A cochlear electrode array with built-in position sensing

A modiolus-hugging thin-film electrode array is being developed for a cochlear prosthesis. The array contains embedded sensors for position and wall contact in order to minimize tissue damage during array insertion. The piezo-resistive polysilicon position sensors have gauge factors of typically 15, permitting array position to be determined to less than 50/spl mu/m and providing wall contact output signals of more than 50mV. The thin-film array substrate was designed to realize devices that hug the modiolus wall in order to minimize stimulation thresholds. The array substrate is pneumatically actuated to maximize insertion depth and perceived frequency range.