A tissue-like optically turbid and electrically conducting phantom for simultaneous EEG and near-infrared imaging

We describe a phantom for simultaneous electroencephalography (EEG) and near-infrared imaging which consists of a solid, optically turbid and electrically conducting interface enclosing a tissue-mimicking aqueous scattering solution. The interface provides an electrical contact impedance comparable to that of the human scalp while the phantom as a whole has optical properties and electrical conductivity equivalent to that of head tissue. The construction is described and our design is evaluated experimentally using an optically absorbing target which also provides an EEG-equivalent electric field source. The results of this simultaneous EEG and near-infrared imaging experiment are presented.