The overall aim of this project is to develop a commercial device for acquiring electrically evoked auditory brainstem responses (eeABR) using direct promontory stimulation for the assessment of 8th nerve function for the determination of cochlear implantation candidacy. The proposed device will be compact and portable using an innovative amplifier hardware design to overcome the limitations of currently available evoked potential systems. New stimulation and data processing strategies will be developed in order to facilitate the extraction of eeABRs. As of 2019, more than 736,900 patients have received cochlear implants (CI) worldwide. It is important to assess the functional status of the cochlea and 8th nerve prior to implant surgery. There is currently no commercially available device for this purpose. As such, in difficult to assess cases, physicians have had to use standard evoked potential systems with prototype or rudimentary electrical stimulation units in order to make the necessary assessments of implantation candidacy. These pieced together configurations are most often fraught with noise problems and/or shortcomings. The present proposal will develop an effective eeABR testing device using bio-amplifiers with hardware blanking and fast recovery circuitry, integrated electrical stimulation circuitry, innovative stimulation techniques, and associated shielded disposable stimulation and recording electrodes. During Phase I, the effectiveness of the proposed device will be tested via animal experiments.