Simultaneous measurements of viscoelasticity and electrical conductivity are performed to study the dynamic characteristics of structures formed in a highly concentrated electrorheological suspension under a de electric field of 1.8 kV/mm. Small amplitude oscillatory shear measurements reveal that there is no direct correlation between the elastic modulus and the electrical conductivity of the suspension. A significant increase in conductivity is observed following large amplitude oscillatory shear and, in this case, the linear elastic modulus is also substantially enhanced. These observations are interpreted according to the concept of contact disorder arising from the anisotropic shape of the particulate phase.