A recent BBC article discusses the emergence of products designed for neurofeedback to aid in stress reduction. The headline asks, “Smart headbands claim to make people calmer. Do they work?” However, the article does not really answer the question, or even get to the heart of the issue. It mostly provide anecdotes and opinions without putting the technology into a clear context. The article focuses mainly on the use of such devices to allegedly improve sports performance.

There are a few premises on which the claims made for such devices are based, varying from well established to questionable. One premise is that we can measure “stress” in the brain using an electroencephalograph (EEG) to measure the electrical activity in the brain. This claim is mostly true, but there is some important background necessary to understand what this means. First, we need to define “stress”. Functionally when researchers are talking about mental stress they mean one of two things, either the stress that results from an immediate physical threat, or the mental stress that results from engaging in a challenging mental task (like doing math in your head while being distracted). For practical purposes the research on EEGs and mental stress use the challenging mental task model.

It his, however, a good representation of stress generally? It is a convenient research paradigm, but how generalizable it is to mental stress is questionable. It can result in objective measures of physiological stress, such as secretion of stress hormones, which is partly why it’s convenient for research and not unreasonable, but it is only a representation of mental stress and might not translate to all “stressful” situations (like sports).

Can EEGs measure this type of mental stress? Yes – a relaxed mind with eyes closed produces a lot of regular alpha waves. A more active mind (and one with eyes open) produces more theta waves and chaotic brainwave activity. EEGs can therefore tell the difference between relaxed and active. How about not just active but stressed? That is trickier, but there are studies which appear to show some statistical differences in the wave patterns regionally with mental stress. So the premise that EEGs can measure certain kinds of mental stress is reasonable, but not as simple as often implied. This also does not necessarily mean that commercial devices claiming to measure EEG markers of stress work.

The other major premise is that biofeedback using EEG (often now referred to as neurofeedback) has superior outcomes to other forms of stress reduction, such as meditation. This, I would argue, is not well-established. A 2013 review notes:

Interestingly, many of the conditions that benefit from Neurofeedback treatment are consistent with the conditions that improve with regular meditation practice. For example, both ADHD patients and individuals diagnosed with depression benefit from meditation training (Hofmann et al., 2010; Grant et al., 2013) as well as neurofeedback training protocols (Arns et al., 2009; Peeters et al., 2013). In addition, both meditation and neurofeedback are methods of training mental states. Thus, it is plausible that the mental training involved in meditation may be fundamentally no different than other types of training and skill acquisition that can induce plastic changes in the brain (Lazar et al., 2005; Pagnoni and Cekic, 2007).

I could not find any studies since then that would change the conclusion. Essentially neurofeedback works in the same conditions and in the same way that meditation works. Mediation, in turn, is a poorly defined entity without a clear operational definition used consistently in research. The totality of the scientific research is consistent with the interpretation that meditation with or without neurofeedback is similar in effectiveness to basic stress reduction techniques. There are individual studies that give a glimmer of difference in one measure or another, but the studies generally do not adequately control for these variables or do not show a significant difference. In other words, many studies do not have a control group with meditation alone, different types of meditation, or basic stress reduction. As the quote above indications – the effectiveness of neurofeedback is suspiciously similar to the effectiveness of basic relaxation techniques.

What about the commercial devices on the market, and their specific claims? Overall, I am not impressed. The device touted in the BBC article is a headband – which means the EEG electrodes are very limited in their distribution around the head. It’s basically measuring frontal lobe activity. A clinical EEG will include preparation of the scalp and using conducting gel to get a good signal. We can’t assume just wearing a headband will give an adequate signal under most conditions. We therefore cannot extrapolate from research using proper EEGs to a commercial headband EEG.

The company is also touting features that don’t necessarily translate to improved efficacy, such as using AI to analyze the signals. The BBC reports:

Max Newlon, president of BrainCo, explains that the headband uses an AI (artificial intelligence) software algorithm to monitor 1,250 “data points” in a person’s brainwave signals.

I’m not even sure what that means. EEGs record channels which are comparisons of two electrodes. That cannot be the “data points” being referred to. It must be temporal, and EEGs can provide high temporal resolution. But does that matter? This sounds like a classic case of useless precision. A temporally high resolution recording of the EEG may be of zero clinical value, and is likely far beyond what is necessary to extract all the useful information from the EEG. I don’t know for sure because all I have is a vague promotional statement from the president of the company.

The product is being sold with the claims that it will help athletes improve their performance. The article does not reference any research, and I could find none to justify this claim. What I would like to see is a blinded clinical study with a treatment arm, a placebo arm (a device that gives simulated feedback only), vs a meditation alone group.

I did find one study of a similar commercial device comparing neurofeedback with the device to unassisted relaxation, found:

Generalized estimating equation models demonstrated a moderate increase in HRV following relaxation exercises, with no observable difference between MARE and URE conditions. Both MARE and URE conditions produced equally effective short-term increases in heart rate variability, without additional benefit from neurofeedback.

In other words, the device didn’t work, meaning it provided to benefit in addition to just using basic relaxation exercises. We don’t know if this is a technical failure of the device (for the reasons I discussed above) or a failure of the entire concept of using neurofeedback to enhance relaxation.

Perhaps just taking time to mentally relax is all that is needed. It’s possible that some meditation techniques may help people learn how to relax. And there is lots of evidence that using some kind of biofeedback may help people learn to relax quicker, although I’m not convinced that this is a clinically significant effect or sufficient to justify using the feedback. We might get more bang for the buck just from researching and learning how to maximize relaxation techniques. As much of a technophile as I am generally, this seems to me like a case of trying to get a shortcut with gee whiz technology, and companies are leveraging that bias. Cool technology may not be needed or useful if your goal is to simply learn how to relax and focus. It’s even possible that relying on such devices can be counterproductive, if people see them as a short cut and put less effort into learning how to relax on their own.

The entire field can benefit from more and better research, specifically, in my opinion, in doing high quality clinical research that adequately controls for all the variables.