Aim: To determine whether bimodal listening with a hearing aid programmed using a dedicated bimodal fitting formula, which aligns the frequency response, loudness growth functions, and automatic gain control (AGC) characteristics between the cochlear implant speech processor and the hearing aid brings additional benefit over bimodal listening with the subject's clinical hearing instrument via the use of using a comprehensive battery of speech perception tests aimed at different aspects of binaural hearing as well as the contribution of the unique bimodal complementary effect. A secondary goal is to identify the tests that are best suited to predicting and evaluating bimodal benefit.