Epilepsy

The Wada test is widely used in the presurgical evaluation of potential temporal lobectomy patients to predict postoperative memory function. Expected asymmetry (EA), defined as Wada memory lateralized to the nonsurgical hemisphere, or a higher score after injection of the surgical hemisphere would be considered favorable in terms of postoperative memory outcome. However, in some cases, nonlateralized memory (NM) results, with no appreciable asymmetry, may occur because of impaired scores after both injections, often leading to denial of surgery...

Closed-loop, responsive focal brain stimulation provides a new treatment option for patients with refractory partial onset seizures who are not good candidates for potentially curative epilepsy surgery. The first responsive brain neurostimulator (RNS® System, NeuroPace), provides stimulation directly to the seizure focus when abnormal electrocorticographic is detected. Seizure reductions of 44% at one year increase to 60 to 66% at years 3 to 6 of treatment. There is no negative impact on cognition and mood...

Several palliative neuromodulation treatment modalities are currently available for adjunctive use in the treatment of medically intractable epilepsy. Over the past decades, a variety of different central and peripheral nervous system sites have been identified, clinically and experimentally, as potential targets for chronic, nonresponsive therapeutic neurostimulation. Currently, the main modalities in clinical use, from most invasive to least invasive, are anterior thalamus deep brain stimulation, vagus nerve stimulation, and trigeminal nerve stimulation...

We evaluate and discuss the various functional imaging techniques that are currently in use to assess the eligibility of a refractory temporal lobe epilepsy (TLE) patient for treatment with medial temporal lobe surgery. The assessment of eligibility for treatment is challenging and relies heavily on functional imaging modalities that provide physiological information, in addition to structural data acquired by different imaging techniques. This review is the final segment of a two part study, the first of which focused on the structural and anatomical imaging modalities that are in use for the surgical treatment of TLE...

High frequency oscillations (HFOs) are estimated as a potential marker for epileptogenicity. Current research strives for valid evidence that these HFOs could aid the delineation of the to-be resected area in patients with refractory epilepsy and improve surgical outcomes. In the present meta-analysis, we evaluated the relation between resection of regions from which HFOs can be detected and outcome after epilepsy surgery. We conducted a systematic review of all studies that related the resection of HFO-generating areas to postsurgical outcome...

In today's practice, epileptologists and neurosurgeons have several options for seizure localization with intracranial electrodes during phase II evaluations. Traditionally, centers in North America have used subdural electrode grids (SDE or SDG) for intracranial seizure localization. However, improvements in technology led to the popularization of stereo-encephalography (SEEG) using depth electrodes. Epilepsy surgery centers highest in volume now offer both SDE and SEEG for seizure localization. This article provides a general guide for considering SEEG versus SDE for intracranial seizure localization based on our experience with both...

The term "Wernicke's area" is most often used as an anatomical label for the gyri forming the lower posterior left sylvian fissure. Although traditionally this region was held to support language comprehension, modern imaging and neuropsychological studies converge on the conclusion that this region plays a much larger role in speech production. This evidence is briefly reviewed, and a simple schematic model of posterior cortical language processing is described.

For about 30% of patients with epilepsy the cause is unknown. Even in patients with a known risk factor for epilepsy, such as ischaemic stroke, only a subpopulation of patients develops epilepsy. Factors that contribute to the risk for epileptogenesis in a given individual generally remain unknown. Studies in the past decade on epilepsy in patients with ischaemic stroke suggest that, in addition to the primary ischaemic injury, existing difficult-to-detect microscale changes in blood vessels and white matter present as epileptogenic pathologies...

OBJECTIVES: The objective of this cohort study was to compare neuropsychological outcomes following left temporal lobe resection (TLR) in patients with epilepsy who had or had not undergone prior invasive monitoring. METHODS: Data were obtained from an institutional review board-approved, neuropsychology registry for patients who underwent epilepsy surgery at Cleveland Clinic between 1997 and 2013. A total of 176 patients (45 with and 131 without invasive EEG) met inclusion criteria...

OBJECTIVE: Predicting cognitive function following resective surgery remains an important clinical goal. Each MRI neuroimaging technique can potentially provide unique and distinct insight into changes that occur in the structural or functional organization of "at-risk" cognitive functions. The authors tested for the singular and combined power of 3 imaging techniques (functional MRI [fMRI], resting state fMRI, diffusion tensor imaging) to predict cognitive outcome following left (dominant) anterior temporal lobectomy for intractable epilepsy...

OBJECTIVES: Several studies have suggested an asymmetry in Meyer's loop in individuals, with the left loop anterior to the right. In this study we test the hypothesis that there is an association between Meyer's loop asymmetry (MLA) and language lateralisation. METHODS: 57 patients with epilepsy were identified with language functional MRI (fMRI) and diffusion MRI acquisition. Language lateralisation indices from fMRI(LI) and optic radiation and arcuate fasciculus probabilistic tractography was performed for each subject...

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Epilepsy is the third most common neurological illness, affecting 1% of the world's population. Despite advances in medicine, about 25 to 30% of the patients do not respond to or cannot tolerate the severe side effects of medical treatment, and surgery is not an option for the majority of patients with epilepsy. The objective of this article is to review the current state of research on seizure detection based on cerebral blood flow (CBF) data acquired by thermal diffusion flowmetry (TDF), and CBF-based seizure prediction...

OBJECTIVE: The purpose of this study was to develop a quantitative framework to estimate the likelihood of multifocal epilepsy based on the number of unifocal seizures observed in the epilepsy monitoring unit (EMU). METHODS: Patient records from the EMU at Massachusetts General Hospital (MGH) from 2012 to 2014 were assessed for the presence of multifocal seizures as well the presence of multifocal interictal discharges and multifocal structural imaging abnormalities during the course of the EMU admission...

Status epilepticus is a common neurological emergency with considerable associated health-care costs, morbidity, and mortality. The definition of status epilepticus as a prolonged seizure or a series of seizures with incomplete return to baseline is under reconsideration in an effort to establish a more practical definition to guide management. Clinical research has focused on early seizure termination in the prehospital setting. The approach of early escalation to anaesthetic agents for refractory generalised convulsive status epilepticus, rather than additional trials of second-line anti-epileptic drugs, to avoid neuronal injury and pharmaco-resistance associated with prolonged seizures is gaining momentum...

For unknown reasons, placebos reduce seizures in clinical trials in many patients. It is also unclear why some drugs showing statistical superiority to placebo in one trial may fail to do so in another. Using Seizuretracker.com, a patient-centered database of 684,825 seizures, we simulated "placebo" and "drug" trials. These simulations were employed to clarify the sources of placebo effects in epilepsy, and to identify methods of diminishing placebo effects. Simulation 1 included 9 trials with a 6-week baseline and 6-week test period, starting at time 0, 3, 6…24 months...

BACKGROUND AND PURPOSE: The frequency of seizures is an important factor that can alter functional brain connectivity. Analysis of this factor in patients with epilepsy is complex because of disease- and medication-induced confounders. Because patients with hot-water epilepsy generally are not on long-term drug therapy, we used seed-based connectivity analysis in these patients to assess connectivity changes associated with seizure frequency without confounding from antiepileptic drugs...

OBJECT: Temporal lobe epilepsy (TLE) in the absence of MRI abnormalities and memory deficits is often presumed to have an extramesial or even extratemporal source. In this paper the authors report the results of a comprehensive stereoelectroencephalography (SEEG) analysis in patients with TLE with normal MRI images and memory scores. METHODS: Eighteen patients with medically refractory epilepsy who also had unremarkable MR images and normal verbal and visual memory scores on neuropsychological testing were included in the study...

OBJECT: Radiofrequency thermocoagulation (RF-TC) of presumed epileptogenic lesions and/or structures has gained new popularity as a treatment option for drug-resistant focal epilepsy, mainly in patients with mesial temporal lobe epilepsy. The role of this minimally invasive procedure in more complex cases of drug-resistant epilepsy, which may require intracranial electroencephalographic evaluation, has not been fully assessed. This retrospective study reports on a case series of patients with particularly complex focal epilepsy who underwent stereoelectroencephalography (SEEG) evaluation with stereotactically implanted multicontact intracerebral electrodes for the detailed identification of the epileptogenic zone (EZ) and who received RF-TC in their supposed EZ (according to SEEG findings)...

OBJECTIVE: Hippocampal sclerosis is a common finding in patients with temporal lobe epilepsy (TLE), and magnetic resonance imaging (MRI) studies associate the reduction of hippocampal volume with the neuron loss seen on histologic evaluation. Astrogliosis and increased levels of chondroitin sulfate, a major component of brain extracellular matrix, are also seen in hippocampal sclerosis. Our aim was to evaluate the association between hippocampal volume and chondroitin sulfate, as well as neuronal and astroglial populations in the hippocampus of patients with TLE...