46 research outputs found

    An unusual case of loss of consciousness: when an epileptic brain let the heart slow down

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    The differential diagnosis of an episode of transient loss of consciousness can be sometimes very tricking, in particular when symptoms peculiar of syncope are mixed with focal neurological symptoms. We report the case of a 54-year-old woman who suddenly claimed, during a polygraphic recording (electroencephalography/electrocardiogram), a feeling of fear and tachycardia followed by loss of consciousness and then a tonic posturing of the left limbs. Polygraphic recording showed a critical electroencephalographic pattern starting from left temporo-zygomatic channels followed after few seconds by a sudden slowing of cortical background activity associated with an episode of asystole, as witnessed simultaneously by electrocardiogram. Muscular activity covered electroencephalographic activity of following minutes. This case provides an opportunity to highlight the existence of rare conditions such as ictal arrhythmias which should be considered in the differential diagnosis of episodes of transient loss of consciousness in particular when dysautonomic and neurological symptoms are intermingled. Autonomic symptoms (vomiting, tachycardia, cyanosis, bradycardia and asystole) may be also more frequent in idiopathic (more rarely symptomatic) epilepsies of childhood (Panayiotopoulos syndrome)

    Nonconvulsive Seizures and Dementia: A Case Report

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    Nonconvulsive status epilepticus (NCSE) is a severe medical condition that shows increased incidence in the elderly and is frequently underdiagnosed because of its pleomorphic presentation. We report an NCSE in a 76-year-old woman affected by dementia with acute change of cognitive status and behavior. Intravenous diazepam solved clinical and electroencephalographic manifestations. Neuropsychological assessment after NCSE conclusion showed impairment of several fields that remained unchanged at 3-month followup. NCSE should be considered when sudden and transient cognitive fluctuations appear in the elderly. Epileptic events in dementia occur frequently and are often underrecognized; this could be a misleading factor when considering a quick progression of mnesic performances. Moreover, recent findings both in animal models and in humans demonstrated the deep link between epilepsy and dementia, also supporting the hypothesis that epileptiform activity could contribute to cognitive impairment

    Combined Analysis of Cortical (EEG) and Nerve Stump Signals Improves Robotic Hand Control

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    Background. Interfacing an amputee's upper-extremity stump nerves to control a robotic hand requires training of the individual and algorithms to process interactions between cortical and peripheral signals. Objective. To evaluate for the first time whether EEG-driven analysis of peripheral neural signals as an amputee practices could improve the classification of motor commands. Methods. Four thin-film longitudinal intrafascicular electrodes (tf-LIFEs-4) were implanted in the median and ulnar nerves of the stump in the distal upper arm for 4 weeks. Artificial intelligence classifiers were implemented to analyze LIFE signals recorded while the participant tried to perform 3 different hand and finger movements as pictures representing these tasks were randomly presented on a screen. In the final week, the participant was trained to perform the same movements with a robotic hand prosthesis through modulation of tf-LIFE-4 signals. To improve the classification performance, an event-related desynchronization/synchronization (ERD/ERS) procedure was applied to EEG data to identify the exact timing of each motor command. Results. Real-time control of neural (motor) output was achieved by the participant. By focusing electroneurographic (ENG) signal analysis in an EEG-driven time window, movement classification performance improved. After training, the participant regained normal modulation of background rhythms for movement preparation (?/? band desynchronization) in the sensorimotor area contralateral to the missing limb. Moreover, coherence analysis found a restored ? band synchronization of Rolandic area with frontal and parietal ipsilateral regions, similar to that observed in the opposite hemisphere for movement of the intact hand. Of note, phantom limb pain (PLP) resolved for several months. Conclusions. Combining information from both cortical (EEG) and stump nerve (ENG) signals improved the classification performance compared with tf-LIFE signals processing alone; training led to cortical reorganization and mitigation of PLP

    Transcranial Magnetic Stimulation Studies in Alzheimer's Disease

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    Although motor deficits affect patients with Alzheimer's disease (AD) only at later stages, recent studies demonstrated that primary motor cortex is precociously affected by neuronal degeneration. It is conceivable that neuronal loss is compensated by reorganization of the neural circuitries, thereby maintaining motor performances in daily living. Effectively several transcranial magnetic stimulation (TMS) studies have demonstrated that cortical excitability is enhanced in AD and primary motor cortex presents functional reorganization. Although the best hypothesis for the pathogenesis of AD remains the degeneration of cholinergic neurons in specific regions of the basal forebrain, the application of specific TMS protocols pointed out a role of other neurotransmitters. The present paper provides a perspective of the TMS techniques used to study neurophysiological aspects of AD showing also that, based on different patterns of cortical excitability, TMS may be useful in discriminating between physiological and pathological brain aging at least at the group level. Moreover repetitive TMS might become useful in the rehabilitation of AD patients. Finally integrated approaches utilizing TMS together with others neuro-physiological techniques, such as high-density EEG, and structural and functional imaging as well as biological markers are proposed as promising tool for large-scale, low-cost, and noninvasive evaluation of at-risk populations

    Decoding of grasping information from neural signals recorded using peripheral intrafascicular interfaces

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    The restoration of complex hand functions by creating a novel bidirectional link between the nervous system and a dexterous hand prosthesis is currently pursued by several research groups. This connection must be fast, intuitive, with a high success rate and quite natural to allow an effective bidirectional flow of information between the user's nervous system and the smart artificial device. This goal can be achieved with several approaches and among them, the use of implantable interfaces connected with the peripheral nervous system, namely intrafascicular electrodes, is considered particularly interesting

    Prospects of brain–machine interfaces for space system control

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    The dream of controlling and guiding computer-based systems using human brain signals has slowly but steadily become a reality. The available technology allows real-time implementation of systems that measure neuronal activity, convert their signals, and translate their output for the purpose of controlling mechanical and electronic systems. This paper describes the state of the art of non-invasive brain-machine interfaces (BMIs) and critically investigates both the current technological limits and the future potential that BMIs have for space applications. We present an assessment of the advantages that BMIs can provide and justify the preferred candidate concepts for space applications together with a vision of future directions for their implementation. © 2008 Elsevier Ltd. All rights reserved

    Power Spectral Differences between Transient Epileptic and Global Amnesia: An eLORETA Quantitative EEG Study

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    Transient epileptic amnesia (TEA) is a rare epileptic condition, often confused with transient global amnesia (TGA). In a real-life scenario, differential diagnosis between these two conditions can be hard. In this study we use power spectral analysis empowered by exact Low Resolution Brain Electromagnetic Tomography (eLORETA) to evidence the differences between TEA and TGA. Fifteen patients affected by TEA (64.2 ± 5.2 y.o.; 11 female/4 male; 10 left and 5 right temporal epileptic focus) and 15 patients affected by TGA (65.8 ± 7.2 y.o.; 11 females/4 males) were retrospectively identified in our clinical records. All patients recorded EEGs after symptoms offset. EEGs were analyzed with eLORETA to evidence power spectral contrast between the two conditions. We used an inverse problem solution to localize the source of spectral differences. We found a significant increase in beta band power over the affected hemisphere of TEA patients. Significant results corresponded to the uncus and para-hippocampal gyrus, respectively Brodmann’s Areas: 36, 35, 28, 34. We present original evidence of an increase in beta power in the affected hemisphere (AH) of TEA as compared to TGA. These differences involve key areas of the memory network located in the mesial temporal lobe. Spectral asymmetries could be used in the future to recognize cases of amnesia with a high risk of epilepsy

    Biosorption Of Binary Heavy Metal Systems: Phenomenological Mathematical Modeling

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    Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)A phenomenological mathematical modeling approach was applied in order to describe the biosorption of binary heavy metal systems. The mathematical modeling here proposed was verified with the biosorption of Cu(II)-Ni(II) systems onto residue of alginate extraction from Sargassum filipendula. Equilibrium studies were carried out in order to elucidate the competition between the ions in the process. The Cu (II) ions showed a higher affinity with the biosorbent, while the Ni(II) removal was highly dependent on the presence of Cu(II) ions (i.e., the Cu(II) ions inhibit the removal of Ni(II)). According to the Akaike criterion, the equilibrium experimental data was better described by the Langmuir-Freundlich model, which considers the competition among ions for the active sites. The phenomenological mathematical modeling of the kinetics of biosorption was based on binary equilibrium equations, material balances and possible limiting mass transfer steps instead of the empirical models usually applied. The model was then adjusted to the experimental kinetic data and validated by a simulation in a different condition. According to the model, the internal mass transfer resistance (intra-particle diffusion) is the limiting step that controls the kinetics of the process. Therefore, due to its high predictive capacity, the phenomenological approach described in this work can be applied as a tool for design and optimization of binary heavy metal adsorption systems. (C)2016 Elsevier B.V. All rights reserved.313364373CAPES (Coordination for the Improvement of Higher Education Personnel)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES
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