Physiological and clinical aspects of the rehabilitation of total deafness by implantation of multiple intracochlear electrodes.

Many instances of total deafness are due to destruction of the organ of Corti, contrasting with the partial or complete preservation of the function of the cochlear nerve. In such cases, it is possible to restore some hearing by stimulating electrically the fibres of the cochlear nerve with the help of implanted electrodes. By means of several fenestrations, it is possible to construct electrically insulated compartments in the scala tympani of the cochlea, and to implant eight electrodes. This procedure allows discrimination of sound frequencies because the electrical stimulation of each electrode gives a sound sensation which depends on the electrode stimulated. This enabled us to elaborate a map of frequencies of the human cochlea and to make some physiological observations and achieve clinical results in seven cases of total bilateral deafness.