Epilepsy research
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Diffusion tensor tractography of the anterior extent of the optic radiation - Meyer's loop - prior to temporal lobe resection (TLR) may reduce the risk for postoperative visual field defect. Currently there is no standardized way to perform tractography. ⋯ Choice of tractography method affected the visualized location of Meyer's loop significantly in a heterogeneous, clinically relevant study group. For the controls, PTG at probability levels ≤1% was a closer match to dissection studies. To determine the anterior extent of Meyer's loop, PTG is superior to DTG and the probability level of PTG matters.
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The present study was aimed to investigate the effects of repetitive transcranial magnetic stimulation (rTMS) on kindling-induced synaptic potentiation and to study the effect of frequency and coil shape on rTMS effectiveness. Seizures were induced in rats by perforant path stimulation in a rapid kindling manner (12 stimulations/day). rTMS was applied at different frequencies (0.5, 1 and 2 Hz), using either figure-8 shaped or circular coils at different times (during or before kindling stimulations). rTMS had antiepileptogenic effect at all frequencies and imposed inhibitory effects on enhancement of population excitatory postsynaptic potential slope and population spike amplitude when applied during kindling acquisition. Furthermore, it prevented the kindling-induced changes in paired pulse indices. ⋯ In addition, the results showed that pretreatment of animals by both coils had similar preventing effect on kindling acquisition as well as kindling-induced synaptic potentiation. Obtained results demonstrated that the antiepileptogenic effect of low frequency rTMS is accompanied with the preventing of the kindling induced potentiation. This effect is dependent on rTMS frequency and slightly on coil-type.
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Comorbid conditions may affect the quality of life in persons with epilepsy (PWE) more than seizures. Using legally mandated healthcare encounter data, somatic, psychiatric, and neurodevelopmental comorbidities in a large population-based cohort of PWE, were compared to persons with migraine (PWM), a similar neurologic condition, and lower extremity fracture (PWLF), otherwise healthy controls. 64,188 PWE, 121,990 PWM, and 89,808 PWLF were identified from inpatient, outpatient, and emergency department from 2000 to 2011. Epilepsy was ascertained with ICD-9-CM code 345; migraine with 346; fracture of the tibia, fibula, and ankle with 823 and 824. ⋯ The absolute risk increase in PWE compared with PWM for any somatic or psychiatric/neurodevelopmental comorbidity was 58.8% and 94.3%, respectively. Identifying comorbidities that are strongly and consistently associated with seizures, particularly disorders with shared underlying pathophysiology, is critical in identifying specific research and practice goals that may ultimately improve the quality of life for PWE. This study contributes to that effort by providing population-based comorbidity data for PWE compared with PWM and PWLF.
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MRI is routinely used in patients undergoing intracerebral electroencephalography (icEEG) in order to precisely locate the position of intracerebral electrodes. In contrast, fMRI has been considered unsafe due to suspected greater risk of radiofrequency-induced (RF) tissue heating at the vicinity of intracerebral electrodes. We determined the possible temperature change at the tip of such electrodes during fMRI sessions in phantom and animals. ⋯ Variation of the temperature depends on the electrode and wire position relative to the transmit body coil and orientation of the constant magnetic field (B0). EPI sequence with intracerebral electrodes appears as safe as standard T1 and T2 sequence for implanted electrodes placed perpendicular to the z-axis of the magnetic bore, using a 1.5T MRI system, with the free-end wires moving posteriorly, in phantom and animals.
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The structural connection patterns of the human brain are the underlying bases for functional connectivity. Although abnormal functional connectivity has been uncovered in childhood absence epilepsy (CAE) in previous electroencephalography and functional magnetic resonance imaging studies, little is known regarding the structural connectivity in CAE. We hypothesized that the structural connectivity would be disrupted in response to the decreased brain function in CAE. ⋯ The present study demonstrated, for the first time, the disrupted topological organization of WM networks in CAE. The decreased connectivity and efficiency in the orbitofrontal and sub-cortical regions may serve as anatomical evidence to support the functional abnormalities related to the epileptic discharges observed in CAE. Moreover, the orbitofrontal sub-network may play a key role in CAE. These findings open up new avenues toward the understanding of absence epilepsy.