Cochlear implants: what can be achieved?

Cochlear implants in children are effective in terms of speech perception and production. Onset of deafness, date of implantation, and duration of deafness are important prognostic factors for long-term results. Sophisticated intraoperative and postoperative device control measurements enable detection of partial or total device failure and calculation of the reliability of the implant. However, the present technological status is far from an optimal device. Future developments will include improvements of both electrode design and speech processing. The number and separation of channels will be increased, and the pattern of stimulation will approach the natural excitation pattern of the auditory nerve. Behind-the-ear implants or totally implantable devices will further increase the acceptance and reliability of this technology. The implant systems will become more versatile and adaptable to the physiological conditions of the individual patient. Apart from these technological improvements, rehabilitation and proper selection of patients will still play a major role in successful implantation in children. Outcome studies are necessary to calculate the cost-benefit ratio and justify a further extension of implantation. We are still on the way toward the artificial ear.