“You’ve achieved 40 seconds of uninterrupted focus.”
Apparently, this is cause for celebration. For the past 10 minutes, I have been staring at my phone, trying to move a digital ball up a hill using nothing but the power of my mind. The Mendi headset I am wearing is analysing my brain activity and reflecting that back into the game. The more I concentrate, the higher the ball climbs.
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This exercise is supposedly working out my mental muscle, just as one might use weights to train physical muscle, ultimately improving my focus and reducing my stress.
Like thousands of others, I have spent years wearing a smartwatch that helps me track my fitness and improve my physical health. But the wearables industry has its sights set on a new target: our mental health. We now have smartwatches and brainwave-reading devices that not only analyse the state of our nervous system, but actively intervene to supposedly improve our well-being, making mental health support more accessible – and wearable – than ever before. “We are leveraging the brain’s ability to rewire itself so that you can increase your emotional control,” says , Mendi’s chief product and science officer.
As someone who suffers from stress and anxiety, I am eager to try anything that will help me control it. But with my background in neuroscience, I am cautious of believing the hype. So I delved into the growing range of devices that target concentration, focus, stress and anxiety to figure out how they might work and which might really make a difference to my well-being.
The first wearable I was eager to use was the , as I trialled an early prototype more than a decade ago. There are two devices to choose from – the Muse 2, a hard headband aimed at reducing stress and improving mood, and the Muse S, which uses soft sensors that can be comfortably worn at night to also track sleep. Muse is fairly unique among wearables for being a clinical-grade electroencephalography (EEG) device, which means that, as well as being a consumer product, it is used by researchers to investigate everything from the to .
I try the Muse S. It’s a simple set-up: the headband uses seven sensors to measure the brain’s electrical activity together with your heart rate, breath rhythm and movement. This data is analysed and fed back to you via earphones. The device picks up neural oscillations, or brainwaves, with different frequencies corresponding with different mindsets. More alpha waves are associated with a relaxed, calm state. Beta waves are present when you are actively thinking about something, whereas delta waves are in abundance when you are in deep sleep.
At night, Muse analyses your brainwaves and uses responsive audio – guided meditation, sleep stories or soundscapes – to nudge you back to sleep when it recognises that you are waking up. During waking hours, Muse supposedly reduces stress and improves mood by providing live feedback to help you meditate.
Reading brainwaves
I pop the device on my head and close my eyes. I immediately hear a loud wind blowing around me. When the Muse S registers brainwaves reflective of a meditative state, the wind dies down and birds start to chirp. “People who’ve never meditated before are like, ‘Oh my god, what am I supposed to be doing?’ ” says , a neuroscientist and co-founder of Muse. “We solved that problem by reading your brain activity and telling you when you’re doing it right.”
When my mind wanders, the birds fly away, and as my brain starts concerning itself with what time I need to leave the house, a storm starts rumbling. I refocus my attention and gradually manage to coax the odd twitter again. “You’re getting this beautiful real-time feedback that lets you know that you are in the state of focused attention – you’re meditating,” says Garten. There was no doubt I felt more relaxed after each session, and I certainly got better at meditating over time, hearing just 11 birds on my first session and conjuring 46 on my last, five weeks later. But does the device, which costs around $300, really reduce stress and anxiety?
First, let’s consider meditation itself. Although this topic isn’t without controversies, in general, research suggests that meditation can have benefits. These include small improvements in our ability to when trying to reach a goal, potentially making us more productive, as well as some signs that it
Muse itself has no shortage of studies that test its abilities – I was sent at least 50 by the company. On the positive side, most of these are independent, so shouldn’t be biased. However, they are limited by being quite small or lacking a well-matched control. One small study that did have a control found that US school students aged 13 to 14 with behavioural problems who used Muse regularly compared with a group who didn’t take part in any mindfulness training.
I also wasn’t entirely clear on whether any observed effects are due to the technology itself. Would I see the same results if I merely sat quietly for the same amount of time?
Perhaps not. In an , 40 young adults with mild stress were split into two groups. One group received daily meditation training of up to 20 minutes for a month using Muse. The other group meditated for the same amount of time while listening to sounds like those provided by Muse, but without any real-time feedback on their mental state. Muse users showed greater improvements in stress tests and increased executive control – the ability to focus your attention where needed. They also displayed stronger brain activity associated with the relaxed mindset at the end of the experiment.
You get real-time feedback that tells you that you're in a state of focused attention
I asked , a cognitive neuroscientist at Western University in Ontario, Canada, for his view of the device. He had recently completed a study of meditation, sleep and cognition using Muse. His paper, which is under peer review, shows that the Muse headband improved people’s sleep quality by 20 per cent but had no direct effect on cognition. “I do think the device is a useful one,” says Owen. “As a simple consumer neurofeedback device, I think it is one of the front-runners.”
Other similar devices exist. I also tried the Mendi headset, which costs around $300 and employs a technique called functional near-infrared spectroscopy (fNIRS) to detect changes in the brain’s blood flow and oxygenation in response to brain activity and uses that information to determine when you are calm and focused. Rather than feed that data back to you through birdsong, it translates it into the movement of a ball on your mobile device. My children preferred the Mendi because they found it easier to control a visual stimulus than an auditory one, whereas I liked closing my eyes while meditating and so preferred the Muse.
Like Muse, Mendi points to several studies that support its claims. However, the field of wearable fNIRS is young and there is a lack of large, gold-standard efficacy trials. One review of the field found that people can , which may enable them to reduce symptoms of anxiety, but it states that any conclusions about its clinical utility “are premature”.
Rather than massage the nervous system through meditation, other wearables aim to manipulate it through neuromodulation, where technology is used to alter nerve activity through direct or indirect stimulation. Take for example, a device that clips onto your tragus – the fleshy cartilage in front of your ear – and sends electrical messages towards the vagus nerve. Regular use of this device, according to its website, not only promises to reduce fatigue, depression and anxiety, but also to help treat long covid, improve heart health and more.
The vagus nerve has been getting a lot of attention lately. It is actually a pair of nerves that link the brainstem with several vital organs, controlling our involuntary functions such as breathing, digestion and immune response. It also plays a critical role in our parasympathetic nervous system, which governs the “rest and relax” activity that helps us recover after our sympathetic nervous system, or “fight and flight” responses, have kicked in during a period of stress.
In the 1980s, doctors targeted the vagus nerve by implanting electrical stimulators into the necks of people with epilepsy. The devices suppressed their seizures but also influenced their well-being. Since then, it has seemed as if stimulating the vagus nerve helps with every condition under the sun. “The vagus nerve is held up as a panacea because it is large and connected to a great many organs and systems. It can have an effect on everything from inflammation to cardiac control,” says at the University of Bath, UK, who has done some of the only experiments that have recorded electrical signals from within the vagus nerve directly.
According to , head of research at Parasym, the firm behind Nurosym, their device targets a branch of the vagus nerve that travels towards the brainstem to modulate parasympathetic activity, helping calm your immune response and reduce your stress.
Inflammation control
In a small trial of 19 people with heart failure, those who received 4 hours of neuromodulation using Nurosym twice daily throughout their stay in hospital had and fewer signs of oxidative stress, which can damage cells, compared with those who received a sham treatment. A separate pilot study of 24 people with long covid saw after using Nurosym for 30 minutes twice daily for 10 days.
I was particularly interested in some small independent studies that showed how short sessions of around 5 minutes with Nurosym are associated with increased heart rate variability (HRV) – the variation over time of the period between consecutive heartbeats.
HRV is an increasingly well-respected marker of physical and mental health: exercise, a healthy diet and better sleep all help to increase it, whereas alcohol, chronic stress and poor sleep lower it. Low HRV is predictive of increased inflammation – known to be a precursor of many diseases, and of . Increasing it suggests that you may well be experiencing less stress. I used Nurosym several times, but I found it uncomfortable to wear, so didn’t feel motivated to use it for any length of time.
When it comes to vagus nerve stimulation, studies are mixed. “We are trying to generate more data, but there is still a long way to go,” says Burchi.
For now, Metcalfe remains unconvinced. He says there is no clear consensus as to whether non-invasive stimulation of the vagus nerve has any targeted benefit. He says his team has run several unpublished tests of non-invasive vagus stimulation with a range of devices and hasn’t found any significant benefits. “I wish we had. It would make our research so much easier,” he says.
Metcalfe explains that the vagus nerve is made up of 20 to 30 bundles of fibres called fascicles. Each tends to have a different job: one might control heart rate, another the immune system. Selecting one of the bundles is difficult even when you are implanting a stimulation device, he says, let alone when you are doing it non-invasively.
However, he suspects that a lot of vagus nerve devices probably show efficacy not through direct vagal modulation, but through up or down-regulating the nervous system via other pathways, such as the body merely responding to an unusual sensory input. Think of how you might pat a baby’s bottom to lull it to sleep. “I think it is likely that you can achieve the same calming effect as stimulation simply through breathing exercises or meditation,” says Metcalfe.
Vibration technology
Speaking of unusual sensory input, I also trialled the , a wristband that uses vibrations to tackle stress, improve focus and increase sleep. The device, which costs around $350, tracks data such as HRV and provides different patterns of vibration depending on whether you are using it to relax or improve your focus. The exact patterns and frequencies are under wraps, as the company is applying for patents, but they generally felt like a gentle throbbing. They were pretty indistinguishable from one another, in my experience, and I am wary of claims made by the app that certain patterns can help you focus, feel energised, feel calm and promote several other states, having not seen any convincing evidence yet that vibration can modulate mood so specifically.
It is the patterns and frequency of the vibration that are key to its effects, says , co-founder of Apollo Neuro. There is some early research suggesting that certain frequencies of vibration are able to . However, only one clinical trial of Apollo itself has been published, on people with systemic sclerosis, a painful autoimmune condition. Participants using the device for at least 15 minutes a day for four weeks showed a , as well as improved quality of life and fewer symptoms of depression.
Rabin says that in unpublished trials, the device was also able to increase HRV and that it works by indirectly stimulating the vagus nerve, modulating parasympathetic activity.
Conscious of Metcalfe’s criticisms of external vagal nerve devices, I ask Rabin whether he thinks the effects of Apollo might be replicated simply by practising breathing exercises or meditation. He says he has spent his entire medical career teaching people breathing exercises, but despite knowing they work to reduce stress, people just don’t do them. “No matter how much we try to teach people, they forget to do it. And when they’re stressed, they forget even more often,” says Rabin.” We’ve created a device that bypasses that process of calming yourself, because you can just strap it on and it does the work for you.”
With no large, placebo-controlled trials of Apollo yet published, it is hard to reach any firm conclusions about it. Vibration technology is intriguing, though. There is some research suggesting , brain cells that are involved in the , says at Grand View University in Iowa. Studies in rats also show that vibration can improve depression-like symptoms by .
Scanning through the hundreds of devices on the market, I am a little overwhelmed with what to try next. Do I don the popular Oura ring, worn on a finger, that promises to track sleep’s effect on my mental health, or start using the Nowatch, a screenless watch-like device that tracks my physiological data to help me monitor my stress?
None of these devices comes cheap, and with the industry in its youth, each has a long way to go to prove its worth. Personally, I will continue to use my meditation devices, if only because they motivate me to take moments of quiet. But I will keep watch on the field in the hope that some of this technology ultimately proves successful.
The more tools we have to help us live calmer, more focused lives, the better.
