Infra Low Frequency Neurofeedback

and Infraslow Brain potential explained

  Neurofeedback training is a form of brain training that allow the brain to change its states and traits through self-directed neuroplasticity and endogenous self-regulation

Recently in the article by Siegfried Othmer "Endogenous Neuromodulation at Infra-Low Frequencies" he explained that ..."Cerebral regulation rests on the frequency-based organization of the glial/neuronal system, with primary responsibility falling on the infra-low frequency regime that lies below the EEG spectrum. Conventionally, enhancement of self-regulatory competence is pursued by challenge-based methods targeting either the
EEG spectral range or the Slow Cortical Potential domain. They appeal to the fast and
the slow control systems, respectively. The virtues of training the slow control system
directly with a frequency-based schema is explored in this chapter." (From the book “Introduction to Quantitative EEG and Neurofeedback”, Third Edition (Elsevier, 2023)

Neurofeedback is increasingly used as a therapeutic tool in a variety of disorders, with growing scientific and clinical interest in the last two decades. Different Neurofeedback approaches have been developed over time, so it is now important to be able to distinguish between them and investigate the effectiveness and efficiency characteristics of each specific protocol. 

Brain states include arousal or activation and can be explained in terms of car motor being engaged by pushing the accelerator pedal. We can continue this analogy to include breaks, which in brain terms called inhibition. Just as cars, brains can go into neutral gear which put them into the state of calm alertness and ready for action while staying still at the traffic light. These analogies though don't reflect on full brain complexity. What makes it complex is that brain self-regulates and constantly changes. It adapts to the environment by activating certain networks as well as epigenetic and genetic resources.  Underlying processes of the brain functioning include very slow fluctuations in the brain that aim to preserve homeostasis and energy, integrity of the organism and its systems.

Recently Professor Juri Kropotov published an article in the Frontiers in Human Neuroscience journal titled " The enigma of infra-slow fluctuations in the human EEG:

We recorded a webinar with Prof. Yury Kropotov explaining physiology of slow brain potential:


Here is also a recent interview with Siegfried Othmer who was involved in the development of this method

Summary on ILF Neurofeedback or Othmer method of endogenous Neuromodulation

  1. Infra-low frequency neurofeedback (ILF neurofeedback) is a type of neurofeedback training that targets the brain's extremely low-frequency oscillations, typically in the range of 0.01 to 0.1 Hz or even lower. It involves monitoring and modulating these infra-low frequency brainwaves to potentially improve brain function and address specific conditions or symptoms.
  2. Targeting Infra-Low Frequencies: ILF neurofeedback focuses on the slowest oscillations of the brain, which are generally not accessible through conventional neurofeedback protocols that typically concentrate on higher-frequency brainwave bands like alpha, beta, theta, or delta.
  3. Monitoring and Feedback: During an ILF neurofeedback session, sensors are placed on the scalp to measure the infra-low frequency brainwaves. The brainwave activity is then fed into a computer system that analyzes and provides real-time feedback to the individual, typically in the form of visual or auditory cues.
  4. Training Protocols: ILF neurofeedback protocols may vary depending on the goals and needs of the individual. The feedback provided can be designed to encourage or modulate specific patterns of infra-low frequency brainwave activity. The intention is to promote self-regulation and optimize brain functioning.
  5. Potential Benefits: Proponents of ILF neurofeedback suggest that it may have applications in various areas, including promoting relaxation, reducing anxiety, improving sleep, enhancing cognitive performance, and supporting emotional regulation. 

Development of Othmer Method

Neurofeedback has evolved significantly since its discovery in the 1960s, with the growth of entirely new forms of application, as well as an increase in opportunities for use. The so-called ILF neurofeedback, often referred to as the Othmer method, is of outstanding importance because its development has been initiated by the US Scientists Siegfried and Susan Othmer and has been in continuous development for decades. The following article describes the origin of this method from the classical beta/SMR neurofeedback, its change to an effective individual neurofeedback approach, and how this development was systematically driven by the Othmers’ commitment.
The origin of neurofeedback

Before the potential of neurofeedback was discovered, it was a purely diagnostic tool to measure and analyse cerebral waves via the EEG. The American psychologist Barry Sterman recorded EEGs to study the activity of the brain in various sleep phases in cats. At some point he discovered a unique pattern in the EEG of these test animals. This ranged from 12 to 15 Hertz and was similar to ‘sleep spindles’, which typically appear while falling asleep. These spindles indicate the brain’s ability to suppress alertness and sensation of external stimuli in order to stabilise and enter deeper phases of sleep. But actually, the cats in Sternman’s experiment were not sleeping. They were relaxed but fully awake, conscious and attentive to external stimuli.

Sterman referred to the discovery of this pattern as ‘sensorimotor rhythm’ (SMR), named after the area on the cerebral cortex where he recorded it using electrodes. He then tried to see if the cats could be trained to produce more of this specific pattern intentionally, using a training that followed an operational conditioning procedure. Whenever SMR appeared in the EEG, the animals were rewarded with food. This approach was in fact successful: the frequency of the SMR increased as well as the associated state of relaxed consciousness. This was the first time that cerebral waves were used to influence the behavior of a living organism.

Initially these findings were not linked to therapeutic use, but by coincidence that soon changed. Barry Sterman experimented with the cats on behalf of NASA to investigate potentially harmful effects of a new rocket fuel on living organisms. Almost all cats suffered an epileptic seizure within a small period of time after being exposed to a certain dose of the fuel chemical — only one group of cats responded differently: epileptic seizures either did not occur at all or there was a time delay to exhibiting a seizure. Those cats were the very same ones which had previously been trained to produce more SMR rhythms. An employee in Sterman’s laboratory was particularly fascinated by this result because of her own clinical history of epileptic seizures which did not respond to medication at all. So she agreed to an experiment, in which her brain was conditioned to produce more specific brain activity and to reach SMR state intentionally. In fact, this significantly reduced the number of her seizures. This self-testing was the first time that neurofeedback was clinically applied to human beings.

Shortly after this successful experiment with Sterman’s employee, more patients with epilepsy were treated with the revolutionary procedure and even more beneficial effects were observed: improved sleep problems, reduction in hyperactive behavior and better ability to focus and concentrate were reported by the subjects. Following this, insomnia and ADHD became additional important indications for neurofeedback training. One pioneer of early research in this area was Joel Lubar, a staff member from Sterman’s Laboratory, who subsequently did a lot of great research on neurofeedback in ADHD.


The Frequency Band Training

The process discovered by Barry Sterman is one of what is called today ‘Classical Frequency Band Training’. The electrical waves of cerebral activity seen in the EEG can be divided into six groups, the so-called frequency bands. One of these is Sterman’s SMR, while there are five further frequency bands (see box). Dominant frequency patterns seen in the EEG can be used to estimate the brain’s level of vigilance, as specific arousal levels are associated with frequency bands.

The first neurofeedback applications were primarily just SMR training, but soon developed into beta/SMR training. Clients train to produce fewer frequencies associated with inattentiveness (Theta) and tension (High-Beta) in the EEG. Simultaneously they train to produce more SMR and (Low) Beta Frequencies.

The goal is to enter a relaxed but attentive, focused and aware state and to intensify this state. The feedback reward to clients for showing specific frequencies, is usually a pleasant sound or the appearance of a positive reward symbol. If amplitudes of unwanted frequencies increase, this reward is withdrawn or even replaced by an unpleasant warning sound as an inhibit marker.

Classical Frequency Band Training is based on prescribed rules.  For example which frequencies are inhibited or rewarded is determined prior to the training, on the basis of theoretical considerations. This could be compared to not being able to set equipment in the gym to one’s individual physical conditions but to operate all the machines with the same predetermined weights and adjustments for everyone. This also applies to SCP training (see box), another form of neurofeedback developed alongside German universities and being used with good success in the treatment of epilepsy and AD(H)D. *SCP training is therefore another prescriptive procedure. 


The evolution of the Othmer method

Frequency Band Training as a prescriptive method, is grounded on the assumption that there are specific desirable as well as undesirable frequencies in the brain’s activity during? cognitive skills training. The definition of those inhibit and reward frequencies are based on theoretical or statistical considerations on what should be the “norm” in the brain’s activity.  At first there was little reason to question those theoretical considerations, especially as impressive results could be achieved with the beta/SMR training. Nowadays, such general definitions on one individual’s brain activity can be doubted - because we are familiar with the concept of neuroplasticity which was not well-known back then.

Dr Siegfried Othmer and his wife Susan Othmer came into contact with neurofeedback as a powerful therapy option for their son – who was autistic - and became enthusiastic about the method. As a neuroscientist, Susan Othmer had an immediate professional interest in neurofeedback — and her husband Siegfried Othmer, a physicist – was the perfect complement for developing solutions for technical requirements. Together they started their own neurofeedback development institution (EEG Spectrum Inc.) in the mid-80s in Los Angeles, which later expanded to include a clinic and the name was changed to EEG Institute.

The Othmers worked with the beta/SMR training first, but they soon developed the first improvement in the procedure. They decided to no longer simply reward exceeding a single threshold level, but to work with the dynamic of the reward frequency band. The clients were now given feedback of their brain activity from an animation in which a bar moved up or down. The bar represents the proportion of Beta/SMR frequencies in the Frequency Bands recorded from the EEG.

Working with dynamic feedback has been made possible by advances in computer technology, which, moreover, could increasingly reflect the EEG signals in ‘real time’, with almost no  delay. Using the dynamic of reward frequency bands as a feedback signal marked the first of many subsequent shifts away from the initial explanatory model because this neurofeedback was no longer based on operant conditioning.

For further reading please find here the complete whitepaper :


Research and Evidence:

You can explore current  publications on ILF: List ILF Research.pdf

Here are some important references and resources for further exploration of ILF NF.

  1. Endogenous Neuromodulation at Infra-Low Frequencies (2023)

by Siegfried Othmer

Citation: Othmer, S. (2023). Endogenous Neuromodulation at infra-low frequencies, Chapter 17, Introduction to Quantitative EEG and Neurofeedback, Third Edition, Chartier, DR, Dellinger, MB, Evans, JR, Budzynski, HK, editors, Academic Press, London, pp. 283-299   DOI:

 Many resources are avilable at

The study "Case Report: Infra-Low-Frequency Neurofeedback for PTSD: A Therapist's

Perspective" by Spreyermann (2022) shows how a combined therapy of trauma psychotherapy and neurofeedback, specifically ILF neurofeedback and alpha-theta training, can be used with patients diagnosed with complex post-traumatic stress disorder (C-PTSD). Read a summary here.

Intrinsic brain activity in the low-frequency (<0.1 Hz) is organized into distinct large-scale networks, as temporally coherent (or synchronous) slow fluctuations across spatially distributed brain areas [ 7, 8 ], and is shaped by the anatomical organization of the cortex and its sensorimotor and associative areas [  

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