Multi-center Study to Examine Changes to the Environment Surrounding the Electrodes in the Cochlea and to Capture the Most Challenging Listening Environments Experienced by Persons With a Cochlear Implant

Inclusion Criteria: * Aged 18 years or older (no upper age limit). * Implanted with CIC4-based implant with a Contour Advance, Slim Straight or Slim Modiolar electrode array with at least 6 months experience. * Candidate is a fluent speaker in the language used to assess speech perception performance, as determined by the investigator. * Willing and able to provide written informed consent. Exclusion Criteria: * Score below 3 on the screening subset of questions from the Mobile Device Proficiency Questionnaire (digital literacy check). * A failed ECE1 or ECE2 (i.e. flagged, open circuit or short circuit) * Additional health factors, known to the investigator, that would prevent or restrict participation in the evaluations, including significant visual impairment and/or dexterity issues. * 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 a spouse, parent, child, or sibling. * Cochlear employees or employees of Contract Research Organisations or contractors engaged by Cochlear for the purposes of this investigation. * Current participation, or participation in another interventional clinical study/trial in the past 30 days, involving an investigational drug or device (unless the other investigation was/is a Cochlear sponsored investigation and determined by the investigator or Sponsor to not impact this investigation)