A Thin-Film Cochlear Electrode Array With Integrated Position Sensing

Abstract

A thin-film electrode array with integrated position sensors has been developed for a cochlear prosthesis. The array is designed to minimize tissue damage during array insertion and achieve deep implants that hug the modiolus inside the cochlea. The array is fabricated using bulk micromachining technology and contains embedded polysilicon piezoresistive sensors for wallcontact detection and array-shape recognition. Nine strain gauges are distributed at the tip and along the array, covering the 8-mmlong shank. Each sensor is arranged in a half Wheatstone bridge whose output signal is time multiplexed, amplified (10 or 30 times), and band limited. The equivalent gauge factors are typically about 15, permitting array-tip position to be determined within a 50-μm resolution while providing wall-contact output signals of more than 50 mV at the tip. The arrays use a parylene-silicondielectric-electrode structure, improving flexibility while maintaining enough robustness to facilitate a modiolus-hugging shape defined by a polymeric backing device. Integrated with an articulated position-control device, such arrays are the first step toward providing closed-loop control of array insertion and improved perception of speech and music.[2007-0222]

Towards inferring positioning of straight cochlear‐implant electrode arrays during insertion using real‐time impedance sensing

“…For example, imaging feedback tools for analysis of CI placement include postoperative CT, 6 preoperative Magnetic Resonance Imaging to determine candidacy, 7 and real‐time fluoroscopy during surgery, 8 but these techniques are burdened by cost, patient radiation exposure, and/or lack of true real‐time visualisation 9 . Custom EAs have also been designed that incorporate strain gauges, 10 scanning electrochemical microscopy, 11 a fibre‐optic imaging probe, 12 or an electromagnetic sensor 13 for position sensing. Polymer optical fibre Bragg gratings have also recently been integrated into an experimental EA to detect forces and insertion trajectories 14 .…”

Robot-assisted three-dimensional registration for cochlear implant surgery using a common-path swept-source optical coherence tomography probe

“…14 Recent research into cochlear implant surgery assistance has ranged from developing novel piezoresistive-sensing electrodes to patient-customized drill guides. 15,16 In this work, we focus on a three-dimensional (3-D) optical coherence tomography (OCT) image registration to navigate scala tympani anatomy and plan the surgical procedure. OCT is an ideal modality for this aim as it uses biologically safe infrared light and is capable of producing high-resolution 3-D images of biological tissue.…”

Scanning Electrochemical Microscopy as a Novel Proximity Sensor for Atraumatic Cochlear Implant Insertion

“…Currently, CI designers aim at optimizing the mechanical properties of CIs for atraumatic insertion to be as easy as possible for surgeons [10]. Second, the narrowly coiled ST space imposes a strict constraint on the design of CIs when the engineers and researchers keep improving the mechanical properties and, more dramatically, try to invent intelligent and active CIs with the incorporation of actuators or sensors [11]–[13]. A high-resolution sensor with miniaturization capability can be a breakthrough toward the complete atraumatic insertion of CIs.…”