What are brainwaves and what do they reveal about emotion?

You feel tense, but you can't quite say why. You're restless after an ordinary workday, or oddly calm during something that would normally stress you out. What's happening in your head at that moment usually stays invisible. It can, however, be measured, in the form of brainwaves.

What brainwaves actually are

Your brain is made up of billions of cells that constantly communicate through electrical signals. When large groups of those cells become active more or less at the same time, a rhythmic pattern emerges that can be measured from outside the skull. That pattern is what we call a brainwave.

Scientists typically group brainwaves into a few types, ranked by speed:

•       Delta, the slowest waves, associated with deep sleep

•       Theta, a bit faster, associated with relaxation and daydreaming

•       Alpha, associated with a calm, alert state

•       Beta, associated with active thinking and concentration

•       Gamma, the fastest waves, linked to intensive processing of information

No single wave type works in isolation. Your brain combines them constantly, and which combination dominates at any moment depends on what you're doing and how you feel.

Let’s make something clear from the start. The Kalmoa scan does not technically work the same as an EEG scan, there are differences. However, the results are practically the same, both scans produce a brainwave pattern that can be read and compared. However, as EEG is the industry standard it has a large amount of research attached to it. This article dives into a century of research done in the field of brainwave analysis. 

A technique more than a century old

Measuring brain activity through EEG isn't a new invention. The technique has existed for more than a hundred years and is firmly established in clinical neuroscience. What has changed in recent years is the scale at which it's become accessible: from extensive lab setups to compact, wearable systems that can collect usable data outside a research center too.

How brainwaves and emotions are connected

Research on brain activity has shown for decades that certain patterns correlate with emotional states. The cortex is dominated by alpha waves when the body is relaxed, while the beta rhythm gradually decreases as emotional activity increases, and the alpha signal weakens while the beta signal strengthens once the central nervous system is under strain. In other words, a shift between these two patterns can say something about the level of relaxation or tension someone is experiencing (PubMed Central).

That's exactly why physiological signals like EEG are interesting for emotion recognition. Affective computing, a branch of artificial intelligence focused on recognizing and interpreting human emotion, has grown substantially in recent years thanks to the rise of wearable, non-invasive sensor technology like brain-computer interfaces. Facial expressions, speech, and posture can be consciously or unconsciously masked, physiological signals are harder to control, and as a result often give a more complete picture.

Worth being honest about here: brainwaves don't “prove” exactly what you feel, and they don't replace a conversation with a professional if there's a serious concern. What they can do is surface a pattern you might not have noticed yourself.

Why EEG is usually combined with other signals

Brainwaves provide valuable information, but scientists emphasize that combining it with other measurements gives a fuller picture. Research shows that adding heart rate variability alongside EEG improves the detection of stress and emotional arousal, resulting in more accurate classification than when EEG is used alone (ScienceDirect). That's not a weakness of EEG itself, it's the reason serious applications rarely treat it as an isolated data point, and why context and repeated measurement are more valuable than a single reading.

Why this is now measurable outside the lab

For a long time, this kind of measurement could only happen in a lab, with a specialist and extensive equipment. What's changed in recent years is that the technology behind measuring brain activity has become smaller, faster, and more accessible. Where you once had to visit a research center, a measurement can now take a few minutes at home.

What you can do with this yourself

The value isn't only in the measurement itself, it's mostly in the results that are given back to you; the Well-Being Index and the Deep Report and what you do with it after you receive these deep insights. If a reading shows you're regularly in a state of heightened tension, or you are not actively showing up for yourself, even if you didn't feel that yourself, that's a concrete starting point. You can start paying attention to what precedes it, as stated in the Deep Report under Underlying Themes. This allows you to work deliberately on yourself at moments that suit you, instead of guessing at what's “really” going on or ignoring that you actually don’t feel as well as you know you could. 

Curious what a Kalmoa scan measures? See how it works.

From measuring to insight

This is exactly what Kalmoa taps into. Instead of talking through what you feel, a short scan with the Kalmoa headset maps your brainwaves and translates it into understandable insight about your mental well-being, across multiple measurements over time.

Source:

PubMed Central — cited for the alpha/beta shift under relaxation versus stress.

ScienceDirect — cited for the accuracy improvement from combining EEG with heart rate variability.

Human emotion recognition from EEG-based brain-computer interface using machine learning: a comprehensive review. Neural Computing and Applications (Springer Nature), 2022.

https://link.springer.com/article/10.1007/s00521-022-07292-4

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