What's New in Neurofeedback

A Monthly Summary of News and Events

Vol. 11 No. 9 - September 2008

This newsletter is sponsored by EEG Spectrum International, Inc.,
the leader in providing neurotherapeutic services and training professionals.

Past issues are available at start.eegspectrum.com/Newsletter/
To subscribe via yahoogroups.com or cancel a subscription, see info at the bottom.
Opinions in this newsletter reflect those of the author only.
Copyright (c) 2008 by ESII or David Kaiser, Ph.D. All rights reserved.


  • Announcements  - News
  • In the Spotlight     - Journal of Neurotherapy, 1995-2001
  • News & Reviews - Books & journal papers
  • Events & Locations - Conferences, Courses
  • Last Word    - Square roots are hard: Magnitude vs Power

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    Announcements


     

    In the Spotlight

    Journal of Neurotherapy, 1995-2001

    The secret to creativity is knowing how to hide your sources. - Albert Einstein

    Below is a part 1 of a list of scientific articles published in the Journal of Neurotherapy. Part 2 will be published in next month's newsletter. JN, as it is abbreviated, was originally self-published, then published by Haworth Press, and now by Taylor and Francis (which acquired Haworth recently). It has taken many years to get back on schedule and only now is JN hitting its publications dates. It is currently index by PsycInfo and other medical/psychological indices, with a goal of be including in Medline after volume 13. Below is a chronological index of its scientific articles, formatted with article title first:

    -DK

     

    News & Reviews NEW BOOKS

    Journeys Through ADDulthood

    by Sari Solden A response to how ADHD treatment focuses on overcoming its symptoms rather than leading a fulfilling life. -- www.amazon.com/exec/obidos/ASIN/0802713769/eegspectrum

    Awareness Deficit after Brain Injury
    by George P. Prigatano
    Describes treatment and condition of loss of awareness after TBI -- www.amazon.com/exec/obidos/ASIN/0195059417/eegspectrum

    American Psychiatric Publishing Textbook of Mood Disorders
    by Dan J. Stein, David J. Kupfer, AF Schatzberg
    Authoritative reference for current information about mood disorders. -- www.amazon.com/exec/obidos/ASIN/158562151X/eegspectrum

    Neuroimaging
    by Michael F. Glabus
    Two-volume set covers methods and application of various neuroimaging techniques for clinical use and research. -- www.amazon.com/exec/obidos/ASIN/0123668778/eegspectrum

    Addiction and Change: How Addictions Develop and Addicted People Recover
    by Carlo C. DiClemente
    Paradigm for understanding addictive behavior. -- www.amazon.com/exec/obidos/ASIN/1593853440/eegspectrum

     

    JOURNAL PAPERS

    Orbitofrontal Dysfunction in Boys With Pure Conduct Disorder : During reward conditions, conduct disorder children show underactivation in the right orbitofrontal cortex, while ADHD showed dysfunction in the posterior cingulate gyrus. http://www.ncbi.nlm.nih.gov/pubmed/18829871

    Aggression after paediatric traumatic brain injury: a theoretical approach. : Children with TBI report more aggression than controls, though this aggression is mostly out of frustration and not to dominate or acquire objects. http://www.ncbi.nlm.nih.gov/pubmed/18850342

    Adolescent insomnia as a risk factor for early adult depression and substance abuse. : Teen insomnia was associated with alcohol and cannabis use, depression; suicide ideation; and suicide attempts. http://www.ncbi.nlm.nih.gov/pubmed/18853932

    Anger style, psychopathology, and regional brain activity. : Trait anger predicts left-biased asymmetry at medial frontal EEG. http://www.ncbi.nlm.nih.gov/pubmed/18837620

    Sleep architecture, cocaine and visual learning. : Authors conclude that treatments directed at sleep could offset physiological consequences of cocaine abstinence. http://www.ncbi.nlm.nih.gov/pubmed/18855824

     

     

    Events & Locations

    Upcoming Courses

      4-Day Comprehensive Course on Neurotherapy (dates subject to change)
    • Durham NC Nov 13-16
    • Glendale CA Dec 11-14

    Our course is a hands-on experience right from the start. Attendees consistently say this format is a very good way to learn neurofeedback.

    "Neurofeedback should be viewed as one of the three essential or primary forms of intervention - psychotherapy, psychopharmacology, and neurofeedback. In my experience, neurofeedback is every bit as important and powerful as the other two forms of treatment." - Dr. Laurence Hirshberg, Brown University Medical School, psychologist specializing in Developmental Disorders and Autism.

    Contact Karie Kramer, our training coordinator, for more information 818-789-3456 ext 847 or see www.eegspectrum.com/Training

    * EEG Spectrum International, Inc. is approved by the APA to offer continuing education to psychologists. ESII maintains responsibility for the program.

    Conferences for Neurofeedback Clinicians & Researchers

    CONFERENCELOCATIONDATES
    AAPB - aapb.orgAlbuquerque, NMApr 2-4

     

    Last Word

    Square roots are hard to do: Magnitude vs Power

    I was recently asked again, for the 100th time, why EEG researchers traditionally used spectral power instead of just spectral magnitude? Here is my response:

    Spectral power refers to the average rhythm amplitude squared. Spectral magnitude is the average rhythm amplitude. I've attempted an intellectual archeology to try to understand why spectral power (which is spectral magnitude squared) is ubiquitous despite its many drawbacks (e.g., non-normality for EEG, sensitivity to epoch length, sensitivity to single outliers):

    Prior to 1965, spectral analysis was performed using DFT (cosines and sines). In 1965 the FFT was invented (or rediscovered, according to Gauss fans) by Cooley and Tukey. [Cooley, James W., and John W. Tukey, "An algorithm for the machine calculation of complex Fourier series," Math. Comput. 19, 297–301 (1965).] The FFT is very easy to do, computationally speaking -- no messy floating point multiplication of cosine and sine. The FFT is a mere resorting of time values in such a way as to produce frequency information on the spot, with no further mathematical operations except addition. It was amazingly simple and easy to do for 1965-era computers. After sorting, the FFT gives us the real components and the imaginary components but not the vector between them, which is what we generally are interested in. There is one more step to figuring out vector length between two orthogonal axes, the Pythagorean theorem, which is real squared + imaginary squared = magnitude squared. Magnitude squared is power.

    Square roots were and are computationally expensive, so Tukey and Cooley stayed at the squared vector value, partly because they were interested in amplifying outliers, detecting abnormalities generally, and less interested in central tendency of any rhythm. Tukey's work at this time concerned aviation -- wind sheer, wing vibration -- and Cooley's the periodicity of helium and other stuff where outlier detection was key. The first to take the FFT into EEG analysis was Dumermuth and Flühler (1967) and people followed them and Tukey and analyzed spectral power instead of spectral magnitude. Ironically, the first to quantify EEG rhythms (Dietsch, 1932, and Berger soon after) were concerned with spectral magnitude, not power.

    But the real issue for power vs magnitude is a scientific one, more than mathematical or statistical. We have two domains of measurement -- brain activity and mental state/clinical symptoms. How do they relate? That is the important question, and generally you'll see that the power transformation to the brain activity makes the correspondence weaker. The psychophysics relationship from world-to-brain-to-mind is a log-linear one. We compress energies from without, and squaring them at the midpoint of this process makes little sense.

    Spectral power has one advantage, besides easy to get mathematically (a^2+b^2 = power), and that is Parseval's theorem, which is a statement of uniformity across transformations, that is keeping the same variance across the entire spectrum. It is a minor advantage, far less important than the empirical correspondence issue above. I believe that we will find in fact that compression of the rhythm amplitude will provide the best correspondence between EEG voltages and clinical conditions and mental states, but that is down the road.

    Mean power typically reflects the sum of mean magnitude and its variance. As more people look at variance as a measure of interest, we will get a sequence of magnitude, power, magnitude variance where the middle will be recognized as a composite.

    -DK