Simple, cost-effective technique for portable digital eletrocorticography

Abstract

-We revised 16 patients submitted to epilepsy surgery using a new method of digital, real-time, portable electrocorticography. Patients were operated upon over a period of 28 months. There were no complications. The exam was useful in 13 cases. The low installation and operational costs, the reliability and simplicity of the method, indicate it may be useful for defining the epileptogenic regions in a variety of circumnstances, including surgery for tumors, vascular malformations, and other cortical lesions associated with seizure disorders.KEY WORDS: epilepsy, epilepsy surgery, EEG, EcoG.Eletrocorticografia digital portátil: uma técnica simples e de boa relação custo versus benefício RESUMO -Revisamos 16 pacientes submetidos a cirurgia de epilepsia utilizando um novo método de eletrocorticografia digital, portátil, em tempo real. Os pacientes foram operados num período de 28 meses. Não ocorreram complicações. A eletrocorticografia digital foi útil em 13 casos. O baixo custo de instalação e operação, a confiabilidade e simplicidade do método indicam que ele pode ser útil para definir as regiões epileptogênicas em uma variedade de circunstâncias, inclusive cirurgias de tumores, malformações vasculares, e outras lesões corticais.PALAVRAS-CHAVE: epilepsia, cirurgia de epilepsia, EEG, ECoG.The indications of invasive EEG techniques have decreased with the rapid progress observed in the field of epilepsy surgery over the past decade 1 . Most centers now carry out invasive EEG techniques in less than 50% of the cases. The majority of patients may nowadays have their epileptogenic regions identified by non-invasive investigation, including videomonitoring of seizures, magnetic resonance imaging, single-photon emmission computerized tomography, and neuropsychological investigation 1 . In the same period a number of different invasive techniques have been developed, including the placement of grids and strips of electrodes in the subdural space 2,3 . These refinements have been added to the standard electrocorticography (EcoG) 4,5 and intracerebral depth electrodes (6), developed many decades ago. In all these techniques the patients need to be connected to large, complex electrical and digital equipment, with consequent requirements of electrical safety and constraints on the quality of the recordings made. These requirements are more stringent than usual in the case of ECoG given the fact that recordings are being made on the brain surface or very close to it 7 .Invasive EEG may be subdivided in surgical and extra-surgical. The former includes ECoG and depth electrodes. The latter includes subdural and depth electrodes. Surgical invasive EEG, traditionally, has been carried out in dedicated rooms, where a glass wall separates the actual surgical