

One question you may still be asking is whether this ‘intervention’ had an impact on people’s opinions. When the researchers compared the views expressed when the article was published, compared to service as usual, they found that there was a 2.3% shift in opinions to those expressed in the article. Now this is tiny, but it would be interesting to see whether larger effects could be found in heavy-hitting media outlets. Whether such a study is even possible remains to be seen.

The most exciting thing about this study is that it was possible to carry out an experimental, and relatively well-controlled, study to assess the impact of media reporting on social media conversations. The effects were small, and it was far from perfect (although impressive given how difficult it must have been to set-up), but it was an excellent proof of concept. Personally, science journalism can feel like it is speaking out to the converted but if research can validate that such articles are getting people talking, discussing, and (heaven forbid) changing their opinions on key area such as climate science then I’m sure many journalists would sleep much sounder.

Hey, look at that, I did manage to fit sleep into this article. Go me!

Inquisitive Tortoise

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Reference:

King, G., Schneer, B., & White, A. (2017). How the news media activate public expression and influence national agendas. Science, 358(6364), 776-780.

 

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Why we should be logging off from social media well before bedtime

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Photo @BrickinNick

So I am trying to experiment with shorter style articles a little bit. For those lovely people out there reading this, any feedback you have on this short pieces would be much loved! 

It is a fact universally acknowledged that a single man in possession of a smartphone must be in want of all of the notifications. I think that’s how that saying goes anyway…

It should come as no surprise that social media use is far from ideal for our mental health. It is an addictive and impulsive activity which can leave us constantly checking for any activity on our posts or feeds. It’s also a force for good but there is the need to understand where its use becomes pathological. For example, a study (poll) published earlier this year linked the usage of social media platforms such as Instagram to poorer mental health outcomes. It would be unfair to claim that social media can solely be blamed for mental health difficulties facing adolescents, but it is equally naïve to suggest it plays no part. How does sleep come into this equation then? Well, besides the sleep-interfering influence of the blue light emitted from devices to browse social media, it appears its usage can mess with our ability to drift off peacefully at night.

A recent study published last month by researchers at the University of Pittsburgh addressed this exact question: is social media usage before bed predictive of disturbed sleep? More specifically, they examined whether habitual social media usage in the 30 minutes before bed would interfere with the sleep of a large sample of American participants (n=1736). The researchers asked participants to report on their level of sleep disturbance over the 7 days and based on this they were identified as either having low, medium or high sleep disturbance. The participants’ social media usage before bed was rated as: rarely or very rarely, sometimes, often or very often. This was asked in respect to the past year.

So, what did the researchers find? Well, perhaps unsurprisingly, they found that social media usage 30 minutes prior to bed was predictive of poorer sleep. This was still the case when overall social media usage was controlled for which suggests that targeting social media usage before bed might be a useful strategy to improve sleep in habitual users. Interestingly, this research supports a well conducted study published last year in the Journal of Adolescence which also corroborates the role of night-time social media use on sleep quality.

However, why do we need to be careful about these findings? Well there are a number of issues I can think of which take away from this study. For example, a validated measure of sleep loss would have been more informative than the broad categories used to identify sleep disturbance in this study. Admittedly, the authors do highlight this in the discussion section of the paper too. Furthermore, the use of social media usage before bed in the last year is something which I imagine would fluctuate considerably. To me, it makes more sense to ask about social media usage in the past week if your sleep measure is concerned with this time-frame too. The best way to do this would be to track social media usage and sleep daily. You could not say that one causes the other with this approach but it would be more informative. Finally, it is unclear from this study whether social media usage before bed was responsible for the sleep disturbance. Poor sleep could be responsible for the increased social media use before bed or there might be some other variable entirely which explains both increased social media usage before bed and the disturbed sleep.

Of course, this work should not be surprising to any one of us and it makes reasoned sense that using a device just before bed is likely to interrupt with your ability to sleep properly. I think the merit of this paper is that it reminds us that perhaps a blanket ban on social media is not needed. If social media usage can be curtailed when we should be doing more important things (e.g. sleeping) then perhaps this can start to reduce the negative impact it has on our mental health. As with all research this is just a tiny part of a much bigger picture but it is an issue which will only increase – not decrease any time soon.

Until that future research is forthcoming, avoid endlessly scrolling for likes before bed if you want to be on peak witty tweet form the next day. Or, you know, you just want to feel less tired. Either is fine.

Inquisitive Tortoise

References

Levenson, J. C., Shensa, A., Sidani, J. E., Colditz, J. B., & Primack, B. A. (2017). Social Media Use Before Bed and Sleep Disturbance Among Young Adults in the United States: A Nationally Representative Study. Sleep, zsx113.

Woods, H. C., & Scott, H. (2016). # Sleepyteens: social media use in adolescence is associated with poor sleep quality, anxiety, depression and low self-esteem. Journal of adolescence51, 41-49.

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Twitter, chronobiology, Trump, and Questions You Didn’t Realise Needed Answering

Twitter

Tweets in their natural environment

Scientists are a weird bunch. We spend our lives getting very excited about niche and bizarre things. As a result we have a habit of spending our free time trying to get others to understand our excitement. There are also times when these strange topics align with the wider interests of the general population. For example, we may ask the big questions which are important and crucial for a functioning society.  However, there are also times when we wonder whether we can put to bed (pun fully intended) whether Donald Trump is a keyboard bashing night-owl or a keyboard bashing early riser. But you don’t want to know about that, right?

Well in case you do, luckily one rather eminent (and fun) chronobiologist felt that it was appropriate to answer that singularly important question. Don’t worry, we’ll come to why this is actually an important question later. Now, social media can be used to identify a lot about us and it is not that hard to use all of the data from platforms such as Facebook to track (loosely) a friend’s sleep. It also seems that social media can also be used to determine your activity patterns and assess biological rhythms besides sleep.

For anyone who has ever logged onto Twitter, you are probably aware of the late-night tweets of @realDonaldTrump and their varying levels of coherence. However, do these few late-night tweet fests correlate with the normal chronotype of the president? Firstly, what do we mean by chronotype? Chronotype is the term used to refer the times at which individuals tend to be awake and active. For example, you are probably familiar with the concept of morning and evening types. These relate to our internal body clocks and govern whether we are happy to work late or decide to retire early on. Although society seems to associate the early birds with success, there are issues when our body clocks do not align with the pressures of a society which is regimented and requires us to wake up at the set times – whether for work or school. In fact, there is growing and convincing evidence to suggest that delaying school start to fit with adolescent’s chronotype would be beneficial .

Typically, we assess chronotype through the use of questionnaires or by tracking activity of an individual over an extended period of time. Yet, how can we assess Trump’s chronotype if we can’t handily give him a detailed questionnaire or activity tracker? Simple, we mine his Twitter data and assess his activity based on tweets. Luckily for us, the current President likes to tweet – a lot. This gives interested researchers plenty of time points to assess how his activity changes over time.

Professor Roennenberg applied his analysis to 12,000 tweets from December 2014 to March 2017. Out of all these tweets, there were three main devices they were sent from: an android device, an iPhone device, and other miscellaneous devices. The majority of the tweets were from the android device and it was suggested that the android phone was likely Trump’s personal phone. With all of this rich data, it was possible to identify the peak tweeting periods and how these changed month by month over the 830 days of tweets analysed.

So, what was found? Well, contrary to expectations, it appears that Trump is actually a consistent morning type. There was a clear patterning in the peak times at which he was tweeting. There tended to be a peak in the morning between 5:10am-9:40am (around sunrise) and a peak in the evening 5:00pm-11:00pm (around sunset) that shifted through the year with the change in hours of sunlight. For example, during the summer months, Trump had peaks of tweets earlier in the day and during the winter months these were later during the day. This is a clear pattern of tweeting which fits seasonal changes in light levels.

By contrast, tweets sent from the iPhone showed peaks of activity between 8am and 4pm which highlights a mixture of working hours and staff activity. It was hard to assess circadian patterning using this account as it appeared that multiple people contributed to these data. The ‘MiscDevices’ showed peak activity during between 8.20am and 4.50pm which suggested that this was used during the working day. On the basis of this, the study showed that it is possible determine patterning of activity over a long period of time from tweet data alone. In this case, it shows the peak tweet activity for Donald Trump and in turn this allows us to determine (roughly) his chronotype and probable sleep period.

Why is this worth reporting on? Honestly, to begin with, it is hilarious. I love the author of this piece for taking a ridiculous question and applying the full force of the scientific process to it. Personally, I think this research should be considered for an IgNoble award. However, when you move past the fun of this piece it also highlights a powerful research tool. The use of social media data in research is increasing and there are some great and novel studies which have taken this approach. This method can allow us to, as in this paper, track the sleep, circadian and seasonality patterns of an account – provided it has sufficient data points. In this case, Trump was a perfect proof of concept. Moreover, this technique could also be used to not just track sleep patterns but also be mined for content. Roennenberg makes a quick allusion to the content of Trump’s early morning tweets but this approach has implications for research. This data mining of social media approach would enable questions to be asked not just about the patterning of account activity but also how this activity might be associated with, for example, mental health. To me this is an exciting tool which has considerable potential albeit with significant ethical concerns attached.

Until then we can use this technique to open a window into the life of the rather prolific tweeter that is Donald Trump. Now don’t tell me science isn’t tackling the big (so big) questions.

Inquisitive Tortoise

References

Roenneberg, T. (2017). Twitter as a means to study temporal behaviour. Current Biology27(17), R830-R832.

Berry, N., Lobban, F., Belousov, M., Emsley, R., Nenadic, G., & Bucci, S. (2017). # WhyWeTweetMH: Understanding Why People Use Twitter to Discuss Mental Health Problems. Journal of medical Internet research19(4).

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The Human Microbiome: A Teeming Ecosystem Within Your Own Body

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Meet the neighbours: here’s Paul, Sandra, Jack, Lily, and so on and so on

“Why have you stopped speaking about sleep?”

“I can have other interests!”

“I don’t know man, you’ve changed. Why should I care about anything you have to say now?”

“…”

What is a microbiome? That’s a very good question. For a start, it’s not some artificial eco-project which is attempting to save the world or even, I’m sorry to disappoint you, some form of miniaturised food either. The microbiome refers to the different ecosystems of microbes which we have all over our body. These microbes use us as their home and in turn can benefit us, live mutually alongside us, or cause us problems. They form a complex and important addition to the multitude of cells which make up our own bodies and recent estimates suggest there are as many microbial cells as there are cells which make us up. One particularly well studied microbiome requires us to get to the bowels of every one of us. Quite literally. This ecosystem is the one we find in the human gut. This microbiome has also attracted a lot of interest because of its impact on the brain known as the gut-brain axis (more of this in the next article). In general, microbiome research is still in its infancy and everyone wants a piece of it. This is likely because it seems to play an important role in a number of different mental and physical functions and there is even talk of this ecosystem containing our ‘second genome’. So, what does this all really mean and why should we care?

The ecosystem of microbes (e.g. bacteria, fungi and viruses) which live alongside us help to break down food, protect us from invaders and produce nutrients necessary for our health. One good example of the benefits of the gut microbiome is evident in looking at babies and breast milk. There is a particular group of complex sugars known as human milk oligosaccharides (HMOs) which make up a considerable amount of breast milk. However, despite their prevalence in mother’s milk babies do not have the ability to break them down. This should make them rather useless to the baby and a waste of resources for the already energy-stretched mother. Indeed, this finding initially stumped scientists as breast milk has evolved to be the perfect nutrition for an infant – why should it contain something a baby cannot digest? However, it seems that a specific HMO, B. infantis, in the infant’s gut is the intended target of this sugar instead. B. infantis can break down the complex sugar and in turn flourish in its presence. Why is this a good thing? Well it is hypothesised that the healthy colony of B. infantis force out more harmful bacteria from making their home in the infant and act as decoys for potential pathogens keen on harming the bleary eyed newborn. Moreover, this rather nifty bacterium promotes gut health and has anti-inflammatory properties. The mother’s breast milk helps ensure this positive bacterium survives and in turn the bacterium ensures the baby is more likely to survive.

How about in adulthood though? What are some of the functions of our microbiomes scattered around our body? Well the ‘second genome’ seems to play an important role in our behaviour and health. For example, in a series of experiments which looked at the effects of transferring human bacteria from obese and lean twins to germ-free mice. The researchers found that when the mice were given the bacteria from the lean twin they stayed the same weight; however, when the bacteria were from an obese twin they gained weight. This is despite the mice all being given the same amount of food to eat. Furthermore, it seems that lean mice which live together with obese mice have the capacity to transfer their ‘healthy’ microbiome. Yet, the obese mice could not transfer their bacteria to the lean mice. This, it is argued, was because the obese mice have a lower diversity of bacteria within their gut microbiome and this leaves space for new species (found in the lean mice) to colonise and flourish. The bacteria of the lean mice tend to win in these situations. However, the positive effect of the transfer of bacteria on the obese mice is not universal. It requires that the obese mice have the right diet in the first place. If the obese mice were fed a westernised diet high in junk food and saturated fats then the positive impact of the bacteria from lean mice was non-existent. The positive effect was seen only if the obese mice were eating a healthier diet from the start. It could be speculated that this is because the high-fat diet does not promote the survival of the bacteria found in the lean mice’s gut. This opens up the exciting possibility that our gut bacteria are having an important role in our weight and health. It is possible that a particular diet might be able to promote the colonisation of new species of bacteria within our microbiome and, in turn, help promote weight-loss.

The human microbiome has also been linked to illnesses characterised by disruption of the normal functioning of the immune system. It has been argued that autoimmune conditions such as crohn’s disease and ulcerative colitis may be linked to a failure of the gut microbiome to develop appropriately during childhood. It’s claimed that this is because of the increased use of antibiotics and high-fat, low-fibre, diets which characterise the western world. The presence of these environmental factors reduces the diversity of the gut microbiome and interferes with the normal process of teaching the immune system how to function. In addition, certain species of bacteria appear to have anti-inflammatory effects which researchers are trying to capitalise on as treatment possibilities for inflammatory bowel diseases (IBD).

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Understanding the gut microbiome holds promise for the treatment of IBD.

So, it looks like the gut microbiome can have profound effects on our health. With this in mind, can we change our gut bacteria? Well, there are a lot of potential problems with this. Our gut microbiome seems to be influenced by the microbes which our mother and father impart upon us at birth (particularly from our mother). However, during infancy we go through a fluctuating development of our microbiota and the constituent microbes change considerably as we progress to adulthood. This is why some researchers believe that it is during early childhood that any attempts to modify the microbiome will be most effective. It is during this period of flux for our plucky neighbours that attempts to modify the microbiome are likely to be most effective and long-lasting. If there is a link between our gut microbiome and autoimmune disorders it is likely that this stage of our development is critical to reduce the risk of IBD. However, during adulthood there is more stability of our microbiome. The gut microbiome appears resilient to change following diet in the short-term but it is possible that long-term dietary changes might create a more favourable environment for new microbial species. For example, when the initial gut bacteria colonise an area they change the environment so it is more beneficial to their survival compared to other species. Therefore, although there is an obvious benefit to improving our diet, whether this boosts our microbiome is not quite known yet.

The human microbiome is not confined to our guts but our mouths, throats, noses, genitals and skin, to name but a few, are also examples of microbiota within the human body. For example, we contain our own signature of gut bacteria on our hands although there is considerable variation between individuals and even between our own two hands. It is not known exactly what is responsible for this variation but a mixture of genetic and environmental (e.g. hand-washing, climate, sex, etc.) factors seem to be important. It is also possible to shift the microbial constitution of someone else’s hand through direct contact – a handshake. How long the changes remain, however, is not clear and it is likely that the ecosystem carved out by your own skin microbiome favours the microbes usually residing on and in your skin. This is perhaps something to keep in mind when meeting your hero and desperately trying to shake their hand. It may be that greatness can rub off on others through a firm handshake. Also, in a similar manner to the gut microbiome, the composition of microbes on the skin has also been linked to health and disease. A good example of this is psoriasis which involves the development of plaques on the skin of those affected. In a similar manner to the gut microbiome, it is likely that a wider diversity of the skin microbiome has anti-inflammatory properties which are protective against auto-immune disorders such as psoriasis.

So, does this mean that all of us need to alter our eating habits to ensure that our gut bacteria are working at their best? Probably not for the time being. This is the nature of any research in its infancy and beware of any book or news article which claims that changing your microbiome through diet will improve your health. Despite all the excitement surrounding the microbiome at the moment we need to be aware of the limitations of research which seems to be ‘in vogue’. There is plenty of high-quality research which is being carried out in this area but much of this research is conducted in mice and the human research is largely correlational. It’s currently difficult to infer cause and effect – does poor health causes changes in our microbiome or vice-versa or, more likely, is it a mixture of the two? We need to be aware of how little we really know about the microbiome at this current moment. For example, we don’t know what a healthy microbiome looks like. Is there one individual ‘optimal’ combination of microbes to strive for or is it that a greater diversity, in general, is best? There seems to be some evidence of ‘types’ of stable microbiomes in adults but this work is still in development. There is also some evidence which links a healthier, fibre-rich, diet to a greater diversity of microbes within the gut microbiome but it is unclear what impact this has on health and behaviour. Currently, the Human Microbiome Project is trying to understand what the normal limits of the microbial ecosystems look like and how they might be implicated in health and disease. Although they started in 2008 and have received considerable funding there is still a long way to go before we see these findings directly influencing health. There is plenty of excitement about the microbiome but it is still early days for this field. For now, the human microbiome holds a plethora of secrets yet to be unlocked about the teeming, fluctuating, and enigmatic organisms we share our body with.

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References / Recommended Reading:

http://www.nature.com/news/bacteria-from-lean-cage-mates-help-mice-stay-slim-1.13693#/ref-link-1

https://www.nature.com/articles/srep32484

http://www.nytimes.com/2013/05/19/magazine/say-hello-to-the-100-trillion-bacteria-that-make-up-your-microbiome.html

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3535073/

https://www.nature.com/cti/journal/v5/n4/full/cti201612a.html

http://www.nature.com/news/scientists-bust-myth-that-our-bodies-have-more-bacteria-than-human-cells-1.19136

http://hmpdacc.org/ (Human Microbiome Project Website)

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3577372/

https://www.ncbi.nlm.nih.gov/pubmed/20668239/

http://www.newyorker.com/tech/elements/breast-feeding-the-microbiome (An extract from the amazing Ed Yong’s book, ‘I contain multitudes’)

http://www.radiolab.org/story/funky-hand-jive/ (A hilarious and brilliant podcast on this topic)

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Filed under General Interest, IBD, Microbiome, Psychology

Can we modify specific stages of sleep to improve our memory?

Sleeping Kitten

Our memory is far from perfect. You have probably gone into another room and completely forgot what you went in there for. You stare into space and hope it will come back to you. Was it to pick up keys, tidy something or speak to someone? Nope, it just doesn’t come and you walk back slightly dazed and annoyed at your ailing memory. This is just a small example of the times our memory fail us during our day-to-day lives. However, what if we could improve our memory while we sleep?

Sleep is important. I’d like to think that I’ve impressed on you all by now. It protects us from certain metabolic disorders, keeps us alert to our surroundings and maintains our mental health and overall mood. There is some evidence to suggest it helps the brain’s natural waste disposal systems but that’s still in its very early days (despite some bold claims in the mainstream media). All of these areas have garnered substantial interest from scientists but memory is the one we’ll be focusing on. Typically, studies show that our ability to lay down new memories improves after a simple nap or a good night’s sleep. This, of course, isn’t always practical but it provides us some insight into what is happening in the brain when we drift off. It also should remind anyone revising for exams that sacrificing sleep is a false economy – unless of course you need to cram. Sleep can only help you so far there.

The link between sleep and memory raises an interesting question: what is it about this period of seeming inactivity that may help improve our memory? Sleep is far from a unitary construct and if we could identify the specific stage or stages which are crucial for memory then perhaps we could capitalise on this. We go through different stages of sleep, broadly, broken down into Non-REM and REM, and these are made up of different brain cell oscillations (see picture below) within the brain. Through probing the different stages, we can start to understand which are more important for memory. So, what are some of the candidates for sleep’s role in memory? The main contenders are sleep spindles and slow wave sleep (although REM has also been claimed to play a role in memory too).

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Stages of sleep recorded from EEG

Sleep spindles are characteristic of sleep stage 2 and are brief bursts of activity seen when using a brain imaging device known as electroencephalography (EEG). Imagine one of the funny caps with electrodes protruding out as you probably have a good idea of the typically EEG setup. Sleep spindles have been claimed to be important for memory consolidation and form a key part of one of the main hypotheses for how sleep might boost our memory. More specifically, it is argued that sleep spindles may facilitate the movement of memories from temporary consolidation in a part of the brain known as the hippocampus to the rest of the brain. Interestingly, sleep spindle activity correlates with performance on memory recall following sleep, and spindles show an increase following learning. The activity location of the spindles seems to be associated with the location of brain activity engaged during intensive learning of a specific function. As a result, some have suggested that sleep spindle activity may be used as a marker for learning potential (Fogel & Smith, 2011). However, the reality is likely more complex than this. Nonetheless, it does point towards spindles as a potential marker of memory consolidation during sleep.

In addition, slow wave activity (SWA) has also been shown to be important for memory. These are the slow (1Hz) oscillations characteristic of deep sleep. It has been this stage of sleep which has primarily been targeted to improve memory in previous studies. More recently, slow wave activity and sleep spindles have been successfully modified through the use of electrical stimulation of the scalp, drugs, playing sounds throughout the night (specifically timed and not so loud as to wake the participants), and even by presenting odours present at the time words were initially memorised.  These manipulations have been shown to improve memory and it seems it does this by increasing the amount of slow wave activity and sleep spindles. This work, although still in its infancy, suggests that it possible to stimulate specific features of sleep and, in turn, improve a vital cognitive function. It is at this point that a recent study in the aptly titled journal ‘Sleep’ comes in.

A group at the University of Helsinki in March this year (https://www.ncbi.nlm.nih.gov/pubmed/28364428) built on these previous findings by trying to identify a way to automate this process of stimulating slow wave activity. The success of this aim would increase the ease of introducing this technique into a home-setting and allow for the modification of sleep coveniently. The group decided to try to find a way to target sound stimuli to slow waves automatically in the hope of improving specific types of memory without affecting the sleep quality or mood of the participant. This is crucial as it is little use improving memory and modifying sleep if it causes other problems at the same time.

How did the researchers attempt to automate this process? They recorded electrical activity from the brain during sleep and were able to identify slow wave activity automatically by looking out for a specific frequency band (i.e. how often a waveform occurs over a set period of time). Whenever slow wave activity, indicative of deep sleep, was identified in the sleeping participant, a computer program sent a message to another device which played a brief sound. This meant that the sound was played just after a period of slow wave activity. Following this, there was a break of least 2 seconds between each sound being played. The loudness of the noise was changed automatically in response to cues from the participant. For example, if it seemed that the participant was waking up then the sound was lowered.

With the system in place, a total of 15 participants were invited into the lab for three days, each day separated by a week, to test out the automated approach to increase slow wave activity. The first day involved a familiarisation night so that the participants could get used to sleeping in the lab and with the equipment setup. During day two, one half of the participants heard the automated sounds and the other half did not. This was then switched for the third and final day. This allowed the researchers to compare performance on memory tasks when the sounds were not played and when they were not.

So, what did they find? Firstly, and importantly, they showed that their automated enhancement of slow wave activity was successful and viable. It managed to increase slow wave activity and sleep spindles. Moreover, the automated sounds were also found to increase memory overnight. They showed that word-pairs could be enhanced by playing a relatively quiet sound during slow wave activity. The interesting outcome of this study is that the possibility of having an automated system which people could use at home to boost memory. For populations who have poor memory this could hold promise as a therapeutic tool. It is a while off anything like this being available but it tells us something about how sleep contributes to memory and the potential ways we can exploit this in the future.

Although it is still unclear how exactly sleep is linked to memory, it is research like this which is starting to uncover that our brains are anything but quiet during sleep. Although there is likely to be no device which will improve your memory overnight on the market any time soon, scientists are working on the concepts necessary for this to become a reality. For now, perhaps you could try writing down what you’re about to do before walking into a new room?

ResearchBlogging.org Leminen MM, Virkkala J, Saure E, Paajanen T, Zee PC, Santostasi G, Hublin C, Müller K, Porkka-Heiskanen T, Huotilainen M, & Paunio T (2017). Enhanced Memory Consolidation Via Automatic Sound Stimulation During Non-REM Sleep. Sleep, 40 (3) PMID: 28364428

Additional References

Fogel, S. M., & Smith, C. T. (2011). The function of the sleep spindle: a physiological index of intelligence and a mechanism for sleep-dependent memory consolidation. Neuroscience & Biobehavioral Reviews, 35(5), 1154-1165.

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Sleeping Cat (Header)

Sleep Stages (Body Text)

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Should We Be Napping More?

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Please tweet me and other sleep scientists at the University of Manchester your sleep questions using the hashtag above! #msf16

 

“Why don’t you just take a nap if you’re so tired? It’ll probably help and give me a break from your whining…”

“I can’t nap! I feel all groggy after a nap. Besides, I find the complaining is helping me through the fatigue”

“…”

Napping is something which divides opinions. It’s no yeast-based snack featured heavily in the news recently, but there are certainly strong proponents of the will-nap and won’t-nap camps. However, what does the research say about napping? Can it help us get through the day and feel better able to deal with the challenges which face us?

Firstly, sleep in general is something taken for granted. We’re all guilty of it. On average we need about eight hours sleep, with some individual variation, but yet on average the general population is shy of this by one and a half hours. Although we should really be focusing on ensuring we get the right amount of sleep, at the right time, for our own body, it may be that napping may alleviate some of the symptoms of poor sleep such as fatigue and mood changes.

Regardless of your own personal views on this topic, it seems that naps are effective in easing fatigue, increasing our concentration, improving mood and even reaction times. Interestingly enough, even a relatively short nap of 10 minutes has been shown to improve alertness and decrease feelings of fatigue. Moreover, the positive effects were more immediate than for short (e.g. 10 minutes) compared to longer naps (e.g. 30 minutes). On a more practical level, there is evidence to suggest that a 15-minute nap could help reduce the number of road accidents.

It is key to remember that napping is a broad term. The short periods of sleep, typically during the day, which we call naps can vary in their duration and in the type of sleep which an individual might get. This could start to explain why some people love to nap and others despise it, but more on that later.

Great, so we should all be trying to sneak a nap in during office hours? Well you might want to think about the time at which you take a brief trip into sleep. During the average day, we tend to have a post-lunch dip in concentration and energy which lasts from around 1pm-4pm. Research has found that naps, whether brief or long, are most effective when taken during this post-lunch dip.

At this point, it looks like napping, albeit at the right time, can have some benefits. Yet, why might some people not actually end up benefiting? There are two possible explanations for this.

One is that disgruntled nappers may sleep for too long and focus on the grogginess upon awakening. The longer an individual naps for, the more likely they are to feel sluggish upon awakening – also referred to as sleep inertia. The positive effects of longer naps are felt for longer, but it takes longer for them to be realised.

Another explanation may depend on how serious nappers are about well… napping! Those who have more experience with napping were found to benefit more from a brief nap than those who don’t nap. This suggests that napping might have a greater effect for those who do it more frequently. Then again, it may simply be that habitual nappers are habitual because of the fact they benefit from those short slumbers. Rather than experience, it may just be individual differences. This is a question we don’t have the answer to quite yet before you try to discipline yourself into daily naps!

So what’s the verdict overall? Napping can be beneficial and if you can work through the sleep inertia longer naps will have a longer effect on your functioning. That been said, even naps as short as 10 minutes can have a positive impact. There are individual differences in our response to napping but that shouldn’t hinder us from feeling rested. Napping may be useful to ease fatigue but the ideal way to manage daytime sleepiness is to make sure you are getting better quality sleep during the night. Naps should not be a substitute for poor sleep if it can be helped!

One more thing…

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Time for ‘shameless plug time’. I am volunteering with the Manchester Science Festival as part of their sleep installation known as the Chronarium. It aims to immerse participants in specially selected lights and sounds which are used to promote relaxation and sleep. Would-be nappers are suspended in sturdy hammocks and are gently rocked into a peaceful state while the hustle and bustle of the busy shopping centre outside the fabric walls feels like a distant world.

The Chronarium is currently open as part of the Manchester Science Festival and can be found in the Manchester Arndale Centre. It is open until the 30th October. For those Mancunion readers amongst you, it’s free entry and well worth trying out!

Inquisitive Tortoise

References:

Tietzel, A. J., & Lack, L. C. (2002). The recuperative value of brief and ultra‐brief naps on alertness and cognitive performance. Journal of sleep research, 11(3), 213-218.

Brooks, A., & Lack, L. (2006). A brief afternoon nap following nocturnal sleep restriction: which nap duration is most recuperative?. SLEEP-NEW YORK THEN WESTCHESTER-, 29(6), 831.

Reyner, L. A., & Horne, J. A. (1997). Suppression of sleepiness in drivers: combination of caffeine with a short nap. Psychophysiology, 34(6), 721-725.

For more info on the Chronarium:

The Chronarium Sleep Lab

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Can a Lack of Sleep Kill You?

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“Have you forgotten so easily?” the subject asked. “We are you. We are the madness that lurks within you all, begging to be free at every moment in your deepest animal mind. We are what you hide from in your beds every night. We are what you sedate into silence and paralysis when you go to the nocturnal haven where we cannot tread.”

Surviving participant from ‘The Russian Sleep Experiment’ in the late 1940s. This volunteer went 15 days without sleep.

Before you start looking over your shoulder for the demonic presence presented above, don’t be alarmed. The quote above is from a piece of horror fiction from a website called Creepy Pasta and is completely fake. I hope.

I wanted to start with this as Halloween is fast approaching and I thought that a more fiendish sleep myth was worth looking at. Can a lack of sleep be directly responsible for your death?

A complete lack of sleep is something new parents and those of us with upcoming deadlines may know all too well. It’s draining, depressing, and leaves us eyeing up any available floor space as prime real-estate for your exhausted brain and body.

We have already looked at the effects of getting too little or too much sleep in my earlier post, but not the more extreme side of this. Research conducted with animals at the end of the 19th and the start of the 20th century suggests that not only is sleep important, but that it is vital for sustaining life. In experiments which looked at puppies, cats and rats, it was found that after anything from a few days to around a month of no to very little sleep would lead to death in these animals. This should be taken with a pinch of salt as animals tend to have to be forced to stay awake, and this is typically through stressful contraptions.

How about humans though? What is the longest any one has gone without sleep and gone on to tell the tale?

Well there are two main sources which we can look at. Firstly, there are the people who have willingly deprived themselves of sleep and secondly we can look at people who no longer sleep. Starting with those strange souls who willingly deprive themselves of shut-eye we can look towards a reality TV-show, our trusty sleep-deprived student population, and a couple of radio DJs to start to answer this question.

People are seemingly keen to show off their endurance when it comes to neglecting or overindulging in the necessities of life. Some will do it to win a fabulous prize and others because… Well I’m sure they know why they do it. Anyway, one such contest is relevant here.

The reality TV show ‘Shattered’ provided contestants a chance to win £100,000. All they had to do was be the last one standing in a competition to stay awake the longest. The show was screened on channel 4 in 2004 and its questionable premise didn’t put off a group of eager participants keen to deprive themselves of sleep for fame and glory. The winner stayed awake ultimately for 178 hours. The show capped the length of time participants could remain awake for, and a number of increasingly soporific tasks eventually weeded out one overall victor. If you are interested in this ‘experiment’ you can watch it here.

However, 178 hours was meagre compared to the next contenders. It seems that at the end of the 1950s and early 1960s there was a surge in radio DJs attempting to promote themselves and further their careers in bizarre ways. Collectively they felt that staying awake and parading their increasingly fatigued selves in a department store window was the way to do this.

Our first member of the media to tackle a lack of sleep was a young radio announcer referred to as W.A. He managed to stay awake for a total of 220 hours or just over 9 days. Previously, another radio DJ by the name of Peter Tripp had managed to last 201 hours without sleep. Finally, our last radio DJ, Tom Rounds, shortly after moving to Honolulu in 1959, managed to stay awake for 260 hours and appeared to suffer no long-term effects of his sleep deprivation.

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Is sleep necessary for sustaining life?

However, their collective records did not last long. The radio DJs were swiftly beaten in 1964 by the efforts of a student called Randy Gardener. Randy was a 17 years old student who felt that he could provide something more interesting than a papier-mâché volcano to present at his school’s science fair. He went without sleep for 264.4 hours, which equates to about 11 days and 24 minutes, and supposedly suffered no long-term problems. The often cited report claims that Randy suffered no ill effects of his experiment, yet others claim he experienced hallucinations, paranoia, fluctuations in mood, and problems in short term memory and concentration. The latter would fit with what we know about acute sleep disturbances (Petrovsky et al. 2014; Kahn-Greene et al., 2007).

Interesting, there have been reports of others having seemingly beaten Randy’s record and by a sizeable margin. These have not been validated in part due to scientists and those responsible for recording ‘world records’ not wanting to encourage these record attempts. For example, the Guinness Book of World Records no longer prints updates to the sleep deprivation record since Randy Gardener.

Okay, so far it looks like we can go a long time without sleep and survive. This seems to suggest that although we need sleep (try not sleeping tonight if you’re not convinced), an acute loss is not going to be directly responsible for your demise (but likely indirectly).

Let’s move to the second source of human sleep loss evidence now: those who no longer possess the ability to sleep.

We’ve already looked at people who for one reason or another have decided to willingly deprive themselves of sleep. Yet, for some the ability to sleep is lost. Although insomnia fits this bill, in this case we are referring to the rare genetic brain disease known as Fatal Familial Insomnia (FFI). As the name suggests, this disease is associated with a prolonged and severe insomnia which ultimately leads to death. There are some experimental treatments to delay the fatal consequences but these may only provide a couple of extra years at best.

Fatal familial insomnia is a prion disease. Prions are misfolded proteins that cause damage to the brain as they clump together. In the case of FFI, these prions clump at a specific part of the brain known as the thalamus. The thalamus plays a prominent role in regulating sleep and in coordinating the brain as it drifts deeper and deeper in somnolence. As a result, as the damage to the thalamus accumulates this unsurprisingly leads to worsening insomnia.

These individuals seemingly sleep very little or not at all and will survive from a few months to about several years following the presentation of symptoms. The course of this illness would suggest that it is possible to die from sleep deprivation, at least at extreme durations. However, we can’t say that it is the complete lack of sleep alone which kills those with FFI as damage to the thalamus affects other functions rather than just sleep. Moreover, as this disease is so rare that it would be wrong to make a firm conclusion based on this alone. More likely, it seems that the lack of sleep contributes significantly, but not completely, to the decline of those with this illness.

So, what’s the verdict on sleep deprivation being capable of deadly consequences?

The research in animals suggests it can be but the human studies tell another story. Although common myths and horror stories might like to toy with our inbuilt fears about the unknown, it looks like a lack of sleep will not directly lead to your death. Instead, the host of effects already covered may be the true driver between mortality and sleep loss.

Inquisitive Tortoise

References:

Luby, E. D., Frohman, C. E., Grisell, J. L., Lenzo, J. E., & Gottlieb, J. S. (1960). Sleep deprivation: effects on behavior, thinking, motor performance, and biological energy transfer systems. Psychosomatic Medicine, 22(3), 182-192.

Petrovsky, N., Ettinger, U., Hill, A., Frenzel, L., Meyhöfer, I., Wagner, M., … & Kumari, V. (2014). Sleep deprivation disrupts prepulse inhibition and induces psychosis-like symptoms in healthy humans. The Journal of Neuroscience, 34(27), 9134-9140.

** http://creepypasta.wikia.com/wiki/The_Russian_Sleep_Experiment

**In case you find yourself wanting to read the rest of the fictitious foray into the effects of sleep deprivation.

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Why Do We Sleep? Keeping Those Pesky Excitable Neurons in Line

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“The subject of sleeplessness is once more under public discussion. The hurry and excitement of modern life is quite correctly held to be responsible for much of the insomnia of which we hear: and most of the articles and letters are full of good advice to live more quietly and of platitudes concerning the harmfulness of rush and worry. The pity of it is that so many people are unable to follow this good advice and are obliged to lead a life of anxiety and high tension. Hence the search for some sovereign panacea…” (British Medical Journal, SEPT. 29, 1894, Sleeplessness)

I am sure until you glanced at the date you could easily be forgiven for thinking this quotation was written only last week. The disturbance of “modern life” is far from a novel phenomenon that plagues the 21st century, and smartphones and technology cannot be solely to blame for the problems we see. As the quotation continues (you can read the full article here, page 719), it is clear that attempts to treat insomnia were not all that different from remedies people might turn to now.

Disturbed sleep is something we’ve all experienced at one point or another. That sleepless night before an important meeting, interview, or exam stress leaves us feeling groggy, less responsive, and annoyingly less prepared for the problem we have to face. It’s clear that even a night of poor sleep can cause a plethora of problems which make restoration theories of sleep enticing and convincing. However, it is still not certain how sleep might rectify the impaired functioning associated with a night of tossing and turning in bed.

One theory argues that sleep acts to quieten down brain activity which becomes increasingly noisy during the day. This ‘noise’ makes it harder to function in terms of laying down new memories, remaining vigilant, and maintaining a positive mood. There are plenty of studies which highlight problems in each of these areas following poor, or a complete absence of, sleep for even a single night.

Now, the brain is a noisy organ and is constantly busy keeping you alive and functioning. Even when you’re not ‘thinking’ anything, it is still possible to detect a network of activity associated with this resting state. However, when ‘noisy’ is used here, it is in reference to noise which may be more indiscriminate and impede normal brain functioning.

Synaptic Homeostasis Hypothesis

This theory is known as the synaptic homeostasis hypothesis and was put forward in 2003 by the psychiatrist, Dr. Giulio Tononi of the University of Wisconsin-Madison. This theory centres on the important role of slow wave sleep (SWS) during a night’s sleep. SWS is the predominant neural signal found during the third stage of NREM sleep, and is characterised by slow-synchronised oscillations across the cortex. It is associated with the deepest stage of sleep and with many restorative properties of sleep.

A paper by Christoph Nissen and colleagues, published just this week in Nature Communications, has shed more light on how sleep may help us function on a day to day basis, and has provided further support for the synaptic homeostasis hypothesis. Currently, most of the evidence for this theory comes from animal studies and indirect evidence from a handful of human studies. That is what made the recent study by Nissen particularly exciting.

Christoph Nissen and colleagues at the University of Freiburg explored how sleep, compared to sleep deprivation, was associated with changes in memory encoding, cortical excitability and neural mechanisms behind brain plasticity and learning. They examined a group of 20 healthy university students who all took part in the normal sleep and sleep deprivation portions of the experiment.

The team examined cortical excitability following a normal night’s sleep and sleep deprivation using transcranial magnetic stimulation (TMS) to induce a twitch in a participant’s hand. The TMS device allows scientists to deliver a pulse which can be used to inhibit or excite the neurons underneath its coil. A pulse to the appropriate location on the right side of the brain will produce a corresponding twitch to the muscle in the participant’s left hand. The strength of the pulse needed to produce a response, or twitch, can be used as a marker of how excitable that particular patch of neurons is. As a result, this technique provides a non-invasive and relatively simple way to test one of the synaptic homeostasis hypothesis’ predictions.

In addition, the group examined brain activity using electroencephalography (EEG) to further explore alterations produced by extended wakefulness.They also tested performance by examining participant’s memory through the use of a simple word pair test, and through their capacity for LTP-like plasticity using a paired stimulation method.  LTP, or long-term potentiation to give it its full name, has been argued to be the mechanism within the nervous system through which learning occurs. It is argued to play a large role in memory formation and so provides the researchers with another way to assess performance following extended wakefulness or sleep.

In their student sample, Nissen and colleagues found evidence of increased cortical excitability, poorer memory performance, and reduced LTP-like plasticity following a night of sleep deprivation compared to wakefulness. All of these support the synaptic homeostasis hypothesis and support the role of sleep in ‘resetting’ the neural activity to a baseline. It is argued that this is what allows us to continue on at our best after a night’s sleep and allows us to start efficiently storing memories of cute animal videos while at work.

Yet, the evidence for this is still in its infancy and it would be unwise to jump to conclusions about this research. Rather, it is another hat to throw into the ring of sleep science.

This work is still just a start, but it is an interesting and exciting foray into further understanding how sleep serves its important role in our lives. Furthermore, it also provides some interesting avenues for therapies which might try to capitalise on the ability of sleep to return neural activity to a set-point. There is already some evidence to support short-term sleep deprivation to help depression. A further understanding of sleep’s impact on the brain, or lack thereof, may help us manipulate this to our advantage.

Inquisitive Tortoise

References:

Kuhn, M. et al. Sleep recalibrates homeostatic and associative synaptic plasticity in the human cortex. Nat. Commun. 7:12455

Tononi, G., & Cirelli, C. (2003). Sleep and synaptic homeostasis: a hypothesis. Brain research bulletin, 62(2), 143-150.

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Sleep Roundup 12/07/16

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So, being the geek that I am I come across lots of interesting sleep talks online and resources which help me with my day to day research. Here’s a roundup of the current sleep talks / podcasts online over this past week or so which grabbed my attention.

This may become a regular thing if I find enough interesting sleep research / talks (organisation permitting, no doubt).

For now enjoy two the latest episode of the Infinite Monkey Cage which is focused on sleep in general and How Much Sleep Do We Need from the BBC. Also, if you don’t already listen to the infinite monkey cage, do so now!

Inquisitive Tortoise

 

 

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Sleep Trackers: Do They Work?

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“What makes a good sleep tracker?”

“I didn’t sleep too well last night, and I felt so groggy this morning”

“Stressful day at work?”

“No, my stupid SleepApp didn’t work properly and I spent the night trying to get it to play relaxing whale noises. When I did drift off by myself, it didn’t wake me up in between sleep cycles. It better not fail tonight, I’ve got an important meeting tomorrow and I can’t sleep properly without it…”

“Uh-huh…”

Stilted conversation aside, we spend a large amount of our daily lives glued to screens of some description. These keep us active and engaged well beyond the time when we should be switching off for the night. For example, light from phones and laptops can alter our normal patterns of sleep and make it harder for us to drift off in the evening. This plays havoc with the body’s multitudinous clocks which naturally set in motion a number of chemical changes that allow us to unwind steadily before we drift off to sleep. However, that’s a point for another day.

For now, I want to talk about how we use technology to seemingly help us get to sleep and to, in want of a better way of putting it, tell us that we were in fact asleep the previous night (with or without a pretty graph to go with it).

Commercial ways to assess sleep:

There were two main ways of objectively measuring sleep in the research community: actigraphy and polysomnography (See what makes a good sleep tracker?) However, the business world has managed to split this up into a large selection of methods to tell us whether we’re sleeping enough. It may be that these different commercially available devices and apps are actually pretty good but the available evidence tells a different story.

Types of Sleep Tracker

I won’t go into too much detail about all of the different types of sleep tracking devices, of which there are many, but the purpose of the below list is to show the range of ways you can measure your sleep outside of the lab.

Movement-Based

Sleep apps developed for use on phones (e.g. Android or Apple stores) vary in cost and features which they promise. A popular sleep app for android users, ‘Sleep as Android’, has over 10 million downloads and boasts the ability to differentiate between wakefulness, light sleep and deep sleep. It also claims that it can wake you up during your lightest sleep stages in the morning to promote a “natural” awakening which supposedly avoids the grogginess and tiredness of waking up in the deeper stages of sleep. This app, amongst others, relies on movement-based information.

Movement-based trackers can also take the form of watches which track our sleep (alongside activity, exercise, and heart rate). Both of these aim to give us lots of detail about our sleep and provide us with statistics which try to educate us about our own sleep – mainly with the intention of helping you sleep better. These works by applying an algorithm to movement data which is logged by something called an accelerometer. This is already present in your mobile phone and the app simply makes use of this data to predict your sleep.

Brain-activity Based

There are a number of devices which you can buy which will offer a rudimentary attempt to track brain activity. Typically, if you want a good picture of your sleep you will track a wide range of different bodily functions in something known as polysomnography (see what makes a good sleep tracker?) However, these trackers try to track sleep through the use of a couple of electrodes placed on the scalp during sleep.

Temperature / Heart Rate / Muscle Response Based

Typically, these will be used alongside movement data to attempt to give a more accurate estimate of sleep.

Bed-Based

Again, these are technically based on movement and temperature data but are placed on the bed in some respect and not worn. These can take the form of a bed covering (link), or even a trendy looking ball such as Sense.

What makes a good sleep tracker?

So what does an ideal measurement of sleep look like?

Polysomnography

The gold-standard measure of sleep is known as called polysomnography. This measures a number of different things including:

  • Electroencephalogram (EEG; records electrical activity produced by cells in the brain)
  • Electrooculography (EOG; records eye movements)
  • Electromyography (EMG; records electrical activity generated by muscle activity)
  • Cardiac rhythms (ECG)
  • Respiratory activity

This setup, understandably, requires you to come into a sleep laboratory and sleep in a rather unfamiliar bed with electrodes planted on your head and body. This enables sleep researchers to record brain activity, eye movements, muscle activity and heart rhythms. Together, these readings allow us to identify how long you sleep, how often you wake up, how long it takes for you to get to sleep, when you wake up, and to identify the individual sleep stages and cycles which make up a normal night’s sleep. There are problems with this approach but it is the best option we have for understanding more about an individual’s sleep. As you’ll likely agree, this is a lot of information to obtain and wade through. Sleep apps and watches cannot possible recreate this and so are limited, but this is not necessarily a problem if they correlate well with other less rigorous but well accepted measures used in sleep research.

For example, most sleep apps and watches work by determining how often you move on a given night and use the times you are moving less as sleep and the times you are moving more as awake. These devices measure movement by using a little device called an accelerometer which is found within your smartphone and watches such as the FitBit.

Actigraphy

Within sleep research, we also use a device which is based on this same technology. The device is known as an actigraphy watch and it is generally seen an acceptable alternative to sleep lab measurements which are often costly, time-consuming and cumbersome. An actigraphy watch is usually worn on the non-dominant wrist, can be used outside a sleep lab, and thus allows researchers to assess sleep objectively as people go about their normal day-to-day lives. Actigraphy also works by detecting movement through accelerometers, and algorithms are applied to this data to explore certain facets of sleep (there are limits to this) in a more portable format.

Do these sleep apps actually work?

The main question you’ve probably come here to hear answered. The short answer: yes, but there are limitations to them all.

Quite simply put, there is a lack of research conducted here and the sample sizes are miniscule at best for the ones that do currently exist. Yet, these research studies do hint that perhaps sleep apps and wearable devices are actually assessing your levels of sleep in terms of duration, sleep efficiency and how often and for how long you are awake during a night of recording.

When sleep researchers try to determine whether wearables are actually tracking sleep they look for the following things: sensitivity (e.g. the ability of the app / device to measure when you’re actually asleep), specificity (e.g. the ability of the app / device to measure when you’re actually awake) and accuracy (e.g. is it measuring when you’re truly awake and truly asleep).

What does the current science say about commercial sleep trackers (e.g. FitBit)?

Wearables, or commercial sleep trackers, tend to show the same pattern when it comes to estimating our sleep patterns as that which is seen in actigraphy. Wearables using movement data typically overestimate total sleep time and sleep latency (how long it takes you to fall asleep) but are generally pretty accurate at telling when you’re asleep and for how long. By contrast, wearables such as the FitBit are poor at identifying periods of wakefulness during the night and will significantly underestimate disruptions in the night – known as wake after sleep onset (WASO). So, for the average person it is fair to say that wearables such as the numerous reincarnations of the FitBit may give you some insight into what your sleep looks like. However, if you are prone to fitful sleep or suffering from insomnia then these apps will be less accurate (despite claims on FitBit’s website that they may have a fix for people with disrupted sleep) and should not be depended upon. This is doubly the case if you consider using these in lieu of a going to a doctor about your sleep issues.

How about the claims made by, worryingly, many sleep apps and wearables that they can track different stages of sleep? The bold claim that a sleep app can measure REM sleep, for a start, is simply not known and extremely doubtful, even if some apps do add in more than just movement measures (e.g. heart rate). Other wearables such as the Jawbone UP make more reasonable claims that they can detect “light” versus “sound” sleep over a given night. Although it’s not entirely clear what “sound” sleep actually means, one research team took this to mean deep sleep and examined whether there was any truth behind this claim. In a large sample of adolescents, they found that the light and sound sleep measures were rather poor at measuring what they claimed to. Rather worryingly the ‘light’ sleep was found to be associated with time spent in the deepest stage of sleep which highlights that healthy skepticism should be applied to apps claiming they can pick out individual, or broad, sleep stages (see further reading).

Further Reading

A study by de Zambotti and colleagues examined the sensitivity and specificity of a different wearable, the Jawbone UP, compared to polysomnography and actigraphy in a group of middle aged women (average age 50 years old). They found, like others, that the Jawbone UP was generally accurate at determining when and for how long participants slept (but overestimated this value), but was pretty poor at determining when participants woke up during the night (underestimated this value, so had a good sensitivity but poor specificity). The ability to detect periods of waking and total sleep during the night were notably bad during particularly disrupted sleep as detected by PSG. This suggests that the Jawbone UP and FitBit Ultra are not particularly accurate at detecting the amount of sleep and waking in individuals with disrupted / fragmented sleep.

When the same research group (de Zambotti et al., 2015b) also examined the Jawbone UP in a sample of adolescents and young adults (age range 12-22 years old) and found similar results. That is, that the Jawbone UP overestimated total sleep time, sleep efficiency and sleep onset latency but underestimated total wake time during the night (it was much worse at detecting time spent awake than any of the sleep measures). Overall, it was found that the Jawbone UP was good at detecting when participants were asleep, but rather poor at identifying when they woke up during the night. This is important as fragmentation of your sleep will impact on sleep quality.

The same study also tried to examine whether the Jawbone UP’s dichotomisation of ‘sound sleep’ versus ‘light sleep’ were appropriately linked to deep versus light stages of sleep as assessed in the sleep laboratory. The ‘light sleep’ count was linked to movement and awakenings, and also to stage 3 of sleep (known as the deepest stage of sleep). In fact, none of the lightest stages of sleep were shown to be associated with the ‘light sleep’ count produced by Jawbone UP. The opposite was found for the ‘sound sleep’ count whereby typically deep stages of sleep were not found to be associated with this measure, but rather overall measurement of movement (specifically reduced movements) was. This suggests that wearables such as Jawbone and FitBit may be reasonable at detecting sleep during the night, but not night-time awakenings or the different stages of sleep. Furthermore, in populations where sleep is fitful or fragmented the accuracy of these apps reduces to a greater extent.

A previous study by one of the study’s authors, Hawley Montgomery, in 2012 found that a wrist-worn FitBit was comparable to actigraphy, but poorer than polysomnography in detecting when people were asleep. However, the FitBit was particularly poor in identifying when people woke up compared to actigraphy. This suggests that the healthy adult populations could still gain useful information from a FitBit but, as the authors highlight, it is a far way off being appropriate for measuring sleep in people with diagnosed or suspected sleep disorders.

As you can hopefully see, there are only a handful of studies which have attempted to understand how good market-leading wearables are in detecting sleep and wake. The emphasis on sleep and wake is intentional. These apps have not been assessed for their ability to assess anything beyond total sleep time, wake after sleep onset, sleep onset latency and sleep efficiency.

Smart Alarms

Other sleep apps also include a measure to wake individuals up during the lighter stages of sleep to enable them to feel more wakeful in the morning. The alarm sounds after tracking an individual’s pattern of sleep to create an ‘optimal’ window to wake up during which the alarm will try to target. Alarm PicHowever, there is currently limited evidence to back up these claims (Kelly et al., 2012), and there needs to be considerably more research here before such claims can be validated and backed up (SLEEPIO Article). It is somewhat surprising that such research has not been carried out considering how easy it would be to create an experiment where participants are randomized to either an optimal or sub-optimal wake-up alarm condition over 1-2 weeks (See Kelly et al., 2012 for expansion on this very point).

Concluding Thoughts

Sleep is something which can be fickle at many times throughout our lives, and it is not surprising that we would want to learn more about it. However, for those of us who suffer with our sleep on a regular basis, there is an obvious appeal to be able to track our sleep in the comfort of our own homes and on a regular (perhaps even nightly) basis. It may provide a skewed notion of how an individual is sleeping (for better or for worse) and this can provide unfounded alarm or comfort. The current wearables have a reasonable ability to tell when and for how long you’re asleep but be sceptical on their ability to tell you anything about the quality of your sleep. If you are genuinely concerned about your sleep then please consult your doctor.

Sleep apps, wearables and other sleep trackers are a fantastic idea and if they can prove to be comparable to other methods such as actigraphy then I see few reasons to discourage their use. However, there is a lack of available data to really understand whether these different sleep trackers are accurate. If they are simply measuring time spent asleep and awake then they seem to be okay, and comparable to measures used in sleep experiments. Yet, bolder claims about smart alarms, tracking individual sleep stages, and their use in sleep disorders are not conclusively studied at this moment in time. That is not to say they will not, but there is a sensible reason to be cautious until that evidence is available to us. So, by all means use these trackers and add them to part of your daily routine if you so wish. However, understand their limitations and be aware that paying minute detail to your sleep may also create its own problems. More on that point in my next post.

Inquisitive Tortoise

References

de Zambotti, M., Baker, F. C., & Colrain, I. M. (2014). Validation of Sleep-Tracking Technology Compared with Polysomnography in Adolescents. Sleep, 38(9), 1461-1468.

de Zambotti, M., Claudatos, S., Inkelis, S., Colrain, I. M., & Baker, F. C. (2015). Evaluation of a consumer fitness-tracking device to assess sleep in adults. Chronobiology international, 32(7), 1024-1028.

** Kelly, J. M., Strecker, R. E., & Bianchi, M. T. (2012). Recent developments in home sleep-monitoring devices. ISRN neurology, 2012. (Good expansion on the different sleep trackers available)

Montgomery-Downs, H. E., Insana, S. P., & Bond, J. A. (2012). Movement toward a novel activity monitoring device. Sleep and Breathing, 16(3), 913-917.

Montgomery-Downs, H. E., Insana, S. P., & Bond, J. A. (2012). Movement toward a novel activity monitoring device. Sleep and Breathing, 16(3), 913-917.

Further Reading

http://www.huffingtonpost.com/dr-christopher-winter/sleep-tips_b_4792760.html

https://www.sleepio.com/articles/sleep-aids/sleep-apps/

Image Credits:

Main Pic

Alarm Pic

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Filed under General Interest, PhD, Psychology, Sleep Science