Disclosed herein are medical prostheses including a cochlear implant that includes circuitry enclosed within a housing and at least one electrode lead extending from the housing. The electrode lead comprises a conducting pathway and an electrode terminal at one end of the electrode lead. The conducting pathway connects the circuitry with the electrode terminal, and insulation (or an insulating sleeve) encloses at least a portion of the conducting pathway. In some embodiments, the electrode terminal has a lower thermal conductivity relative to the implant housing. In further embodiments, the insulation has thermal conductivity and thermal conduction properties that cause at least some thermal energy in the conducting pathway to flow into the insulation rather than to the electrode terminal. In still further embodiments, at least one of the electrode terminal or the electrode lead includes at least one thermal mass enhancing structure.
