You are on the right track! Cochlear implants are currently approved for persons with bilateral severe to profound hearing loss. To date, there are very limited case reports from independent studies with the implantation of persons with unilateral deafness or a mild to moderately severe hearing loss opposite an ear that qualified for a cochlear implant. Given that the two forms of sound stimulation are very different as you indicate, further research is needed to investigate the feasibility of any clinical application for cochlear implants in persons with unilateral deafness. The current candidacy criteria as approved by the FDA does indicate bilateral severe or greater hearing loss.