A Study to Evaluate Clinical Benefit, Performance and Safety of Cochlear Implants in Adults

Inclusion criteria: * Aged 18 years or older (at time of consent). * Clinically established post-linguistic moderately severe to profound sensorineural hearing loss, in the ear to be implanted. * Compromised functional hearing with hearing aid(s) or unlikely to receive benefit with hearing aid(s) in the ear to be implanted. * Cochlear implant candidate as determined by the Principal Investigator. Meets local candidacy criteria for cochlear implantation. * Candidate is a fluent speaker in the language used to assess speech perception performance. * Willing and able to comply with study follow-up schedule. * Willing and able to provide written informed consent. * Candidate has access to a Smartphone compatible with Nucleus Smart App. Exclusion criteria: * Prior cochlear implantation in the ear to be implanted. * Unrealistic expectations regarding the possible benefit, risks and limitations that are inherent to the surgical procedure and prosthetic device as determined by the investigator. * Any contraindications for cochlear implantation listed in the relevant product physician's guide (to be specified per sub-investigation). * Unable or unwilling to comply with the requirements of the clinical investigation as determined by the Investigator. * 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 this investigation. * Women who are pregnant. * Current participation, or participation in an 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).