Discussion on ratios and reversals of EEG bands as related to brain function and training.
Ratios
There are actually two ratios I like to look at to give a quick picture of the brain’s activation style: theta/beta and alpha/theta. Theta represents the subconscious mind and, in terms of processing style, it represents creative/intuitive thought. Beta represents the conscious mind and, in terms of processing style, it represents logical/rational/sequential processing. Theta thought uses images; beta thought uses language. Alpha represents the bridge between the subconscious and conscious, and it is not a processing speed. It represents pure awareness states.
The theta/beta ratio shows us the balance struck by a particular brain at a particular site in a particular state (e.g. eyes closed, eyes open or performing a task) between logical/rational and creative/intuitive processing. Higher ratios indicate the top number is dominating (theta in this case) and lower ratios indicate the bottom number is dominating.
Alpha/theta ratios show us the relationship between a person’s ability to be in the sub-conscious processes and that person’s ability to bring sub-conscious material into conscious awareness. People with low A/T ratios often act out of sub-conscious motivations, but they have no idea where the behavior is coming from. So, to continue the bridge analogy, a brain that produces low A/T ratios doesn’t have a bridge–it has a ravine–between sub-conscious and conscious. A brain with “normal” A/T ratios has the ability to move information back and forth between these states. And a brain with a very high A/T ratio has a drawbridge stuck open. The bridge is there, but it still doesn’t allow information to pass from one state to the other (as in, for example, fibromyalgia, chronic fatigue, etc.)
A/T ratios need to be looked at in terms of their values in the front, middle and back of the head, and they should show a specific pattern of change when we go from eyes-closed to eyes-open to task states.
More on Theta-Beta Ratios
T/B ratio is a measure of the relationship between interenal, image-based processing (slow activity) and sequential, language-based processing (fast activity). When eyes are closed, most of us either shift into alpha (pure awareness states) or into slower frequencies. People with fast eyes-closed EEG’s are processing in a resting state (the “back-seat driver” is chattering away in many cases) and may be anxious, obsessive, etc. When the eyes open, the ratio may go up or down.
When we do a task (especially the tasks in the TQ Assessment, which are all sequential or language based processing tasks), the amount of more global and regional theta, delta and alpha activity blocks and we shift into local activity (beta) oriented to the task being performed. Thus, overall amplitudes generally drop and the ratio shifts into lower levels.
Remember that you can always tell what is happening in a ratio using this rule of thumb: If the bottom part of the ratio becomes stronger (e.g. beta in the theta/beta ratio goes up relative to theta), the ratio goes down (toward the bottom). If the top part of the ratio increases relatively, the the ratio goes up (toward the top).
However, the key to the theta/beta ratio is that it can be low, it can be high, or it can be in range. If it is low (dominated by the bottom, beta, values), that suggests filtering or anxiety/obsessive-type thinking. In filtering clients, the ratio will actually go UP, but go into the target range, at task. This is not really reverse activation. In anxious types, it may NOT go up but stay low at task.
In Processing type problems, the ratio can be fine with eyes closed or open, but it may “reverse activate”–shift toward the internal image-based processing when we give it a sequential, language-based task to perform–under task. The brain can’t sustain the faster processing speeds required to perform the task.
Cz is where the published research was done on theta-beta ratios. The TQ looks in all areas and especially looks at how the brain activates or de-activates going from eyes-open baseline to task.
Theta/beta power ratios (4-8 Hz/13-21 Hz) has, in the brain-trainer system, 3 possible ranges.
Values below 1.2 indicate a strong activation in both fast and slow frequencies, which usually results in very low mid-frequency values, forming a “scoop” pattern with Eyes Open. These are consistent with physical restlessness, sleep-onset insomnia, impulsivity and distractibility, tendency toward irritability and/or anxiety, sometimes allergies or asthma, etc.
Values above 2 for adults–or up to 3 for 6-7 year-kids–indicate a dominance of slow-frequency activity. These are consistent with difficulty paying attention, starting and finishing tasks, processing language for information and organizing. Usually sleeps easily/heavily but may not feel rested. May wet the bed. Possibly low-energy, depressed, withdrawn.
Between these two ranges, the brain is probably performing cognitive tasks fairly efficiently,
Training one frequency in one place–even this one–with what we have accessible today is like pushing a car down to the mailbox and back to keep the mail from getting wet. It’s a very safe option, and it’s likely to give most people a boost at least temporarily, but it’s a very limited use of a very powerful technology
Swingle Ratio
Paul Swingle is, among many other things, the developer of a one-electrode assessment, which he teaches. I adopted the ratio from him (as I have from many other sources). Paul looks at High Beta/Beta ratios at Fz. The way he measures it, he considers between 0.45 and 0.55 to be a normal range (that is, high beta is roughly half beta amplitude). I use Paul’s corollaries, where are: the higher above 0.55 the ratio goes, the more strong-willed, stubborn, OCD (choose your own words); the lower below 0.45 the ratio goes, the more passive, unmotivated, etc.
The Swingle Ratio is a ratio of high beta to beta (23-38 Hz divided by–I think–15-29 Hz). I’ve never used it much because the TQ7 includes the whole section on Blocking on the Analyze page. The fact that Fz has a lot of high beta relative to beta may mean very little if F3 and F4 and C3 and C4 ALSO have a lot of high beta relative to beta. The idea of the Locking area is to look at the anterior cingulate by comparing it against the sites on either side. Since the anterior cingulate runs beneath the midline between the hemispheres, and it is one of the three structures in the brain that produce readable EEG, when we see a significant difference between the midline sites in the F and C areas and the sites over the two hemispheres, it’s a good bet that we’re seeing the “shadow” of the cingulate.