Post-Market Clinical Investigation of the IotaSOFT Insertion System

Inclusion Criteria: 1. Candidates with sensorineural hearing loss who received or will receive unilateral or bilateral cochlear implantation according to indications for use with FDA approved cochlear implant devices, as listed below: 1. Advanced Bionics HiFocus SlimJ 2. Cochlear Slim Straight 3. MED-EL Flex 24 and 28 2. Age 12 years or older at the time of CI surgery. 3. Willingness to participate in the study and able to comply with the follow-up visit requirements. Exclusion Criteria: 1. Prior cochlear implantation in the ear to be implanted. 2. Ossification or any other cochlear anomaly that might prevent complete insertion of the electrode array or present an increased risk of aberrant insertion. 3. Craniofacial abnormality, temporal squamosal skull thickness less than 3mm, major cochlear lesions (e.g., fibrosis, fracture, or ossification), or cochlear malformations. 4. Deafness due to lesions of the acoustic nerve or central auditory pathway. 5. Diagnosis of auditory neuropathy. 6. Active middle-ear infection or tympanic membrane perforation in the presence of active middle ear disease. 7. Absence of cochlear development. 8. Additional medical concerns that would prevent participation in evaluations as determined by the investigator. 9. Unrealistic expectations on the part of the subject, regarding the possible benefits, risks, and limitations that are inherent to the procedure and investigational device. 10. Non-native English speakers who are unable to read, understand and/or speak English for completion of required procedures 11. Planned or current participation in a clinical study of an investigational device or drug. 12. Must not fit the definition of a vulnerable subjects, as per FDA regulations 21 CFR Parts 50 and 56