Neurofeedback

Neurofeedback (also EEG feedback) is a special direction of biofeedback. When Neurofeedback brain current curves ( EEG waves ) are analyzed by a computer in real time, broken down according to their frequency components and displayed on a computer screen. The thus determined frequency distribution of attention or consciousness ( eg awake, asleep, alert, relaxed, stressed ) depends, can be used (by means of feedback training ) for training. The subjects it is possible to achieve through feedback of your own brain wave pattern, a better self-regulation.

• 3.1 Amplitude and frequency band training workout
• 3.2 Z -value method, or Z-score training
• 3.3 Training of connectivity of the EEG
• 3.4 SCP training
• 3.5 Other variants of neurofeedback

• 4.1 Books
• 4.2 Magazines

Theory

The effect of neurofeedback training is explained by the so-called operant conditioning. This is essentially a learning process, in which a behavior is enhanced. Because this takes place without awareness, this is no conscious effort is needed. In principle, each person can learn Neurofeedback. (→ learning theory ).

For Neurofeedback training the EEG signal is used as a basis. This is largely determined by its strength (amplitude ) and the number of vibrations ( frequency of the individual frequency bands ) was determined. To this end, the raw EEG signal is received by the electrodes on the scalp to be initially sufficiently reinforced.

The EEG amplifier transmits the signals directly to a computer where they are processed by a special program for training purposes. This happens, for example, by the decomposition of the raw EEGs in various wave components, known to us brain frequencies such as alpha, beta, delta, theta or gamma.

In this way, physiological processes, which otherwise lie hidden, made ​​perceptible, so the body can ever get feedback. An audible and / or visual feedback (for example, music, sound, video clip or computer animation) is from the computer then given when the EEG waves of the brain have a desired composition. This is done by a continuous analysis of the signal by the computer program calculates trends in fluctuations of brain waves and compares this with a predetermined threshold value in a fraction of a second. Are now in a certain desired extent thresholds are exceeded or under -, this brain activity is amplified by a reward stimulus. See also positive reinforcement.

Model of neural dysregulation

There are a number of models that can be associated with the onset of symptoms. Theorists of neurofeedback training to see the cause of many central nervous disorders in a dysregulation of cortical and subcortical structures established, which can be globally organized in four classes cause. These are: over-stimulation ( Overarousal ), under stimulation ( Underarousal ), lack of inhibition ( disinhibition ) and instability. The aim is to influence by shutting training or exercising of certain up- wave components symptoms positive. Direct treatment of the symptoms does not occur.

Historical antecedents

Procedure (Training Logs )

Important before each treatment initially is a detailed medical history, diagnosis, and clinical results. The result gives the neurofeedback therapist important clues about what type of central nervous excitement it the patient or the patient has to do. So is, for example, poor sleep often ( cortical ) hyperarousal, ADD (without hyperactivity) often ( cortical ) underexcitation in conjunction. Migraine, various seizure disorders, but also tics are more unstable with arousal in context. Using a so-called " symptom checklist " can then be determined which type predominates. But that is only vague statements are true about frequency range in which there is too much or too little activity. Therefore, in addition to the purely symptom-oriented approach in the diagnosis and quantitative analysis of the EEG ( QEEG ) is applied. With the help of scientifically created databases can be normal from impaired brain function today differ much more accurate. This in turn allows a more accurate selection of appropriate neurofeedback protocols.

Amplitude and frequency band training workout

A major concern is with the neurofeedback on the training to increase or decrease the vibration amplitude of the frequencies of an EEG frequency band.

The voltage appearing in the EEG is greater, "fire" locally synchronous ever more nerve cells. When neurofeedback amplitude training so local synchronicities are trained in the brain eventually. In this case, an increased synchrony does not necessarily have to be desired, often achieving a lower amplitude, less synchrony is occupied with positive feedback. Furthermore, often trained several conditions simultaneously. So there is for the respondent only positive feedback if he in a frequency range achieved, for example, a higher amplitude and at the same time in a different frequency range, a lower amplitude. May be targeted so that received the composition of the entire EEG of a subject.

This means that EEG wave components ( frequency ranges) that are known to be beneficial will be rewarded when it occurs, such as SMR ( Sensomotoric rhythm ) and beta. Frequency band amplitudes that are known to be less advantageous ( such as the low theta - typical of lack of concentration - and high beta - stress, hectic thought processes ) are suppressed or it will be rewarded in this case when the amplitude decreases. Neurofeedback works exclusively with belohnendem feedback.

Z -value method, or Z-score training

The basic idea here is based on EEG databases. An EEG EEG database contains values ​​of a determined by scientific criteria healthy norm population in terms of amplitude, coherence, asymmetry and phase.

Training of connectivity of the EEG

Neurofeedback can also train the coherence of the signals of two electrodes places or regions of the brain in a selected frequency band. Coherence is a measure of the interaction of different localities of the cerebral cortex here. For example, the coherence between Broca's area and Wernicke's area crucial for language ability. Too much or too little cooperation can make observations, for example in speech disorders. The coherence has a value range from 0 to 1 (in practice, sometimes even as a 0 to 100% referred ). When coherence training, this value will be trained to a certain target value, so that it should achieve, for example, the measured value of a healthy control population.

SCP Training

When SCP training the value of the DC component (so-called slow cortical potentials, SCP ) is trained. This type of neurofeedback is due to a very significant extent of the research group at Niels Birbaumer. Slow cortical potentials play an important role in, among other so-called brain -computer interfaces ( Brain- Computer Interfaces BCI), in their research and development Birbaumer is significantly involved.

Other variants of neurofeedback

Bipolar Training, Z- value - based training ( Z-score training), LENS ( Low Energy Neurofeedback System by Len Ochs ), alpha-theta training, Loreta Neurofeedback ( Low Resolution Electromagnetic Tomography ) (3- D).