History of the Cochlear Implant

Dr. Gantz maintains that there need not be a sense of urgency to implant children prior to the age of eight months, the age when a behavioral audiogram can be performed. Based on 25 years of longitudinal follow-up on children receiving CIs at his institution, he has found that at age 7 years, children who had received implants between the ages of 2 and 4 years did not show significantly different reading, language and speech perception from those who received the implants between 11 months and 2 years of age.” If you implant an infant who might have some low frequency residual hearing, you are destroying it, and that could be very useful to preserve,” he said. “The residual low frequency acoustic hearing might assist the individual to hear better in noisy environments and to appreciate music in the future.”

Adrien A. Eshraghi, MD, associate professor and chief at Jackson Memorial Otology and Neurotology Clinics and director of the University of Miami Hearing Research Laboratory, department of otolaryngology, University of Miami Miller School of Medicine, and colleagues established that the implantation procedure itself can induce apoptosis, thus impeding reestablishment of residual hearing in damaged cochlear structures. Although manufacturers have worked to make coils that are less traumatic, Dr. Eshraghi pointed out that insertion of the CI electrode into the cochlea stimulates the production of inflammatory cytokines and oxidative stress, resulting in irreversible damage. His laboratory, in collaboration with microbiologist Thomas R. van de Water, PhD, professor and director of the Cochlear Implant Research Program at the University of Miami, is now working to better understand apoptosis post-implantation and to develop drug delivery strategies to prevent the problem. By reducing implantation trauma, he said, “you may be able to use electric acoustic stimulation with a hybrid device, or possibly even use the patient’s residual hearing.”