A sensor may include a substrate having a sensing portion defining a sensor thereon and a circuit mounting portion defining at least one electrically conductive pad that is electrically connected to the sensor. The sensor may be configured to produce a signal indicative of a condition of the patient. An anisotropic medium may be disposed on the circuit mounting portion and may be electrically conductive in a direction through the medium and electrically insulating in directions along the medium. An electrical circuit may be mechanically mounted to the circuit mounting portion of the first substrate via the anisotropic medium with at least one electrically conductive terminal juxtaposed over the at least one electrically conductive pad. The anisotropic medium may establish local electrical contact between the at least one electrically conductive terminal and the at least one electrically conductive pad.