Current Outcomes and Future Perspectives of Cochlear Implants

Cochlear implants (CI) are semi-implantable devices for the rehabilitation of profound deafness due to loss of sensory hair cells in the cochlea. They have enabled more than 60,000 deaf people with no benefit from traditional acoustic amplification to restore a functional hearing. Although individual performance is variable, most adults with postverbal onset of deafness can talk on the phone in a quiet environment. Children born deaf who receive a CI before the age of two years can develop normal language perception and production, and the majority can attend the mainstream schools. Technological advances and positive outcomes have expanded the CI candidacy. Current areas of clinical research are: 1) the sparing of residual hearing in the low frequencies in order to allow the combined use of an hearing aid; 2) the use of perimodiolar electrodes which minimize the spread of neural excitation and the battery consumption; 3) new hardware, such as the behind-the-ear speech processors, and more flexible speech processing strategies; 4) binaural implantation, for stereophonic sound processing. The present paper reviews expected performances in different categories of subjects undergoing cochlear implantation. Future developments such as the totally implantable device and the delivery of pharmacologic agents to the inner ear via an adjunctive channel are discussed.