The purpose of the proposed study is to evaluate the continued safety of the iotaSOFT Insertion System when used by a surgeon to assist with inserting a CI electrode array in one ear per subject

available iotaSOFT Insertion System when used per intended use for insertion of a cochlear implant electrode array in subjects 12 years and older. The purpose of the study is to collect additional safety data in retrospective and prospective subjects. The primary object of the study is to demonstrate post-market safe use of the commercially available iotaSOFT Insertion System. The secondary objective of the study is to define procedural characteristics including device deficiencies, electrode array insertion speed, rate of tip fold-over, and objective measures of cochlear implant functionality to demonstrate effective use of the commercially available 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

A minimum of 50 subjects with sensorineural hearing loss and who have received a cochlear implant using the commercially available iotaSOFT insertion system or are scheduled for unilateral or bilateral cochlear implant surgery will be enrolled, such that a minimum of 50 subjects/ears using iotaSOFT will be attempted

Cohort data will be provided for analysis for publication and presentation and individual data points will be pulled for reporting requirements only. Primary and secondary endpoint data will be exported and analyzed for required reporting.