When the incisions from the procedure are fully healed, usually within two to three weeks, the implant device can be switched on and programmed (a process called mapping) to optimise the patient’s hearing outcome. Although useful sound and speech perception often occurs at the time of switching on the device, it usually takes many months to reach the best possible hearing outcomes. Persistence with the rehabilitation program is required.
Many factors determine the hearing outcomes of cochlear implantation. These include the following:
- the nature of the hearing loss – including age of onset (pre- or postlingual), duration of deafness and degree of residual hearing
- patient factors – including age, level of cognition and auditory stimulation and persistence with the rehabilitation program
- the experience of the cochlear implantation team – including completeness of electrode insertion, type of implant and persistence with the rehabilitation program.
Well-selected candidates with reasonable expectations of what is involved in the cochlear implantation process can achieve highly satisfying outcomes, including benefits to auditory communication within their work and social environments. Previously employed and socially active adults often return to their usual work and social roles. Elderly patients and their families report a reduced sense of social isolation and the ability to continue living independently and safely as a result of the cochlear implant. Many patients can return to fluent listening over the phone and some to music appreciation. Quality of life, mood and sense of vitality and energy can also be enhanced following cochlear implantation. In general terms, people with well-performing cochlear implants can hear in quiet environments as effectively as matched patients with aided moderate hearing losses.3
Limitations to cochlear implantation are important for patients to understand and accept before embarking on surgery. Although outcomes are clustered at the higher range of the hearing spectrum, some patients derive only modest benefit with perception of environmental sounds and very limited speech understanding. Occasionally, such patients become nonusers of their implant.