A microsystem with varying-length electrode arrays for auditory nerve prostheses.

Area of Science:

• Biomedical Engineering
• Neuroscience
• Electrical Engineering

Background:

• Auditory nerve prostheses aim to restore hearing by stimulating remaining auditory nerve fibers.
• Current prostheses face challenges in accessing diverse nerve fascicles for broad tonotopic stimulation.
• Efficient, low-power electronics are crucial for implantable neural devices.

Purpose of the Study:

• To design, fabricate, and simulate a novel micromachined electrode array with varying lengths for auditory nerve prostheses.
• To develop and test a multichannel, ultra-low power integrated circuit for neural signal recording.
• To improve the potential for broad tonotopic stimulation within the auditory nerve.

Main Methods:

• Fabrication of a 10x10 electrode array on silicon using bulk micromachining technology.
• Varying electrode lengths from 200 to 400 micrometers to target different nerve fascicles.
• Design and fabrication of a multichannel ultra-low power circuit using 0.5 microm AMI CMOS technology.

Main Results:

• Successful design and simulation of a novel micromachined electrode array with variable lengths.
• Fabrication of a 1mm² electrode array on silicon.
• Development of a 1.5mm x 1.5mm integrated circuit with total power consumption under 100 microwatts.

Conclusions:

• The novel electrode array design offers potential for accessing most auditory nerve fascicles.
• This design facilitates stimulation across a broad tonotopic range within the nerve fiber.
• The developed ultra-low power circuit is suitable for neural signal recording in implantable devices.