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Use of EEG technology is shared by at least two disciplines

Use of EEG technology is shared by at least two disciplines. As EEG is used for different goals by different groups, the same is true for other tools such as hammers. We do not require a gavel to be manufactured using specifications of a carpenter’s hammer. Standard 19 electrode positions.

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Use of EEG technology is shared by at least two disciplines

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  1. Use of EEG technology is shared by at least two disciplines

  2. As EEG is used for different goals by different groups, the same is true for other tools such as hammers We do not require a gavel to be manufactured using specifications of a carpenter’s hammer

  3. Standard 19 electrode positions

  4. Survey of 2009 EEG papers on Medline for humans waking state, 25% clinical, 75% quantitative Over 40,000 QEEG papers since 1965 First QEEG paper = 1932 Dietsch (1932) analyzed EEG using discrete Fourier transforms (1831). Fast Fourier Transform (FFT) algorithm invented (Cooley & Tukey, 1965) , allowing practical spectral applications Dumermuth & Fluhler (1967) applied FFT to EEG

  5. Frequency analysis Jean Baptiste Joseph Fourier(1768-1830)

  6. Energy (Amplitude) & Speed (Frequency)

  7. SKIL Database – Individual dominant frequency

  8. Some of the signal properties that can be quantified

  9. Evaluation of cortical activity. Each brain map consists of 19 electrode sites evenly spaced across the head. Color indicates microvolts (data or raw view) or statistical deviation from a comparison group average (stat view). Spectral magnitude coefficients that exceed +/- 2 standard deviations are indicative of localized hyper- or hypo-excitability in cortical neuronal pools, depending upon the frequency of interest

  10. SKIL Database Peer review publications of SKIL database Johnston et al, 2005 (Clinical EEG) Lorensen & Dickson, 2003 (J Neurotherapy) Mean 28.2 years+/- 6.4 years 75% male n=135 using replicated files from each participant

  11. Why amplify? • 102 volts - Wall socket • 10-3 volts - EKG • (millivolts) • 10-5 volts – EOG • 10-6 volts – EEG • (microvolts)

  12. Sources of Artifact • Equipment • Computational • Neural, non-cerebral (muscle) • Neural, cerebral, mixed states • alertness changes, sleep, unstable background • transients • Inferential • Improper mental processes • Improper frequency correspondence

  13. Brain Maturation 4-8 Hz 8-12 Hz Healthy Child Healthy Adult

  14. The more neurons recruited into a rhythm, the higher the spectral magnitude (or power)

  15. Time delay between brain areas recruited into the same rhythm is indicated by phase

  16. Activity and Connectivity

  17. How to show 361 (19x19) site-pairs Raw Data VIEWS Statistical

  18. Data and Statistical (z) views

  19. Network Maps (anterior callosotomy case)

  20. Behavioral differences from norma Activity Connectivity

  21. Frequency informationlocalized and shared • Coherence • (Wiener, 1930; Goodman, 1957; Walter, 1968) • Comodulation • (Pearson, 1896; Kaiser, 1994)

  22. Signals are … …coherent when phase difference is stable …comodulated when magnitude difference is stable

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