Active middle ear implants are devices aiming to transfer mechanical energy to the ossicular chain or directly to the inner ear fluids through the round or oval windows. They are an alternative to hearing aids, traditional reconstructive middle ear surgery, and bone conduction devices and are intended for people who cannot use these conventional solutions or who gain insufficient benefit from them. They are totally or partially implantable, and they comprise internal and external parts (microphone, audio processor, receiver unit, and transducer). The transducer can use piezoelectric, electromagnetic, or electromechanical energy. The main advantage of middle ear implants over conventional hearing aids is that they produce greater functional gain, with less distortion and feedback.