Fully-implantable auditory prostheses: restoring hearing to the profoundly deaf

Present cochlear prostheses employ up to 24 electrodes to electrically stimulate the auditory nerve with currents of 200-800 /spl mu/A, charge-balanced pulse rates of 100 Kpps or more, and pulse widths of 20-200 /spl mu/sec/phase. To explore performance limits, MEMS-based microsystems will soon provide as many as 128 electrode sites and up to 16 parallel data channels. Fully-implantable microsystems for the cochlear nucleus are also being developed using 3D arrays of penetrating electrodes. Button-size implant prototypes with 1024 multiplexed electrode sites on 400 /spl mu/m centers have been realized. Packaging techniques are consistent with many decades of use in-vivo, while wireless interfaces can provide data at over 1 Mb/s in addition to power. These implantable microsystems will restore hearing to an expanding population of individuals during the coming decade as well as serve as a generic platform for dealing with a number of other disorders.