Crowdsourcing reproducible seizure forecasting in human and canine epilepsy.

SEE MORMANN AND ANDRZEJAK DOI101093/BRAIN/AWW091 FOR A SCIENTIFIC COMMENTARY ON THIS ARTICLE  : Accurate forecasting of epileptic seizures has the potential to transform clinical epilepsy care. However, progress toward reliable seizure forecasting has been hampered by lack of open access to long duration recordings with an adequate number of seizures for investigators to rigorously compare algorithms and results. A seizure forecasting competition was conducted on kaggle.

The functional organization of human epileptic hippocampus.

The function and connectivity of human brain is disrupted in epilepsy. We previously reported that the region of epileptic brain generating focal seizures, i.e.

Routine vs extended outpatient EEG for the detection of interictal epileptiform discharges.

Objective: To compare the yield of epileptiform abnormalities on 30-minute recordings with those greater than 45 minutes.

Methods: We performed a prospective observational cross-sectional study of all outpatient routine EEGs comparing the rate of interictal epileptiform discharges (IEDs) and clinical events during the initial 30 minutes (routine) with those occurring in the remaining 30-60 minutes (extended). A relative increase of 10% was considered clinically significant.

Interictal high-frequency oscillations in focal human epilepsy.

Purpose Of Review: Localization of focal epileptic brain is critical for successful epilepsy surgery and focal brain stimulation. Despite significant progress, roughly half of all patients undergoing focal surgical resection, and most patients receiving focal electrical stimulation, are not seizure free. There is intense interest in high-frequency oscillations (HFOs) recorded with intracranial electroencephalography as potential biomarkers to improve epileptogenic brain localization, resective surgery, and focal electrical stimulation.

Connectivity of epileptic brain regions in wake and sleep.

Focal epileptic brain is characterized by a region of pathological tissue seizure onset zone (SOZ) - the pathologic tissue generating seizures. During the interictal period (nonseizure) the SOZ is characterized by epileptiform activity - interictal spikes & high-frequency oscillations (HFO). The SOZ also exhibits hyper-synchrony and functional disconnection from the surrounding areas.

Mining continuous intracranial EEG in focal canine epilepsy: Relating interictal bursts to seizure onsets.

Objective: Brain regions are localized for resection during epilepsy surgery based on rare seizures observed during a short period of intracranial electroencephalography (iEEG) monitoring. Interictal epileptiform bursts, which are more prevalent than seizures, may provide complementary information to aid in epilepsy evaluation. In this study, we leverage a long-term iEEG dataset from canines with naturally occurring epilepsy to investigate interictal bursts and their electrographic relationship to seizures.

Correlation of EEG with neuropsychological status in children with epilepsy.

Objective: To determine correlations of the EEG frequency spectrum with neuropsychological status in children with idiopathic epilepsy.

Methods: Forty-six children ages 8-18 years old with idiopathic epilepsy were retrospectively identified and analyzed for correlations between EEG spectra and neuropsychological status using multivariate linear regression. In addition, the theta/beta ratio, which has been suggested as a clinically useful EEG marker of attention-deficit hyperactivity disorder (ADHD), and an EEG spike count were calculated for each subject.

The evolution of epilepsy surgery between 1991 and 2011 in nine major epilepsy centers across the United States, Germany, and Australia.

Objective: Epilepsy surgery is the most effective treatment for select patients with drug-resistant epilepsy. In this article, we aim to provide an accurate understanding of the current epidemiologic characteristics of this intervention, as this knowledge is critical for guiding educational, academic, and resource priorities.

Methods: We profile the practice of epilepsy surgery between 1991 and 2011 in nine major epilepsy surgery centers in the United States, Germany, and Australia.

Forecasting Seizures Using Intracranial EEG Measures and SVM in Naturally Occurring Canine Epilepsy.

Management of drug resistant focal epilepsy would be greatly assisted by a reliable warning system capable of alerting patients prior to seizures to allow the patient to adjust activities or medication. Such a system requires successful identification of a preictal, or seizure-prone state. Identification of preictal states in continuous long- duration intracranial electroencephalographic (iEEG) recordings of dogs with naturally occurring epilepsy was investigated using a support vector machine (SVM) algorithm.

Combined Single Neuron Unit Activity and Local Field Potential Oscillations in a Human Visual Recognition Memory Task.

Goal: Activities of neuronal networks range from action potential firing of individual neurons, coordinated oscillations of local neuronal assemblies, and distributed neural populations. Here, we describe recordings using hybrid electrodes, containing both micro- and clinical macroelectrodes, to simultaneously sample both large-scale network oscillations and single neuron spiking activity in the medial temporal lobe structures of human subjects during a visual recognition memory task. We quantify and compare single neuron unit activity (SUA) with high-frequency macrofield oscillations (HFOs) for decoding visual images.

Collaborating and sharing data in epilepsy research.

Technological advances are dramatically advancing translational research in Epilepsy. Neurophysiology, imaging, and metadata are now recorded digitally in most centers, enabling quantitative analysis. Basic and translational research opportunities to use these data are exploding, but academic and funding cultures prevent this potential from being realized.

Anterior nuclear deep brain stimulation guided by concordant hippocampal recording.

Object: Anterior nuclear (AN) stimulation has been reported to reduce the frequency of seizures, in some cases dramatically; however, it has not been approved by the US Food and Drug Administration. The anterior nucleus is difficult to target because of its sequestered location, partially surrounded by the ventricle. It has traditionally been targeted by using transventricular or lateral transcortical routes.

Lateralization of mesial temporal lobe epilepsy with chronic ambulatory electrocorticography.

Objective: Patients with suspected mesial temporal lobe (MTL) epilepsy typically undergo inpatient video-electroencephalography (EEG) monitoring with scalp and/or intracranial electrodes for 1 to 2 weeks to localize and lateralize the seizure focus or foci. Chronic ambulatory electrocorticography (ECoG) in patients with MTL epilepsy may provide additional information about seizure lateralization. This analysis describes data obtained from chronic ambulatory ECoG in patients with suspected bilateral MTL epilepsy in order to assess the time required to determine the seizure lateralization and whether this information could influence treatment decisions.

Defects of mutant DNMT1 are linked to a spectrum of neurological disorders.

We report a broader than previously appreciated clinical spectrum for hereditary sensory and autonomic neuropathy type 1E (HSAN1E) and a potential pathogenic mechanism for DNA methyltransferase (DNMT1) mutations. The clinical presentations and genetic characteristics of nine newly identified HSAN1E kinships (45 affected subjects) were investigated. Five novel mutations of DNMT1 were discovered; p.

Development and validation of nomograms to provide individualised predictions of seizure outcomes after epilepsy surgery: a retrospective analysis.

Background: Half of patients who have resective brain surgery for drug-resistant epilepsy have recurrent postoperative seizures. Although several single predictors of seizure outcome have been identified, no validated method incorporates a patient's complex clinical characteristics into an instrument to predict an individual's post-surgery seizure outcome.

Methods: We developed nomograms to predict complete freedom from seizures and Engel score of 1 (eventual freedom from seizures allowing for some initial postoperative seizures, or seizures occurring only with physiological stress such as drug withdrawal) at 2 years and 5 years after surgery on the basis of sex, seizure frequency, secondary seizure generalisation, type of surgery, pathological cause, age at epilepsy onset, age at surgery, epilepsy duration at time of surgery, and surgical side.

Long-term treatment with responsive brain stimulation in adults with refractory partial seizures.

Objective: The long-term efficacy and safety of responsive direct neurostimulation was assessed in adults with medically refractory partial onset seizures.

Methods: All participants were treated with a cranially implanted responsive neurostimulator that delivers stimulation to 1 or 2 seizure foci via chronically implanted electrodes when specific electrocorticographic patterns are detected (RNS System). Participants had completed a 2-year primarily open-label safety study (n = 65) or a 2-year randomized blinded controlled safety and efficacy study (n = 191); 230 participants transitioned into an ongoing 7-year study to assess safety and efficacy.

Evidence for consolidation of neuronal assemblies after seizures in humans.

The establishment of memories involves reactivation of waking neuronal activity patterns and strengthening of associated neural circuits during slow-wave sleep (SWS), a process known as "cellular consolidation" (Dudai and Morris, 2013). Reactivation of neural activity patterns during waking behaviors that occurs on a timescale of seconds to minutes is thought to constitute memory recall (O'Keefe and Nadel, 1978), whereas consolidation of memory traces may be revealed and served by correlated firing (reactivation) that appears during sleep under conditions suitable for synaptic modification (Buhry et al., 2011).

Gamma oscillations precede interictal epileptiform spikes in the seizure onset zone.

Objective: To investigate the generation, spectral characteristics, and potential clinical significance of brain activity preceding interictal epileptiform spike discharges (IEDs) recorded with intracranial EEG.

Methods: Seventeen adult patients with drug-resistant temporal lobe epilepsy were implanted with intracranial electrodes as part of their evaluation for epilepsy surgery. IEDs detected on clinical macro- and research microelectrodes were analyzed using time-frequency spectral analysis.

Using functional MRI alone for localization in focal epilepsy.

In the present study, we developed a method for the purpose of localizing epilepsy related hemodynamic foci for patients suffering intractable focal epilepsy using resting state fMRI alone. We studied two groups of subjects: five patients with intractable focal epilepsy, and ten healthy volunteers performing motor tasks. Spatial independent component analysis (ICA) was performed on the fMRI alone data and a set of independent component (IC) selection criteria was developed to identify epilepsy related ICs.

Proceedings of the Fifth International Workshop on Advances in Electrocorticography.

The Fifth International Workshop on Advances in Electrocorticography convened in San Diego, CA, on November 7-8, 2013. Advancements in methodology, implementation, and commercialization across both research and in the interval year since the last workshop were the focus of the gathering. Electrocorticography (ECoG) is now firmly established as a preferred signal source for advanced research in functional, cognitive, and neuroprosthetic domains.

Electrical stimulation of hippocampus for the treatment of refractory temporal lobe epilepsy.

Temporal lobe epilepsy (TLE) is the most common epilepsy syndrome and is often associated with pharmacoresistance. Patients with pharmacoresistant TLE may be candidates for epilepsy surgery, and anterior temporal lobectomy if indicated is the most effective known treatment and has the best chance of a seizure-free outcome. For many patients with TLE, epilepsy surgery is not an option, for example when the seizure onset zone co-localizes with eloquent brain function and cannot be resected, or the seizure onset zone is not well localized, or when seizures independently originate from both temporal lobes.

Factors contributing to the yield of asymmetric bilateral implantation of intracranial electrodes.

Objective: To determine the outcome of implanting fewer electrodes over the hemisphere with less supporting presurgical localizing data.

Methods: We retrospectively reviewed our epilepsy surgery database at Mayo Clinic, Rochester, Minnesota, between January 1, 1999, and December 31, 2011, to identify patients who had an asymmetric number of electrode contacts implanted in each hemisphere for seizure localization. We scored each presurgical noninvasive data point (0, 0.

What is the importance of abnormal "background" activity in seizure generation?

Investigations of interictal epileptiform spikes and seizures have played a central role in the study of epilepsy. The background EEG activity, however, has received less attention. In this chapter we discuss the characteristic features of the background activity of the brain when individuals are at rest and awake (resting wake) and during sleep.