How does Neurofeedback Work?: Looking at Different Techniques
Neurofeedback is a Collection of Different Approaches to Training the Brain
If you do a web search on "neurofeedback" or "brain biofeedback", you will discover a huge number of pages and articles. (Hey -- you probably already did this and found my site - I'm flattered! ;-)
Although these all may sound like the same approach, there are a number of different technologies people have developed to change brain functioning. Let's take a little "tour" of these approaches.
- EEG / brain wave training, and
- HEG / brain blood-flow training
Within these groups, there are also some differences it is important for you to understand if you are interested in using neurofeedback.
Let's start with the EEG approaches.
There are basically 3 approaches to EEG neurofeedback as I see them.
1) QEEG-driven Neurofeedback Training
This is the most "medical model" approach. Folks who practice this way start by doing what is called a "quantitative EEG" (QEEG). This uses many sensors all over your head to measure how your brain is functioning compared to a database of "normal" brains. The idea is that differences from "normal" brain activity likely account for symptoms or inefficiencies and they target these differences when they do training. For example, you may have statistically lower levels of alpha waves in the left than right frontal lobe, which would explain depressive symptoms. So they would use sensors at the frontal lobe sites to teach you to change the amount of relative alpha waves.
During the actual neurofeedback training session, you watch the screen showing feedback about what your brain is doing and learn to shift the activity in the direction recommended by your practitioner.
2) Targeted Neurofeedback training
In this approach, practitioners don't use a database. They work from the literature and clinical experience to determine which areas of your brain and kinds of brain activity will likely produce changes in your area of concern. The way they do the training would look similar to the QEEG group, but without using the guidance of the "normal" database.
Also, in both groups 1 and 2, if what they start with doesn't have the effects you want, they may do what is called "site-shifting", which refers to moving the sensors to different sites on the scalp and/or targeting different kinds of brain activity.
3) Comprehensive Adaptive Renormalization of the EEG (CARE) Neurofeedback
(Bias warning - this is the approach I use. ;-)
This approach to neurofeedback views the brain/body as a whole system - jump in anywhere and you will affect the whole thing.
If one looks at the literature, there are very few exceptions to the general rule that excessive "slow wave" activity is related to symptoms and inefficiencies.
The easiest way to think about this is like imagining a new driver trying to stay in their lane. They tend to go slow, trying to maintain "maximum" control, which actually makes it harder to make the subtle adjustments they need. They tend to go too far in one direction, then overcorrect and go too far the other direction.
This translates in the brain into turbulence - big energy "bursts" - that uses a lot of energy inefficiently.
Neurofeedback training using the CARE approach uses sensors on the scalp locations associated with the most brain interconnections and focuses on training your brain not to have these big "bursts" of activity, thus decreasing the turbulence and increasing the efficiency.
As your brain gets more efficient, it also gets more effective -- the energy starts to shift to more productive frequencies for whatever you are trying to do -- and the "symptoms"/barriers you experienced associated with the brain inefficiency drop away as they "transform" into more productive brain waves.
What I particularly like about the CARE neurofeedback approach is that I am not "choosing" how the person's brain "should" function; it is sorting itself out (and the brain is a self-organizing system!).
And that is the idea behind "renormalization" -- it's not about trying to give you a "normal" brain; it's about trying to give your brain the information about itself it needs to get back to its own best "normal".
But how could this CARE approach really work?
OK - take a deep breath. Next --
How do I Choose?
There is no "best" EEG neurofeedback approach (apart from personal biases, anyway ;-).
I suggest it depends on:
- your own personal philosophy and comfort levels
- what you want to achieve with the training
- your "fit" with the practitioner
One of the differences to think about in these three neurofeedback approaches that can be important is the level of effort required to achieve changes.
The first two approaches are based on a learning theory or behaviour modification approach. In sessions using these approaches, you actually learn to change your brain wave patterns "on purpose" to match the patterns targeted by the trainer.
The CARe approach doesn't require you to do anything active other than to "stay in the moment", letting the background music play and watching a visual display. Your brain responds to the feedback information provided by the audio-visual displays and changes what it does in response. So you'll feel less "in control" of what happens during the session, but you also don't have to "work so hard" to achieve change.
Now, let's take a quick look at HEG training...
Hemoencephalography: Brain Blood-Flow Biofeedback
This a different approach to training the brain.
Instead of using brain waves as guidance, we are using feedback about the blood flow in the brain to allow the person to learn to increase the activity level of the area under a sensor. This is a useful neurofeedback approach especially when we want to target certain skills or areas of damage.
I recommend it especially for strengthening of "executive skills" associated with the frontal lobes of the brain: organization, attention, planning, etc. (Stay tuned for an article available about the frontal lobes - they're oh-so-important in almost everything we do!)
A HEG session uses an infrared thermometer that shines light through the skin and skull to assess the amount of oxygen in the brain's blood in that area. The harder the brain works, the more demand for nutrition there is. This results in faster blood flow and redder blood in the tissues, strengthening the activity of the brain in that area and resulting in improvements of the skills associated with the frontal lobes.
I like to combine HEG training with heart rate variability training - to see why, jump over to [link still to come - but come back soon!].
OK- you've covered the basics!Now you're prepared to explore links between brain activity and specific areas of concern and the impact of the neurofeedback on each of those.Or - if you're interested more in personal evolution and growth, click over to that section of the website.