Abstracts

Rationale: The dura, which covers the cortical surface, is less conductive than cerebrospinal fluid (CSF) and brain tissue. As a result, the dura restricts the flow of volume of electrical currents originating from brain tissue and traversing the skull and scalp layers. Thus, although scalp EEGs must be severely influenced by the dura layer, this effect has not been previously quantified. The purpose of this project is to examine the effect of dura on simulated scalp EEG. Methods: We examined the effect of dura with a detailed finite element model of the human head constructed from segmented MR images. The model included 20 different tissue-types, including, CSF, gray and white matter, dura layer, soft and hard skull bone, scalp, muscle, etc. The model resolution was 1x1x1 mm and extended from top of the head to the upper cervical region. The electrical activity was simulated with random dipole distributions in the cortex having a uniform intensity distribution in the range of 0.0 to 0.1 mA. Scalp EEGs were simulated for two head models with an adaptive finite element solver. One model had the dura layer and in the other model, the dura layer was replaced with the CSF. Results: Spatial contour plots of the scalp potentials over the cranium were constructed. We was found that the inclusion of dura layer reduced the scalp potentials by about 33% as compared to not including dura layer in the model. Conclusions: For accurate simulation of scalp EEG, the dura layer along with skull bone, should be included in the model