Est-ce que l'eeg a toujours sa place en 2019?

Transcription

1 Est-ce que l'eeg a toujours sa place en 2019? Thomas Bast Epilepsy Center Kork, Germany

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3 Does EEG still play a role in 2019? What a question 7T-MRI, fmri, DTI, MEG, SISCOM, Of ieeg course! /HFO, Genetics EEG

4 What makes the surface EEG unique? Spatial resolution (mm) Invasiveness EEG SPECT MEG ieeg fmri PET Time resolution (sec)

5 Surface EEG in clinical epilepsy research Electric source analysis in presurgical evaluation Functional connectivity studies

6 High-resolution EEG with up to 256 surface electrodes 14 Patients with FLE, 7 resective surgery 76 channel surface EEG vs. ieeg In comparison to conventional EEG, SISCOM Correct lateralization heeg 14/14, ceeg 9/14 Concordant to ieeg heeg 12/14 ceeg 3/14 SISCOM 3/12 Feyissa et al. High density scalp EEG in frontal lobe epilepsy. Epilepsy Res 2017

7 What is EEG source analysis? or Electric Source Imaging (ESI)? (Geneva) Visual inspection Pattern recognition Spikes are similar Maximum negativity FC5/F3/F7

8 What is EEG source analysis? Every EEG reviewer builds a hypothesis on the localization of the underlying cortical generator of interictal and/or ictal epileptic activity Quality of this hypothesis depends on experience Source analysis leads to more stable hypotheses and allows for better visualization by MRI co-registration Dipole model L2 minimum norm 8

9 Success of EEG source localization depends on Optimized individual head model

10 Success of EEG source localization depends on Optimized individual head model Number of electrodes High-resolution EEG (HR-EEG) or High-density EEG (HD-EEG) Seeck et al. Clin Neurophysiol 2017 Sohrabpour et al. Effect of EEG electrode number on epileptic source localization in pediatric patients. Clin Neurophysiol

11 Success of EEG source localization depends on Optimized individual head model Number of electrodes High-resolution EEG (HR-EEG) or High-density EEG (HD-EEG) Analysis of spike onset instead of (potentially propagated) peak activity Averaging of similar spikes 11

12 EEG dipole localization depends on SNR Bast et al., J Clin Neurophysiol 2006

13 ESI in presurgical evaluation 152 patients, follow-up 1 year, MRI normal in 10 Brodbeck et al. Electroencephalographic source imaging: a prospective study of 152 operated epileptic patients. Brain 2011

14 ESI in presurgical evaluation Brodbeck et al. Electroencephalographic source imaging: a prospective study of 152 operated epileptic patients. Brain 2011

15 ESI in presurgical evaluation Brodbeck et al. Electroencephalographic source imaging: a prospective study of 152 operated epileptic patients. Brain 2011

16 ESI in presurgical evaluation Prospective study in 190 operated patients (TLE 154) Follow-up 1 year, 77.8% seizure free 58 underwent examinations with all methods Lascano et al. Yield of MRI, high-density electric source imaging (HD-ESI), SPECT and PET in epilepsy surgery candidates. Clin Neurophysiol 2016

17 Source analysis of ictal activity Mégevand & Seek. Electroencephalography, magnetoencephalography and source localization: their value in epilepsy. Curr Opin Neurol 2018

18 High-frequency oscillations (ripples, Hz) in vs. HD-EEG Kuhnke et al. Brain Topogr 2018

19 High-frequency oscillations (ripples, Hz) in vs. HD-EEG 13 patients vs. 128 channel vs. ieeg 12/13 with ripples Kuhnke et al. High Frequency Oscillations in the Ripple Band ( Hz) in Scalp EEG: Higher Density of Electrodes Allows for Better Localization of the Seizure Onset Zone. Brain Topogr 2018

20 Surface EEG in clinical epilepsy research Electric source analysis in presurgical evaluation Functional connectivity studies

21 Resting state functional connectivity - fmri Spontaneous brain activity ~ coherent and correlated fluctuations of activity in specific sets of brain areas Biswal, Yetkin, Haughton, & Hyde, 1995; Damoiseaux et al., 2006; Raichle et al., 2001 Resting state network = areas showing increased and correlated activations at rest ~ correspond spatially to networks associated with specific tasks areas (somatosensory, motor, visual, cognitive, ) ~ correlate with structural connectivity patterns Honey at al Coito et al. Directed functional connections underlying spontaneous brain activity. Hum Brain Map 2018

22 Resting state functional connectivity - fmri Language network Auditory network Default Mode Network = mainly: Posterior cingulate cortex Medial prefrontal cortex Medial temporal regions Inferior parietal cortex Smitha et al. Resting state fmri: A review on methods in resting state connectivity analysis and resting state networks. Neuroradiol J 2017

23 Functional connectivity analysis: Default Mode Network 5 healthy subjects, 256 channel EEG (204 included), 1000 Hz sampling, 60 * 1 sec. epochs simplified realistic head model (3D-T1) linear distributed inverse solution: LAURA = local auto-regressive averages 82 ROI each subject mean spectral power, normalization (0 1) across regions, time and frequencies (1 40 Hz) by subtracting the minimum power and dividing by the range Estimation of the directed functional connections between source regions by PDC= partial directed coherence Investigation of the directionality of functional brain connections in the frequency domain by Granger-causality approach = weighted PDC Coito et al. Directed functional connections underlying spontaneous brain activity. Hum Brain Map 2018

24 Functional connectivity analysis: Default Mode Network Coito et al. Directed functional connections underlying spontaneous brain activity. Hum Brain Map 2018

25 Functional connectivity analysis: Default Mode Network PCC = strongest driver (highest integration and segregation importance), 2 nd = mtl regions Coito et al. Hum Brain Map 2018

26 Functional connectivity analysis in epilepsy 20 LTLE, 20 RTLE, 20 controls Resting-state HD-EEG recording channels, Hz in the absence of ED Methods ~ Coito et al. Hum Brain Map 2018 Coito et al. Altered directed functional connectivity in temporal lobe epilepsy in the absence of interictal spikes: A high density EEG study. Epilepsia 2016

27 Functional connectivity analysis in epilepsy Coito et al. Altered directed functional connectivity in temporal lobe epilepsy in the absence of interictal spikes: A high density EEG study. Epilepsia 2016

28 Functional connectivity analysis in epilepsy Coito et al. Altered directed functional connectivity in temporal lobe epilepsy in the absence of interictal spikes: A high density EEG study. Epilepsia 2016

29 Functional connectivity analysis in epilepsy 20 LTLE, 20 RTLE, 20 controls Resting-state HD-EEG recording channels, Hz in the absence of ED Methods ~ Coito et al. Hum Brain Map 2018 RTLE: epilepsy duration ~ less driving from ipsilateral and contralateral mesiolimbic structures Learning defects or depression ~ lower outflow from anterior cingulum Coito et al. Altered directed functional connectivity in temporal lobe epilepsy in the absence of interictal spikes: A high density EEG study. Epilepsia 2016

30 Functional connectivity analysis in epilepsy 30 TLE, 31 ETLE, 31 controls MEG global functional connectivity maps Englot et al. Global and regional functional connectivity maps of neural oscillations in focal epilepsy. Brain 2015

31 Functional connectivity analysis in epilepsy Englot et al. Global and regional functional connectivity maps of neural oscillations in focal epilepsy. Brain 2015

32 Functional connectivity analysis in epilepsy Englot et al. Global and regional functional connectivity maps of neural oscillations in focal epilepsy. Brain 2015

33 Functional connectivity analysis in epilepsy 30 TLE, 31 ETLE, 31 controls MEG global functional connectivity maps regional functional connectivity maps at the region of resection compared to the homotopic non-epileptogenic region in the contralateral hemisphere Englot et al. Global and regional functional connectivity maps of neural oscillations in focal epilepsy. Brain 2015

34 Functional connectivity analysis in epilepsy 111 seizures in 27 patients with postoperative outcome Engel 1 ( 1y) 24h-EEG, electrodes ESI plus functional connectivity LORETA, spectrum-weighted Adaptive Directed Transfer Function Staljanssens et al. EEG source connectivity to localize the seizure onset zone with drug resistant epilepsy. Neuroimage Clin 2017

35 Siniatchkin & Capovilla. Functional neuroimaging in epileptic encephalopathies Epilepsia 2013

36 Networks in West syndrome Japaridze et al. Neuronal Networks in West Syndrome as Revealed by Source Analysis and Renormalized Partial Directed Coherence. Brain Topogr 2013

37 Networks in West syndrome Japaridze et al. Neuronal Networks in West Syndrome as Revealed by Source Analysis and Renormalized Partial Directed Coherence. Brain Topogr 2013

38 CSWS networks Japaridze et al. Neuronal networks in epileptic encephalopathies with CSWS. Epilepsia 2016

39 CSWS networks Mean follow-up 3 years CSWS resolved Persisting CSWS Japaridze et al. Neuronal networks in epileptic encephalopathies with CSWS. Epilepsia 2016

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41 Summary EEG is THE important diagnostic tool in the management of epilepsy Availability, repeatability High temporal resolution Satisfying spatial resolution Long-term recordings Source analysis of interictal and ictal epileptiform activity is an additional diagnostic tool in presurgical evaluation. The combination with functional connectivity analysis may improve the accuracy. These functional studies can improve our understanding of the pathophysiology of different epileptic syndromes.

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