Atypical duration of epileptic and psychogenic nonepileptic events.

OBJECTIVES: We aimed to estimate the frequency of epileptic seizures (ES) and psychogenic nonepileptic seizures (PNES) with atypical duration in our epilepsy monitoring unit (EMU), in order to raise awareness of atypical durations of both types of events. MATERIALS & METHODS: We retrospectively reviewed all consecutive video-electroencephalogram (vEEG) recordings in our medical center's EMU from January 2013 to December 2017 and identified patients with seizures with atypical duration. Short PNES were defined as those lasting fewer than 2 min and long ES as those lasting for more than 5 min. RESULTS: The files of 830 adult (age >16 years) patients were reviewed, of whom 26 patients (3.1%, mean age: 33.3 ±â€¯9.8 years, 12 females) were diagnosed as having an unusual seizure duration. Among 432 patients with ES during monitoring, fourteen patients [3.2% (95% confidence interval (CI): 1.5%-5.0%), mean age: 33.0 ±â€¯12.2, 5 females [had long ES durations (exceeding 5 min). In 64% of patients with long ES, the events were provoked by antiepileptic drug (AED) withdrawal during vEEG, 62% had focal lesion on brain imaging, and 64% had a frontotemporal or a temporal seizure focus. Among 223 patients diagnosed with PNES, 12 patients [5.4% (95% CI: 2.2%-8.6%), mean age: 33.6 ±â€¯6.6, 7 females] had short PNES durations (less than 2 min) and demonstrated motor (9/12, 75%), altered responsiveness (6/12, 50%), and vocalization (5/12, 42%) as the most prominent clinical features. CONCLUSIONS: The data from our case files highlight two main considerations in the diagnosis of paroxysmal events: prolonged event can be due to ES, while short events can be psychogenic.

Spatial distribution and hemispheric asymmetry of electrically evoked experiential phenomena in the human brain.

OBJECTIVE: Experiential phenomena (EP), such as illusions and complex hallucinations, are vivid experiences created in one's mind. They can occur spontaneously as epileptic auras or can be elicited by electrical brain stimulation (EBS) in patients undergoing presurgical evaluation for drug-resistant epilepsy. Previous work suggests that EP arise from activation of different nodes within interconnected neural networks mainly in the temporal lobes. Yet, the anatomical extent of these neural networks has not been described and the question of lateralization of EP has not been fully addressed. To this end, an extended number of brain regions in which electrical stimulation elicited EP were studied to test whether there is a lateralization propensity to EP phenomena. METHODS: A total of 19 drug-resistant focal epilepsy patients who underwent EBS as part of invasive presurgical evaluation and who experienced EP during the stimulation were included. Spatial dispersion of visual and auditory illusions and complex hallucinations in each hemisphere was determined by calculation of Euclidean distances between electrodes and their centroid in common space, based on (x, y, z) Cartesian coordinates of electrode locations. RESULTS: In total, 5857 stimulation epochs were analyzed; 917 stimulations elicited responses, out of which 130 elicited EP. Complex visual hallucinations were found to be widely dispersed in the right hemisphere, while they were tightly clustered in the occipital lobe of the left hemisphere. Visual illusions were elicited mostly in the occipital lobes bilaterally. Auditory illusions and hallucinations were evoked symmetrically in the temporal lobes. CONCLUSIONS: These findings suggest that complex visual hallucinations arise from wider spread in the right compared to the left hemisphere, possibly mirroring the asymmetry in the white matter organization of the two hemispheres. These results offer some insights into lateralized differences in functional organization and connectivity that may be important for functional mapping and planning of surgical resections in patients with epilepsy.

Systemic thrombin inhibition ameliorates seizures in a mouse model of pilocarpine-induced status epilepticus.

Status epilepticus (SE) is a life-threatening condition characterized by ongoing seizure activity which can lead to severe brain damage and death if not treated properly. Recent work suggests that alterations in blood-brain barrier (BBB) function and subsequent cortical exposure to coagulation factors may initiate, promote, and/or sustain SE. This suggestion is based on the observation that the serine protease thrombin, which plays a fundamental role in the blood coagulation cascade, increases neural excitability through the activation of protease-activated receptor 1 (PAR1). However, it remains unclear whether systemic inhibition of thrombin asserts "anti-epileptic" effects in vivo. We here used the pilocarpine model of SE in adult 3-month-old male mice to address the question whether intraperitoneal injection of the thrombin inhibitor α-NAPAP (0.75 mg/kg) counters SE. Indeed, pharmacological inhibition of thrombin ameliorates the behavioral outcome of pilocarpine-induced SE. Similar results are obtained when the thrombin receptor PAR1 is pharmacologically blocked using intraperitoneal injection of SCH79797 (25 µg/kg) prior to SE induction. Consistent with these results, an increase in thrombin immunofluorescence is detected in the hippocampus of pilocarpine-treated animals. Moreover, increased hippocampal serine protease activity is detected 90 min after SE induction, which is not observed in animals treated with α-NAPAP prior to SE induction. Together, these results corroborate and extend recent studies suggesting that novel oral anticoagulants which target thrombin (and PAR1) may assert anti-epileptic effects in vivo. KEY MESSAGES: Systemic thrombin/PAR1-inhibition ameliorates anticoagulants behavioral seizures. Status epilepticus increases thrombin levels in the hippocampus. Increased serine protease activity in the hippocampus after status epileptic. Anti-epileptic potential of clinically used anticoagulants must be evaluated.

Therapeutic levetiracetam monitoring during pregnancy: "mind the gap".

BACKGROUND: Epilepsy is one of the most common chronic neurological conditions and its treatment during pregnancy is challenging. Levetiracetam (LEV) is an antiepileptic medication frequently used during pregnancy. Only a few small studies have been published on LEV monitoring during pregnancy, demonstrating decreased serum LEV levels during the first and second trimester; however, the most significant decrease was observed during the third trimester of pregnancy. In this study we aimed to evaluate LEV pharmacokinetics during different stages of pregnancy. METHODS: We followed up and monitored serum levels of pregnant women treated with LEV for epilepsy. RESULTS: Fifty-nine women with 66 pregnancies during the study period were included. The lowest raw LEV serum concentrations were observed during the first trimester. Compared with the pre-pregnancy period, raw serum concentration was lower by 5.76 mg/L [95% confidence interval (CI) (2.78, 8.75), p = 0.039] during the first trimester. Comparing the decrease in the first trimester with either the second or the third, no significant changes were observed (p = 0.945, p = 0.866). Compared with pre-pregnancy measurements, apparent clearance was increased by 71.08 L/day [95%CI (16.34, 125.83), p = 0.011] during the first trimester. About 30% of LEV serum levels during pregnancy were below the laboratory quoted reference range. CONCLUSIONS: Raw LEV serum levels tend to decrease during pregnancy, mainly during the first trimester contrary to previous reports. Monitoring of LEV serum levels is essential upon planning pregnancy and thereafter if pre-pregnancy LEV levels are to be maintained. However, more studies are needed to assess the correlation with clinical outcome.

Vocational factors which predict seizure prognosis in young adults during military service.

BACKGROUND: The vocational parameters regarding epilepsy are not well established. Our aim was to assess the risk of seizures as a function of occupational stress and disease severity in military recruits of the IDF (Israel Defense Force) and to examine the effect of new classification criteria (used between the late nineties and early two thousands) in comparison with that of previous criteria (used during the mid-eighties to mid-nineties). METHODS: The medical records of over 150,000 18-year-old men recruited to the IDF between the mid-nineties and the mid-two thousands were used to assemble a cohort, which was followed for a period of 36months. The severity of the disease was determined according to 3 categories, according to the medical history. The recruits were subdivided according to their occupational categories to Combat Units (CUs), Maintenance Units (MUs), and Administrative Units (AUs). We compared the incidence rates of the different groups with the findings from a previous follow-up. RESULTS: The annual incidence rates during 36months of follow-up were 0.026%, 4.7%, and 8.8%, in categories 1 to 3, respectively. The relative risk of seizure incidence in CU and MU was lower than in AU (0.42 and 0.81, p<0.0001). Similar findings were found in other disease categories. CONCLUSIONS: Job assignment to CU (less convenient conditions like sleep deprivation and strenuous physical activity) did not increase the incidence of seizures. It was found that EEG examination is an important criterion in the vocational evaluation of subjects that have had one or more seizures. This study supports the establishment of vocational criteria and recommends the integration of people diagnosed with epilepsy in most occupations.

Use of antiepileptic drugs during pregnancy and lactation: Type of information provided by searching Google.

Surveys among women with epilepsy (WWE) show that they receive their essential pregnancy-related information from many sources, including the internet. Our aim was to assess the types of websites provided by searching Google for the use of four antiepileptic drugs (AEDs) during pregnancy and lactation. The search was performed on 40 computers used by health-care professionals, on 40 computers used by nonhealth-care professionals, and on 5 computers used by WWE in Israel and on 8 computers used by nonhealth-care professionals in the U.S. On each computer, a Google search was conducted for term combinations that included one AED name ("carbamazepine","valproic acid", "lamotrigine", "levetiracetam", or "Keppra") and "Pregnancy", "Lactation", or "Breastfeeding". The top three and top ten websites retrieved in every search were mapped (a total of 45 and 150 websites, respectively, from each computer). Across all searches in English, on both U.S. and Israeli computers, the majority of websites listed among the first three and first ten results were those of independent health portals. The representation of the Epilepsy Foundation website was 10% or less, and only a few results were obtained from the NIH's general public-oriented MedlinePlus. In Hebrew, results included almost exclusively Israeli or Hebrew-translated websites. As in English, results from public-oriented, professionally-written websites in Hebrew accounted for less than 50% of entries. Overall, the availability of readable and high-quality information on AEDs used by pregnant and breastfeeding women is limited. Guiding patients towards accurate web resources can help them navigate among the huge amount of available online information.

An evaluation of pharmacist knowledge on treatment with antiepileptic drugs.

PURPOSE: As pharmacists play an important role in managing antiepileptic drug (AED) therapy, they should be aware of different aspects of the treatment. Our aim was to evaluate pharmacists' knowledge of the pharmacological treatment of epilepsy, and their recommendations under hypothetical situations, through a written questionnaire. METHODS: The questionnaire included 22 questions divided into three sections: demographic data (eight questions), knowledge of specific aspects of AED therapy (true/false; four questions), and actions taken in theoretical situations involving AED therapy (multiple choice; ten questions). The questionnaire was distributed to pharmacists practicing in Israel and working in pharmacies and/or participating in professional meetings and continued education programs. RESULTS: One hundred and twenty one pharmacists completed the questionnaire (response rate 19%). The mean overall score was 48 ± 15% correct answers. Most pharmacists were aware of the need to continue AED treatment during pregnancy, the risk of generic switches, and the need to call the physician for loss of seizure control (92%, 89% and 81% of responders, respectively). Twelve percent identified correctly all three situations in which the clinicians should be contacted urgently, and 27% did not identify any of them. The total score was related to the academic degree (PharmD vs. other) and to the duration since training completion. CONCLUSION: Pharmacists were knowledgeable regarding some aspects of care of people with epilepsy. However, our study, as in previous studies among health care professionals, identified some gaps in knowledge. These findings indicate the need for better education of pharmacists regarding epilepsy and its treatment.

Asystole in the epilepsy unit.

BACKGROUND: Early identification of cardiac asystole as a reason for syncope is of uttermost significance, as insertion of a cardiac pacemaker can save the patient's life and prevent severe injury. The aim of this work was to emphasize the subtle and unusual presentations of asystole in patients evaluated in epilepsy units. METHODS: We reviewed the clinical presentation, ECG and EEG data of a series of seven patients who were evaluated in four epilepsy units and were diagnosed with asystole. RESULTS: Three patients had unusual clinical manifestations of cardiac asystole, resembling epileptic seizures. Three patients had asystole induced by epileptic seizures and in one patient the diagnosis was not clear. All patients except one were implanted with a pacemaker and improved clinically. CONCLUSIONS: Seizure-induced asystole is a rare complication of epilepsy and asystole may clinically mimic epileptic seizures. A high level of suspicion and thorough prolonged cardiac and EEG monitoring are mandatory for reaching the right diagnosis. As the diagnosis is rare and difficult to reach, a flow chart to assist diagnosis is suggested.

Distinct iEEG activity patterns in temporal-limbic and prefrontal sites induced by emotional intentionality.

Our emotions tend to be directed towards someone or something. Such emotional intentionality calls for the integration between two streams of information; abstract hedonic value and its associated concrete content. In a previous functional magnetic resonance imaging (fMRI) study we found that the combination of these two streams, as modeled by short emotional music excerpts and neutral film clips, was associated with synergistic activation in both temporal-limbic (TL) and ventral-lateral PFC (vLPFC) regions. This additive effect implies the integration of domain-specific 'affective' and 'cognitive' processes. Yet, the low temporal resolution of the fMRI limits the characterization of such cross-domain integration. To this end, we complemented the fMRI data with intracranial electroencephalogram (iEEG) recordings from twelve patients with intractable epilepsy. As expected, the additive fMRI activation in the amygdala and vLPFC was associated with distinct spatio-temporal iEEG patterns among electrodes situated within the vicinity of the fMRI activation foci. On the one hand, TL channels exhibited a transient (0-500 msec) increase in gamma power (61-69 Hz), possibly reflecting initial relevance detection or hedonic value tagging. On the other hand, vLPFC channels showed sustained (1-12 sec) suppression of low frequency power (2.3-24 Hz), possibly mediating changes in gating, enabling an on-going readiness for content-based processing of emotionally tagged signals. Moreover, an additive effect in delta-gamma phase-amplitude coupling (PAC) was found among the TL channels, possibly reflecting the integration between distinct domain specific processes. Together, this study provides a multi-faceted neurophysiological signature for computations that possibly underlie emotional intentionality in humans.

Beyond the double banana: improved recognition of temporal lobe seizures in long-term EEG.

PURPOSE: To investigate whether extending the 10-20 array with 6 electrodes in the inferior temporal chain and constructing computed montages increases the diagnostic value of ictal EEG activity originating in the temporal lobe. In addition, the accuracy of computer-assisted spectral source analysis was investigated. METHODS: Forty EEG samples were reviewed by 7 EEG experts in various montages (longitudinal and transversal bipolar, common average, source derivation, source montage, current source density, and reference-free montages) using 2 electrode arrays (10-20 and the extended one). Spectral source analysis used source montage to calculate density spectral array, defining the earliest oscillatory onset. From this, phase maps were calculated for localization. The reference standard was the decision of the multidisciplinary epilepsy surgery team on the seizure onset zone. Clinical performance was compared with the double banana (longitudinal bipolar montage, 10-20 array). RESULTS: Adding the inferior temporal electrode chain, computed montages (reference free, common average, and source derivation), and voltage maps significantly increased the sensitivity. Phase maps had the highest sensitivity and identified ictal activity at earlier time-point than visual inspection. There was no significant difference concerning specificity. CONCLUSIONS: The findings advocate for the use of these digital EEG technology-derived analysis methods in clinical practice.

Emergence of sensory patterns during sleep highlights differential dynamics of REM and non-REM sleep stages.

Despite the profound reduction in conscious awareness associated with sleep, sensory cortex remains highly active during the different sleep stages, exhibiting complex interactions between different cortical sites. The potential functional significance of such spatial patterns and how they change between different sleep stages is presently unknown. In this electrocorticography study of human patients, we examined this question by studying spatial patterns of activity (broadband gamma power) that emerge during sleep (sleep patterns) and comparing them to the functional organization of sensory cortex that is activated by naturalistic stimuli during the awake state. Our results show a high correlation (p < 10(-4), permutation test) between the sleep spatial patterns and the functional organization found during wakefulness. Examining how the sleep patterns changed through the night highlighted a stage-specific difference, whereby the repertoire of such patterns was significantly larger during rapid eye movement (REM) sleep compared with non-REM stages. These results reveal that intricate spatial patterns of sensory functional organization emerge in a stage-specific manner during sleep.

Acquired oculomotor nerve paresis with cyclic spasms in a young woman, a rare subtype of neuromyotonia.

BACKGROUND: To report an unusual case of cyclic oculomotor nerve paresis and spasms, which developed 5 years following brain radiotherapy for cerebellar medulloblastoma. METHODS: Observational case report. RESULTS: The cyclic oculomotor nerve paresis and spasms resolved in our patient when treated with carbamazepine. However, because of severe photophobia and tearing, carbamazepine had to be discontinued leading to reappearance of the eye movement disorder. CONCLUSION: Cyclic oculomotor nerve paresis and spasms appear to be a delayed effect of radiotherapy and respond to carbamazepine therapy. It may be a rare form of ocular neuromyotonia.

Selectivity of audiovisual ECoG responses revealed under naturalistic stimuli in the human cortex.

A fundamental debate in the study of cortical sensory systems concerns the scale of functional selectivity in cortical networks. Brain imaging studies have repeatedly demonstrated functional selectivity in entire cortical areas and networks using predetermined stimuli. However, it is not clear to what extent these networks are heterogeneous, i.e., whether the selectivity profiles in subregions within each sensory network show significant dissimilarity. Here, we studied local functional selectivity in the human cortex using naturalistic movie clips shown to 12 patients implanted with intracranial electrocorticography electrodes (590 in total), providing extensive cortical coverage. We examined the similarity of response profiles (40- to 80-Hz gamma-power modulations) across electrodes using a novel data driven approach without assuming any predefined category. Our results show that the functional selectivity of each highly responsive electrode was different from that of all other electrodes across the sensory cortex. Thus most responsive electrodes showed an activation profile that was unique in each patient and was similar to that of only 0.3% (1-2) of all other electrodes across all patients. Functional similarity between electrodes was linked to anatomical proximity. While in most electrodes the source of selectivity was complex, a small subset showed the well-documented selectivity to faces and actions. Our results indicate that the human sensory cortex is organized as a mosaic of functionally unique subregions in which each site manifests its own special response profile.

Spatial and object-based attention modulates broadband high-frequency responses across the human visual cortical hierarchy.

One of the puzzling aspects in the visual attention literature is the discrepancy between electrophysiological and fMRI findings: whereas fMRI studies reveal strong attentional modulation in the earliest visual areas, single-unit and local field potential studies yielded mixed results. In addition, it is not clear to what extent spatial attention effects extend from early to high-order visual areas. Here we addressed these issues using electrocorticography recordings in epileptic patients. The patients performed a task that allowed simultaneous manipulation of both spatial and object-based attention. They were presented with composite stimuli, consisting of a small object (face or house) superimposed on a large one, and in separate blocks, were instructed to attend one of the objects. We found a consistent increase in broadband high-frequency (30-90 Hz) power, but not in visual evoked potentials, associated with spatial attention starting with V1/V2 and continuing throughout the visual hierarchy. The magnitude of the attentional modulation was correlated with the spatial selectivity of each electrode and its distance from the occipital pole. Interestingly, the latency of the attentional modulation showed a significant decrease along the visual hierarchy. In addition, electrodes placed over high-order visual areas (e.g., fusiform gyrus) showed both effects of spatial and object-based attention. Overall, our results help to reconcile previous observations of discrepancy between fMRI and electrophysiology. They also imply that spatial attention effects can be found both in early and high-order visual cortical areas, in parallel with their stimulus tuning properties.

Vagal nerve stimulation for refractory epilepsy: the surgical procedure and complications in 100 implantations by a single medical center.

In 1997, the US Food and Drug Administration approved the use of intermittent stimulation of the left vagal nerve as adjunctive therapy for seizure control. Vagal nerve stimulation (VNS) has since been considered a safe and effective treatment for medically intractable seizures. The objective of this study is to present our experience with the surgical procedure and outcomes after VNS insertion in the first 100 consecutive patients treated at the Tel-Aviv "Sourasky" Medical Center (TASMC). All patients who underwent VNS device implantation by the authors at TASMC between 2005 and 2011 were studied. The collected data included age at onset of epilepsy, seizure type, duration of epilepsy, age at VNS device implantation, seizure reduction, surgical complications, and adverse effects of VNS over time. Fifty-three males and 47 females, age 21.2 ± 11.1 years, underwent VNS implantation. Indications for surgery were medically refractory epilepsy. The most common seizure type was focal (55 patients, 55 %). Seizure duration until implantation was 14.4 ± 9 years. Mean follow-up time after device insertion was 24.5 ± 22 months. Complications were encountered in 12 patients. The most common complication was local infection (6 patients, 6 %). Six devices were removed-four due to infection and two due to loss of clinical effect. Currently, 63 patients remain in active long-term follow-up; of these, 35 patients have >50 % reduction in frequency of attacks.VNS is a well-tolerated and effective therapeutic alternative in the management of medically refractory epilepsy. The surgical procedure is safe and has a low complication rate.

Adult-onset temporal lobe epilepsy, cognitive decline, multi-antiepileptic drug hypersensitivity, and Hashimoto's encephalopathy: Two case studies.

Hashimoto's encephalopathy is defined by the coexistence of encephalopathy and antithyroid antibodies. We report two cases of adult-onset temporal lobe epilepsy with subacute cognitive decline, high titers of antithyroid antibodies, multi-antiepileptic drug hypersensitivity, and good response to immunomodulatory treatment. The relevance of multidrug hypersensitivity in the setting of adult-onset epilepsy and the importance of searching for autoimmune causes for epilepsy are discussed.

A widely distributed spectral signature of task-negative electrocorticography responses revealed during a visuomotor task in the human cortex.

While research of human cortical function has typically focused on task-related increases in neuronal activity, there is a growing interest in the complementary phenomenon-namely, task-induced reductions. Recent human BOLD fMRI studies have associated such reductions with a specific network termed the default mode network (DMN). However, detailed understanding of the spatiotemporal patterns of task-negative responses and particularly how they compare across different cortical networks is lacking. Here we examined this issue in a large-scale electrocorticography study in patients performing a demanding backward masking task. Our results uncovered rapid (<1 s) task-induced reductions in gamma power, often concomitant with power increase in alpha/beta bands. Importantly, these responses were found both in the DMN and sensory-motor networks. Comparing the task-negative responses across these different networks revealed similar spectral signatures and dynamics. We hypothesize that the task-negative responses may reflect a cortical switching mechanism whose role is to steer activity away from cortical networks, which are inappropriate for the task at hand.

Sensitivity and specificity of seizure-onset zone estimation by ictal magnetoencephalography.

PURPOSE: Ictal video-electroencephalography (EEG) is commonly used to establish ictal onset-zone location. Recently software development has enabled systematic studies of ictal magnetoencephalography (MEG). In this article, we evaluate the ability of ictal MEG signals to localize the seizure-onset zone. METHODS: Twenty-six patients underwent ictal MEG and epilepsy surgery. Prediction of seizure-onset zone by ictal and interictal MEG was retrospectively compared with ictal-onset area found by intracranial EEG in 12 patients. The specificity and sensitivity of the prediction were calculated at hemisphere-lobe (HL) and at hemisphere-lobe-surface (HLS) levels. KEY FINDINGS: The sensitivity of ictal MEG source localization was 0.958 on HL and 0.706 on HLS levels, and its specificity was 0.900 on HL and 0.731 on HLS levels. The interictal MEG dipole cluster, defined as >10 dipoles on one lobar surface, had sensitivity of 0.400 and specificity of 0.769. Ictal MEG was equally sensitive and specific on dorsolateral and nondorsolateral neocortical surfaces up to a depth of 4 cm from the scalp. SIGNIFICANCE: Sources of ictal-onset MEG signals and interictal dipole clusters are essentially equally specific in estimation of the ictal-onset zone on lobar surface resolution, but ictal MEG is more sensitive. On the lobe resolution, ictal MEG estimates ictal-onset zone with high sensitivity and specificity.

State of consciousness and interictal epileptiform discharges predict seizure occurrence during routine EEG.

OBJECTIVES: To identify the patients who are more likely to experience a seizure during routine electroencephalography (EEG) recording. METHODS: We retrospectively reviewed the EEG recordings and medical records of 262 patients, who were admitted in the Neurology Department in Assaf Harofeh Medical Center and referred to the EEG laboratory between October 2006 and 2008 after a seizure. RESULTS: Eighteen (6.8%) patients had seizures during routine EEG [patients with seizures (PWS)]. The likelihood of seizure occurrence during routine EEG was increased by the presence of interictal epileptiform discharges (odds ratio, 29.85; 95% confidence interval, 6.54-136.21; P=0.001) and abnormal state of consciousness (odds ratio, 9.04; 95% confidence interval, 1.02-80.33; P=0.037). Increased seizure frequency before admission, localization-related epilepsy, and EEG background slowing were significantly more common among PWS compared with patients without seizures on routine EEG (P=0.009, 0.042, and 0.036, respectively). CONCLUSIONS: The presence of interictal epileptiform discharges and decreased state of consciousness increase significantly the likelihood of seizure occurrence during routine EEG. Localization-related epilepsy, increased seizure frequency before admission, and EEG background slowing are more common among PWS.