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Validation d'une nouvelle électrode hybride intracérébrale comportant des tétrodes dans l'épilepsie pharmaco-résistante

Abstract : This thesis was done in collaboration with DIXI medical, the CHU of Toulouse and the Centre de Recherche Cerveau et Cognition in order to validate the use of a new hybrid electrode in drug refractory epileptic patients. These electrodes are used in order to identify the seizure onset zone during stereo-electroencephalography. If this zone can be identified and removed, drug-refractory epileptic patients may become seizure free. In recent years, epilepsy research has focused on high frequency oscillations and more precisely on fast-ripples (200-600 Hz). These oscillations appear to be a good biomarker of the seizure onset zone. Fast-ripples can be detected with clinical macroelectrodes (diameter 800-1300 µm) but their identification is facilitated with microelectrodes (diameter 80 µm). In the CHU of Toulouse, clinical macroelectrodes have a diameter of 800 µm and hybrid electrodes (combining macro and microelectrodes) available on the market have a diameter of 1300 µm. This problem leads to a collaboration with DIXI medical in order to manufacture a new hybrid electrode with the same diameter as the clinical ones. The new hybrid electrode has different advantages: (1) the microelectrodes are, for the first time in the human, in a tetrode configuration (4 microwires bundled together), which facilitates single neuron identification; (2) microelectrodes can be extended up to 2 mm, which enable to search for neurons; (3) microelectrodes can be extended between the macrocontacts, which enable multiscale analysis. This new hybrid electrode is under clinical investigation in the CHU of Toulouse since March 2015. The goal of my thesis is to demonstrate the safety of the electrode and its ability to record EEG signal of interest both in epilepsy and in fundamental research. My thesis is composed of a literature review and 5 studies. The first study is a methodological study, which present the characteristics of the new hybrid electrode and demonstrates its safety. Studies 2, 3 and 4 concern the use of the hybrid electrode in epilepsy. More precisely, the 2nd study describes the case of a patient with a tuberous sclerosis lesion associated with drug-refractory epilepsy. It's the first time that neuronal activity can be recorded and analyzed in vivo in this pathology. The 3rd study is required to CE mark the new electrode. In this study, we verify whether the fast-ripples recorded with the new hybrid electrodes are really a good biomarker of the seizure onset zone. The 4th study is about the neurophysiopathology of fast-ripples. We analyze the relationship between neuronal activities and fast-ripples. Finally, the 5th study describe the spatiotemporal dynamic of visual recognition memory using macro-electrodes. It is a preliminary study to the analyses of neuronal activity during such cognitive task.
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Submitted on : Tuesday, August 25, 2020 - 10:04:21 AM
Last modification on : Thursday, August 27, 2020 - 4:37:02 PM


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  • HAL Id : tel-02894057, version 2



Elodie Despouy. Validation d'une nouvelle électrode hybride intracérébrale comportant des tétrodes dans l'épilepsie pharmaco-résistante. Neurosciences. Université Paul Sabatier - Toulouse III, 2019. Français. ⟨NNT : 2019TOU30070⟩. ⟨tel-02894057v2⟩



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