Epilepsia
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Magnetoencephalography (MEG)-also known as magnetic source imaging when combined with magnetic resonance imaging-has developed to the point that it has now entered routine clinical application. Epilepsy MEG studies show that it can accurately localize spike sources--both ictal and interictal--as compared to both direct (intracranial EEG) and indirect (imaging abnormalities) measures. ⋯ Magnetoencephalography not only provides a novel tool to localize and characterize epileptiform disturbances, it also has an important role in determining the significance of abnormalities seen on both structural and functional imaging. Combined with mapping of normal or eloquent brain function, MEG should ultimately play a major role in the totally noninvasive epilepsy surgery evaluation.
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The surgical outcomes of patients suffering from neocortical epilepsy are not as successful as the surgical outcomes from resections of epilepsy patients with mesial temporal sclerosis. The main difficulty in the treatment of neocortical epilepsy is that current technology has limited accuracy in mapping neocortical epileptogenic tissue. It is known that the optical spectroscopic properties of brain tissue are correlated with changes in neuronal activity. ⋯ Both spontaneous and stimulation-evoked epileptiform activity was monitored. Imaging of intrinsic optical signals was able to localize neocortical epileptic foci precisely by using changes in blood volume in contrast to changes in blood oxygenation. IIOS has the potential to translate from a purely research tool to a new intraoperative approach for the surgical treatment of neocortical epilepsy.
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Tuberous sclerosis complex (TSC) is associated with medically refractory seizures and developmental delay in children. These epilepsies are often resistant to antiepileptic drugs (AEDs), may be quite severe, and usually have a negative impact on the child's neurological and cognitive development. It is believed that functional outcome is improved if seizures can be controlled at an early age. ⋯ Multiple or bilateral seizure foci are not necessarily a contraindication to surgery in selected TSC patients. Long-term follow-up will determine whether this approach has durable effects. We await better methods for identifying the epileptogenic zone, both noninvasive and invasive.
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Long-term outcome of nonsurgical candidates with medically refractory localization-related epilepsy.
Epilepsy surgery can result in complete seizure remission rates of upto 80% in patients with mesial temporal sclerosis and unilateral seizures. The seizure-free rate after surgery for patients with extratemporal nonlesional epilepsy has ranged between 30% and 40%. Some patients with medically refractory localization-related epilepsy cannot be offered surgical resection because of inadequate localization of the epileptogenic zone, documentation of bilateral ictal onsets, or functionally important areas of cortex that prohibit resection. The short-term rate of complete remission with medications in temporal lobe epilepsy is poor. Less is known about remission rates in patients who are not surgical candidates. In this study, we evaluated the outcome of medical treatment in patients with medically refractory partial epilepsy who were evaluated for possible epilepsy surgery but deemed to be inadequate surgical candidates. ⋯ A surprisingly large number of patients we surveyed, with refractory partial epilepsy not eligible for surgical management, reported reduced seizure frequency at follow-up, and 21% were seizure free. Our findings suggest that the long-term prognosis in patients with refractory partial epilepsy who are not surgical candidates may be more positive than might be generally expected.
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To investigate neuronal dysfunction in the thalami of patients with juvenile myoclonic epilepsy (JME) by using proton magnetic resonance spectroscopy (MRS). ⋯ This study shows evidence of neuronal dysfunction in the thalami of patients with JME, which may have relevance for the mechanisms of seizure generation in this form of generalized epilepsy.