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Pairwise Granger Causality Findings in Patients with Partial Epilepsy Refractory to Medical Treatment

Permanent Link: http://ufdc.ufl.edu/UFE0042988/00001

Material Information

Title: Pairwise Granger Causality Findings in Patients with Partial Epilepsy Refractory to Medical Treatment
Physical Description: 1 online resource (63 p.)
Language: english
Creator: ANDRADE,EDGARD OLBANY
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2011

Subjects

Subjects / Keywords: ANOVA -- APPCI -- EEG -- EPILEPSY -- EPILEPTOGENIC -- GABA -- GRANGER -- HIPPOCAMPUS -- ICTAL -- ICTOGENIC -- ILAE -- MEG -- MRI -- PET -- REFRACTORY -- SEIZURES -- SPECT
Clinical Investigation (IDP) -- Dissertations, Academic -- UF
Genre: Medical Sciences thesis, M.S.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: Based on the association between ictal onset (IO) and a neuronal network, we tested the hypothesis that the ictal zone (IZ) in patients with partial epilepsy refractory to medical treatment (PERT) originates in a single network and propagates to the contra-lateral hemisphere (inter-hemispheric theory) as opposed to no contra-lateral ictal propagation (intra-hemispheric) using Linear Pairwise Granger Causality (PGC) analysis of interictal and ictal EEG recordings in a case series study. Hence, we prospectively studied ninety partial complex seizures (PCS) in twenty-three subjects and defined seizure directionality in involved neuronal networks and compared to non-involved control neuronal networks. The EEG raw data were analyzed using linear PGC. Boot-strapping methodologies were used to address the statistical significance of the network interactions defined with PGC. Time frequency distribution was plotted for each seizure and compared versus controls. PGC was statistically significant for intra-hemispheric directionality if the IO was over the right temporal lobe (p=0.0257) and for inter-hemispheric directionality if the IO was over the left frontal lobe (p=0.0028). PGC showed a trend for a significant intra-hemispheric directionality if the IO was over the left temporal (p=0.0548) and right frontal lobe (p=0.0558). Furthermore, there were no significant differences when looking at the inter-hemispheric PGC measures obtained in subjects with seizures with an IO over the left frontal (p=0.2882), left temporal (p=0.1572), right frontal (p=0.6772) and right temporal networks (p=0.7795) when compared against the parietal network. The possible explanations of this last finding are at least three-fold: 1) There is in fact no contra-lateral ictal propagation, 2) contra-lateral ictal propagation is not identifiable with PGC, and/or 3) The hidden element theory may apply, that is, the causal relation of two neurons can be affected by the effects of a third neuron that is not measured. Although this study has several limitations, the findings will serve as a principle for the development of models capable of predicting seizure directionality and for further evaluation of established methodologies such as segmentation and surrogate analysis.
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility: by EDGARD OLBANY ANDRADE.
Thesis: Thesis (M.S.)--University of Florida, 2011.
Local: Adviser: Limacher, Marian C.
Electronic Access: RESTRICTED TO UF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE UNTIL 2013-04-30

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2011
System ID: UFE0042988:00001

Permanent Link: http://ufdc.ufl.edu/UFE0042988/00001

Material Information

Title: Pairwise Granger Causality Findings in Patients with Partial Epilepsy Refractory to Medical Treatment
Physical Description: 1 online resource (63 p.)
Language: english
Creator: ANDRADE,EDGARD OLBANY
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2011

Subjects

Subjects / Keywords: ANOVA -- APPCI -- EEG -- EPILEPSY -- EPILEPTOGENIC -- GABA -- GRANGER -- HIPPOCAMPUS -- ICTAL -- ICTOGENIC -- ILAE -- MEG -- MRI -- PET -- REFRACTORY -- SEIZURES -- SPECT
Clinical Investigation (IDP) -- Dissertations, Academic -- UF
Genre: Medical Sciences thesis, M.S.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: Based on the association between ictal onset (IO) and a neuronal network, we tested the hypothesis that the ictal zone (IZ) in patients with partial epilepsy refractory to medical treatment (PERT) originates in a single network and propagates to the contra-lateral hemisphere (inter-hemispheric theory) as opposed to no contra-lateral ictal propagation (intra-hemispheric) using Linear Pairwise Granger Causality (PGC) analysis of interictal and ictal EEG recordings in a case series study. Hence, we prospectively studied ninety partial complex seizures (PCS) in twenty-three subjects and defined seizure directionality in involved neuronal networks and compared to non-involved control neuronal networks. The EEG raw data were analyzed using linear PGC. Boot-strapping methodologies were used to address the statistical significance of the network interactions defined with PGC. Time frequency distribution was plotted for each seizure and compared versus controls. PGC was statistically significant for intra-hemispheric directionality if the IO was over the right temporal lobe (p=0.0257) and for inter-hemispheric directionality if the IO was over the left frontal lobe (p=0.0028). PGC showed a trend for a significant intra-hemispheric directionality if the IO was over the left temporal (p=0.0548) and right frontal lobe (p=0.0558). Furthermore, there were no significant differences when looking at the inter-hemispheric PGC measures obtained in subjects with seizures with an IO over the left frontal (p=0.2882), left temporal (p=0.1572), right frontal (p=0.6772) and right temporal networks (p=0.7795) when compared against the parietal network. The possible explanations of this last finding are at least three-fold: 1) There is in fact no contra-lateral ictal propagation, 2) contra-lateral ictal propagation is not identifiable with PGC, and/or 3) The hidden element theory may apply, that is, the causal relation of two neurons can be affected by the effects of a third neuron that is not measured. Although this study has several limitations, the findings will serve as a principle for the development of models capable of predicting seizure directionality and for further evaluation of established methodologies such as segmentation and surrogate analysis.
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility: by EDGARD OLBANY ANDRADE.
Thesis: Thesis (M.S.)--University of Florida, 2011.
Local: Adviser: Limacher, Marian C.
Electronic Access: RESTRICTED TO UF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE UNTIL 2013-04-30

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2011
System ID: UFE0042988:00001


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Full Text

PAGE 12

Background

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Epidemiology Significance and Rationale

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Biology of the Neuronal Circuitry Non Lesional Epilepsy

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Is the EEG the Right Tool to Evaluate Ictal Networks?

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Effective and Functional Connectivity Tools in Epilepsy

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General Methods

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Specific Methodology for PGC Analysis

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Statistical Methods

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F7 T8 F7 T7 Inter hemispheric T7 F7 T8 F8 F8 T8 F8 F7 T8 F8 P8 C3 Intra hemispheric Intra hemispheric CASE CONTROL

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