1 / 9

ENTROPIES OF THE EEG: The effects of general anesthesia .

ENTROPIES OF THE EEG: The effects of general anesthesia . J. W. Sleigh 1 , E. Olofsen 2 , A. Dahan 2 , J de Goede 3 & A Steyn-Ross 4 .

abie
Download Presentation

ENTROPIES OF THE EEG: The effects of general anesthesia .

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. ENTROPIES OF THE EEG: The effects of general anesthesia. J. W. Sleigh1, E. Olofsen2, A. Dahan2, J de Goede3 & A Steyn-Ross4. Department of Anaesthesia1, Waikato Hospital, Departments of 2Anaesthesiology and 3Physiology, Leiden University Medical Centre, Leiden, The Netherlands, and Department of Physics4, University of Waikato, Hamilton, New Zealand sleighj@hwl.co.nz

  2. Rationale: Why bother with EEG Entropy Estimators? • The formation and dissolution of cortical microstates = ‘Corticodynamic’ entropy • Limitation of microstates lower entropy • Lower entropyunconsciousness QUESTIONS (1) Is the EEG telling us about the Cortex? (2) Are Entropy Estimators wrecked by artifacts?

  3. Spectral Entropies Spectral Entropy (1:47Hz) Renyi Entropies Kullback-Leibler (=Relative entropy) CUP Fisher I Wavelet HOS Tallis (q) Embedding / Phase-space Entropies = Kolmogorov-Sinai Approximate Entropy and Cross ApEn Singular Value Decomposition Entropy Entropy Bestiary

  4. Patient data: Induction of Anesthesia Spectral Entropy Renyi: GSE ApEn (m=2) ApEn (m=5) DFA SVDen

  5. (Q). Why are the entropy estimators “sort-of-the-same” but “sort-of-different”? (A). See how they perform with controlled “PseudoEEG” signals • 1) AR2 model • 2) White noise + artifacts • 3) Real EEG + oscillations

  6. (1) Pseudo-EEG series (AR2) (1) Decreased by shift to Low-frequency power and Oscillations. < ??EXCEPT DFA ??> (2) ApEn(m=5) and ApEn(m=10) go the opposite direction to ApEn(m=2). ApEn(m=2) ApEn(m=5)

  7. (2) Are the differences just sensitivity to artifact? ApEn SVDen GSE Spectral Entropy Change in Entropy estimator Raw ‘pseudoEEG’ Series Magnitude of Artifact

  8. (3) The effects of oscillations: Patient data Spectral Entropy ApEn Difference in Parameter (raw-osc) DFA SVD en Value of parameter

  9. Conclusions... • (1a) Anesthetics “make the EEG less free”... • (1b) The EEG changes  Corticodynamic entropy... • (2a) Entropy estimators  Correlation-Time estimators...[DFA; ApEn(m=2)  ApEn(m=5)] • (2b) Sensitivity to artifacts  to underlying EEG signal...[SEN>GSE>SVDen,ApEn]

More Related