RESUMO
People with epilepsy face serious driving restrictions, determined using retrospective studies. To relate seizure characteristics to driving impairment, we aimed to study driving behavior during seizures with a simulator. Patients in the Yale New Haven Hospital undergoing video-electroencephalographic monitoring used a laptop-based driving simulator during ictal events. Driving function was evaluated by video review and analyzed in relation to seizure type, impairment of consciousness/responsiveness, or motor impairment during seizures. Fifty-one seizures in 30 patients were studied. In terms of seizure type, we found that focal to bilateral tonic-clonic or myoclonic seizures (5/5) and focal seizures with impaired consciousness/responsiveness (11/11) always led to driving impairment; focal seizures with spared consciousness/responsiveness (0/10) and generalized nonmotor (generalized spike-wave bursts; 1/19) usually did not lead to driving impairment. Regardless of seizure type, we found that seizures with impaired consciousness (15/15) or with motor involvement (13/13) always led to impaired driving, but those with spared consciousness (0/20) or spared motor function (5/38) usually did not. These results suggest that seizure types with impaired consciousness/responsiveness and abnormal motor function contribute to impaired driving. Expanding this work in a larger cohort could further determine how results with a driving simulator may translate into real world driving safety.
Assuntos
Epilepsia , Transtornos Motores , Estado de Consciência , Eletroencefalografia/métodos , Epilepsia/complicações , Epilepsia/diagnóstico , Humanos , Estudos Retrospectivos , Convulsões/diagnósticoRESUMO
OBJECTIVE: Generalized epileptiform discharges (GEDs) can occur during seizures or without obvious clinical accompaniment. Motor vehicle driving risk during apparently subclinical GEDs is uncertain. Our goals were to develop a feasible, realistic test to evaluate driving safety during GEDs, and to begin evaluating electroencephalographic (EEG) features in relation to driving safety. METHODS: Subjects were aged ≥15 years with generalized epilepsy, GEDs on EEG, and no clinical seizures. Using a high-fidelity driving simulator (miniSim) with simultaneous EEG, a red oval visual stimulus was presented every 5 minutes for baseline testing, and with each GED. Participants were instructed to pull over as quickly and safely as possible with each stimulus. We analyzed driving and EEG signals during GEDs. RESULTS: Nine subjects were tested, and five experienced 88 GEDs total with mean duration 2.31 ± 1.89 (SD) seconds. Of these five subjects, three responded appropriately to all stimuli, one failed to respond to 75% of stimuli, and one stopped driving immediately during GEDs. GEDs with no response to stimuli were significantly longer than those with appropriate responses (8.47 ± 3.10 vs 1.85 ± 0.69 seconds, P < .001). Reaction times to stimuli during GEDs were significantly correlated with GED duration (r = 0.30, P = .04). In addition, EEG amplitude was greater for GEDs with no response to stimuli than GEDs with responses, both for overall root mean square voltage amplitude (66.14 µV vs 52.99 µV, P = .02) and for fractional power changes in the frequency range of waves (P < .05) and spikes (P < .001). SIGNIFICANCE: High-fidelity driving simulation is feasible for investigating driving behavior during GEDs. GEDs with longer duration and greater EEG amplitude showed more driving impairment. Future work with a large sample size may ultimately enable classification of GED EEG features to predict individual driving risk.
Assuntos
Condução de Veículo , Convulsões/fisiopatologia , Treinamento por Simulação/métodos , Adolescente , Adulto , Eletroencefalografia , Estudos de Viabilidade , Feminino , Humanos , Masculino , Projetos Piloto , Adulto JovemRESUMO
Generalized spike-wave discharges (SWDs) are the hallmark of generalized epilepsy on the electroencephalogram (EEG). In clinically obvious cases, generalized SWDs produce myoclonic, atonic/tonic, or absence seizures with brief episodes of staring and behavioral unresponsiveness. However, some generalized SWDs have no obvious behavioral effects. A serious challenge arises when patients with no clinical seizures request driving privileges and licensure, yet their EEG shows generalized SWD. Specialized behavioral testing has demonstrated prolonged reaction times or missed responses during SWD, which may present a driving hazard even when patients or family members do not notice any deficits. On the other hand, some SWDs are truly asymptomatic in which case driving privileges should not be restricted. Clinicians often decide on driving privileges based on SWD duration or other EEG features. However, there are currently no empirically-validated guidelines for distinguishing generalized SWDs that are "safe" versus "unsafe" for driving. Here, we review the clinical presentation of generalized SWD and recent work investigating mechanisms of behavioral impairment during SWD with implications for driving safety. As a future approach, computational analysis of large sets of EEG data during simulated driving utilizing machine learning could lead to powerful methods to classify generalized SWD as safe vs. unsafe. This may ultimately provide more objective EEG criteria to guide decisions on driving safety in people with epilepsy.
Assuntos
Condução de Veículo , Eletroencefalografia/métodos , Epilepsia Generalizada/fisiopatologia , Convulsões/fisiopatologia , Condução de Veículo/psicologia , Epilepsia Generalizada/diagnóstico , Epilepsia Generalizada/psicologia , Feminino , Humanos , Masculino , Tempo de Reação/fisiologia , Convulsões/diagnóstico , Convulsões/psicologiaRESUMO
Each year in the United States, 500 patients are hospitalized for cat-scratch disease, caused by Bartonella henselae infection. We report a case of rare but serious neurologic B. henselae infection. When typical features of cat-scratch disease occur with neurologic findings, Bartonella infection should be suspected and diagnostic testing should be performed.
Assuntos
Bartonella , Doença da Arranhadura de Gato/complicações , Mielite Transversa/etiologia , Anti-Infecciosos/uso terapêutico , Doença da Arranhadura de Gato/líquido cefalorraquidiano , Doença da Arranhadura de Gato/tratamento farmacológico , Doença da Arranhadura de Gato/patologia , Feminino , Humanos , Pessoa de Meia-Idade , Mielite Transversa/líquido cefalorraquidiano , Mielite Transversa/tratamento farmacológicoRESUMO
OBJECTIVE: To investigate effects of interictal epileptic activity (IEA) and antiepileptic drugs (AEDs) on reactivity and aspects of the fitness to drive for epilepsy patients. METHODS: Forty-six adult patients with demonstration of focal or generalized bursts of IEA in electroencephalography (EEG) readings within 1 year prior to inclusion irrespective of medication performed a car driving computer test or a single light flash test (39 patients performed both). Reaction times (RTs), virtual crashes, or lapses (RT ≥ 1 s in the car or flash test) were measured in an IEA burst-triggered fashion during IEA and compared with RT-measurements during unremarkable EEG findings in the same session. RESULTS: IEA prolonged RTs both in the flash and car test (p < 0.001) in individual patients up to 200 ms. Generalized IEA with spike/waves (s/w) had the largest effect on RT prolongation (p < 0.001, both tests), whereas mean RT during normal EEG, age, gender, and number of AEDs had no effect. The car test was better than the flash test in detecting RT prolongations (p = 0.030). IEA increased crashes/lapses >26% in sessions with generalized IEA with s/w. The frequency of IEA-associated RT >1 s exceeded predictions (p < 0.001) based on simple RT shift, suggesting functional impairment beyond progressive RT prolongation by IEA. The number of AEDs correlated with prolonged RTs during normal EEG (p < 0.021) but not with IEA-associated RT prolongation or crashes/lapses. SIGNIFICANCE: IEA prolonged RTs to varying extents, dependent on IEA type. IEA-associated RTs >1 s were more frequent than predicted, suggesting beginning cerebral decompensation of visual stimulus processing. AEDs somewhat reduced psychomotor speed, but it was mainly the IEA that contributed to an excess of virtual accidents.
Assuntos
Acidentes de Trânsito , Anticonvulsivantes/uso terapêutico , Epilepsia/tratamento farmacológico , Epilepsia/etiologia , Interface Usuário-Computador , Adolescente , Adulto , Idoso , Eletroencefalografia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Tempo de Reação/efeitos dos fármacos , Adulto JovemRESUMO
Demonstration of survival and outcome of progressive multifocal leukoencephalopathy (PML) in a 56-year-old patient with common variable immunodeficiency, consisting of severe hypogammaglobulinemia and CD4+ T lymphocytopenia, during continuous treatment with mirtazapine (30 mg/day) and mefloquine (250 mg/week) over 23 months. Regular clinical examinations including Rankin scale and Barthel index, nine-hole peg and box and block tests, Berg balance, 10-m walking tests, and Montreal Cognitive Assessment (MoCA) were done. Laboratory diagnostics included complete blood count and JC virus (JCV) concentration in cerebrospinal fluid (CSF). The noncoding control region (NCCR) of JCV, important for neurotropism and neurovirulence, was sequenced. Repetitive MRI investigated the course of brain lesions. JCV was detected in increasing concentrations (peak 2568 copies/ml CSF), and its NCCR was genetically rearranged. Under treatment, the rearrangement changed toward the archetype sequence, and later JCV DNA became undetectable. Total brain lesion volume decreased (8.54 to 3.97 cm(3)) and atrophy increased. Barthel (60 to 100 to 80 points) and Rankin (4 to 2 to 3) scores, gait stability, and box and block (7, 35, 25 pieces) and nine-hole peg (300, 50, 300 s) test performances first improved but subsequently worsened. Cognition and walking speed remained stable. Despite initial rapid deterioration, the patient survived under continuous treatment with mirtazapine and mefloquine even though he belongs to a PML subgroup that is usually fatal within a few months. This course was paralleled by JCV clones with presumably lower replication capability before JCV became undetectable. Neurological deficits were due to PML lesions and progressive brain atrophy.
Assuntos
Antivirais/uso terapêutico , Imunodeficiência de Variável Comum/complicações , Leucoencefalopatia Multifocal Progressiva/complicações , Leucoencefalopatia Multifocal Progressiva/tratamento farmacológico , Mefloquina/uso terapêutico , Mianserina/análogos & derivados , DNA Viral/sangue , Humanos , Vírus JC , Masculino , Mianserina/uso terapêutico , Pessoa de Meia-Idade , Mirtazapina , ViremiaRESUMO
To investigate whether alterations in RNA editing (an enzymatic base-specific change to the RNA sequence during primary transcript formation from DNA) of neurotransmitter receptor genes and of transmembrane ion channel genes play a role in human temporal lobe epilepsy (TLE), this exploratory study analyzed 14 known cerebral editing sites in RNA extracted from the brain tissue of 41 patients who underwent surgery for mesial TLE, 23 with hippocampal sclerosis (MTLE+HS). Because intraoperatively sampled RNA cannot be obtained from healthy controls and the best feasible control is identically sampled RNA from patients with a clinically shorter history of epilepsy, the primary aim of the study was to assess the correlation between epilepsy duration and RNA editing in the homogenous group of MTLE+HS. At the functionally relevant I/V site of the voltage-gated potassium channel Kv1.1, an inverse correlation of RNA editing was found with epilepsy duration (r=-0.52, p=0.01) but not with patient age at surgery, suggesting a specific association with either the epileptic process itself or its antiepileptic medication history. No significant correlations were found between RNA editing and clinical parameters at other sites within glutamate receptor or serotonin 2C receptor gene transcripts. An "all-or-none" (≥95% or ≤5%) editing pattern at most or all sites was discovered in 2 patients. As a secondary part of the study, RNA editing was also analyzed as in the previous literature where up to now, few single editing sites were compared with differently obtained RNA from inhomogenous patient groups and autopsies, and by measuring editing changes in our mouse model. The present screening study is first to identify an editing site correlating with a clinical parameter, and to also provide an estimate of the possible effect size at other sites, which is a prerequisite for power analysis needed in planning future studies.
Assuntos
DNA/genética , Epilepsia do Lobo Temporal/genética , Edição de RNA/fisiologia , RNA/genética , Adolescente , Adulto , Animais , Eletroencefalografia , Feminino , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Humanos , Canal de Potássio Kv1.1/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Receptores de AMPA/genética , Adulto JovemRESUMO
BACKGROUND AND OBJECTIVES: This study aimed to evaluate and predict the effects of interictal epileptiform discharges (IEDs) on driving ability using simple reaction tests and a driving simulator. METHODS: Patients with various epilepsies were evaluated with simultaneous EEGs during their response to visual stimuli in a single-flash test, a car-driving video game, and a realistic driving simulator. Reaction times (RTs) and missed reactions or crashes (miss/crash) during normal EEG and IEDs were measured. IEDs, as considered in this study, were a series of epileptiform potentials (>1 potential) and were classified as generalized typical, generalized atypical, or focal. RT and miss/crash in relation to IED type, duration, and test type were analyzed. RT prolongation, miss/crash probability, and odds ratio (OR) of miss/crash due to IEDs were calculated. RESULTS: Generalized typical IEDs prolonged RT by 164 ms, compared with generalized atypical IEDs (77.0 ms) and focal IEDs (48.0 ms) (p < 0.01). Generalized typical IEDs had a session miss/crash probability of 14.7% compared with a zero median for focal and generalized atypical IEDs (p < 0.01). Long repetitive bursts of focal IEDs lasting >2 seconds had a 2.6% miss/crash probabilityIED. Cumulated miss/crash probability could be predicted from RT prolongation: 90.3 ms yielded a 20% miss/crash probability. All tests were nonsuperior to each other in detecting miss/crash probabilitiesIED (zero median for all 3 tests) or RT prolongations (flash test: 56.4 ms, car-driving video game: 75.5 ms, simulator 86.6 ms). IEDs increased the OR of miss/crash in the simulator by 4.9-fold compared with normal EEG. A table of expected RT prolongations and miss/crash probabilities for IEDs of a given type and duration was created. DISCUSSION: IED-associated miss/crash probability and RT prolongation were comparably well detected by all tests. Long focal IED bursts carry a low risk, while generalized typical IEDs are the primary cause of miss/crash. We propose a cumulative 20% miss/crash risk at an RT prolongation of 90.3 ms as a clinically relevant IED effect. The IED-associated OR in the simulator approximates the effects of sleepiness or low blood alcohol level while driving on real roads. A decision aid for fitness-to-drive evaluation was created by providing the expected RT prolongations and misses/crashes when IEDs of a certain type and duration are detected in routine EEG.
Assuntos
Epilepsia , Jogos de Vídeo , Humanos , Epilepsia/diagnóstico , Eletroencefalografia , Probabilidade , Razão de ChancesRESUMO
Behavior during 3-4 Hz spike-wave discharges (SWDs) in absence epilepsy can vary from obvious behavioral arrest to no detectible deficits. Knowing if behavior is impaired is crucial for clinical care but may be difficult to determine without specialized behavioral testing, often inaccessible in practice. We aimed to develop a pure electroencephalography (EEG)-based machine-learning method to predict SWD-related behavioral impairment. Our classification goals were 100% predictive value, with no behaviorally impaired SWDs misclassified as spared; and maximal sensitivity. First, using labeled data with known behavior (130 SWDs in 34 patients), we extracted EEG time, frequency domain, and common spatial pattern features and applied support vector machines and linear discriminant analysis to classify SWDs as spared or impaired. We evaluated 32 classification models, optimized with 10-fold cross-validation. We then generalized these models to unlabeled data (220 SWDs in 41 patients), where behavior during individual SWDs was not known, but observers reported the presence of clinical seizures. For labeled data, the best classifier achieved 100% spared predictive value and 93% sensitivity. The best classifier on the unlabeled data achieved 100% spared predictive value, but with a lower sensitivity of 35%, corresponding to a conservative classification of 8 patients out of 23 as free of clinical seizures. Our findings demonstrate the feasibility of machine learning to predict impaired behavior during SWDs based on EEG features. With additional validation and optimization in a larger data sample, applications may include EEG-based prediction of driving safety, treatment adjustment, and insight into mechanisms of impaired consciousness in absence seizures.
Assuntos
Epilepsia Tipo Ausência , Estado de Consciência , Eletroencefalografia/métodos , Epilepsia Tipo Ausência/diagnóstico , Humanos , Aprendizado de Máquina , Convulsões/diagnósticoRESUMO
The impact of interictal epileptic activity (IEA) on driving is a rarely investigated issue. We analyzed the impact of IEA on reaction time in a pilot study. Reactions to simple visual stimuli (light flash) in the Flash test or complex visual stimuli (obstacle on a road) in a modified car driving computer game, the Steer Clear, were measured during IEA bursts and unremarkable electroencephalography (EEG) periods. Individual epilepsy patients showed slower reaction times (RTs) during generalized IEA compared to RTs during unremarkable EEG periods. RT differences were approximately 300 ms (p < 0.001) in the Flash test and approximately 200 ms (p < 0.001) in the Steer Clear. Prior work suggested that RT differences >100 ms may become clinically relevant. This occurred in 40% of patients in the Flash test and in up to 50% in the Steer Clear. When RT were pooled, mean RT differences were 157 ms in the Flash test (p < 0.0001) and 116 ms in the Steer Clear (p < 0.0001). Generalized IEA of short duration seems to impair brain function, that is, the ability to react. The reaction-time EEG could be used routinely to assess driving ability.
Assuntos
Condução de Veículo/normas , Eletroencefalografia , Epilepsia/fisiopatologia , Adolescente , Adulto , Encéfalo/fisiopatologia , Avaliação da Deficiência , Humanos , Pessoa de Meia-Idade , Tempo de Reação/fisiologia , Adulto JovemRESUMO
Cardiac myxoma can embolize and cause early and delayed sequelae including stroke, growth into intracranial fusiform aneurysms and cerebral tumors with risk of hemorrhage and mass effect. Here, we report the rare coincidence of all these manifestations in a 63-year-old man who presented with cognitive and behavioral changes, and seizures 9 months after an embolic stroke from the heart tumor. C-reactive protein (CRP) was elevated at the time of stroke and cardiac myxoma diagnosis but was normal at late neurologic manifestation with isolated myxoma-related intracranial tumors and aneurysms. Low-dose whole-brain radiotherapy can be helpful to diminish cerebral myxoma tumors and fusiform aneurysms despite reported increased risk of aneurysm rupture.
Assuntos
Neoplasias Encefálicas/etiologia , AVC Embólico/etiologia , Neoplasias Cardíacas/complicações , Aneurisma Intracraniano/etiologia , Mixoma/complicações , Células Neoplásicas Circulantes/patologia , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/patologia , Proteína C-Reativa/metabolismo , Hemorragia Cerebral/diagnóstico por imagem , Hemorragia Cerebral/etiologia , AVC Embólico/diagnóstico por imagem , Neoplasias Cardíacas/metabolismo , Neoplasias Cardíacas/patologia , Humanos , Aneurisma Intracraniano/diagnóstico por imagem , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Mixoma/diagnóstico por imagem , Mixoma/metabolismo , Mixoma/patologiaRESUMO
PURPOSE: Epilepsy patients consider driving issues to be one of their most serious concerns. Ideally, decisions regarding fitness to drive should be based upon thorough evaluations by specialists in epilepsy care. In 2009, an EU directive was published aiming to harmonize evaluation practices within European countries, but, despite these recommendations, whether all epileptologists use the same criteria is unclear. We therefore conducted this study to investigate routine practices on how epileptologists at European epilepsy centers evaluate fitness to drive. METHODS: A questionnaire was sent to 63 contact persons identified through the European Epi-Care and the E-pilepsy network. The questionnaire addressed how fitness-to-drive evaluations were conducted, the involvement of different professionals, the use and interpretation of EEG, and opinions on existing regulations and guidelines. RESULTS: The questionnaire was completed by 35 participants (56 % response rate). Results showed considerable variation regarding test routines and the emphasis placed on the occurrence and extent of epileptiform discharges revealed by EEG. 82 % of the responders agreed that there was a need for more research on how to better evaluate fitness-to-drive in people with epilepsy, and 89 % agreed that regulations on fitness to drive evaluations should be internationally coordinated. CONCLUSION: Our survey showed considerable variations among European epileptologists regarding use of EEG and how findings of EEG pathology should be assessed in fitness-to-drive evaluations. There is a clear need for more research on this issue and international guidelines on how such evaluations should be carried out would be of value.
Assuntos
Atitude do Pessoal de Saúde , Condução de Veículo/legislação & jurisprudência , Condução de Veículo/estatística & dados numéricos , Avaliação da Deficiência , Epilepsia/epidemiologia , Neurologistas/estatística & dados numéricos , Padrões de Prática Médica/estatística & dados numéricos , Adulto , Eletroencefalografia , Europa (Continente)/epidemiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Inquéritos e QuestionáriosRESUMO
Metabotropic receptors coupled to Gq/G11 family G proteins critically contribute to nervous system functions by modulating synaptic transmission, often facilitating excitation. We investigated the role of Gq/G11 family G proteins in the regulation of neuronal excitability in mice that selectively lack the alpha-subunits of Gq and G11, G alpha q and G alpha 11, respectively, in forebrain principal neurons. Surprisingly, mutant mice exhibited increased seizure susceptibility, and the activation of neuroprotective mechanisms was impaired. We found that endocannabinoid levels were reduced under both basal and excitotoxic conditions and that increased susceptibility to kainic acid could be normalized by the enhancement of endocannabinoid levels with an endocannabinoid reuptake inhibitor, while the competitive cannabinoid type 1 receptor antagonist SR141716A did not cause further aggravation. These findings indicate that Gq/G11 family G proteins negatively regulate neuronal excitability in vivo and suggest that impaired endocannabinoid formation in the absence of Gq/G11 contributes to this phenotype.
Assuntos
Moduladores de Receptores de Canabinoides/biossíntese , Endocanabinoides , Epilepsia/metabolismo , Subunidades alfa Gq-G11 de Proteínas de Ligação ao GTP/metabolismo , Prosencéfalo/metabolismo , Subunidades Proteicas/metabolismo , Fatores Etários , Animais , Agonistas de Aminoácidos Excitatórios/metabolismo , Subunidades alfa Gq-G11 de Proteínas de Ligação ao GTP/genética , Ácido Caínico/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Neurônios/citologia , Neurônios/metabolismo , Técnicas de Patch-Clamp , Prosencéfalo/citologia , Subunidades Proteicas/genéticaRESUMO
Yawning is a clinical sign of the activity of various supra- and infratentorial brain regions including the putative brainstem motor pattern, hypothalamic paraventricular nucleus, probably the insula and limbic structures that are interconnected via a fiber network. This interaction can be seen in analogy to other cerebral functions arising from a network or zone such as language. Within this network, yawning fulfills its function in a stereotype, reflex-like manner; a phylogenetically old function, preserved across species barriers, with the purpose of arousal, communication, and maybe other functions including respiration. Abnormal yawning with ≥3 yawns/15min without obvious cause arises from lesions of brain areas involved in the yawning zone, its trajectories causing a disconnection syndrome, or from alteration of network activity by physical or metabolic etiologies including medication.
Assuntos
Química Encefálica/fisiologia , Lesões Encefálicas/patologia , Encéfalo/anatomia & histologia , Encéfalo/metabolismo , Vias Neurais/fisiologia , Bocejo/fisiologia , Animais , Lesões Encefálicas/fisiopatologia , Humanos , Vias Neurais/anatomia & histologia , Neurotransmissores/metabolismo , Serotonina/metabolismoRESUMO
Compared to sites in protein-coding sequences many more targets undergoing adenosine to inosine (A-to-I) RNA editing were discovered in non-coding regions of human cerebral transcripts, particularly in genetic transposable elements called retrotransposons. We review here the interaction mechanisms of RNA editing and retrotransposons and their impact on normal function and human neurological diseases. Exemplarily, A-to-I editing of retrotransposons embedded in protein-coding mRNAs can contribute to protein abundance and function via circular RNA formation, alternative splicing, and exonization or silencing of retrotransposons. Interactions leading to disease are not very well understood. We describe human diseases with involvement of the central nervous system including inborn errors of metabolism, neurodevelopmental disorders, neuroinflammatory and neurodegenerative and paroxysmal diseases, in which retrotransposons (Alu and/or L1 elements) appear to be causally involved in genetic rearrangements. Sole binding of single-stranded retrotransposon transcripts by RNA editing enzymes rather than enzymatic deamination may have a homeostatic effect on retrotransposon turnover. We also review evidence in support of the emerging pathophysiological function of A-to-I editing of retrotransposons in inflammation and its implication for different neurological diseases including amyotrophic lateral sclerosis, frontotemporal dementia, Alzheimer's and Parkinson's disease, and epilepsy.
RESUMO
Recent advances in sequencing technologies led to the identification of a plethora of different genes and several hundreds of amino acid recoding edited positions. Changes in editing rates of some of these positions were associated with diseases such as atherosclerosis, myopathy, epilepsy, major depression disorder, schizophrenia and other mental disorders as well as cancer and brain tumors. This review article summarizes our current knowledge on that front and presents glycine receptor C-to-U RNA editing as a first example of disease-associated increased RNA editing that includes assessment of disease mechanisms of the corresponding gene product in an animal model.
RESUMO
OBJECTIVE: The aim of this study was to investigate variant patterns of cortical venous oxygenation during status epilepticus (SE) using susceptibility-weighted imaging (SWI). METHODS: We analyzed magnetic resonance imaging (MRI) scans of 26 patients with clinically witnessed prolonged seizures and/or EEG-confirmed SE. All MRI exams encompassed SWI, dynamic susceptibility contrast perfusion MRI (MRI-DSC) and diffusion-weighted imaging (DWI). We aimed to identify distinct patterns of SWI signal alterations that revealed regional or global increases of cerebral blood flow (CBF) and DWI restrictions. We hypothesized that SWI-related oxygenation patterns reflect ictal or postictal patterns that resemble SE or sequelae of seizures. RESULTS: Sixteen patients were examined during nonconvulsive status epilepticus (NCSE) as confirmed by EEG, a further ten patients suffered from witnessed and prolonged seizure episode ahead of imaging without initial EEG. MRI patterns of 15 of the 26 patients revealed generalized hyperoxygenation by SWI in keeping with either global or multifocal cortical hyperperfusion. Eight patients revealed a focal hyperoxygenation pattern related to focal CBF increase and three patients showed a focal deoxygenation pattern related to focal CBF decrease. CONCLUSIONS: SWI-related hyper- and deoxygenation patterns resemble ictal and postictal CBF changes within a range from globally increased to focally decreased perfusion. In all 26 patients the SWI patterns were in keeping with ictal hyperperfusion (hyperoxygenation patterns) or postictal hypoperfusion (deoxygenation patterns) respectively. A new finding of this study is that cortical venous patterns in SWI can be not only focally, but globally attenuated. SWI may thus be considered as an alternative contrast-free MR sequence to identify perfusion changes related to ictal or postictal conditions.
Assuntos
Veias Cerebrais/diagnóstico por imagem , Circulação Cerebrovascular , Imagem de Difusão por Ressonância Magnética , Convulsões/diagnóstico , Convulsões/fisiopatologia , Estado Epiléptico/diagnóstico , Estado Epiléptico/fisiopatologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Mapeamento Encefálico/métodos , Veias Cerebrais/fisiopatologia , Criança , Pré-Escolar , Eletroencefalografia , Feminino , Humanos , Angiografia por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Adulto JovemRESUMO
Premature death from seizures afflicts gene-targeted mice expressing the Q/R site-unedited glutamate receptor subunit GluR-B(Q) of AMPA receptors in central neurons. Early seizure-related death has now been circumvented by a genetic switch that restricts GluR-B(Q) expression to forebrain principal neurons from postnatal stages onward, prominently in hippocampus and striatum and less so in cortex and amygdala. When switched on, functional receptor incorporation of GluR-B(Q) could be demonstrated by imaging evoked AMPA channel-mediated spinous Ca2+ transients in CA1 pyramidal cells. Sustained GluR-B(Q) expression in adult mice led to smaller excitatory postsynaptic responses in the CA1 region with unchanged presynaptic fiber excitability. Notably, despite the smaller excitatory response, the CA1 cells exhibited a reduced population spike threshold, which might underlie the spontaneous manifestations of epilepsy, including myocloni and generalized seizures with limbic components, observed by synchronous video monitoring and electroencephalographic recordings. No neuropathological symptoms developed when GluR-B(Q) expression was restricted to only hippocampal neurons. Our results show that seizure susceptibility is triggered by GluR-B(Q) expression also in the adult brain and that circuit hyperexcitability is not an immediate consequence of GluR-B(Q) but requires yet unknown downstream events, likely to be induced by non-Hebbian plasticity from Ca2+-permeable AMPA channels in principal neurons.
Assuntos
Epilepsia/genética , Receptores de AMPA/genética , Potenciais de Ação , Animais , Cálcio/fisiologia , Eletroencefalografia , Epilepsia/fisiopatologia , Feminino , Hipocampo/crescimento & desenvolvimento , Hipocampo/fisiopatologia , Integrases/biossíntese , Integrases/genética , Masculino , Camundongos , Camundongos Transgênicos , Neurônios/metabolismo , Neurônios/fisiologia , Fenótipo , Prosencéfalo/crescimento & desenvolvimento , Prosencéfalo/metabolismo , Células Piramidais/fisiologia , Receptores de AMPA/biossíntese , Transmissão Sináptica , TransgenesRESUMO
Abnormal yawning is an underappreciated phenomenon in patients with ischemic stroke. We aimed at identifying frequently affected core regions in the supratentorial brain of stroke patients with abnormal yawning and contributing to the anatomical network concept of yawning control. Ten patients with acute anterior circulation stroke and ≥3 yawns/15 min without obvious cause were analyzed. The NIH stroke scale (NIHSS), Glasgow Coma Scale (GCS), symptom onset, period with abnormal yawning, blood oxygen saturation, glucose, body temperature, blood pressure, heart rate, and modified Rankin scale (mRS) were assessed for all patients. MRI lesion maps were segmented on diffusion-weighted images, spatially normalized, and the extent of overlap between the different stroke patterns was determined. Correlations between the period with abnormal yawning and the apparent diffusion coefficient (ADC) in the overlapping regions, total stroke volume, NIHSS and mRS were performed. Periods in which patients presented with episodes of abnormal yawning lasted on average for 58 h. Average GCS, NIHSS, and mRS scores were 12.6, 11.6, and 3.5, respectively. Clinical parameters were within normal limits. Ischemic brain lesions overlapped in nine out of ten patients: in seven patients in the insula and in seven in the caudate nucleus. The decrease of the ADC within the lesions correlated with the period with abnormal yawing (r = -0.76, Bonferroni-corrected p = 0.02). The stroke lesion intensity of the common overlapping regions in the insula and the caudate nucleus correlates with the period with abnormal yawning. The insula might be the long sought-after brain region for serotonin-mediated yawning.
Assuntos
Núcleo Caudado/patologia , Núcleo Caudado/fisiopatologia , Córtex Cerebral/patologia , Córtex Cerebral/fisiopatologia , Acidente Vascular Cerebral/complicações , Bocejo , Idoso , Idoso de 80 Anos ou mais , Imagem de Difusão por Ressonância Magnética , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
INTRODUCTION: A marker predictive of hematoma expansion in the central nervous system could aid the selection of patients for hemostatic or surgical treatment. CASE REPORT: Here, we present a 83-year-old patient with acute spinal subdural hematoma with paraparesis progressing to paraplegia. A contrast extravasation within the intraspinal hematoma was visualized on spinal MR indicating active bleeding (spinal spot sign). A second acquisition of contrast-enhanced MR images showed progression of contrast extravasation helping to different active bleeding from spinal arteriovenous malformations/fistula. CONCLUSIONS: A "spinal spot sign" may be important for treatment decisions, notably in patients with incomplete neurological deficits at the time of imaging.