Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 40
Filtrar
1.
Neuromodulation ; 24(2): 373-379, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33577139

RESUMO

INTRODUCTION: Following electrode implantation, a subgroup of patients treated with deep brain stimulation (DBS) for focal epilepsy exhibits a reduction of seizure frequency before stimulation is initiated. Microlesioning of the target structure has been postulated to be the cause of this "insertional" effect (IE). We examined the occurrence and duration of this IE in a group of patients with focal epilepsy following electrode implantation in the anterior nuclei of the thalamus (ANT) and/or nucleus accumbens (NAC) for DBS treatment. MATERIALS AND METHODS: Changes in monthly seizure frequency compared to preoperative baseline were assessed one month (14 patients) and five months (four patients) after electrode implantation. A group analysis between patients with implantation of bilateral ANT-electrodes (four patients), NAC-electrodes (one patient) as well as ANT and NAC-electrodes (nine patients) was performed. RESULTS: In this cohort, seizure frequency decreased one month after electrode implantation by 57.1 ± 30.1%, p ≤ 0.001 (compared to baseline). No significant difference within stimulation target subcohorts was found (p > 0.05). Out of the four patients without stimulation for five months following electrode insertion, three patients showed seizure frequency reduction lasting two to three months, while blinded to their stimulation status. CONCLUSION: An IE might explain seizure frequency reduction in our cohort. This effect seems to be independent of the number of implanted electrodes and of the target itself. The time course of the blinded subgroup of epilepsy patients suggests a peak of the lesional effect at two to three months after electrode insertion.


Assuntos
Núcleos Anteriores do Tálamo , Estimulação Encefálica Profunda , Epilepsia Resistente a Medicamentos , Epilepsias Parciais , Epilepsia Resistente a Medicamentos/terapia , Eletrodos Implantados , Epilepsias Parciais/terapia , Humanos
2.
Brain ; 142(10): 3059-3071, 2019 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-31373622

RESUMO

The aim of epilepsy surgery in patients with focal, pharmacoresistant epilepsies is to remove the complete epileptogenic zone to achieve long-term seizure freedom. In addition to a spectrum of diagnostic methods, magnetoencephalography focus localization is used for planning of epilepsy surgery. We present results from a retrospective observational cohort study of 1000 patients, evaluated using magnetoencephalography at the University Hospital Erlangen over the time span of 28 years. One thousand consecutive cases were included in the study, evaluated at the University Hospital Erlangen between 1990 and 2018. All patients underwent magnetoencephalography as part of clinical workup for epilepsy surgery. Of these, 405 underwent epilepsy surgery after magnetoencephalography, with postsurgical follow-ups of up to 20 years. Sensitivity for interictal epileptic activity was evaluated, in addition to concordance of localization with the consensus of presurgical workup on a lobar level. We evaluate magnetoencephalography characteristics of patients who underwent epilepsy surgery versus patients who did not proceed to surgery. In operated patients, resection of magnetoencephalography localizations were related to postsurgical seizure outcomes, including long-term results after several years. In comparison, association of lesionectomy with seizure outcomes was analysed. Measures of diagnostic accuracy were calculated for magnetoencephalography resection and lesionectomy. Sensitivity for interictal epileptic activity was 72% with significant differences between temporal and extra-temporal lobe epilepsy. Magnetoencephalography was concordant with the presurgical consensus in 51% and showed additional or more focal involvement in an additional 32%. Patients who proceeded to surgery showed a significantly higher percentage of monofocal magnetoencephalography results. Complete magnetoencephalography resection was associated with significantly higher chances to achieve seizure freedom in the short and long-term. Diagnostic accuracy was significant in temporal and extra-temporal lobe cases, but was significantly higher in extra-temporal lobe epilepsy (diagnostic odds ratios of 4.4 and 41.6). Odds ratios were also higher in non-lesional versus lesional cases (42.0 versus 6.2). The results show that magnetoencephalography provides non-redundant information, which significantly contributes to patient selection, focus localization and ultimately long-term seizure freedom after epilepsy surgery. Specifically in extra-temporal lobe epilepsy and non-lesional cases, magnetoencephalography provides excellent accuracy.


Assuntos
Epilepsia/cirurgia , Magnetoencefalografia/métodos , Adolescente , Adulto , Estudos de Coortes , Eletroencefalografia/métodos , Epilepsias Parciais/diagnóstico , Epilepsias Parciais/cirurgia , Epilepsia/diagnóstico , Epilepsia do Lobo Temporal/cirurgia , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Lobo Temporal/diagnóstico por imagem , Lobo Temporal/cirurgia , Resultado do Tratamento
3.
Neurobiol Learn Mem ; 155: 104-112, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-29981424

RESUMO

Previous imaging studies independently highlighted the role of the anterior thalamus (ANT) and nucleus accumbens (NAcc) in successful memory retrieval. While these findings accord with theoretical models, the precise temporal, oscillatory and network dynamics as well as the interplay between the NAcc and ANT in successfully retrieving information from long-term memory are largely unknown. We addressed this issue by recording intracranial electroencephalography in human epilepsy patients from the NAcc (n = 5) and ANT (n = 4) during an old/new recognition test. Our findings demonstrate that differences in event-related potentials between correctly classified old (i.e., studied) and new (i.e., unstudied) images emerged in the NAcc and ANT already between 200 and 600 ms after stimulus onset. Moreover, time-frequency analyses revealed theta (4-8 Hz) power decreases for old compared to new items in the NAcc and the opposite effect in the ANT. Importantly, Granger causality analyses revealed a directional communication from ANT to NAcc suggesting that entrainment from ANT drives successful memory retrieval. Together, our findings show evidence for the notion that the NAcc and ANT receive memory signals, and that theta oscillations may serve as a mechanism to bind these distributed neural assemblies.


Assuntos
Núcleos Anteriores do Tálamo/fisiologia , Eletrocorticografia/métodos , Potenciais Evocados/fisiologia , Rememoração Mental/fisiologia , Núcleo Accumbens/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Ritmo Teta/fisiologia , Adulto , Epilepsia/fisiopatologia , Humanos , Processamento de Sinais Assistido por Computador
4.
Neuroimage ; 138: 100-108, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27208861

RESUMO

Pre-stimulus theta (4-8Hz) power in the hippocampus and neocortex predicts whether a memory for a subsequent event will be formed. Anatomical studies reveal thalamus-hippocampal connectivity, and lesion, neuroimaging, and electrophysiological studies show that memory processing involves the dorsomedial (DMTN) and anterior thalamic nuclei (ATN). The small size and deep location of these nuclei have limited real-time study of their activity, however, and it is unknown whether pre-stimulus theta power predictive of successful memory formation is also found in these subcortical structures. We recorded human electrophysiological data from the DMTN and ATN of 7 patients receiving deep brain stimulation for refractory epilepsy. We found that greater pre-stimulus theta power in the right DMTN was associated with successful memory encoding, predicting both behavioral outcome and post-stimulus correlates of successful memory formation. In particular, significant correlations were observed between right DMTN theta power and both frontal theta and right ATN gamma (32-50Hz) phase alignment, and frontal-ATN theta-gamma cross-frequency coupling. We draw the following primary conclusions. Our results provide direct electrophysiological evidence in humans of a role for the DMTN as well as the ATN in memory formation. Furthermore, prediction of subsequent memory performance by pre-stimulus thalamic oscillations provides evidence that post-stimulus differences in thalamic activity that index successful and unsuccessful encoding reflect brain processes specifically underpinning memory formation. Finally, the findings broaden the understanding of brain states that facilitate memory encoding to include subcortical as well as cortical structures.


Assuntos
Núcleos Anteriores do Tálamo/fisiologia , Mapeamento Encefálico/métodos , Formação de Conceito/fisiologia , Estimulação Encefálica Profunda/métodos , Núcleo Mediodorsal do Tálamo/fisiologia , Memória/fisiologia , Rede Nervosa/fisiologia , Adulto , Feminino , Humanos , Masculino , Prognóstico , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
5.
J Neurophysiol ; 116(4): 1663-1672, 2016 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-27486103

RESUMO

The human nucleus accumbens is thought to play an important role in guiding future action selection via an evaluation of current action outcomes. Here we provide electrophysiological evidence for a more direct, i.e., online, role during action preparation. We recorded local field potentials from the nucleus accumbens in patients with epilepsy undergoing surgery for deep brain stimulation. We found a consistent decrease in the power of alpha/beta oscillations (10-30 Hz) before and around the time of movements. This perimovement alpha/beta desynchronization was observed in seven of eight patients and was present both before instructed movements in a serial reaction time task as well as before self-paced, deliberate choices in a decision making task. A similar beta decrease over sensorimotor cortex and in the subthalamic nucleus has been directly related to movement preparation and execution. Our results support the idea of a direct role of the human nucleus accumbens in action preparation and execution.


Assuntos
Ritmo alfa/fisiologia , Ritmo beta/fisiologia , Atividade Motora/fisiologia , Núcleo Accumbens/fisiologia , Adulto , Comportamento de Escolha/fisiologia , Sincronização Cortical/fisiologia , Estimulação Encefálica Profunda , Epilepsia/diagnóstico por imagem , Epilepsia/fisiopatologia , Epilepsia/cirurgia , Epilepsia/terapia , Feminino , Dedos/fisiologia , Dedos/fisiopatologia , Lateralidade Funcional , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Movimento/fisiologia , Testes Neuropsicológicos , Núcleo Accumbens/diagnóstico por imagem , Núcleo Accumbens/fisiopatologia , Núcleo Accumbens/cirurgia
6.
Epilepsy Behav ; 58: 111-4, 2016 05.
Artigo em Inglês | MEDLINE | ID: mdl-27064831

RESUMO

PURPOSE: The aim of this study was to evaluate the efficacy and tolerability of lacosamide (LCM) both as add-on therapy and monotherapy in patients with temporal lobe epilepsy (TLE) based on an observational, prospective, multicenter study. METHODS: We enrolled 100 patients (mean age: 43.4±12.53years, 57 females) with nonlesional TLE and TLE with hippocampal sclerosis (HS) that did not respond to the first drug and who were referred to epilepsy centers of the University of Catanzaro, University of Palermo, IRCSS Neuromed of Pozzilli, and Otto-von-Guericke University of Magdeburg. In this open-label, multicenter trial, patients were initiated on oral LCM as add-on therapy to first AED monotherapy or as a later add-on to two concomitant AEDs. Seizure frequency changes and adverse events were recorded for at least six months after LCM was added. RESULTS: Fourteen patients dropped out because of positive MRI findings other than HS. Patients received LCM at 200-400mg/day. Fifty-eight out of these 86 patients with seizures that were previously drug-resistant had reduced seizure frequency after introduction of LCM. Forty-five out of 86 patients were classified as responders (12 were seizure-free, 33 achieved a reduction >50%). Interestingly, five patients out of 86 achieved seizure freedom for at least one year and progressively switched to monotherapy with LCM, and all five remained seizure-free at follow-up (6-48months). CONCLUSIONS: Our results may suggest that LCM at doses of 200 to 400mg/day reduces seizure frequency in adults with TLE regardless of the presence of HS, and that it may be considered as a first add-on treatment for patients with pharmacoresistant TLE.


Assuntos
Acetamidas/administração & dosagem , Anticonvulsivantes/administração & dosagem , Epilepsia do Lobo Temporal/diagnóstico por imagem , Epilepsia do Lobo Temporal/tratamento farmacológico , Adulto , Estudos de Coortes , Quimioterapia Combinada , Epilepsia do Lobo Temporal/fisiopatologia , Feminino , Seguimentos , Humanos , Lacosamida , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Adulto Jovem
7.
J Neurophysiol ; 114(2): 781-92, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26019312

RESUMO

Functional magnetic resonance imaging (fMRI), cyclic voltammetry, and single-unit electrophysiology studies suggest that signals measured in the nucleus accumbens (Nacc) during value-based decision making represent reward prediction errors (RPEs), the difference between actual and predicted rewards. Here, we studied the precise temporal and spectral pattern of reward-related signals in the human Nacc. We recorded local field potentials (LFPs) from the Nacc of six epilepsy patients during an economic decision-making task. On each trial, patients decided whether to accept or reject a gamble with equal probabilities of a monetary gain or loss. The behavior of four patients was consistent with choices being guided by value expectations. Expected value signals before outcome onset were observed in three of those patients, at varying latencies and with nonoverlapping spectral patterns. Signals after outcome onset were correlated with RPE regressors in all subjects. However, further analysis revealed that these signals were better explained as outcome valence rather than RPE signals, with gamble gains and losses differing in the power of beta oscillations and in evoked response amplitudes. Taken together, our results do not support the idea that postsynaptic potentials in the Nacc represent a RPE that unifies outcome magnitude and prior value expectation. We discuss the generalizability of our findings to healthy individuals and the relation of our results to measurements of RPE signals obtained from the Nacc with other methods.


Assuntos
Antecipação Psicológica/fisiologia , Tomada de Decisões/fisiologia , Jogo de Azar/fisiopatologia , Núcleo Accumbens/fisiopatologia , Recompensa , Adulto , Estimulação Encefálica Profunda , Eletrodos Implantados , Epilepsias Parciais/fisiopatologia , Epilepsias Parciais/psicologia , Epilepsias Parciais/cirurgia , Feminino , Jogos Experimentais , Humanos , Masculino , Modelos Psicológicos , Processamento de Sinais Assistido por Computador
8.
J Neurophysiol ; 114(1): 29-39, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25878159

RESUMO

The nucleus accumbens is thought to contribute to action selection by integrating behaviorally relevant information from multiple regions, including prefrontal cortex. Studies in rodents suggest that information flow to the nucleus accumbens may be regulated via task-dependent oscillatory coupling between regions. During instrumental behavior, local field potentials (LFP) in the rat nucleus accumbens and prefrontal cortex are coupled at delta frequencies (Gruber AJ, Hussain RJ, O'Donnell P. PLoS One 4: e5062, 2009), possibly mediating suppression of afferent input from other areas and thereby supporting cortical control (Calhoon GG, O'Donnell P. Neuron 78: 181-190, 2013). In this report, we demonstrate low-frequency cortico-accumbens coupling in humans, both at rest and during a decision-making task. We recorded LFP from the nucleus accumbens in six epilepsy patients who underwent implantation of deep brain stimulation electrodes. All patients showed significant coherence and phase-synchronization between LFP and surface EEG at delta and low theta frequencies. Although the direction of this coupling as indexed by Granger causality varied between subjects in the resting-state data, all patients showed a cortical drive of the nucleus accumbens during action selection in a decision-making task. In three patients this was accompanied by a significant coherence increase over baseline. Our results suggest that low-frequency cortico-accumbens coupling represents a highly conserved regulatory mechanism for action selection.


Assuntos
Córtex Cerebral/fisiologia , Tomada de Decisões/fisiologia , Núcleo Accumbens/fisiologia , Desempenho Psicomotor/fisiologia , Adulto , Estimulação Encefálica Profunda/instrumentação , Ritmo Delta , Eletroencefalografia , Epilepsia/fisiopatologia , Epilepsia/cirurgia , Feminino , Humanos , Neuroestimuladores Implantáveis , Masculino , Vias Neurais/fisiologia , Testes Neuropsicológicos , Periodicidade , Descanso , Ritmo Teta
9.
Epilepsia ; 56(6): e78-82, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25940212

RESUMO

Neuromodulative treatment options are warranted in patients with difficult-to-treat epilepsy. However, acquisition of controlled data on deep brain stimulation has so far been achieved only for the centromedian and anterior thalamic nucleus. In a case series of four patients with intractable partial epilepsy, a randomized controlled cross-over protocol was used to get insight into efficacy and safety of 3-month nucleus accumbens stimulation. Seizure frequency, neurocognitive testing, "Liverpool Seizure Severity Score," "Quality of Life in Epilepsy Inventory," "Beck Depression Inventory," and "Mini International Neuropsychiatric Interview" were obtained at every visit. In a subsequent open-label phase, nucleus accumbens stimulation responders underwent concomitant anterior thalamic nucleus stimulation, whereas nonresponders received solely thalamic stimulation. Under nucleus accumbens stimulation, three of four patients had ≥ 50% reduction in frequency of disabling seizures without further improvement with additional anterior thalamic nucleus stimulation. Patient-reported outcome and neurocognitive testing remained unchanged. Accumbens stimulation is safe and seems to be a suitable option in intractable partial epilepsy. The current findings require substantiation by an adequately powered multicenter study.


Assuntos
Estimulação Encefálica Profunda , Epilepsias Parciais/terapia , Núcleo Accumbens/fisiologia , Adulto , Núcleos Anteriores do Tálamo/fisiologia , Cognição/fisiologia , Estudos Cross-Over , Epilepsias Parciais/psicologia , Feminino , Seguimentos , Humanos , Masculino , Testes Neuropsicológicos , Qualidade de Vida/psicologia , Resultado do Tratamento , Adulto Jovem
10.
Epilepsia ; 56(8): e99-e103, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26041007

RESUMO

In view of the regulatory function of the thalamus in the sleep-wake cycle, the impact of deep brain stimulation (DBS) of the anterior nucleus thalami (ANT) on sleep was assessed in a small consecutive cohort of epilepsy patients with standardized polysomnography (PSG). In nine patients treated with ANT-DBS (voltage 5 V, frequency 145 Hz, cyclic mode), the number of arousals during stimulation and nonstimulation periods, neuropsychiatric symptoms (npS), and seizure frequency were determined. Electroclinical arousals were triggered in 14.0 to 67.0% (mean 42.4 ± SD 16.8%) of all deep brain stimuli. Six patients reported npS. Nocturnal DBS voltages were reduced in eight patients (one patient without npS refused) and PSGs were repeated. Electroclinical arousals occurred between 1.4 and 6.7 (mean 3.3 ± 1.7) times more frequently during stimulation periods compared to nonstimulation periods; the number of arousals positively correlated with the level of DBS voltage (range 1 V to 5 V) (Spearman's rank coefficient 0.53121; p < 0.05). No patient experienced seizure deterioration and four patients reported remission of npS. This case-cohort study provides evidence that ANT-DBS interrupts sleep in a voltage-dependent manner, thus putatively resulting in an increase of npS. Reduction of nocturnal DBS voltage seems to lead to improvement of npS without hampering efficacy of ANT-DBS.


Assuntos
Núcleos Anteriores do Tálamo , Estimulação Encefálica Profunda/efeitos adversos , Epilepsia do Lobo Frontal/terapia , Epilepsia do Lobo Temporal/terapia , Distúrbios do Início e da Manutenção do Sono/etiologia , Adulto , Estudos de Coortes , Epilepsia/terapia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Polissonografia , Sono
11.
J Neurosci ; 33(20): 8764-71, 2013 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-23678119

RESUMO

Theoretical models and empirical work indicate a critical role of the NAcc in salience processing. For instance, the NAcc not only responds to appetitive and aversive information, but it also signals novelty, contextual deviance, and action monitoring. However, because most studies have investigated only one specific type of salience independently, it remains unclear how the NAcc concurrently differentiates between different forms of salience. To investigate this issue, we used intracranial electroencephalography in human epilepsy patients together with a previously established visual oddball paradigm. Here, three different oddball categories (novel, neutral, and target images) were infrequently presented among a standard scene image, and subjects responded to the target via button press. This task allowed us to differentiate "item novelty" (new vs neutral oddballs) from "contextual deviance" (neutral oddballs vs standard images) and "targetness" (target vs neutral oddballs). Time-frequency analysis revealed a dissociation between item novelty and contextual deviance on the basis of decreases in either θ (4-8 Hz) or ß power (20-30 Hz). Targetness, on the other hand, was signaled by positive deflections in the stimulus-locked local field potentials, which, importantly, correlated with subjects' reaction times. These findings indicate that, in an ongoing stream of information, the NAcc differentiates between types of salience by distinct neural mechanisms to guide goal-directed behavior.


Assuntos
Mapeamento Encefálico , Epilepsia/patologia , Potenciais Evocados/fisiologia , Núcleo Accumbens/fisiopatologia , Reconhecimento Psicológico/fisiologia , Adulto , Eletroencefalografia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Estimulação Luminosa , Tempo de Reação , Análise Espectral , Fatores de Tempo , Percepção Visual
12.
Stereotact Funct Neurosurg ; 92(1): 25-30, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24216749

RESUMO

BACKGROUND: The thalamic anteroventral nucleus (AV) is a promising target structure for deep brain stimulation (DBS) in patients suffering from refractory epilepsy. Direct visualization of the AV would improve spatial accuracy in functional stereotactic neurosurgery for treatment of this disease. METHODS: On 3-tesla magnetic resonance imaging (MRI), acquisition parameters were adjusted for optimal demarcation of the AV in 1 healthy subject. Reliability of AV visualization was then evaluated in 5 healthy individuals and 3 patients with refractory epilepsy. RESULTS: In all individuals, an adjusted T1-weighted sequence allowed for demarcation of the AV. It was clearly distinguishable from hyperintense myelin-rich lamellae surrounding it ventrally and laterally and appeared hypo-intense compared to the adjacent thalamic nuclei. Image resolution and contrast facilitated direct stereotactic targeting of the AV prior to DBS surgery in all 3 patients. CONCLUSIONS: Direct targeting of the AV can be achieved, which has immediate implications for the accuracy of MRI-guided DBS in patients with refractory epilepsy.


Assuntos
Núcleos Anteriores do Tálamo/patologia , Estimulação Encefálica Profunda/métodos , Epilepsia/terapia , Imageamento por Ressonância Magnética/métodos , Adulto , Feminino , Humanos , Masculino , Procedimentos Neurocirúrgicos , Reprodutibilidade dos Testes , Técnicas Estereotáxicas
13.
Epilepsia ; 54(1): 75-80, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22998639

RESUMO

PURPOSE: This study investigates immediate efficacy and safety of intravenous application of de novo lacosamide (LCM) as add-on therapy in patients with pharmacoresistant focal epilepsy. METHODS: During presurgical video-electroencephalography (EEG) monitoring, 17 adult inpatients received LCM infusion (200 mg every 12 h for 2-3 days) followed by oral formulation with the same regimen. Before and after intravenous application of LCM, seizures and interictal epileptiform discharges (IEDs) recorded with continuous video-EEG monitoring were analyzed, and an assessment of adverse events (AEs) was performed daily. To evaluate the midterm tolerability and efficacy, follow-up visits were conducted 1 and 3 months after discharge from hospital. KEY FINDINGS: In the acute phase, intravenous initiation of LCM was well tolerated with few mild or moderate AEs (3 of 17, 17.6%). A significant reduction of seizure frequency in the treatment phase as compared to mean seizure frequency in the 2-day baseline phase was achieved (p < 0.05 for the first treatment day, and p < 0.005 for the second treatment day). On the first treatment day, 61.5% of the patients were seizure free, and 84.6% on the second treatment day. IED reduction after intravenous application of LCM was not significant. After 1 month, the 50% responder rate was 46.6% and after the 3-month period, 42.8%. SIGNIFICANCE: Our data suggest that rapid intravenous initiation of de novo LCM is safe and may protect against seizures in a rapid and midterm time window.


Assuntos
Acetamidas/uso terapêutico , Anticonvulsivantes/uso terapêutico , Epilepsias Parciais/tratamento farmacológico , Acetamidas/administração & dosagem , Acetamidas/efeitos adversos , Administração Oral , Adulto , Anticonvulsivantes/administração & dosagem , Anticonvulsivantes/efeitos adversos , Esquema de Medicação , Eletroencefalografia , Epilepsias Parciais/fisiopatologia , Feminino , Humanos , Infusões Intravenosas , Lacosamida , Masculino , Resultado do Tratamento
14.
Nat Commun ; 13(1): 3736, 2022 06 29.
Artigo em Inglês | MEDLINE | ID: mdl-35768419

RESUMO

The thalamus is much more than a simple sensory relay. High-order thalamic nuclei, such as the mediodorsal thalamus, exert a profound influence over animal cognition. However, given the difficulty of directly recording from the thalamus in humans, next-to-nothing is known about thalamic and thalamocortical contributions to human cognition. To address this, we analysed simultaneously-recorded thalamic iEEG and whole-head MEG in six patients (plus MEG recordings from twelve healthy controls) as they completed a visual detection task. We observed that the phase of both ongoing mediodorsal thalamic and prefrontal low-frequency activity was predictive of perceptual performance. Critically however, mediodorsal thalamic activity mediated prefrontal contributions to perceptual performance. These results suggest that it is thalamocortical interactions, rather than cortical activity alone, that is predictive of upcoming perceptual performance and, more generally, highlights the importance of accounting for the thalamus when theorising about cortical contributions to human cognition.


Assuntos
Córtex Pré-Frontal , Tálamo , Animais , Humanos , Vias Neurais , Núcleos Talâmicos , Percepção Visual
15.
Front Cell Neurosci ; 16: 838432, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35480959

RESUMO

The neural extracellular matrix (ECM) composition shapes the neuronal microenvironment and undergoes substantial changes upon development and aging, but also due to cerebral pathologies. In search for potential biomarkers, cerebrospinal fluid (CSF) and serum concentrations of brain ECM molecules have been determined recently to assess ECM changes during neurological conditions including Alzheimer's disease or vascular dementia. Here, we measured the levels of two signature proteoglycans of brain ECM, neurocan and brevican, in the CSF and serum of 96 neurological patients currently understudied regarding ECM alterations: 16 cases with amyotrophic lateral sclerosis (ALS), 26 epilepsy cases, 23 cerebral small vessel disease (CSVD) patients and 31 controls. Analysis of total brevican and neurocan was performed via sandwich Enzyme-linked immunosorbent assays (ELISAs). Major brevican and neurocan cleavage products were measured in the CSF using semiquantitative immunoblotting. Total brevican and neurocan concentrations in serum and CSF did not differ between groups. The 60 kDa brevican fragment resulting from cleavage by the protease ADAMTS-4 was also found unchanged among groups. The presumably intracellularly generated 150 kDa C-terminal neurocan fragment, however, was significantly increased in ALS as compared to all other groups. This group also shows the highest correlation between cleaved and total neurocan in the CSF. Brevican and neurocan levels strongly correlated with each other across all groups, arguing for a joint but yet unknown transport mechanism from the brain parenchyma into CSF. Conclusively our findings suggest an ALS-specific pattern of brain ECM remodeling and may thus contribute to new diagnostic approaches for this disorder.

16.
Epilepsia ; 52(9): e101-5, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21899532

RESUMO

Periventricular nodular heterotopias (PNHs) are frequently associated with pharmacoresistant epilepsy. They are considered part of a dysfunctional network, connected to the overlying cortex. Therefore, removal of the PNHs and additional cortectomy or lobectomy seem to be essential for significant and long-lasting seizure reduction. These procedures, however, can have considerable limitations, especially in patients with functional eloquent cortex adjacent to the PNH. Alternatively, stereotactic neurosurgery can reduce the surgical trauma. Presented is a 56-year-old man who became seizure-free after stereotactically guided radiofrequency lesioning of a solitary PNH.


Assuntos
Ablação por Cateter/métodos , Heterotopia Nodular Periventricular/cirurgia , Eletroencefalografia , Epilepsia/complicações , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Heterotopia Nodular Periventricular/etiologia , Técnicas Estereotáxicas
17.
Neurol Res Pract ; 3(1): 63, 2021 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-34865660

RESUMO

BACKGROUND: With the increased efficacy of stroke treatments, diagnosis and specific treatment needs of patients with post-stroke seizures (PSS) and post-stroke epilepsy have become increasingly important. PSS can complicate the diagnosis of a stroke and the treatment of stroke patients, and can worsen post-stroke morbidity. This narrative review considers current treatment guidelines, the specifics of antiseizure treatment in stroke patients as well as the state-of-the-art in clinical and imaging research of post-stroke epilepsy. Treatment of PSS needs to consider indications for antiseizure medication treatment as well as individual clinical and social factors. Furthermore, potential interactions between stroke and antiseizure treatments must be carefully considered. The relationship between acute recanalizing stroke therapy (intravenous thrombolysis and mechanical thrombectomy) and the emergence of PSS is currently the subject of an intensive discussion. In the subacute and chronic post-stroke phases, important specific interactions between necessary antiseizure and stroke treatments (anticoagulation, cardiac medication) need to be considered. Among all forms of prevention, primary prevention is currently the most intensively researched. This includes specifically the repurposing of drugs that were not originally developed for antiseizure properties, such as statins. PSS are presently the subject of extensive basic clinical research. Of specific interest are the role of post-stroke excitotoxicity and blood-brain barrier disruption for the emergence of PSS in the acute symptomatic as well as late (> 1 week after the stroke) periods. Current magnetic resonance imaging research focussing on glutamate excitotoxicity as well as diffusion-based estimation of blood-brain barrier integrity aim to elucidate the pathophysiology of seizures after stroke and the principles of epileptogenesis in structural epilepsy in general. These approaches may also reveal new imaging-based biomarkers for prediction of PSS and post-stroke epilepsy. CONCLUSION: PSS require the performance of individual risk assessments, accounting for the potential effectiveness and side effects of antiseizure therapy. The use of intravenous thrombolysis and mechanical thrombectomy is not associated with an increased risk of PSS. Advances in stroke imaging may reveal biomarkers for PSS.

18.
Neurosci Biobehav Rev ; 126: 146-158, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33737103

RESUMO

Extensive neuroanatomical connectivity between the anterior thalamic nuclei (ATN) and hippocampus and neocortex renders them well-placed for a role in memory processing, and animal, lesion, and neuroimaging studies support such a notion. The deep location and small size of the ATN have precluded their real-time electrophysiological investigation during human memory processing. However, ATN electrophysiological recordings from patients receiving electrodes implanted for deep brain stimulation for pharmacoresistant focal epilepsy have enabled high temporal resolution study of ATN activity. Theta frequency synchronization of ATN and neocortical oscillations during successful memory encoding, enhanced phase alignment, and coupling between ATN local gamma frequency activity and frontal neocortical and ATN theta oscillations provide evidence of an active role for the ATN in memory encoding, potentially integrating information from widespread neocortical sources. Greater coupling of a broader gamma frequency range with theta oscillations at rest than during memory encoding provides additional support for the hypothesis that the ATN play a role in selecting local, task-relevant high frequency activity associated with particular features of a memory trace.


Assuntos
Núcleos Anteriores do Tálamo , Neocórtex , Animais , Eletroencefalografia , Hipocampo , Humanos , Memória
19.
Seizure ; 91: 228-232, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34233237

RESUMO

BACKGROUND: This observational study was done to develop a score based on clinical predictors that enables a guided decision for the necessity of cerebrospinal fluid (CSF) analysis after first unprovoked epileptic seizures and to validate this score in a retrospective patient cohort. METHODS: Clinical predictors were identified by two panels of epilepsy experts and selected according to content validity ratios. Based on these predictors a score was created and applied to a cohort of patients with first epileptic seizures. RESULTS: The "IDEAL score" consists of 9 items (fever, prolonged disturbance of consciousness, headache, imaging results, cognitive dysfunction, status epilepticus, malignancy, autoimmune encephalitis symptoms) that are collected at two different time points (< 3 h [A-score]; > 3 h [B-score] after hospital admittance). A CSF analysis is recommended, if at least one clinical finding is present, either one of the items evaluated during the acute phase (A-score) or later in the diagnostic process (B-score). In 41 patients (13%) CSF analysis provided essential clues to the cause of the seizure. The combined IDEAL score reached a sensitivity of 98%, a specificity of 53%, a positive predictive value of 24% and a negative predictive value of 99% in this patient cohort. CONCLUSIONS: A CSF analysis after first epileptic seizures provided decisive etiological findings in only 13% of all investigated patients. The IDEAL score offers clinicians a simple and easy-to-implement algorithm to assess the necessity of a CSF analysis, and to prevent unnecessary diagnostic procedures.


Assuntos
Encefalite , Epilepsia , Estado Epiléptico , Epilepsia/diagnóstico , Humanos , Estudos Retrospectivos , Convulsões/diagnóstico
20.
Epilepsy Behav ; 17(4): 565-8, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20189886

RESUMO

In the scenario of refractory status epilepticus, the recommended approach of intensive care treatment is limited with respect to the available pharmacodynamic variability and its impeding, severe side effects. Alternative treatment options are therefore urgently needed. In the case described, a patient with nonlesional frontal lobe epilepsy had a high-frequency series of tonic seizures, which evolved into a malignant form of status epilepticus. Co-administration of verapamil, a potent multidrug transporter inhibitor, was followed by significant reduction in seizure frequency. We discuss the putative role of verapamil and the specific risk factors for this malignant treatment course.


Assuntos
Bloqueadores dos Canais de Cálcio/uso terapêutico , Estado Epiléptico/tratamento farmacológico , Estado Epiléptico/fisiopatologia , Verapamil/uso terapêutico , Eletroencefalografia , Feminino , Humanos , Recidiva , Adulto Jovem
SELEÇÃO DE REFERÊNCIAS
Detalhe da pesquisa