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.

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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

Blindsight: How Brain Sees What You Do Not See
High-altitude Climbing Causes Subtle Loss Of Brain Cells And Motor Function
Obesity, Abnormal 'Reward Circuitry' In Brain Linked
Brain-nourishing Molecule May Predict Schizophrenia Relapse
Searching The Internet Increases Brain Function
People With Autism Make More Rational Decisions
Marijuana Use Takes Toll On Adolescent Brain Function
Neurons In Zebrafish May Reveal Clues To The Wiring Of The Human Ear
Memory Improves If Neurons Are New

Links at http://www.sciencedaily.com/news/mind_brain/

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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:

Attention Deficit Hyperactivity Disorder: Neurological Basis and Treatment Alternatives; Arreed Barabasz, Marianne Barabasz (1995). Journal of Neurotherapy, 1 (1), 1 - 10.

Thoughts About the Study of Cognitive-linked Brain Dysfunction Physiology After Mild Closed-head Trauma; Herbert S. Gross (1995). Journal of Neurotherapy, 1 (1), 11 - 13.

Diagnosis and Treatment of Head Injury; Daniel A. Hoffman, Steven Stockdale, Lana L. Hicks, Jill E. Schwaninger (1995). Journal of Neurotherapy, 1 (1), 14 - 21.

Neurofeedback Therapy for a Mild Head Injury; Alvah P. Byers (1995). Journal of Neurotherapy, 1 (1), 22 - 37.

Topographical Brain Mapping in Depression Following Mild Closed Head Injury: A Case Study; Heath A. Demaree, W. David Crews Jr., David W. Harrison (1995). Journal of Neurotherapy, 1 (1), 38 - 43.

Cognitive Impairment Consistent with Left Fronto-Temporal Abnormality in Schizophrenia Patients; G. Dennis Rains, Kelly Sauer, Carole Kent (1995). Journal of Neurotherapy, 1 (1), 44 - 47.

A Comparison of EEG Biofeedback and Psychostimulants in Treating Attention Deficit/Hyperactivity Disorders; Thomas R. Rossiter, Theodore J. La Vaque, (1995). Journal of Neurotherapy, 1 (1), 48 - 59.

Positive Outcome with Neurofeedback Treatment in a Case of Mild Autism; Arthur G. Sichel, Lester G. Fehmi, David M. Goldstein (1995). Journal of Neurotherapy, 1 (1), 60 - 64.

Mathematics Derived Frequency Correlates in Cerebral Function: Theoretical and Clinical Implications for Neurofeedback Treatment; Marvin W. Sams (1995). Journal of Neurotherapy, 1 (2), 1 - 14.

Gates, States, Rhythms, and Resonance: The Scientific Basis of Neurofeedback Training; Andrew Abarbanel, (1995). Journal of Neurotherapy, 1 (2), 15 - 38.

EEG Biofeedback: A New Treatment Option for ADD/ADHD; Marabella A. Alhambra, Timothy P. Fowler, Antonio A. Alhambra (1995). Journal of Neurotherapy, 1 (2), 39 - 43.

Hostility Following Right CVA: Support for Right Orbital Frontal Deactivation and Right Temporal Activation; D. Erik Everhart, David W. Harrison (1995). Journal of Neurotherapy, 1 (2), 55 - 59.

Neurofeedback and Lyme's Disease: A Clinical Application of the Five Phase Model of CNS Functional Transformation and Integration; Valdeane W. Brown (1995). Journal of Neurotherapy, 1 (2), 60 - 73.

Neurofeedback: One Instrument in the Orchestra; S. Louise Norris (1995). Journal of Neurotherapy, 1 (2), 74 - 76.

Human Steady-State Visual and Auditory Evoked Potential Components During a Selective Discrimination Task; Thomas F. Collura(1995). Journal of Neurotherapy, 1 (3), 1 - 9.

New Technology: A Biological Understanding of Attention Deficit Hyperactivity Disorder and its Treatment; David B. Plude (1995). Journal of Neurotherapy, 1 (3), 10 - 14.

EEG Biofeedback for the Enhancement of Attentional Processing in Normal College Students; Howard Rasey, Joel F. Lubar, Anne McIntyre, Anthony Zoffuto, Paul L. Abbott (1995). Journal of Neurotherapy, 1 (3), 15 - 21.

EEG Biofeedback in the Treatment of Lyme Disease: A Case Study; Russell C. Packard, Lesley P. Ham (1995). Journal of Neurotherapy, 1 (3), 22 - 31.

On the Nature of Artifacting the qEEG; Kirtley E. Thornton (1995). Journal of Neurotherapy, 1 (3), 32 - 39.

Event Related Potentials of Subgroups of Children with Attention Deficit Hyperactivity Disorder and the Implications for EEG Biofeedback; Michael Linden, Richard Gevitz, Robert Isenhart, Todd Fisher (1995). Journal of Neurotherapy, 1 (3), 40 - 49.

Event Related Potentials of Subgroups of Children with Attention Deficit Hyperactivity Disorder and the Implications for EEG Biofeedback; Michael Linden, Richard Gevitz, Robert Isenhart, Todd Fisher (1996). Journal of Neurotherapy, 1 (4), 1 - 11.

A Primer On Clinical Case Study Research In Neurotherapy; Marianne Barabasz, Arreed Barabasz, Neville Blampiedc, FNZPsS (1996). Journal of Neurotherapy, 1 (4), 12 - 14.

Single-Case Research Designs For The Science And Practice Of Neurotherapy; Neville M. Blampiedc, Arreed Barabasz, Marianne Barabasz (1996). Journal of Neurotherapy, 1 (4), 15 - 26.

Improved Neuronal Regulation in ADHD: An Application of 15 Sessions of Photic-Driven EEG Neurotherapy; Graham J. Patrick (1996). Journal of Neurotherapy, 1 (4), 27 - 36.

Quantitative EEG Abnormalities in a Sample of Dyslexic Persons; James R. Evans, Nan-Sook Park (1996). Journal of Neurotherapy, 2 (1), 1 - 5.

Neurotherapy and Drug Therapy in Combination for Adult ADHD, Personality Disorder, and Seizure Disorder: A Case Report; Lisa M. Hansen, David L. Trudeau, Dixie L. Grace (1996). Journal of Neurotherapy, 2 (1), 6 - 14.

Subthreshold 10-Hz Sound Suppresses EEG Theta: Clinical Application for the Potentiation of Neurotherapy Treatment of ADD/ADHD; Paul G. Swingle(1996). Journal of Neurotherapy, 2 (1), 15 - 22.

The FIG (Functional Integrative QEEG) Technique and the Functional Structure of Memory Functioning in Normals and Head Injured Subjects; Kirtley E. Thornton (1996). Journal of Neurotherapy, 2 (1), 23 - 42.

Master Zhu; John F. Gilbert, Robert Moroney(1996). Journal of Neurotherapy, 2 (1), 43 - 49.

Oppositional Children Similar to OCD on SPECT: Implications for Treatment; Daniel G. Amen, Blake Carmichael (1997). Journal of Neurotherapy, 2 (2), 1 - 6.

PMS, EEG, and Photic Stimulation; David Noton (1997). Journal of Neurotherapy, 2 (2), 8 - 13.

Treatment of Chronic Anxiety Disorder with Neurotherapy: A Case Study; Joseph E. Thomas, Elizabeth Sattlberger (1997). Journal of Neurotherapy, 2 (2), 14 - 19.

EEG Patterns and Chronic Fatigue Syndrome; Katherine M. Billiott, Thomas H. Budzynski, Frank Andrasik (1997). Journal of Neurotherapy, 2 (2), 20 - 30.

Quantitative EEG Findings Among Men Convicted of Murder; James R. Evans, Nan-Sook Park (1997). Journal of Neurotherapy, 2 (2), 31 - 39.

EEG Power Spectral and Coherence Differences Between Attentional States During a Complex Auditory Task; Grant Benham, Howard Rasey, Joel F. Lubar, Jon A. Frederick, A. Charles Zuffuto (1997). Journal of Neurotherapy, 2 (3), 1 - 9.

The Clinical Use of an Alpha Asymmetry Protocol in the Neurofeedback Treatment of Depression: Two Case Studies; Elsa Baehr, J. P. Rosenfeld, Rufus Baehr (1997). Journal of Neurotherapy, 2 (3), 10 - 23.

Native Americans, Neurofeedback, and Substance Abuse Theory Three Year Outcome of Alpha/theta Neurofeedback Training of Problem Drinking Among Dine' (Navaho) People; Matthew J. Kelly (1997). Journal of Neurotherapy, 2 (3), 24 - 60.

Single Channel QEEG Amplitudes in a Bright, Normal Young Adult Sample; Doil D. Montgomery, Jennie Robb, Kimberly V. Dwyer, Samual T. Gontkovsky, (1998). Journal of Neurotherapy, 2 (4), 1 - 7.

Normative EEG Databases and EEG Biofeedback; Robert W. Thatcher (1998). Journal of Neurotherapy, 2 (4), 8 - 39.

Treatment Of Dissociative Identity Disorder With Neurotherapy And Group Self-Exploration; Carol Manchester, Tom Allen, Ken H. Tachiki (1998). Journal of Neurotherapy, 2 (4), 40 - 52.

Patient Directed Neurofeedback for AD/HD; Thomas R. Rossiter (1998). Journal of Neurotherapy, 2 (4), 53 - 64.

EEG Biofeedback in the Schools The Use of EEG Biofeedback to Treat ADHD in a School Setting; William D. Boyd, Susan E. Campbell (1998). Journal of Neurotherapy, 2 (4), 64 - 71.

Quantitative Electroencephalographic Correlates of Post-Stroke Depression; Fred A. Ulam, R. Paul Thomlinson, Rodney Quinn, Todd Smith, Theresa Templemeyer (1998). Journal of Neurotherapy, 3 (1), 1 - 8.

Visual-motor Integration and its Relation to EEG Neurofeedback Brain Wave Patterns, Reading Spelling, and Arithmetic Achievement in Attention Deficit Disordered and Learning Disabled Students; T. Nick Fenger (1998). Journal of Neurotherapy, 3 (1), 9 - 20.

Performance Enhancement Training Effects on Attention: A Case Study; S. Louise Norris, Ching-tse Lee, Juan Cea, Dmitry Bursgteyn (1998). Journal of Neurotherapy, 3 (1), 21 - 27.

Frequency Band interaction in ADD/ADHD Neurotherapy; Franklin Ramos (1998). Journal of Neurotherapy, 3 (1), 28 - 46.

Neurofeedback Training In A Case Of Attention Deficit Hyperactivity Disorder; Sonia Wadhwani, Diane C. Radvanski, Dennis P. Carmody (1998). Journal of Neurotherapy, 3 (1), 47 - 54.

History of EEG Hans Berger: Psychophysiologist. A Historical Vignette; T. J. LaVaque (1999). Journal of Neurotherapy, 3 (2), 1 - 9.

Neurofeedback Therapy for ADHD and Related Neurological Disorders; Neil P. Schulenberg (1999). Journal of Neurotherapy, 3 (2), 10 - 20.

Abnormal QEEG Patterns Associated with Dissociation and Violence; James R. Evans, Suzanne Claycomb (1999). Journal of Neurotherapy, 3 (2), 21 - 27.

Single Case Study of EEG Asymmetry Biofeedback for Depression: An Independent Replication in an Adolescent; Carolyn Earnest(1999). Journal of Neurotherapy, 3 (2), 28 - 35.

Reflexology and Its Effect on the EEG; J. A. Putman, Merle Sunde (1999). Journal of Neurotherapy, 3 (2), 36 - 41.

Basic Principles, Clinical Applications and Related Fields; Jay Gunkleman , Haworth Continuing Features Submission (1999). Journal of Neurotherapy, 3 (2), 42 - 43.

Exploratory Analysis: Mild Head Injury, Discriminant Analysis with High Frequency Bands (32-64 Hz) Under Attentional Activation Conditions & Does Time Heal?; Kirtley E. Thornton (1999). Journal of Neurotherapy, 3 (3/4), 1 - 10.

Academic Performance Enhancement with Photic Stimulation and EDR Feedback; Thomas Budzynski, John Jordy , Helen Kogan Budzynski, Hsin-Yi Tang, Keith Claypoole (1999). Journal of Neurotherapy, 3 (3/4),11 - 21.

Effects of 18.5 Hz Auditory and Visual Stimulation on EEG Amplitude at the Vertex; Jon A. Frederick, Joel F. Lubar, Howard W. Rasey, Sheryl A. Brim, Jared Blackburn (1999). Journal of Neurotherapy, 3 (3/4), 23 - 32.

Reading Task and Lambda EEG Activity; Jay Gunkleman (1999). Journal of Neurotherapy, 3 (3/4), 35 - 44.

Effect of Neurofeedback on Variables of Attention in a Large Multi-Center Trial; David A. Kaiser, Siegfried Othmer (2000). Journal of Neurotherapy, 4 (1), 5 - 15.

The Effects of Brief, Eyes-Open Alpha Brain Wave Training with Audio and Video Relaxation Induction on the EEG of 77 Army Reservists; John Putman, (2000). Journal of Neurotherapy, 4 (1), 17 - 28.

Comparison of Alpha-Theta, Alpha and EMG Neurofeedback in the Production of Alpha-Theta Crossover and the Occurrence of Visualizations; John P. Moore, David L. Trudeau, Paul D. Thuras, Yael Rubin, Herbert StockleyW, Teri DimondW (2000). Journal of Neurotherapy, 4 (1), 29 - 42.

The Role of Aspirational Ethics and Licensing Laws in the Practice of Neurofeedback; Sebastian ''Seb'' Striefel (2000). Journal of Neurotherapy, 4 (1), 43 - 55.

Hjorth Referencing in QEEG; Jay Gunkelman (2000). Journal of Neurotherapy, 4 (1), 57 - 62.

Neurofeedback Equipment Study One- Focused Technology F-1000 Main Board Investigation; Robert Hamilton, Timothy Barnes (2000). Journal of Neurotherapy, 4 (1), 63 - 70.

Response to Neurofeedback Equipment Study One- Focused Technology F-1000; Frank Deits (2000). Journal of Neurotherapy, 4 (1), 71 - 72.

Audio-Visual Entrainment Program as a Treatment for Behavior Disorders in a School Setting; Michael Joyce, Dave Siever(2000). Journal of Neurotherapy, 4 (2), 9 - 25.

Changes After EEG Biofeedback and Cognitive Retraining in Adults with Mild Traumatic Brain Injury and Attention Deficit Hyperactivity Disorder; Timothy P. Tinius, Kathleen A. TiniusW (2000). Journal of Neurotherapy, 4 (2), 27 - 44.

Neurofeedback Treatment of Depression with the Roshi; D. Corydon Hammond (2000). Journal of Neurotherapy, 4 (2), 45 - 56.

QEEG: State of the Art, or State of Confusion; David A. Kaiser (2000). Journal of Neurotherapy, 4 (2), 57 - 75.

Theoretical Implications of EEG Reference Choice and Related Methodology Issues; J. Peters Rosenfeld (2000). Journal of Neurotherapy, 4 (2), 77 - 87.

Verification Study on the Focused Technology F1000 Software Update; T. Barnes, R. Hamilton, S. Reed, G. Davis (2000). Journal of Neurotherapy, 4 (2), 105 - 107.

Response to Verification Study; Frank Deits (2000). Journal of Neurotherapy, 4 (2), 109 - 109.

EEG Biofeedback Training and Attention-Deficit/Hyperactivity Disorder in an Elementary School Setting; Dennis P. Carmody, Diane C. Radvanski, Sonia Wadhwani, Mary Jo Sabo, Linda Vergara (2000). Journal of Neurotherapy, 4 (3), 5 - 27.

The Effects of Performance Enhancement Training on Hypertension, Human Attention, Stress, and Brain Wave Patterns: A Case Study; S. Louise Norris, Ching-tse Lee, Dmitry Burshteyn, Juan Cea-Aravena (2000). Journal of Neurotherapy, 4 (3), 29 - 44.

Electrophysiology of Auditory Memory of Paragraphs Towards a Projection/Activation Theory of the Mind; Kirtley E. Thornton (2000). Journal of Neurotherapy, 4 (3), 45 - 72.

Comodulation: A New QEEG Analysis Metric for Assessment of Structural and Functional Disorders of the Central Nervous System; M. Barry Sterman, David Kaiser (2000). Journal of Neurotherapy, 4 (3), 73 - 83.

Automatic Artifact Detection, Overlapping Windows, and State Transitions; David A. Kaiser, M. Barry Sterman (2000). Journal of Neurotherapy, 4 (3), 85 - 92.

What Became of "The Decade of the Brain"; David A. Kaiser (2001). Journal of Neurotherapy, 4 (4), 5 - 9.

Clinical Use of an Alpha Asymmetry Neurofeedback Protocol in the Treatment of Mood Disorders: Follow-Up Study One to Five Years Post Therapy; Elsa Baehr, J. Peter Rosenfeld, Rufus Baehr (2001). Journal of Neurotherapy, 4 (4), 11 - 18.

"Delusions" of Space: A Case Study Utilizing Topographical Brain Mapping and QEEG; D. Erik Everhart, Heath A. Demaree, David W. Harrison, John B. Williamson (2001). Journal of Neurotherapy, 4 (4), 19 - 29.

Low Resolution Brain Electromagnetic Tomography (LORETA): The Technique, Its Validation, and Methods of Analysis; Roberto D. Pascual-Marqui (2001). Journal of Neurotherapy, 4 (4), 31 - 33.

Functional Localization and Functional Connectivity with LORETA: Comparison of Normal Controls and First Episode, Drug Naive Schizophrenics; Roberto D. Pascual-Marqui, M. Koukkou, D. Lehmann, K. Kochi (2001). Journal of Neurotherapy, 4 (4), 35 - 37.

Open Source Method of Graphical QEEG Analysis Using PERL and Visual Basic; Jon Frederick (2001). Journal of Neurotherapy, 4 (4), 39 - 47.

Applied Research Using Alpha/Theta Training for Enhancing Creativity and Well-Being; Tracy Boynton (2001). Journal of Neurotherapy, 5 (1/2),5 - 18.

Neurofeedback Therapy of Attention Deficits in Patients with Traumatic Brain Injury; Ingo Keller (2001). Journal of Neurotherapy, 5 (1/2), 19 - 32.

Optimal Functioning Training with EEG Biofeedback for Clinical Populations: A Case Study; Linda A. Mason, Thomas S. Brownback (2001). Journal of Neurotherapy, 5 (1/2), 33 - 44.

Attention and Neurofeedback Synchrony Training: Clinical Results and Their Significance; J. T. McKnight, L. G. Fehmi (2001). Journal of Neurotherapy, 5 (1/2), 45 - 62.

Changes in Lateralized Memory Performance in Subjects with Epilepsy Following Neurofeedback Training; M. B. Sterman, DeLee Lantz (2001). Journal of Neurotherapy, 5 (1/2), 63 - 72.

Pills, Politics, and Placebos; T. J. LaVaque (2001). Journal of Neurotherapy, 5 (1/2), 73 - 86.

Rethinking Standard Bands; David A. Kaiser (2001). Journal of Neurotherapy, 5 (1/2),87 - 96.
-DK

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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
 

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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

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  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

CONFERENCE      LOCATION       DATES

AAPB - aapb.org Albuquerque, NM Apr 2-4 

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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-->brain-->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

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