A high-density electrode array for a cochlear prosthesis

This paper reports a high-density cochlear electrode array integrated with an articulated backing device. Fabricated on a silicon substrate, the device offers stimulating sites on a pitch of 250 /spl mu/m. The backing device is designed to facilitate a deeper cochlear insertion and position the sites closer to the targeted neural receptors. The device is the first step towards a high-density 128-site array integrated with closed-loop position-sensing and control. Monopolar and bipolar auditory thresholds in guinea pigs are 50 /spl mu/A and 300 /spl mu/A, respectively, with tissue compliance voltages at 500 /spl mu/A of /spl sim/1.0V. A 32-site four-channel active array designed as the forerunner of the 128-site array is also described.