A Pivotal Study to Evaluate the Clinical Benefit, Performance and Safety of a Totally Implantable Cochlear Implant (TICI) System in Adults

Inclusion Criteria: * Individuals aged 18 years and older at time of consent. * Clinically established sensorineural hearing loss (SNHL) defined by a four frequency (500, 1000, 2000, 4000 Hz) pure-tone average unaided threshold (PTA4) of ≥70 dB HL in the ear to be implanted. * Compromised functional hearing in the aided condition defined as ≤40% correct on a word recognition test in the ear to be implanted. * Clinically established SNHL defined by a four-frequency (500, 1000, 2000 \& 4000 Hz) pure-tone average unaided threshold (PTA4) of ≥30 dB HL in the contralateral ear. * Candidate is a fluent speaker in the language used to assess speech perception performance as determined by the investigator. * Direct access to a compatible Smart Phone. * Willing and able to provide written informed consent. Exclusion Criteria: * Prior cochlear implantation, in either ear, or medical plan for cochlear implantation during the clinical investigation, contralateral to the ear to be implanted. * Candidates with single-sided deafness as determined by the investigator. * Intra-axial (within-the-brain) lesions or deafness due to lesions of the acoustic nerve affecting the ear to be implanted. * Middle ear infection (including acute otitis media, chronic otitis media, suppurative otitis media, or serous drainage) in the ear to be implanted either at the time of surgery or within 3 months prior to enrolment. * Presence of a tympanic membrane perforation or a history of otologic surgery within 3 months prior to enrolment, in the ear to be implanted. * Previously reported diagnosis of auditory neuropathy, in the ear to be implanted. * Ossification, malformation or any other cochlear anomaly, such as common cavity, that might prevent complete insertion of the electrode array, in the ear to be implanted. * Current cerebrospinal fluid (CSF) shunts or drains, existing perilymph fistula, skull fracture or CSF leaks. * Severe, or poorer, bilateral sensorineural hearing loss prior to 5 years of age, as reported by the participant. * Severe, or poorer, sensorineural hearing loss for more than 20 years, as reported by the participant, in the ear to be implanted. * Medical or psychological conditions that contraindicate general anaesthesia, surgery, or participation in the clinical investigation as determined by the investigator. * Pre-existing skin condition that could jeopardize wound healing as judged by the investigator e.g., psoriasis, dermatitis, use of corticosteroids, uncontrolled diabetes. * Unrealistic expectations on the part of the participant, regarding the possible benefits, risks, and limitations inherent to the surgical procedure(s) and prosthetic devices, as determined by the Investigator. * Additional disabilities that may affect the participant's participation or safety during the clinical investigation. * Unable or unwilling to comply with all requirements of the clinical investigation, as determined by the investigator. * Pregnant or breastfeeding women. * Investigator site personnel directly affiliated with this study and/or their immediate families. Immediate family is defined as spouse, parent, child or sibling. * Cochlear employees or employees of Contract Research Organisations or contractors engaged by Cochlear for the purposes of the investigation. * Current participation, or participation in another interventional clinical study/trial in the past 30 days, involving an investigational drug or device (unless Cochlear sponsored and determined by Investigator or Sponsor to not impact this investigation).