Calling neurofeedback a revolution is maybe a bit strong for some people, but in actual fact it is an important development amongst a number of technologies that expliot brain plasticity to improve functionality and impact upon mental dysfunction. This emergent technology goes against some well entrenched beliefs, practices and resistant economic interests.
Wide acceptance of neurofeedback, at least as a remedial technology, is going to be contingent on our improving understanding of the how the brain is organised.
In the past, our understanding of "how the brain works" has been fragmented into a debate about soup (neurochemical) or sparks (neuroelectrical) paradigms. More recent research has shown the significance of neural network models and the interconnectedness (coherence) of the brain. There is also recognition that cognition is embodied - we cant deal with a brain is if it is not part of a whole body. Full acceptance will have to wait for acceptance of the proposition that many mental dysfunctions are kept in place by patterns of network organisation that have become fixed in place due to trauma or through a learning process.
Since the beginneings of neurofeedback in the late 1960's several approaches have emerged. In the USA, clinicians and scientists focused on techniques of using neurofeedback to increase the amplitude of energy in particular "frequency bands" of the EEG signal typically between 1 and 30 Hz. The technology of the time (and some systems today) excluded frequencies below 1 Hz because the large variations in amplitude around this frequency would have swamped everything else. These low frequencies were also not considered to be significant and effectively artefacts.
In Europe and especially Germany there was specific interest in these lower fequencies within the EEG signal. Attention on Slow Cortical Potentials (SCP), reflecting episodes of cortical activation, was possible as the EEG amplifiers utilised were capable of working at much lower frequencies.
Early work in both the USA and Europe gathered EEG signals from the sensorimotor strip (cz, c3, c4) across the top of the head in the internationsal 10-20 system.
A question still remains unanswered. Should neurofeedback training be individualised or will a one size fits all approach be OK. Research and evidence-based medicine favours the one size fits all approach as this suggests that results will not vary with the skills of the clinician. The individualised approach is favoured by the experienced practitioner who senses that training can be fine tuned to the needs of each person. Brains like people can be somewhat unpredictable.
One trend is to derive a training plan from a norm-based interpretation of QEEG data - comparing the particular individual with EEG data in a database of matched "norms". Another trend is to allow the change in EEG data to guide the training. The client's brain could be trained to reward amplitudes in the frequency bands where the amplitude is low compared to some reference values and conversely inhibit amplitudes in frequency bands where the amplitude is too high. Juri Kropotov calls this the "bulldozer approach" as it levels out the highs and lows of the EEG spectrum. Much work remains to be done. Neurofeedback is evolving but is not yet the revolution it promises to be.
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