QUANTITATIVE electroencephalography (QEEG) and neurofeedback (NFB)

NFB is a form of biofeedback that is over 50 years old when it was initially used to treat seizures, attention deficits and addictions. Biofeedback is a method to give you feedback regarding your physiology, usually with the use of technology. 

An example..

A thermometer gives you feedback about your physiology so that is biofeedback. If you were to hold the thermometer in your fingertips and try to increase its temperature (this is possible!), you will get feedback as to how successful your strategy is – usually and internal strategy that is challenging to explain, usually it’s something you feel. Then based on that feedback, you can do more of the same – if the thermometer shows your strategy is working – or you can change your strategy – if the thermometer shows that your strategy is not working. 

How effectively biofeedback is in helping in changing physiology is based on Learning Theory, beyond the scope of this article, however, briefly, it outlines the ideal parameters to encourage learning – when to reward the patient, when to remove that reward, how much of feedback lag there is (very small), how often to train, etc. 

NFB is focused on giving patients feedback about their brainwaves. And then through Operant Conditioning (A theory of learning) the brain takes that feedback and influences the state of its electrophysiology towards the desired direction.

For example, to increase certain brainwaves in certain areas of the brain, an electrode is set up over that area of the brain to sense its brainwaves. The patient is then given the task of exploring ways of increasing a specific brain wave signal in that area. If patients succeed, they are given a reward in the form of a real-time pleasant, satisfying sound or video. This will let them know to keep on doing what they are doing and they will become more familiar with the strategy that works. Eventually, they will be able to generalize these strategies to real-life situations when biofeedback equipment is not being used.

Biofeedback devices are FDA approved for relaxation training and for improving self-regulation. They haven’t been FDA approved to be a treatment for DSM diagnoses. The rigor of research required and the practical challenges with studying NFB as you would a medication (experimental drug vs. placebo) make it challenging for BFB to achieve this level of FDA clearance.

That being said, stress, relaxation and self-regulation are a part of most health conditions. Certain brainwave patterns in a child with ADHD can cause significant distress as can a certain brainwave patterns in an adult with depression. Thus, in this sense, people can deem training self-regulation to be helpful in improving ADHD or depression, although technically it would be considered to be an off-label use of biofeedback. In effect, all medical conditions can be treated off-label by varying methods of regulating psychophysiology; in fact, most of psychotherapy can be considered ‘off-label’ for many diagnoses although it is commonplace and widely accepted. For example, a some stress management techniques may mitigate stress enough that it results in lower blood pressure, say for example the technique used was tapping. Then tapping can be seen as an off-label treatment of hypertension as there is no evidenced-based study showing its efficacy.

It is a picture that shows the nature of the electrical activity of your brain. It can show the types of brainwaves that are being generated as detected from different regions of the scalp. Unlike an MRI that shows a picture of the brain’s structure, this picture is correlated with the brain’s function. The brainwaves that have been identified and are being studied are grouped into 5 main categories – delta, theta, alpha, beta and gamma, with some subdivisions. There are some generalizations about how each of these brainwaves will affect one’s functional ability. By knowing where these brainwaves originate (i.e., which regions of the brain) and the function of those regions of the brain, we can get an idea of patients’ tendencies and how that may relate to their clinical pictures. This is achieved by uploading the measured raw EEG data into a computer, and processing it with mathematical methods. Like this, a patient’s brain map can be compared to any population we desire by the use of databases.

The brain map does not offer a diagnosis.

For example, currently in mental health, the DSM (the Diagnostic and Statistical Manual of Mental Disorders) is the method by which people receive diagnosis. Some behaviours or tendencies, while not a disorder (i.e., do not qualify for a diagnosis in the DSM), may still be seen as a problem by the patient, or be identified as an area where they can improve. That is, not being perfect is not a disorder! However, many of us may wish to improve some aspect of our performance (e.g., sleep, energy, focus) to improve our quality of life.

Now that being said, certain brain map patterns will correlate with certain diagnosis, and as such, lend support to that diagnosis. More importantly, the clinical diagnosis is a crude label that we can all see.

But is all that lays under still waters the same?

We know that we are all genetically unique; and this equips us with some relative innate strengths and weaknesses compared to others. However, Warren Buffet is said to naturally have a shy temperament and was frightened of public speaking; however, you would never know it by hearing him speak (Alberti et al., 2017). Like that, one’s genetics are not a life sentence, and will not necessarily etch in stone the outcome. We all have the ability to learn and work with what we got. As this idea relates to qEEG, we have the ability to change the EEG to change our performance. The EEG pattern is known as the intermediate phenotype (Gunkelman, 2005).

So, an interesting question is…Does any given diagnosis in the DSM only have one intermediate phenotype? That is to say, will all people with say, OCD, have the same brain maps?

The answer is no. There have been 3 distinct brain map patterns (i.e., intermediate phenotypes) that have been identified to correlate with the DSM diagnosis of OCD; 11 with ADHD (Gunkelman, personal communication); several for alcoholism. What’s more, knowing these intermediate phenotypes has been shown to correlate with likelihood of success in managing certain conditions with certain medications.

Take alcoholism for example.

EEG investigations of alcoholics and their children have documented that even after long periods of abstinence, they have lower levels of alpha and theta brainwaves and an excess of fast beta brainwaves. This suggests a genetic predisposition for alcoholism and difficulty with relaxing, which has already been corroborated with clinical, non-EEG, studies. Alcohol is known to increase theta and alpha brainwaves, feeding into the notion of self-medicating. In a sense, pleasant brainwaves reinforces alcohol intake proportionately more for these individuals relative to others who don’t have this genetic predisposition (Hammond, 2011). Moreover, studies have shown that the best predictor of relapse is the amount of excessive beta brainwave activity that is present (Bauer, 2001). Studies by Peniston and Kulkosky (1999) have shown that training alcoholic patients to increase alpha and theta brainwaves significantly increased the level of sobriety and that 4 years out, 80% of the group that received NFB training remained abstinent whereas only 20% remained abstinent in the non-NFB group. What’s more, beta-endorphins (a marker of stress) were shown to be increased in the conventional treatment group whereas that was not the case in the NFB group.

In this instance, the assessment, diagnosis and treatment were delivered in a conventional medical paradigm but the addition of NFB training was found to be a useful tool.

Furthermore, in alcoholics (i.e., those meeting DSM criteria for alcoholism) who do not display the pattern of brainwaves mentioned above, emphasis on different aspects of the treatment plan may be different. For example, it is known that mental health issues tend to carry significant medical comorbidity. So for example, a patient with ADHD will be more likely to face clinical distress than one without ADHD and this may result in increased alcoholism or substance use. Now, from an EEG perspective, there have been different patterns of EEG (i.e., different intermediate phenotypes) seen in those diagnosed with ADHD. For example Suffin et al. (1995) showed that some people with ADHD have elevated frontal lobe beta activity (fast brainwave activity) rather than the more slow wave brainwave activity. But, if an ADHD patient with elevated slow brainwave activity (i.e., elevated theta like the majority of those with ADHD) were to also have alcoholism, the alpha-theta training protocol would not be indicated (i.e., we wouldn’t want to train more slow brainwaves, like we would for the group that have a low amount of slow brainwave activity).

The management of alcoholism is a large topic consisting of multimodal, multidisciplinary care; NFB is but one modality that sheds more light as to the nature of one’s tendency towards alcoholism. From the examples above, you can see resorting to alcohol to help relax is fundamentally different than resorting to alcohol to help forget or cope. The former would benefit from relaxation training and the latter from coping strategies and improving ADHD management; in turn, the potential NFB training protocols would be different despite both individuals having the same diagnosis of alcoholism, and both individuals receiving a lot of the same type of therapy.

In a sense, clinical management (i.e., history, physical exam, investigations, tests, questionnaires, etc.) decides where the patient is on the map (i.e., of illness) and where the patient wants to arrive; and NFB can give information to help choose a more efficient path of getting there, in addition to the other treatment options.

]Different regions of the brain are responsible for different emotions and processes.

For example, the right hemisphere of the brain is responsible for what we know to be the: EQ (emotional quotient), swearing, early self-concept, social skills and encoding, facial recognition, emotional process, negative emotions, empathy, nonverbal expression and association, spatial memory and problem solving, auditory processing and musical processing. The left hemisphere of the brain is involved in: IQ (intelligence quotient), logic, verbal association, verbal expression, verbal memory, auditory processing, word recognition, math and grammar and problem solving (Longo, 2018).

Likewise, within the cortex there are areas known as Brodmann areas, each area being structurally unique and having a unique role in neurophysiology. Subcortical structures also are a source of EEG and have unique roles too; these are better highlighted using sLORETA and eLORETA QEEG techniques.

Let us give you an example of how knowledge of neurophysiology can facilitate clinical improvement (read our post on “First get your bearings…“).

What about the brainwaves (Delta, Theta, Alpha, Beta, Gamma?)

Brain waves that we measure are generally categorized into five categories: Theta, Delta, Alpha, Beta, Gamma. These are categorized to reflect how fast the brain waves are, or what their frequencies are.

Delta waves are commonly associated with sleep and deep levels of relaxation. This can be abnormally present during learning disabilities, problems with attention and cognition, and traumatic brain injury.

Theta waves are the next slowest and they are associated with inattention and dissociation but also associated with creativity and imagination. These waves can be dominant and people with ADHD and impulsivity. Too little of this may cause someone to have poor emotional awareness.

Alpha waves are the next fastest waves and they are associated with being in an idle state, or when the brain is not really dealing with something. Like that, it is associated with being in a relaxed and calm state, and ready to go. Too little alpha can indicate stress, decreased cognitive stamina, and cognitive processing deficits.

Beta waves are the next fastest waves and are associated with logical thinking, learning, and conscious thought. Too much of this can be correlated with too much stress and anxiety, hyper-arousal, or an inability to relax. Too little of this and you may find problems with concentration, find yourself daydreaming a lot, feeling more depressed and having poor cognition.

Obviously, these are generalizations and how any brainwave type affects you depends in which area the brainwaves are found and how they communicate with other parts of the brain.

Read our article Preparing for your QEEG Assessment (Brain Map) for more information on how to get the most accurate test results.

Applying the cap (that contains 19 sensors)

Your forehead, earlobes and scalp are cleaned with a special cleanser. The properly fitting cap is then placed on your head. A blunt thin tube is used to abrade the scalp and earlobes slightly so that we get good impedance values (i.e., get low resistance to acquiring EEG signal) – this will be verified by the technician before the recording process is begun. Some people feel that this is a bit uncomfortable. Gel is then inserted into the electrode ports on the scalp. These electrode sites are standardized and follow the 10-20 system (see image). 

Getting the Recording

You are then sit in a comfortable chair and instructed to sit up straight with both feet on the ground. Turn your cell phone on silent or turn it off. Keep it at least 3 feet away from your person as to not allow the phone’s electromagnetic radiation to interfere with the equipment. Measurements are then taken with your eyes closed and eyes open. The process of data collection takes between 15 to 30 minutes and is more efficient if you can relax and minimize movement. Movements like eye blinking, eye movements, muscle furrowing, swallowing, tongue moving will obscure the EEG signal we are trying to collect. The technician will show you the effects of the movements mentioned above on the EEG to give you that biofeedback so you can endeavour to avoid it. The effects of these movements on the EEG can be removed afterwards but sometimes it does affect the interpretation, even after the artifact has been removed, hence the dictum ‘an ounce of prevention is worth a pound of editing’.

Reviewing the results

Once the raw EEG is cleaned up and artifacts are removed, then the results are interpreted. It is important to have a good knowledge of neurophysiology so you can correlate the brainwaves measured to the regions of the brain from which they were measured.This is then correlated to your clinical situation so we can see brain tendencies that may contribute to the same. This is useful because it can directly suggest certain behavioural and NFB training strategies to influence your neurophysiology and, in turn, your clinical situation.

The most common benefits are feeling more calm, having better focus, and sleeping more soundly. This may lead to improved work performance, better time management, fewer headaches, etc.

It’s pretty common to not feel much effect with NFB for the first 5-6 sessions. After that, patients usually notice differences in how they think, feel, and behave. At that time, they are usually more aware of the effects of NFB. At first, they may notice that the benefits of a NFB training session lasts for 1 to 2 days. After 20 or more sessions, it is common to feel benefits lasting up to a week. Obviously, the goal is to no longer require to come in and receive biofeedback, but to have internalized the skills that you learned with the use of biofeedback. The more mindful and intuitive you are, the more committed you are to practicing the skills on a daily basis, the more efficient your results will be.

Functionally, as patients progress with NFB training, they will usually notice changes in many facets of their lives.

Socially: they may notice a more peaceful social life; people may comment about positive changes they have noticed.

Biologically: You may require less medication or may consume less alcohol. You may notice improvements in health conditions like gastrointestinal issues, headaches, sleep quality, etc.

Professionally: they may notice improved focus, time management and stress resilience.

One’s lifestyle is not only a measure that can be used to gauge positive effects of NFB training, it is also an area that can hinder or support NFB-related benefits.

There are aspects of our lifestyles that can hinder the utility of NFB training. 

Lifestyle: Nutritional deficits, lack of regular exercise, unrefreshing sleep, stressful lifestyle, etc. are all factors that can mitigate benefits from NFB training. By improving your dietexercise regimensleepcoping strategiescognitive compensatory measuresenergy management strategies, you will enhance the efficacy of NFB training. Generally, a routine and lifestyle consisting of regular bedtimes, nutritious and consistent meals, a regular exercise program including cardiovascular exercise, and avoidance of situations that are known to be stressful. Obviously, it is not practical to eliminate all stress from one’s lifestyle. Try to employ a good stress management techniques and assertiveness. Try not to ruminate on negative thoughts and emotions. Practising mindfulness and living in a supportive environment is helpful.

Social: A stressful home environment, a deficient support system, isolation, etc. are all factors that can mitigate benefits from NFB training. These can be tougher to accept and regulate your emotions in the face of them.

Professional: Toxic work environments or extreme work stress including excessive hours of work will be incompatible with effective NFB training for most patients. There are many strategies that can be used to help with this including assertiveness training.

Health: unstable medical conditions will make it challenging to participate in NFB training. It is advisable to regulate these more to allow for effective participation in NFB training. For example, those with chronic migraines may find that the energy expended during NFB training further aggravates their migraines making it counterproductive; the very brain we are trying to regulate is being pushed further into dysregulation. Another example would be serious mental health issues that involve delusions, hallucinations, mania or suicidality. The severity of these conditions will hinder motivation and not afford one with the requisite self-regulation required to benefit from NFB training. You should discuss with your primary healthcare providers if they feel 

Performance: Practicing heart rate variability, psychotherapeutic techniques and/or other measures of self-regulation are a prerequisite for successful NFB campaign.

The number of sessions varies from patient to patient as many factors weigh in:

  1. Lifestyle and social circumstances as mentioned above. 
  2. Brainwave characteristics. 
  3. The clinical situation including its severity
  4. Medical comorbidities
  5. Your goals. 

Number of sessions usually range from 10 to 60 sessions with the majority being between 30 to 40. NFB sessions usually last about 30 minutes.

2-3 sessions per week is ideal. Practically speaking, many people can’t make this level of commitment and it may be better to look for another treatment modality. Doing it less frequently is usually inefficient as you have to relearn things that you had already learned but never solidified. Doing it more frequently is similarly inefficient because you were still likely internalizing some of the lessons from the previous lesson; It takes time for the brain to organize what it has learned and to change its functioning.

QEEG Assessment

Quite often patients feel irritated by the findings of the QEEG report. The QEEG report will suggest personality and behavioural tendencies and sometimes it may not be pleasant to receive this, even if the findings corroborate your suspicions. Some patients have reported feeling vulnerable upon reviewing the QEEG Assessment’s findings; others have reported feeling validated. It’s a good idea to be prepared that the brainwaves measured show a pattern of tendencies that may not be flattering in all aspects of your life. None of us are perfect. An awareness of how we can improve our lifestyles and brainwave patterns is a starting point that can make our lives more satisfying.


NFB is generally considered to be safe and non-intrusive; it generally does not produce harmful side effects. Sometimes, if the wrong conclusions are reached, e.g., a patient is labelled as having ADHD clinically but evidence of epilepsy (e.g., absence seizures) is missed in the QEEG, a patient may be given ADHD medication which may actually make seizures worse. Now this would likely have occurred even if a QEEG was not done, further highlighting that QEEG does not reveal diagnosis; it is a tool available for use as part of the assessment battery.

The potential side effects sometimes relate to the health condition the patient has and the treatment protocol. For example, in a study of alcoholic American war veterans of the Vietnam War who underwent intense twice daily NFB training using the alpha-theta training protocol, nearly half of the study’s participants demonstrated something dubbed the “Peniston effect” – losing drug-related effects and becoming allergic to the substances they had been abusing. The participants were required to sign a waiver stating that they acknowledged the Peniston effect (Peniston and Kulkosky, 1999).

Side effects are usually short-lived and usually resolves within a day or two if they are experienced. They may include issues with sleep, energy, anxiety, focus, attention, memory, emotional regulation, dreams, irritability, headaches and anxiety (Longo, 2018). More commonly, in the few patients who experience side effects, they revolve around the effort required to participate in NFB training in the context of their lifestyle and health situation. For example, as with any form of training, at first there is some effort involved. Effort, focus, and making time for NFB training at first may not be relaxing/calming and so may lead to side effects of fatigue, headaches, lightheadedness, dizziness, irritability, moodiness, weeping, insomnia, agitation, and difficulties with focus and anxiety. These reactions if they occur are temporary. And typically last 24 to 48 hours. Like with any investment, at first your down payment may be uncomfortable but the potential for rewards make it worthwhile. However, if the side effects persist or are problematic, the NFB training protocol may need to be changed or it may not be the right time to participate in NFB training. There are always other areas of treatment that can receive attention in the interim (see above: What are things that I can do to enhance my NFB training?)

One should know if that even transcendental meditation for relaxation improved health can have negative side effects like relaxation-induced anxiety, less motivation in life, boredom, pain, impaired reality testing, confusion and disorientation, feeling spaced out, depression, increased negativity, being more judgemental, feeling addicted to meditation, uncomfortable kinesthetic sensations, mild dissociation, feelings of guilt, psychosis-like symptoms, grandiosity, elation, destructive behavior, suicidal feelings, defenselessness, fear, anger, apprehension and despair (Perez-De-Albeniz et al., 2000).

This depends on how accurately the situation has been assessed and the efficiency of the treatment plan. A comprehensive treatment plan will involve more than just NFB training protocols as mentioned above. That is, relying exclusively on NFB for treating your condition is not likely to be successful; it may have a role in the bigger game plan. Success in changing brainwave habits by operant conditioning is just like learning how to do anything; it is possible with dedication and a methodological approach, with the caveat that some things are more challenging to learn than others.

Alberti, Robert; Emmons, Michael. Your Perfect Right: Assertiveness and Equality in Your Life and Relationships. Impact; 10th Edition (May 21, 2017).

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Demos, John N. Getting Started with EEG Neurofeedback. W.W. Norton & Company; 2nd Edition (2019).

Phd, Jack & Gunkelman, Jay & Lunt, J. (2005). Clinical Database Development: Characterization of EEG Phenotypes. Clinical EEG and neuroscience : official journal of the EEG and Clinical Neuroscience Society (ENCS). 36. 99-107. 0.1177/155005940503600209. 

Hammond, D & Kirk, Lynda. (2008). First, Do No Harm: Adverse Effects and the Need for Practice Standards in Neurofeedback. Journal of Neurotherapy. 12. 79-88. 10.1080/10874200802219947. 

Hammond, D. (2011). What is Neurofeedback: An Update. Journal of Neurotherapy. 15. 305-336. 10.1080/10874208.2011.623090. 

Longo, Robert E. A Consumer’s Guide to Understanding QEEG Brain Mapping and Neurofeedback Training. iUniverse; (Jan 5, 2018).

Peniston, Eugene & J. Kulkosky, Paul. (1999). Neurofeedback in the Treatment of Addictive Disorders. 10.1016/B978-012243790-8/50008-0. 

Perez-De-Albeniz, Alberto & Holmes, Jeremy. (2000). Meditation: Concepts, effect and uses in therapy. International Journal of Psychotherapy. 5. 10.1080/13569080050020263. 

Suffin SC(1), Emory WH. Neurometric subgroups in attentional and affective disorders and their association with pharmacotherapeutic outcome. Clin Electroencephalogr. 1995 Apr;26(2):76-83.

Research & writing: Dr. Taher Chugh

Last update: August 2019