Slow Cortical Potential Training

by Siegfried Othmer | May 21st, 2008

The work with slow cortical potential training (SCP) is migrating from Tübingen to other universities in Europe where it is also being evaluated. It is therefore gaining quite a foothold, and we may even come to see an identification of neurofeedback with this particular approach among the academic community that is willing to study neurofeedback.

On the positive side of the scale, we have a technique here that seems to be as diagnostically non-specific as frequency-based feedback. SCP training has been applied to the control of seizures and migraines as well as to conditions as varied as ADHD, depression, and schizophrenia. The technique is absolutely identical in all these applications.

So here we have yet another technique which must be understood in terms of improving self-regulatory status generally as opposed to targeting specific features of specific disorders. It has this in common not only with protocol-based Neurofeedback / EEG Biofeedback training but also with Heart Rate Variability (HRV) and other peripheral biofeedback modalities. HRV is not something different in application to asthma than in application to myofascial pain. It is what it is, and you get what you get.

This generic quality of the intervention is really the rule much more than the exception in all of biofeedback. But uniquely in EEG feedback there is the thrust to make it into something more palatable to the mainstream medical model, namely as a specific treatment for specific disorders. And preferably these disorders should be discernible in specific features of the QEEG.

Given this general yearning for support of the claims of specificity, we are happy to find more colleagues in arms as we resist the tide. In our migration to the slow cortical potential domain for much of our work, we find that Niels Birbaumer’s research group has already been there for some decades. So if we now proclaim that the low-frequency reward can be most helpful for the control of seizures, migraines, ADHD, and depression in some individuals, we are only following in the footsteps of researchers who have already been there and done that.

In fact, the only novelty we have contributed to this enterprise is to show that the slow cortical potential training can be carried off perfectly well in the frequency domain. Moreover, a shift to frequency-based training has a number of ancillary virtues vis-à-vis the transient-based training. First of all, the cognitive demand is reduced considerably. No one has to explain anything to the trainee. Secondly, the frequency-based training offers a nearly 100% duty cycle. The training is not epochal. Thirdly, the appropriateness of the low-frequency approach becomes apparent almost immediately as the client responds to the training. Those who are not suitable to this training will not feel good with it, and that will usually become obvious in the first or second session. This deals with the issue of non-responders that is so prevalent with the transient-based SCP training. Essentially no one will be left spinning their wheels on a task that is not ultimately going to pay off for them.

The price paid for the conversion to frequency-based training is that the clinician must be attentive to the particulars because the choice of reward frequency may be crucial. In that process, many will be found whose training optimizes at higher frequencies, and one simply proceeds with the training there. The issue to be resolved is whether the non-responders in the transient-based training are the same people who don’t optimize in the low-frequency regime. This could be easily checked.

One of the features that has been adopted in much of transient SCP training is the use of bilateral challenges, with some challenges being in the direction of less activation, and other challenges being in the opposite direction. The frequency-based training offers the same feature, in that 50% of the time the waveform will be in the positive half of the cycle and 50% in the negative half. Training toward higher signal amplitude drives us more strongly in both directions alternately. In the case of the frequency-based approach, the bilaterality is built-in. We have no choice in the matter. By contrast, in the transient case the choice to do bilateral training is explicit, and this supports the argument that the target of training is enhanced self-regulatory capacity rather that either diminished or enhanced levels of activation.

Siegfried Othmer Ph.D.

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