Medical devices include stimulation and/or sensing circuitry that is interconnected to electrical components by a flexible circuit body having exposed portions of circuit traces that are attached to electrical contacts of the electrical components. Each circuit trace may span a separate window formed in an insulative body of the flexible circuit body, or a plurality of circuit traces may span a single window or may be freely extending from the insulative body. The exposed portion of the circuit trace may be plated with a conductive metal and then attached to the electrical contact of the electrical component. The flexible circuit body may be an extension from a flexible electrical circuit board containing the circuit. The circuit may be present on a circuit board that includes electrical contacts and where the flexible circuit body has exposed portions of circuit traces attached to the electrical contacts of the circuit board.