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Published on: December 18, 2016
Cerebral Cavernous Malformations and Focal Drug-Resistant Epilepsy: Behind a Quid Pro Quo of Lesion and Epileptogenic
Ionuț-Flavius Bratu1,2, Lucie de Clerck1, Hélène Catenoix3,4
1Department of Epileptology and Cerebral Rhythmology, Timone Hospital, Marseille, France.
Background:
Cerebral cavernous malformations (CCMs) contribute to focal drug-resistant epilepsy (fDRE), with surgical outcomes varying due to an incomplete understanding of the interplay between CCM-impacted regions and areas exhibiting ictal or interictal epileptogenicity. This study quantified the epileptogenicity of brain structures sampled by stereo-electroencephalography (SEEG) electrodes in patients with fDRE and supratentorial CCMs, focusing on the irritative zone (IZN) and epileptogenic-zone network (EZN). It also established a framework for describing EZN organization relative to CCM-affected regions.
Methods:
Retrospective multicentric cohort study involving fDRE patients with supratentorial CCMs, explored using SEEG, recruited from five French tertiary epilepsy centers. SEEG-sampled brain regions were classified as lesional, perilesional, or non-lesion-associated according to their anatomic relationship with the CCMs and using the Virtual Epileptic Patient brain atlas parcellation. IZN quantification was performed using spike rates per minute. EZN was evaluated using the Epileptogenicity Index or Permutation Entropy Index according to the seizure-onset pattern. Data were analyzed using both descriptive and inferential statistics.
Results:
The study included 22 patients, 10 of whom underwent post-SEEG epilepsy surgery. IZN biomarkers differed significantly between lesional, perilesional, and non-lesion-associated areas, whereas EZN biomarkers did not. EZN included lesional areas in 50% of cases, with complex multi-lobar networks identified in most patients. Postsurgical seizure freedom was achieved in 70% of SEEG-explored patients.
Conclusions:
Our findings highlight the complex relationship between CCMs and the EZN, supporting SEEG in the presurgical work-up of selected patients with CCMs and fDRE. A network-based surgical approach may improve outcomes by tailoring resections to the EZN.
Insights
Stereo-electroencephalography (SEEG) helps map the epileptogenic zone network in cerebral cavernous malformations (CCMs) causing drug-resistant epilepsy. Network-based surgery tailored to the EZN improves seizure freedom in these patients.
Area of Science:
- Neuroscience
- Epileptology
- Neurosurgery
Background:
- Cerebral cavernous malformations (CCMs) are a cause of focal drug-resistant epilepsy (fDRE).
- Understanding the relationship between CCMs and epileptogenic zones is crucial for surgical planning.
- Current surgical outcomes vary due to incomplete knowledge of CCM-epileptogenicity interplay.
Purpose of the Study:
- To quantify brain structure epileptogenicity in patients with fDRE and supratentorial CCMs using SEEG.
- To analyze the irritative zone (IZN) and epileptogenic-zone network (EZN) in relation to CCMs.
- To establish a framework for describing EZN organization within CCM-affected regions.
Main Methods:
- Retrospective multicentric cohort study of fDRE patients with supratentorial CCMs.
- Stereo-electroencephalography (SEEG) used for brain region exploration.
- Classification of SEEG-sampled regions as lesional, perilesional, or non-lesion-associated.
- Quantification of IZN using spike rates and EZN using Epileptogenicity Index or Permutation Entropy Index.
Main Results:
- Included 22 patients; 10 underwent epilepsy surgery.
- IZN biomarkers differed significantly across lesional, perilesional, and non-lesion-associated areas.
- EZN included lesional areas in 50% of cases, with complex multi-lobar networks in most.
- 70% of SEEG-explored patients achieved postsurgical seizure freedom.
Conclusions:
- CCMs exhibit a complex relationship with the epileptogenic zone network (EZN).
- SEEG is valuable for presurgical work-up in selected CCMs and fDRE patients.
- A network-based surgical approach, tailored to the EZN, may enhance seizure control.
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