In patients with drug‐resistant epilepsy (DRE) who are not candidates for resective surgery, various thalamic nuclei, including the anterior, centromedian, and pulvinar nuclei, have been extensively ...investigated as targets for neuromodulation. However, the therapeutic effects of different targets for thalamic neuromodulation on various types of epilepsy are not well understood. Here, we present a 32‐year‐old patient with multifocal bilateral temporoparieto‐occipital epilepsy and bilateral malformations of cortical development (MCDs) who underwent bilateral stereoelectroencephalographic (SEEG) recordings of the aforementioned three thalamic nuclei bilaterally. The change in the rate of interictal epileptiform discharges (IEDs) from baseline were compared in temporal, central, parietal, and occipital regions after direct electrical stimulation (DES) of each thalamic nucleus. A significant decrease in the rate of IEDs (33% from baseline) in the posterior quadrant regions was noted in the ipsilateral as well as contralateral hemisphere following DES of the pulvinar. A scoping review was also performed to better understand the current standpoint of pulvinar thalamic stimulation in the treatment of DRE. The therapeutic effect of neuromodulation can differ among thalamic nuclei targets and epileptogenic zones (EZs). In patients with multifocal EZs with extensive MCDs, personalized thalamic targeting could be achieved through DES with thalamic SEEG electrodes.
Poly(monothiocarbonate)s are an interesting class of sulfur‐containing materials whose application as solid polymer electrolytes was barely studied, certainly due to the elusive production of ...diversified polymer architectures. Herein, a new liquid CO2‐sourced bis(α‐alkylidene cyclic carbonate) monomer was designed at high yield to allow its one‐step and solvent‐free copolymerization with thiols to produce linear and cross‐linked polymers in mild conditions. The influence of the monomer structure on the thermal properties and the ionic conductivity of linear polymers was assessed. The polymer network showed to be thermally re‐processable owing to the dynamic nature of the monothiocarbonate bonds. A solid polymer electrolyte was easily obtained from the cross‐linked material when combined with LiTFSI salt. The solid polymer electrolyte was characterized by an ionic conductivity reaching 6×10−6 S cm−1 at room temperature with a lithium transference number of 0.37 and a wide electrochemical stability window (4.0 V vs Li0/Li+) valid for lithium cycling. This work thus reports an attractive valorizing approach for carbon dioxide to deliver under mild operating conditions poly(monothiocarbonate)‐containing novel covalent adaptable network materials of high potential for energy applications, especially as solid electrolytes for batteries.
New electrolyte: A novel liquid bis(α‐alkylidene cyclic carbonate) monomer was designed to allow one‐step and solvent‐free poly(monothiocarbonate) formation in mild conditions. Polymer covalent adaptable networks could be easily synthesized and re‐processed to the desired shape. Upon addition of lithium salt, the doped material could be used as solid polymer electrolyte for safer Li‐ion batteries.
Automatic generation control (AGC) in multi-area interconnected power systems is experiencing several adaptions due to increasing level of power converter based components in the system. The concept ...of virtual synchronous power (VSP) to simulate the dynamic effects of virtual inertia emulations by HVDC links for higher level control applications is introduced and reflected in the multi-area AGC model. By using this proposed combination in the AGC model, the dynamic performance of the studied system shows a significant improvement. The proposed formulation is generalized for multi-area systems with multiple HVDC links. The active power loop control in VSP-based HVDC links has a second-order characteristic, which makes a simultaneous enabling of damping and inertia emulations into the system. Trajectory sensitivities are also used to analyze the effects of VSP's parameters on the system stability. The effectiveness of the proposed concept on dynamic improvements is tested through MATLAB simulation of a four-area system.
A spatial analysis of hydrochemical data of groundwater and surface water was undertaken to identify groundwater-surface water connectivity in the headwaters of the Condamine River catchment, ...Southeast Queensland, Australia. An assessment of long-term hydrochemical and water level data supplemented by stable- and radioisotope measurements following a prolonged dry period dominated by baseflow, helped in determining patterns of interaction in different tributaries of the upper Condamine catchment. A conceptual hydrological model representing the major hydrochemical processes and their implications for stream-aquifer connectivity was developed and tested using multiple lines of evidence.
The results of a multivariate statistical analysis highlight that there are two main regions with distinct hydrochemical facies (salinity, alkalinity, and predominant ions) in surface water. Geomorphology, geology, anthropogenic and climate influence were identified as the most relevant controlling factors of the spatial variability in water quality.
Stable isotope data confirmed a clear evaporation trend in almost all surface water samples during baseflow conditions. Two water types can be identified and separated by the degree of evaporation and the proximity of one group to the local meteoric water line. The results confirm the discharge of groundwater from aquifers recharged by rainfall and located upstream of the surface water sampling sites.
Overall, 222Rn data show a trend of increased activity in surface water towards the upstream portions of these tributaries, validating the use of this tracer to estimate groundwater input to the local creeks. The proportion of groundwater contribution to stream flow calculated by 222Rn and chloride mass balance is in agreement, and ranges between 20–70% in tributaries in the northern areas, and between 8–50% in the upper reaches of the main river channel.
This study shows the efficacy of an integrated approach combining long-term hydrochemical data interpreted via multivariate statistics, hydraulic water level data and stable and radiogenic isotope hydrology for the determination of groundwater–surface interactions in headwater catchments.
•Two distinct surface water groups identified by multivariate statistical analysis•Groundwater contribution into creek flows estimated using hydrochemistry and 222Rn•Stable and radioisotopes greatly assisted in assessing GW–SW interactions.•A conceptual model describing GW–SW connectivity was developed.
Objective
In the presurgical workup of magnetic resonance imaging (MRI)‐negative (MRI− or “nonlesional”) pharmacoresistant focal epilepsy (PFE) patients, discovering a previously undetected lesion ...can drastically change the evaluation and likely improve surgical outcome. Our study utilizes a voxel‐based MRI postprocessing technique, implemented in a morphometric analysis program (MAP), to facilitate detection of subtle abnormalities in a consecutive cohort of MRI− surgical candidates.
Methods
Included in this retrospective study was a consecutive cohort of 150 MRI− surgical patients. MAP was performed on T1‐weighted MRI, with comparison to a scanner‐specific normal database. Review and analysis of MAP were performed blinded to patients' clinical information. The pertinence of MAP+ areas was confirmed by surgical outcome and pathology.
Results
MAP showed a 43% positive rate, sensitivity of 0.9, and specificity of 0.67. Overall, patients with the MAP+ region completely resected had the best seizure outcomes, followed by the MAP− patients, and patients who had no/partial resection of the MAP+ region had the worst outcome (p < 0.001). Subgroup analysis revealed that visually identified subtle findings are more likely correct if also MAP+. False‐positive rate in 52 normal controls was 2%. Surgical pathology of the resected MAP+ areas contained mainly non–balloon‐cell focal cortical dysplasia (FCD). Multiple MAP+ regions were present in 7% of patients.
Interpretation
MAP can be a practical and valuable tool to: (1) guide the search for subtle MRI abnormalities and (2) confirm visually identified questionable abnormalities in patients with PFE due to suspected FCD. A MAP+ region, when concordant with the patient's electroclinical presentation, should provide a legitimate target for surgical exploration. Ann Neurol 2015;77:1060–1075
We determined the incidence of post‐traumatic epilepsy after severe traumatic brain injury. Of 392 patients surviving to discharge, cumulative incidence of post‐traumatic epilepsy was 25% at 5 years ...and 32% at 15 years, an increase compared with historical reports. Among patients with one late seizure (>7 days post‐trauma), the risk of seizure recurrence was 62% after 1 year and 82% at 10 years. Competing hazards regression identified age, decompressive hemicraniectomy, and intracranial infection as independent predictors of post‐traumatic epilepsy. Patients with severe traumatic brain injury and a single late post‐traumatic seizure will likely require long‐term antiseizure medicines. ANN NEUROL 2022;92:663–669
Summary
Purpose: Stereo‐electroencephalography (SEEG) enables precise recordings from deep cortical structures, multiple noncontiguous lobes, as well as bilateral explorations while avoiding large ...craniotomies. Despite a long reported successful record, its application in the United States has not been widely adopted. We report on our initial experience with the SEEG methodology in the extraoperative mapping of refractory focal epilepsy in patients who were not considered optimal surgical candidates for other methods of invasive monitoring. We focused on the applied surgical technique and its utility and efficacy in this subgroup of patients.
Methods: Between March 2009 and May 2011, 100 patients with the diagnosis of medically refractory focal epilepsy who were not considered optimal candidates for subdural grids and strips placement underwent SEEG implantation at Cleveland Clinic Epilepsy Center. Demographics, noninvasive clinical data, number and location of implanted electrodes, electrophysiologic localization of the epileptic zone, complications, and short‐term seizure outcome after resection were prospectively collected and analyzed.
Key Findings: Mean age was 32 years (range 5–68 years); 54 were male and 46 female. The mean follow‐up after resection was 15 months. In total, 1,310 electrodes were implanted. Analyses of the SEEG recordings resulted in the electrographic localization of the epileptogenic focus in 96 patients. In the group of 75 patients who underwent resection, only 53 had at least 12 months follow‐up. From this group, 33 patients (62.3%) were seizure‐free at the end of the follow‐up period. The presence of abnormal pathologic finding was strongly associated with postoperative seizure control (p = 0.005). The risk of hemorrhagic complications per electrode was 0.2%.
Significance: In patients who are not considered to be ideal candidates for subdural grids and strips implantation, the SEEG methodology is a safe, useful and reliable alternative option for invasive monitoring in patients with refractory focal epilepsy, providing an additional mean for seizure localization and control in a “difficult to localize” subgroup of patients.
Abstract
Previously, signalling status had been primarily studied from the conspicuousness of luxury brands, including high prices and prominent designs. However, less attention has been directed ...toward other elements of brands that could be strategically managed in order to enable consumers signalling status. This study synthesizes the literature using a framework based on four intangible attributes of luxury brands: user profile, purchase usage, personality and values and heritage. The topics studied under each of the four intangible attributes were analysed using a systematic approach. Based on the interconnectedness of the topics studied, this review proposes that the intangible attributes used as a framework may have a synergistic interaction, in contrast with the current perspective that considers them as independently and equally relevant for consumers signalling status. It also reports the psychological function of these intangible attributes and supports the notion that consumers use luxury brands either to routinely affirm their status within a group or to enhance that status. This review contributes to the literature on luxury and signalling by considering luxury consumption as a social process. A functional perspective on the intangible attributes of luxury brands provides the basis for some insightful directions to advance this field of research.
Objective
Posttraumatic epilepsy (PTE) develops in as many as one third of severe traumatic brain injury (TBI) patients, often years after injury. Analysis of early electroencephalographic (EEG) ...features, by both standardized visual interpretation (viEEG) and quantitative EEG (qEEG) analysis, may aid early identification of patients at high risk for PTE.
Methods
We performed a case–control study using a prospective database of severe TBI patients treated at a single center from 2011 to 2018. We identified patients who survived 2 years postinjury and matched patients with PTE to those without using age and admission Glasgow Coma Scale score. A neuropsychologist recorded outcomes at 1 year using the Expanded Glasgow Outcomes Scale (GOSE). All patients underwent continuous EEG for 3–5 days. A board‐certified epileptologist, blinded to outcomes, described viEEG features using standardized descriptions. We extracted 14 qEEG features from an early 5‐min epoch, described them using qualitative statistics, then developed two multivariable models to predict long‐term risk of PTE (random forest and logistic regression).
Results
We identified 27 patients with and 35 without PTE. GOSE scores were similar at 1 year (p = .93). The median time to onset of PTE was 7.2 months posttrauma (interquartile range = 2.2–22.2 months). None of the viEEG features was different between the groups. On qEEG, the PTE cohort had higher spectral power in the delta frequencies, more power variance in the delta and theta frequencies, and higher peak envelope (all p < .01). Using random forest, combining qEEG and clinical features produced an area under the curve of .76. Using logistic regression, increases in the delta:theta power ratio (odds ratio OR = 1.3, p < .01) and peak envelope (OR = 1.1, p < .01) predicted risk for PTE.
Significance
In a cohort of severe TBI patients, acute phase EEG features may predict PTE. Predictive models, as applied to this study, may help identify patients at high risk for PTE, assist early clinical management, and guide patient selection for clinical trials.
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