The Influence of Electrode Size on EEG Lead Field Sensitivity Distributions

We examined the effect of electrode contact size on EEG measurement sensitivity distributions. We used concentric spheres and realistic head models to evaluate electrode diameters of 1 mm, 5 mm, 10 mm and 15 mm. We used the half sensitivity volume (HSV) to evaluate the results. The spherical model results show that the farther the electrode pairs are spaced (i.e. lower resolution EEG) the more the cortical sensitivity distributions are affected by the electrode contact area; however, the realistic models indicate that the cerebrospinal fluid (CSF) thickness overshadows the influence of electrode contact size.