Inclusion Criteria:  For individuals ages 18 years-old and above, limited benefit from unilateral amplification is defined by test scores of 5% correct or less on monosyllabic consonant-nucleus-consonant (CNC) words in quiet when tested in the ear to be implanted alone. Before implantation with a cochlear implant, individuals with SSD or AHL must have at least 1-month experience wearing a Contra Lateral Routing of Signal (CROS) hearing aid or other relevant device and not show any subjective benefit. Medical and surgical clearance for cochlear implantation.  Exclusion Criteria:  Not meeting FDA candidacy criteria for cochlear implantation in SSD Inability to perform audiologic tasks (e.g. non-English speaking) Medical or surgical contraindication to general anesthesia or cochlear implant surgery Does not wish to participate