Theta/beta or (theta/beta)2

[Guest guest]

I hope someone can help me finally understand this. We always look for the

theta to beta ratio and the cutoff from research that I have heard is theta/beta

where beta is 13-21, of about 2 for adults.

Now I know the TLC uses power numbers which is (theta/beta)squared. I also know

that this was used in research and it came up with a cutoff of 2 for adults.

But theta/beta and (theta/beta)squared are two completely different numbers.

For instance, a theta/beta of 2 would be a (theta/beta)squared or 4. One would

be borderline and the other would be significant.

Can someone help me here? I have gotten some ratios of 9 in the TLC but the

theta/beta ratio would be 3. Since these were children, this difference is

very significant.

What am I missing?

Thanks, Connie

[Guest guest]

Connie,You are still combining information, I think.  The 1999 article which published the cutoffs was not done using QEEG's, so there was no norming done (unless they tried to create age-specific norms from several hundred cases, which I doubt Vince and would have done--and even more doubt that Neuropsychology would have published).  When you start talking about 1.5 SD above the mean, you are talking QEEG data.  Since you are only talking about one tail of the distribution (the upper end) 6.7% of a normally distributed population would be above those cutoffs (if they are correct.)

Again, I worked on that project probably 12 years ago and never put much stock in it because I saw so many people who had T/B ratios that were fine but still had serious attention or control issues.  My recollection was that, in the 1999 article the number was around 1.5 for adults, but that's just from memory.

Pete-- Van Deusenpvdtlc@...

http://www.brain-trainer.comUSA 305 433 3160BR 47 3346 6235The Learning Curve, Inc.

On Sun, Apr 18, 2010 at 4:01 PM, Connie Welsh <conniewelsh@...> wrote:

I have emailed the man on the list specifically and he said that

these numbers were for POWER values.

From what I can tell right now,  it appears that most

people do not get this and they were the ones that were confusing meJ

I wanted to post this so others on the list will understand.

So my understanding is at this time,  the numbers I posted

are POWER numbers that are at 1.5 standard deviations above the norm.