Decrease in Propagation of Interictal Epileptiform Activity After Introduction of Levetiracetam Visualized with Electric Source Imaging

Different neuroimaging techniques (fMRI, spectroscopy, PET) are being used to evaluate candidate drugs in pharmacological development. In patients with epilepsy fast propagation of the epileptiform activity between different brain areas occurs. Electric Source Imaging (ESI), in contrast to the aforementioned techniques, has a millisecond time resolution, allowing visualization of this fast propagation. The purpose of the current project was to use ESI to investigate whether introduction of an antiepileptic drug (levetiracetam, LEV) would change the propagation patterns of the interictal epileptiform activity. Thirty patients with epilepsy were subject to an EEG recording before (pre-LEV) and after (in-LEV) introduction of LEV. Interictal spikes with similar topographic distribution were averaged within each subject, and a distributed source model was used to localize the EEG sources of the epileptiform activity. The temporal development of the activity within 20 regions of interest (ROIs) was determined, and source propagation between different regions was compared between the pre-LEV and in-LEV recordings. Patients with epileptic seizures showed propagation in 22/24 identified spike types in the pre-LEV recordings. In the in-LEV recordings only 7/15 spike types showed propagation, and six of these seven propagating spikes were recorded in patients with poor effect of treatment. Also in patients without seizures LEV tended to suppress propagation. We conclude that the observed suppression of source propagation can be considered as an indicator of effective antiepileptic treatment. ESI might thus become a useful tool in the early clinical evaluation of new candidate drugs in pharmacological development.     

Electric source imaging of human brain functions

We review recent methodological advances in electromagnetic source imaging and present EEG data from our laboratory obtained by application of these methods. There are two principal steps in our analysis of multichannel electromagnetic recordings: (i) the determination of functionally relevant time periods in the ongoing electric activity and (ii) the localization of the sources in the brain that generate these activities recorded on the scalp. We propose a temporal segmentation of the time-varying activity, which is based on determination of changes in the topography of the electric fields, as an approach to the first step, and a distributed linear inverse solution based on realistic head models as an approach to the second step. Data from studies of visual motion perception, visuo-motor transfer, mental imagery, semantic decision, and cognitive interference illustrate that this analysis allows us to define the patterns of electric activity that are present at given time periods after stimulus presentation, as well as those time periods where significantly different patterns appear between different stimuli and tasks. The presented data show rapid and parallel activation of different areas within complex neuronal networks, including early activity of brain regions remote from the primary sensory areas. In addition, the data indicate information exchange between homologous areas of the two hemispheres in cases where unilateral stimulus presentation requires interhemispheric transfer.     

Extended Versus Limited Lymph Node Dissection in Bladder Cancer Patients Undergoing Radical Cystectomy: Survival Results from a Prospective,Randomized Trial

Background

The extent of lymph node dissection (LND) in bladder cancer (BCa) patients at the time of radical cystectomy may affect oncologic outcome.

Nonconvulsive status epilepticus following cardiac arrest—are we missing the beginning?

Background

Status epilepticus (SE) is a common complication in patients surviving a cardiac arrest, but little is known about the frequency of nonconvulsive status epilepticus (NCSE).

Objectives

To compile the first the evidence from the literature of the overall frequency of NCSE in adults with persistent coma following cardiac arrest. Secondarily, to assess the emergence of NCSE in comatose resuscitated patients within the first hours of the return of spontaneous circulation (ROSC) and before inducing target temperature management.

Material and methods

The medical search engine PubMed was screened to identify prospective and retrospective studies in English reporting on the frequency of NCSE in comatose post-resuscitated patients. Study design, time of EEG performance, detection of SE and NCSE, outcomes, and targeted temperature management were assessed.

Results

Only three cohort studies (one prospective and two retrospective) reported on the EEG evaluation describing NCSE during ongoing sedation and target temperature management. Overall, we identified 213 patients with SE in 18–38% and NCSE in 5–12%. Our review found no study reporting NCSE in resuscitated adult patients remaining in coma within the first hours of ROSC and prior to targeted temperature management and sedation.

Conclusion

Studies of NCSE after ROSC in adults are rare and mostly nonsystematic. This and the low proportion of patients reported having NCSE following ROSC suggest that NCSE before target temperature management and sedation is often overlooked. The limited quality of the data does not allow firm conclusions to be drawn regarding the effects of NCSE on outcome calling for further investigations. Clinicians should suspect NCSE in patients with persistent coma before starting sedation and targeted temperature management.

     

Revised version of quality guidelines for presurgical epilepsy evaluation and surgical epilepsy therapy issued by the Austrian,German, and Swiss working group on presurgical epilepsy diagnosis and operative epilepsy treatment

The definition of minimal standards remains pivotal as a basis for a high standard of care and as a basis for staff allocation or reimbursement. Only limited publications are available regarding the required staffing or methodologic expertise in epilepsy centers. The executive board of the working group (WG) on presurgical epilepsy diagnosis and operative epilepsy treatment published the first guidelines in 2000 for Austria, Germany, and Switzerland. In 2014, revised guidelines were published and the WG decided to publish an unaltered English translation in this report. Because epilepsy surgery is an elective procedure, quality standards are particularly high. As detailed in the first edition of these guidelines, quality control relates to seven different domains: (1) establishing centers with a sufficient number of sufficiently and specifically trained personnel, (2) minimum technical standards and equipment, (3) continuous medical education of employees, (4) surveillance by trained personnel during video electroencephalography (EEG) monitoring (VEM), (5) systematic acquisition of clinical and outcome data, (6) the minimum number of preoperative evaluations and epilepsy surgery procedures, and (7) the cooperation of epilepsy centers. These standards required the certification of the different professions involved and minimum numbers of procedures. In the subsequent decade, quite a number of colleagues were certified by the trinational WG; therefore, the executive board of the WG decided in 2013 to make these standards obligatory. This revised version is particularly relevant given that the German procedure classification explicitly refers to the guidelines of the WG with regard to noninvasive/invasive preoperative video‐EEG monitoring and invasive intraoperative diagnostics in epilepsy.