multi-electrode-array-recordings-human-epileptic-postoperative

Multi-electrode Array Recordings of Human Epileptic Postoperative Cortical Tissue

Epilepsy, affecting about 1% of the population, comprises a group of neurological disorders characterized by the periodic occurrence of seizures, which ...

Paris Descartes University, Sorbonne Paris Cité, CEA

Paris Descartes University

Five to ten percent of pediatric brain tumors are located in the ventricles. Among them, forniceal lesions are rare and their management has not often been described. The aim of this study was to review the clinical, radiological, and histopathological features as well as the feasibility of surgical excision and the outcomes in these patients.

Forniceal glioma in children. Clinical article.

In reflex epilepsies, alteration of γ oscillations may mediate transition between interictal and ictal states. Here, we explored a patient having seizures triggered by syrup intake. From intracranial electroencephalography combined with functional MRI, the overlap of the gustatory cortex and of the preictal and ictal onset zones, as defined by early gamma changes, motivated the successful resective surgery of the middle short gyrus of the right insula. This case provides a rare demonstration from human gamma activity that the route to seizure may be supported by the interplay between physiological and epileptogenic networks.

Multimodal imaging reveals the role of γ activity in eating-reflex seizures.

Subdural collection is a possible adverse event that can occur after hemispherotomy.

Corticotomy closure avoids subdural collections after hemispherotomy.

Cortical stimulation is under investigation in clinical trials of drug-resistant epilepsy. Results are heterogeneous; therefore, more evidence from animal studies is required.

Cortical stimulation of the epileptogenic zone for the treatment of focal motor seizures: an experimental study in the nonhuman primate.

In cryptogenic epilepsy or when multifocal seizure onset is suspected, intracranial monitoring of the EEG is required.

Adverse events occurring during invasive electroencephalogram recordings in children.

Stereo-electroencephalography is used to localize the seizure onset zone and connected neuronal networks in surgical candidates suffering from intractable focal epilepsy. The concept of an epileptogenicity index has been proposed recently to represent the likelihood of various regions being part of the seizure onset zone. It quantifies low-voltage fast activity, the electrophysiological signature of seizure onset usually assessed visually by neurologists. Here, we revisit epileptogenicity in light of neuroimaging tools such as those provided in statistical parametric mapping software. Our goal is to propose a robust approach, allowing easy exploration of patients' brains in time and space. The procedure is based upon statistical parametric mapping, which is an established framework for comparing multi-dimensional image data that allows one to correct for inherent multiple comparisons. Statistics can also be performed at the group level, between seizures in the same patient or between patients suffering from the same type of epilepsy using normalization of brains to a common anatomic atlas. Results are obtained from three case studies (insular reflex epilepsy, cryptogenic frontal epilepsy and lesional occipital epilepsy) where tailored resection was performed, and from a group of 10 patients suffering from mesial temporal lobe epilepsy. They illustrate the basics of the technique and demonstrate its very good reproducibility and specificity. Most importantly, the proposed approach to the quantification of the seizure onset zone allows one to summarize complex signals in terms of a time-series of statistical parametric maps that can support clinical decisions. Quantitative neuroimaging of stereo-electroencephalographic features of seizures might thus help to provide better pre-surgical assessment of patients undergoing resective surgery.

Imaging the seizure onset zone with stereo-electroencephalography.

The aim of this prospective study was to analyze the changes in cerebrospinal fluid (CSF) distribution after endoscopic third ventriculocisternostomy (ETV).

Changes in intracranial CSF distribution after ETV.

Symptomatic posterior fossa hematoma in the term newborn is rare.

The management of birth-related posterior fossa hematomas in neonates.

Failure of anterior temporal lobectomy for temporal lobe epilepsy has raised the question of insular cortex involvement in these seizures. Because of difficulties in exploring the insula with invasive electroencephalography (EEG) recordings, only few studies have been performed and this question remains unanswered.

Prognostic value of insular lobe involvement in temporal lobe epilepsy: a stereoelectroencephalographic study.

De novo arteriovenous malformation after brain radiotherapy for medulloblastoma in a child.

Diffuse intrinsic pontine gliomas (DIPGs), with a median survival of 9 months, represent the biggest therapeutic challenge in pediatric neuro-oncology. Despite many clinical trials, no major improvements in treatment have been made over the past 30 years. In most cases, biopsy is not needed for diagnosis because DIPG diagnosis is based on a typical clinical picture with radiologic evidence on magnetic resonance imaging. Therefore, little data on newly diagnosed DIPG have been published and are confounded by including autopsy (i.e., postradiation therapy) cases. In most cancers, advancing to cure has been linked to the discovery of relevant biomarkers, only found by access to tissue. Therefore, to further understand the biology of DIPG, fresh tissue samples must be obtained at diagnosis. However, most neurosurgical teams are reluctant to perform biopsy in pediatric patients, citing potential risks and lack of direct benefit. Yet, in reviewing 90 patients with and the published data on brainstem biopsy, these procedures have a diagnostic yield and morbidity and mortality rates similar to those reported for other brain locations. In addition, the quality and quantity of the material obtained confirm the diagnosis and inform an extended molecular screen, including biomarker study-information important to designing next-generation trials with targeted agents. Stereotactic biopsies can be considered a safe procedure in well-trained neurosurgical teams and could be incorporated in well-defined protocols for patients with DIPG.

Is biopsy safe in children with newly diagnosed diffuse intrinsic pontine glioma?

Subdural hematoma (SDH) is the most common finding on cranial CT in pediatric victims of abusive head trauma (AHT). The hematomas are commonly bilateral and sometimes associated with interhemispheric hyperdensity and/or convexity hemorrhages. There is no consensus regarding the best surgical treatment in such cases nor are there standardized surgical protocols. The authors report their experience and discuss the routine surgical options in the management of traumatic SDH at a Level 1 Pediatric Trauma Center.

Surgical options for treatment of traumatic subdural hematomas in children younger than 2 years of age.

Childhood intracerebral hemorrhage is mainly attributable to underlying brain arteriovenous malformations (bAVMs). Multimodal treatment options for bAVMs include microsurgery and embolization, allowing an immediate cure, and radiosurgery, entailing longer obliteration times. Follow-up data on pediatric ruptured bAVMs are scarce, making it difficult to assess the risk of subsequent intracerebral hemorrhage. Our aim was to assess the clinical and angiographic outcome and to analyze risk factors for rebleeding during and after combined treatment of pediatric bAVMs.

Long-term outcome of 106 consecutive pediatric ruptured brain arteriovenous malformations after combined treatment.

Epilepsy is a paroxysmal condition characterized by repeated transient seizures separated by longer interictal periods. Ictogenesis describes the processes of transition from the interictal state to a seizure. The processes include a preictal state, with specific clinical signs and a distinct electrophysiology which may provide opportunities to anticipate, or even prevent, seizures. Biological mechanisms of ictogenesis remain poorly understood and may vary between conditions/syndromes. We review here ictogenic processes including the involvement of pyramidal cells, interneurons and astrocytes, GABAergic and glutamatergic signaling, and ionic perturbations. Our review suggests that specific excitatory influences at the transition to an ictal event include (1) GABA receptor activation with a neuronal Cl(-) load and (2) a transient increase in external K(+).

Mechanisms of ictogenesis.

To address risk of first or recurrent cerebral haemorrhage in children with sickle-cell disease (SCD) who are being managed with modern stroke prevention strategies.

Article	Year
Forniceal glioma in children. Clinical article. Journal of neurosurgery. Pediatrics\| PubMed ID: 19772409	2009
Multimodal imaging reveals the role of γ activity in eating-reflex seizures. Journal of neurology, neurosurgery, and psychiatry\| PubMed ID: 21097547	2011
Corticotomy closure avoids subdural collections after hemispherotomy. Neurosurgery\| PubMed ID: 21099576	2010
Cortical stimulation of the epileptogenic zone for the treatment of focal motor seizures: an experimental study in the nonhuman primate. Neurosurgery\| PubMed ID: 21135746	2011
Adverse events occurring during invasive electroencephalogram recordings in children. Neurosurgery\| PubMed ID: 21441838	2011
Imaging the seizure onset zone with stereo-electroencephalography. Brain : a journal of neurology\| PubMed ID: 21975587	2011
Changes in intracranial CSF distribution after ETV. Child's nervous system : ChNS : official journal of the International Society for Pediatric Neurosurgery\| PubMed ID: 22588619	2012
The management of birth-related posterior fossa hematomas in neonates. Neurosurgery\| PubMed ID: 23328686	2013
Prognostic value of insular lobe involvement in temporal lobe epilepsy: a stereoelectroencephalographic study. Epilepsia\| PubMed ID: 23848549	2013
De novo arteriovenous malformation after brain radiotherapy for medulloblastoma in a child. Neurology\| PubMed ID: 23877796	2013
Is biopsy safe in children with newly diagnosed diffuse intrinsic pontine glioma? American Society of Clinical Oncology educational book / ASCO. American Society of Clinical Oncology. Meeting\| PubMed ID: 24451809	2012
Surgical options for treatment of traumatic subdural hematomas in children younger than 2 years of age. Journal of neurosurgery. Pediatrics\| PubMed ID: 24559279	2014
Long-term outcome of 106 consecutive pediatric ruptured brain arteriovenous malformations after combined treatment. Stroke; a journal of cerebral circulation\| PubMed ID: 24788975	2014
Mechanisms of ictogenesis. International review of neurobiology\| PubMed ID: 25078502	2014
Cerebral haemorrhagic risk in children with sickle-cell disease. Developmental medicine and child neurology\| PubMed ID: 25174812	2014

Thomas Blauwblomme

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