EEG is chasing foamy waves

Each couple of years there are more and more devices that allow one to measure the bioelectrical activity of the brain at home. They use the phenomenon of raising different frequencies of brain waves depending on the current psychophysical condition of the user. Inclined to pandemic attachment to my place of residence, I decided to buy one of these gadgets and after a few weeks I attempted to do a subjective review of the selected model and an experiment utilizing raw data.

I had been intending to purchase an electroencephalography device for a long time, but the prices or unusual communication interfaces were discouraging me to do it. The situation started to change a few years ago when several manufacturers started to offer these types of instruments intended for home use.

Home EEGs work similarly to those used in the medical industry, with some notable exceptions:

• They do not use a large number of channels (on average it is 4 to 12).

• In many cases the use of electrodes requiring the application of a special conductive gel were abandoned.

• It has been accepted that cheaper and smaller sensors may generate noise and be susceptible to changing environmental conditions, however, this is compensated by appropriate algorithms calibrating the data during processing by an application created for a specific purpose. If the main goal is to develop concentration then you do not need the exact, absolute values of the signals corresponding to the brain waves; approximate readings, relative to the levels measured at the beginning of the session, are sufficient.

Choice

Different brain activity measuring products have different uses. Some will allow you to control the computer with the use of appropriate thought sequences to, for example, move the characters in games in this way. For others the main feature is the support of biological feedback (biofeedback) which is helpful in practicing concentration or relaxation. In addition, there are also devices for DIY enthusiasts and scientists, as well as products designed for imaging brain activity in real time.

My choice fell on the Muse 2 headband which is designed for those who wish to exercise their ability to concentrate and be mindful. The first months of the coronavirus pandemic took a toll on me so I decided to actively improve my well-being by applying a proper diet, some physical training and exercises related to cognitive processes.

My decision was also influenced by the willingness to verify the various techniques of working with the mind which I have used over the years. In order to be able to compare their effectiveness and usefulness in the context of achieving specific states, I had to find appropriate lexicons and maps that would be common to different systems, as well as turn to pragmatic methods of examining the quality of basic mind functions such as alertness, mindfulness, focus or awareness. It would be ideal to have an fMRI device at your disposal and visualize the activity of all areas of the brain in real time, but a simple EEG can also help a lot by answering the question of whether the state I subjectively consider to be the focus really is the focus, and if so, whether my experience of strong or weak focus is true in relation to my personal mean?

Product

Muse 2 is a forehead, plastic headband with sensors, an amplifier and a signal sampler, built-in battery and Bluetooth transmitter. It is equipped with the following sensors:

• 5 EEG sensors for testing the activity of brain waves,
• gyroscope for examining the position of the head in 3D space,
• accelerometer for checking the acceleration of head movements,
• photoplethysmograph for measuring heart rate and blood oxygenation.

Thanks to the above we are able to use the following types of biological feedback:

• EEG biofeedback (using information about brain activity),
• HRV biofeedback (based on heart rate variability),
• respiratory biofeedback (giving the information about breathing),
• postural biofeedback (checking the head position).

It is worth mentioning that the hardware interface of the headband is also equipped with additional, interesting indicators which can be used by the software:

• jaw clenching detector,
• eye blinking detector,
• forehead touching detector,
• horseshoe adhesion indicators.

An important element of the set is the Muse: Meditation & Sleep application, intended for mobile devices (mobile phones and tablets) with Android or iOS operating systems. Its name already suggests the target category of the gadget which is supporting meditation and relaxation practices. We can find different categories of exercises which use different types of biofeedback, as well as many so-called guided meditations inspired by both traditional and modern practices.

How does it work?

Using the Muse 2 consists of turning on the band by clicking the button located on the right side, pairing it with a phone or tablet and starting the application. It is also a good idea to prepare headphones if you want to take advantage of the biofeedback.

What is biological feedback? In 1885 the physiologist Ivan Tarkhanov – to whom we owe the creation of a polygraph (colloquially known as a lie detector) – noticed that a person can control their own heart rate by using impulses from the cerebral cortex, not just by slowing down the breathing. It means that we are able to control some physiological processes that appear to be completely autonomous.

In biofeedback we deal with the examination of certain functions of the body (e.g. heart rate, breathing, body posture, temperature, etc.) using appropriate devices or by consciously directing attention to selected areas of the body in order to then influence them with voluntary effort. For example, by listening to the heartbeat we are able to accelerate or slow down its rate and observe the effect of our actions. These types of exercises can have salutary psychological effects because at a very basic level they increase the sense of coherence and develop the habit of being mindful.

In the Muse application we can choose the category of an exercise which translates into the kind of feedback used:

• Mind Meditation - supports calming the mind by analyzing brain activity,

• Heart Meditation - teaches how to control the heart rate,

• Body Meditation - makes one aware of the right posture,

• Breath Meditation - helps in conscious breathing.

Additionally, we can also have a session without any feedback. There is no need to wear a headband in such case and the application will simply measure the remaining time (Timer mode) and (optionally) play some instructions.

There is also another category called Guided Meditation for which biofeedback is also used and we can download meditation instructions supplied by various creators for free or for a fee (if the cheaper version of the headband was purchased).

After setting the basic session parameters (duration, background sound and decisions regarding the activation of verbal instructions) we click the Start Session button and the session begins. Depending on the selected category for the first several or several dozen seconds we will participate in the calibration process during which the application will learn the initial state of our body and mind.

The application lets us know about our current condition with the use of background sounds. When they worsen (e.g. we become distracted or our heart rate increases), we will hear the appropriate noise (e.g. raindrops in the case of Mind Meditation). The more we deviate from the optimal values of the measured parameters, the louder the sound will become. However, if we do well and deepen our state, the background will become silent and in the case of Mind Meditation we will hear birds chirping.

The session ends with a graph showing the quality of the practice over time. In case of Mind Meditation (with neurological feedback) there is a calculated level of calmness which may belong to three ranges, named respectively: active, neutral and calm. We also get a certain number of so-called muse points. We are rewarded with them for the length of the session, and additionally for deepening the desired state.

By using the application we gain access to the historical records of our sessions as well as their short summaries in the form of virtual badges which we can share on social networks.

Attempts

I started examining the Muse 2 band on October 12, 2020 with trying different modes as well as adjusting the session parameters. The chosen type of practice in my case was Mind Meditation which I decided to try according to the given voice instructions trying to forget about the methods that I already knew.

I prepared an appropriate diagnostic stand and, in accordance with the principles of Asian art, placed it next to the wall – which for the next weeks became my temporary landscape. On the left side I put a bell to communicate that the journey into myself begins or ends – an auxiliary aesthetic element.

During the first few sessions I had to deal with the feeling of being assessed which translated into some tension preventing me from fully relaxing. While browsing the Internet I came across opinions of people for whom the EEG feedback was like a red rag for a bull. Hearing the rising sound of rain the user gets a message that he is doing something wrong, but in this particular type of exercise that kind of information triggers an emotional reaction that affects the quality of the session. It’s a feedback but a negative one.

After couple of tries I noticed exactly what condition the software was rewarding. In my internal vocabulary I refer to it as “mudding”. It turns out that, according to the published materials, the calming level is a product of appropriately weighted values representing the absolute values of signals representing individual brainwave bands. What matters is the reduction of their amplitude. This can be achieved not only by focusing but also by allowing yourself to fall into trance-like or near sleep states.

Armed with this knowledge I decided to keep trying and started to get used to the evaluation mechanism. I have learned to treat the sound of the rain as a pleasant and momentary object of concentration. As the sounds of the bids were stopping, I was trying to sink deeper into the soft, slimy feeling of soaking into the sensations of the body and the breath. It also helped to focus more on the exhalations than the inhalations. It also helped to incidentally lengthen the breath and trying to look far into blurry vision until the sense of sight was turned off.

The results were better but I wondered if it was possible to achieve a 100% calm factor. After a few more tries I decided to make two important changes:

• Mute feedback sounds (in app settings).

• Give up the original assumption of relying solely on application instructions and benefit from experience in zazen, one variant of which also involves working with breathing.

In the practice mentioned in point 2, relaxation and calmness are not the main parameters keeping the direction of practice in check – the ability to stay with the object of focus is more important while the calmness of the mind may appear as a side effect of concentration. The instructions given to us by the application sound very similar but the purpose of this practice is different, as well as the level of determination during training. In zazen you breathe with 100% attention, you become the breathing while touching the edge between tension and peace. However, this does not exclude a benevolent attitude towards oneself, a gentle return to concentration when we get drawn into thoughts – and this is, among other things, the point.

Right after the first session in the new model I had the impression that it would be the least calm exercise. It seemed to me that my state hadn’t changed much and there was even more space for randomly flowing thoughts that drifted somewhere in the background. This subjective assessment, however, turned out to be incorrect. Following the breath with the eyes open and maintaining a proper body posture led to the development of a mental condition that the device rated highly on a calmness scale.

I later found out that this state could be further deepened by using an accelerated, sharp way of letting go of emerging thoughts by redirecting attention and intensifying focus on the breath. This approach is tiring in the long run because we cut off thoughts before they ever have the chance to develop, which over time may result in an energy loss, the source of which is the free flow of internal experiences. However, when our temporary goal is to increase the number of points in the application we can use this tactic for a few or several minutes and it will be easier to approach a state resembling falling asleep where lines of thought which were previously cut can seep and envelop the mind, although without having a strong constructive and stimulating quality.

After the testing period I started using the Muse device with fully muted feedback sounds, averaging more than 95% calmness. For longer sessions I’m no longer wearing the band but use the application to count down the time.

I can recommend the device to anyone who wants to try biological feedback in reducing stress or increasing the level of concentration in controlled conditions. However, I would like to forewarn those who have been practicing in some system for longer against surprising (at least at the beginning) results. It may turn out that the method used induces states that are not highly scored. In practices with multi-object visualizations, as well as where one is working with emotional experiences or physical sensations, the application may falsely indicate anxiety. That is because some areas of the brain become active which leads to the generation of brainwaves of undesirable frequencies in the context of evaluated level of calmness.

In retrospect, I do not regret choosing this particular device model. It’s a good idea to check your own condition once in a while by applying objective indicators to things as subjective as focus or peace of mind. It is also nice to observe the adaptive abilities that you can then show to yourself and to your readers. Even nicer it is to hope that calming and concentration need not be a goal in itself but rather a means of facilitating insight and shifting perspective.

In the application I missed a mode that would allow me to access the so-called raw data or visualization of individual brainwave frequency bands. I could then use the headband for various exercises, not only those proposed by the manufacturer. Moreover, I would be able to investigate how the techniques of affecting the bioelectrical activity of particular regions of the brain.

Experiment

Two weeks after the end of the tests I began to wonder how else the headband could be used. There was an idea to test some meditation techniques that I know. However, it seemed problematic that the presented parameter of calmness is based on an already calibrated and calculated value, the source of which is data from EEG sensors. Maybe there would be a way to gain direct access to them?

It turns out that the headband which communicates with the application via Bluetooth sends data from each sensor separately. In 2016 there was even an additional application for enthusiasts to access this information. Besides that there was a Software Development Kit (SDK) published by the manufacturer thanks to which interested parties could integrate their own applications with Muse bands. The idea was abandoned and currently (2020) the most reliable (in my opinion) method of obtaining raw sensor data is to use one of the unofficial mobile applications: Wave or Mind Monitor. The former is a simple oscilloscope that can save EEG data as CSV files (Comma-separated values) while the latter is a more advanced tool with multiple chart types, streaming server and Dropbox integration.

Brainwaves

Before moving on to the description of the experiment I will explain what are brainwaves or (more specifically) the cycles of bioelectrical activity of the brain which can be read using electroencephalographic sensors.

It was 1924 when the German psychiatrist Hans Berger proposed the term electroencephalography (EEG) for measuring the electrical activity of the brain using electrodes placed on the scalp. He noticed that depending on a person’s mood, arousal, level of focus, i.e. the current state of consciousness, electrical potentials change and the change is wave-like. This paved the way for further research and allowed to “look” into heads in a more objective way than an interview or observation of behaviour.

It turns out that groups of neurons in different areas of our brain generate delicate electrical impulses with wave characteristics when cooperating with each other. Echoes of that activity can be measured on the surface of the head using appropriately sensitive instruments.

However, it is worth knowing that we deal with an input that consists of many signals of different frequencies. The equipment should therefore filter them properly and split into separate bands. As a result we will get several graphs showing the time-varying signal that belongs to the appropriate frequency band. Each of such bands in this spectrum has its common name and – in simplified terms – we can distinguish various types of the so-called brainwaves:

• delta waves (δ) - oscillate from ¹⁄₂ to 3 times per second, have a high amplitude and are dominant during the 4^th phase of dreamless sleep (NREM);

• theta waves (θ) - oscillate in the range from 4 to 7 times per second and appear in deep meditation, hypnosis as well as when experiencing intense emotional states;

• alpha (α) waves - oscillate in the range of 8 to 13 times per second and will be strengthened when we experience relaxation and calm concentration;

• beta (β) waves - oscillate in the range from 12 to 28 times per second and indicate everyday life functioning (normal perception, mental effort);

• gamma (γ) waves - oscillate in the range from 30 to even 100 times per second and signal movement, intense memory operation, as well as synthesizing sensory stimuli into conceptual content but in meditation they indicate high awareness and/or working with higher feelings.

Of the listed above, alpha waves are the most known to the general public. Many books were written about them and at the end of the last millennium they were promoted as the key to quick memorization. We can experience alpha activity every morning (right after waking up) and evening (before going to bed) and also when we rest.

To talk about being in some state of the brainwaves is a simplification. When we look at the EEG record we see that there are signals from all of these bands. It happens, however, that some of them are dominant – either their amplitude is higher than it should be or their duration indicates a specific state of consciousness (e.g. in the case of the gamma range).

Measuring brainwaves is carried out by adding up the amplitudes of signals belonging to all of the available bands within some time frame and calculating the average. It then becomes the base value against which the power of each separate band is reported.

Goal, means, methods

The goal of my experiment was to test several popular meditation techniques and see which of them have the greatest potential for changing my state of consciousness.

From a neuroscientific point of view, meditation practice is about inducing altered states of consciousness by changing the default balance of the nervous system’s activity. The most common purpose of meditation is transformation of perceptions associated with getting insight into the true nature of mind and reality. As a result, there may be permanent changes in the perspective of experiencing both oneself and the world.

I assumed that I will focus on three types of waves: alpha, theta and gamma. These are the signals in these frequency bands that will interest me because they indicate calming the mind (alpha), deep meditation (theta) and deep insight or higher feelings (gamma). If necessary, I will discredit the beta (wakefulness) and delta waves (deep sleep) to negatively score states of intellectual agitation or fatigue.

During my research I decided to do each of the following practices:

• breath counting with eyes opened,
• following the breath with eyes opened,
• meditation without an object of focus,
• tantric practice with yidam and mantra,
• the cultivation of benevolence.

The first practice, breath counting, is a concentration exercise that consists of counting out exhalations or whole breaths from 1 to 10. It allows one to achieve a relative calmness of the mind and can be a prelude to following the breath.

Following the breath is a technique that leads to the achievement of the so-called access concentration (Pāli: upacāra samādhi). This kind of concentration leads to calming the mind (Pāli: samatha, Sanskrit: śamatha, Tibetan: shyiné) which opens the way to other practices and associated states of consciousness: meditative absorption (Pāli: jhāna, Sanskrit: dhyāna), mindfulness (Pāli: sati) which is the basis of insight (Pāli: vipassanā), as well as the methods of triggering pure awareness without a specific object.

Meditation without an object (also called objectless meditation or meditation without seed) is based on maintaining concentration without focusing on a single object or hopping between several objects of attention. It increases awareness and leads to insight quickly but can be difficult for beginners due to the ease of being absorbed by strings of thoughts. Its variant includes the practice of just-sitting (Japanese: shikantaza) known from the Soto school of Zen.

The Tibetan practice of yoga tantra (one of the classes of tantra in Sarma variant of Mahamudra) consists in calming the mind, adopting the right attitude, arousing the mind of awakening (Sanskrit: bodhicitta) and visualizing a meditative deity (Tibetan: yidam, Sanskrit: iṣṭadevatā) in close proximity. These stages are followed by the mantra phase, that is, the repetition of syllables related to the meditative aspect. Focus can be transferred between objects, which are, for example: the sound of the mantra, yidam qualities, relationship with the yidam, letters symbolizing the mantra (which is repeated aloud or in the mind). Practice ends by dissolving the yidam in oneself and/or dissolving all the phenomenal world.

The last method tested is metta meditation also known as loving-kindness meditation or cultivation of benevolence (Pāli: mettā bhāvanā). After calming the mind for a while one works with an intention (that may be supported by visualization) in which the wishes are formulated for benefit and happiness of all beings which leads to awakening oneself in loving-kindness (Sanskrit: Maitrī, Pāli: Mettā). There may appear pleasant emotional or bodily states, similar to those experienced during initial absorption in concentration practices.

Execution

I reserved about 5 minutes for each practice. It may not seem much but this is enough to notice the different characteristics of the EEG. The exercise began with taking a posture and relaxation for about a minute and ended with relaxation and body movement (after the counted time). The idea was not to transfer states of consciousness between testing of the successive methods.

I had a plan prepared for each exercise that was read by my companion so that I would know when to start and end certain phases of meditation and refer to them in my calculations.

During the meditations I used the Muse 2 band connected to the Wave application which recorded 5 frequency bands of my brainwaves. Here is a visualisation of their changes in real time with background music added later:

You can enable captions in the player using the CC button – English and Polish are available. They contain additional information about the steps of each method. Additionally there are links opening the clip at moments where the subsequent practices are recorded. They can be found in the description of this material on the video hosting site or bellow:

• breath counting,
• following the breath,
• tantric practice with yidam and mantra,
• objectless meditation,
• the cultivation of benevolence.

Data

Having the EEG record in the form of CSV files I was able to start the calculations. I was interested in which practices alpha, theta and gamma waves are the strongest.

Looking at the data from the CSV file we can see that there are absolute signal values for each frequency band. The name of the first column suggests that there is also information about the so-called frame. This is de facto the number of the next sample collected over time (at a sampling rate of 10 times per second).

I consolidated the data from individual sessions (saved in separate files) using the popular Excel spreadsheet. In total, there were not so many of them that it would require writing a computer program and the calculations are not so complicated that a spreadsheet could not handle them.

After consolidation it is time to choose the most interesting moments, that is to remove the “warm-ups” and endings of each practice. It is enough to replace the frame numbers with a time interval (expressed in minutes and seconds) and we can go for it.

From the five-minute sampling periods of each session I extracted a 3-minute and 15-second timeframe which included the most important parts. The opening cut was performed at 1.30 (after relaxation and initial mental calm) and the final cut at 4.45 (before the end of session).

In the screenshot above you can see some extra columns with data:

• F Time is the relative time calculated from the sample number,
• G Session stores the name of the meditation session,
• H Floor (beta+delta) is the sum of signals for the beta and delta bands,
• I Alpha rel is the difference between alpha power and the floor from H,
• J Theta rel is the difference between theta power and the floor from H,
• K Gamma rel is the difference between gamma power and the floor from H,
• L Alpha rel B is the difference between alpha power and beta from B,
• M Theta rel B is the difference between theta power and beta from B,
• N Gamma rel B is the difference between gamma power and beta from B.

The columns with “rel” in their names are used to correct the absolute values of the signals representing alpha, theta and gamma waves. The first three will correct them by subtracting the sum of beta and delta powers from them and the second three just beta. In this way, it will be possible to obtain the greatest difference between the strength of a given signal and the strength of signals that are undesirable from the point of view of meditation practice.

In the first correction group (I, J, K) I take the delta waves into account since such short practice does not indicate a deep altered state, but rather ordinary fatigue and sleepiness. In the second group (L, M, N) a beta value is the only subtrahend. This difference will hopefully give me more accurate data about how altered the meditation state is since I’m only subtracting values of beta signal power, leaving delta band signals which are known to naturally have high amplitudes.

Calculations

Let’s do the calculations for each practice. From the data series reflecting signal strengths of alpha, theta and gamma brainwaves I will calculate averages and medians and then make comparisons (direct or by introducing some relativizing coefficients).

The average and median values of signal strengths for the essential types of brainwaves were adjusted using the three methods (mentioned earlier) before being applied in calculations:

• absolute (unchanged values),
• relative to the sum of the values of beta and delta signals,
• relative to the value of the beta signal.

When presenting the results, I omit the obtained average values because they do not differ so much from the medians and lead to the same conclusions.

Absolute Medians

The absolute values of the signal strengths will be used to compare the strengths of individual waves in order to reveal the dominant bands in particular techniques. Such an analysis will tell us nothing about the “purity” of a practice and its effectiveness in achieving the intended state because we do not take into account the influence of undesirable waves.

Winning methods:

• concentration, deep meditation: following the breath;
• synthesis / higher feelings: yoga-tantra with mantra.

Means of Absolute Medians

The average of medians from the Absolute Medians table will allow us to calculate the relative level of calmness and mental activity (arousal) in a similar way as neurofeedback apps do.

Winning methods:

• the highest arousal: yoga-tantra with mantra;
• the highest calmness: objectless meditation.

Medians Relative to β+δ

The values of the signal strengths for the bands of interest which are reduced by the strengths of the beta and delta signals will be used to investigate which bands stand out from the others and which have relatively similar amplitudes.

Winning methods:

• concentration, deep meditation: objectless meditation;
• synthesis / higher feelings: loving-kindness.

Means of Medians Relative to β+δ

Based on the data from the table Medians Relative to β+δ we can calculate the averages that will allow us to see for which practice we are dealing with waves with the highest signal power on average.

Winning methods:

• the greatest distinction of the bands of interest: objectless meditation;
• the greatest diversity of all bands: yoga-tantra with mantra.

Medians Relative to β

Values corrected by the strength of beta wave signals will make it possible to select techniques that alter the state of consciousness the most, that is, are the most different from the brainwave patterns of ordinary activity.

Using this frame of reference to compare the dominant waves in specific methods would, however, be burdened with the error resulting from ignoring the states of sleepiness (delta waves).

Winning methods:

• concentration, deep meditation: following the breath;
• synthesis / higher feelings: loving-kindness.

Means of Medians Relative to β

Winning methods:

• the most altered state: yoga-tantra with mantra;
• the most ordinary state: loving-kindness.

Waves Plebiscite

The calculations below are meant to show brainwaves specific to each practice. Since their amplitudes in different frequency bands are different we must first calculate the proper weights in order to be able to convert values from different brainwave types to a common range.

Comparing the absolute values from different wavelengths or even the values corrected by the initial calibration reading (not used here) would be based on a flawed frame of reference since signal amplitudes have their own natural characteristics related to the specificity of the respective brain regions. For example, some types of brainwaves will always have lower minimum and maximum values, not much different from the calculated average, although when a certain threshold would be exceeded it would indicate an unusual phenomenon. So let’s try to assume the scales based on the mean values from those previously presented in the Absolute Medians table for individual practices. By using medians instead of all the values as base we will highlight the differences a bit:

On the basis of the means of the individual brainwave bands from the previous table of medians and the average of these means we can calculate the comparison coefficients (Cs):

Now we just need to use the medians obtained earlier and calculate the values using the coefficients to compare the different brainwave types across each practice. We are looking for distinctive values in each row:

As a result:

• in breath counting the distinctive brainwaves are alpha,
• in following the breath the distinctive brainwaves are theta,
• in yidam and mantra practice the distinctive brainwaves are gamma,
• in objectless meditation the distinctive brainwaves are alpha,
• in loving-kindness meditation the distinctive brainwaves are gamma.

By the term “distinct” I mean the dominance of the weighted median of the brainwave signal belonging to certain band transformed using a coefficient calculated by using closed series of experimental data. This means that we detect the most significant deviations of brainwave types in relation to the compared practices. For example, in counting breaths, the differences in the signal values between alpha brainwaves and the values of the other brainwave bands are the greatest. It does not mean that in this practice other brainwave signals measured in an absolute way will not dominate. This means that in the case of counting breaths alpha waves showed the greatest positive change in relation to the change in comparison to other practices.

Of course, the above applies to my brain, my mind, and my practices. It is possible that other people and under different conditions we would have obtained different results. On the other hand, these results are largely in line with the commonly available knowledge about the influence of meditation on the brain’s bioelectrical activity.

Weighted Medians Relative to β+δ

Having the comparison coefficients, it is worth calculating one more table that would indicate the “purity” of the practice by examining only those signals that are desired in a particular method. This will be an improved version of the Means of Medians Relative to β+δ table. First, I will create an auxiliary table based on Medians Relative to β+δ but I will convert the values using the coefficients.

Weighted Means of Medians Relative to β+δ

Winning method:

• the best “purity”: objectless meditation.

Optimal practice

By “optimal practice”, I mean one which:

• Comes to me best.
• Provides the expected results in terms of altering the state of consciousness.

Thanks to the calculations carried out before I can focus on relatively objective indicators in the above matters. Therefore, I assume the following understanding of the term “Comes to me best”:

• The method is “pure”, meaning there is a big gap of signal amplitudes between wanted and unwanted brainwave bands.

• The method leads to fairly good level of calmness, meaning all brainwave signals are below certain value when taking the absolute values;

• The method leads to deep meditation in the context of altered states of consciousness.

The first information (reflecting the quality of “purity”) can be obtained from the tables Weighted Medians Relative to β+δ and Weighted Means of Medians Relative to β+δ. The second (ability to calm the mind) from the Absolute Medians table. The third from the Means of Medians Relative to β table supplemented with information from the section Waves Plebiscite.

The criteria is a result of my chosen direction of development, i.e. I want to deepen the level of calming the mind in order to explore techniques related to meditative absorption and I treat the level of “purity” of the practice as an indicator of my mind’s predisposition to use it.

Regarding delivery of the expected results by a method, the last calculation (entitled Waves Plebiscite) will be useful. Since certain frequency bands of brainwaves are associated with specific states of consciousness, it is sufficient to find out which practices have the potential to induce them. Let me add the secondary characteristic type of brainwaves occurring in a given method in order to enrich the list with some additional “flavors” of practices.

An example that draws attention to carefully formulating conclusions based solely on a comparison of the most outstanding brainwave signals for each practice is objectless meditation. Here it is presented having the same qualities as counting breaths, the most preliminary method, being characterized by alpha brainwaves that are dominant in concentration and relaxation, as well as by moments of deep meditation. However, this information does not tell us about the negative (in a positive sense) aspect, that is, how much of other brainwave signals were damped during and what was the distance between their average signals and the average of alpha signals.

Therefore, it is necessary to refer to the tables Medians Relative to β+δ and Means of Absolute Medians. We will learn from them that objectless practice has the largest gap between the desired brainwave bands and undesirable ones, which in this particular method means the strongest concentration and potential for deep meditation (alpha and theta waves dominated). Besides that, this method has the highest absolute level of calming the mind. So it is very different from counting breaths, although we observe similar states of consciousness – at least during the first five minutes!

Summary

Let me summarize the collected information in a table of characteristics:

Legend:

• FB – following the breath
• BC – breath counting
• OM – objectless meditation
• YT – yoga-tantra with mantra
• LK – loving-kindness
• ✅ – primary quality
• ✓ – secondary quality

Let’s see which practice has the most positive qualities, so it’s somehow more suited to my mind. I will score double distinguishing qualities and single secondary qualities. I will also take into account the initial assumptions, i.e. the practice must calm the mind, have a high degree of “purity” and change the state of consciousness.

In order to compare more features with each other it is worth having a more precise set of measurable parameters representing them. I will consolidate the opposites (e.g. activity and calm, as well as the altered state and ordinary state):

In the case of the data in the row titled “arousal” (which is the opposition to calmness in terms of the absolute activity of signals from all bands) I will let myself transform them to “calmness”” by mirroring the values against their mean:

Now I will equalize the scales of individual qualities by transforming their values to comparable dimensions. I will use 1^st degree polynomials with the following, previously calculated parameters (I assumed scaling each value to the range from 0 to 1):

• purity: a=0,63 b=0,84;
• calmness: a=5,5 b=-1,1;
• altered state: a=3,7 b=-0,48.

The resulting sheet looks like that (I rounded the boundary hundredths to zeros or ones):

Of the above techniques, the following have the characteristics that best meet the original assumptions about measurable indicators related to the desired qualities:

1. objectless meditation (0,79)
2. yoga-tantra with mantra (0,45)
3. following the breath (0,40).

The most optimal method for the assumptions made is objectless meditation. Such a choice, however, involves a certain technical problem, because in the practice of absorptions, which I have been recently interested in, a pleasant mental formation becomes the object of concentration after some time, which causes the focus to stay with it by itself and the state to deepen. I think that with this particular path I will be practicing following the breath and moving to objectless practice when the absorption does not occur after some period of time or after it has occurred.

An interesting fact is the tantric practice in the second position which was characterized by the most altered state of consciousness and the lowest level of absolute calmness among other methods. This was due to the presence of gamma and theta brainwaves the strengthening of which took place without the gradual deepening of the focus. This was thanks to the psychological trigger associated with a specific meditation deity which led to an immediate alteration of state within a dozen or so seconds.

I hope that this experiment will inspire someone to practice and/or undertake similar research on the border of neuroscience and practical spirituality.

Conclusions

Biological feedback, and neurofeedback in particular, can be a good support in meditation and relaxation practices. Thanks to the neuroplasticity of our brains we are able to develop our ability to concentrate and calm our mind by observing the effects day by day. EEG biofeedback is also useful during periods of doubt. It may help when we have a problem with the subjective assessment of the level of concentration yet we need to “tune” the practice to our present condition. It then becomes a kind of automated and soulless version of a meditation teacher. :)

For the Muse 2, which was designed with the mind exercising in mind, I can share the following observations:

• If the feedback on successes and failures causes tensions and acts contrary to the goal, it is worth reducing the volume of the feedback sounds (in the application settings). I also encourage you to spend a few sessions listening to the sound of rain being played to develop the habit of associating it with a calming sensation, without worrying about the number of points.

• While doing custom meditation practices you can still measure the level of calmness but for some meditation techniques it can get you completely unpredictable results. This is a natural effect due to the fact that not all methods of working with the mind rely on total relaxation in which all types of brain waves will be less powerful.

• From time to time, it is worth trying other available exercises (e.g. related to heartbeat, breathing or maintaining the correct body posture) even when your goal is to concentrate or calm down. This way the body will be better prepared to work with the mind and it will positively influence the quality of the practice.

• It is a good habit to carry out the practice systematically and even better at about the same time each day (and rather before eating). Just like in sports you cannot train your mind in advance. Even 10 minutes a day will give better results than a few hours once every few weeks.

• You can quickly achieve 100% level of calm by using various tricks that affect the bioelectric activity of the brain but in the long run this type of exercise will create harmful habits and you may become more tense, withdrawn or deprived of energy in a daily situations. It is worth giving yourself some time and space to experience relaxation, even at the cost of a few muse points. It will make it easier to return to practice by associating it with something pleasant and non-judgmental rather than another obligation.

• When you have prior experience of working with the mind and have practiced meditation for a long time you may have an inadequate, subjective belief that your own calmness is low. Reading the EEG then helps you see that calming your mind depends on your concentration, especially in the early stages of meditation sessions. So it is not undesirable to have a certain mental discipline in the first moments of doing the practice which can sometimes be misdiagnosed as being too tense, especially when you watched popular instructions published all over the Internet which emphasize relaxation. Relaxation is important but concentration is the key to success with most methods. It is a matter of some balance.