Cochlear Electrode Arrays: Past, Present and Future

Abstract

Cochlear implants are very successful devices: more than 60000 people use them throughout the world. Key to the success of these prostheses is the development of electrode arrays that place contacts close to the target neurons, survive for decades in the tissues of the inner ear, and that provide reliable and repeatable excitation to the cells of the auditory nerve. This article describes the early electrode arrays and their development into the arrays that are used presently in clinical cochlear prostheses. While integrated circuit techniques were proposed and tested in the laboratory two decades ago, the present clinical devices still are hand built and made of wire-based technologies. Current approaches that seek to automate the construction of cochlear electrode arrays are described and discussed.

Cochlear implants: A remarkable past and a brilliant future

“…However, a large gain in the number of independent sites may well require a fundamentally new type of electrode, or a fundamentally different placement of electrodes, or a fundamentally different type or mode of stimulation. The many issues related to electrode design, along with prospects for the future, are discussed in , Spelman (2006), Middlebrooks and Snyder (2007 and this issue), Anderson (this issue), and Wise et al (this issue). Additionally, a new approach using optical rather than electrical stimulation of auditory neurons is described by Richter et al in this issue.…”

“…Such growth would bring the target to the electrodes. Another possibility is to implant an array of electrodes directly within the auditory nerve (an intramodiolar implant), through an opening made in the basal part of the cochlea (Arts et al, 2003;Badi et al, 2003Badi et al, , 2007Hillman et al, 2003;Spelman, 2006;Middlebrooks and Snyder, 2007 and this issue; Anderson, this issue). In this case, the electrodes would be placed immediately adjacent to axons of the auditory nerve.…”

Cochlear implants: Current designs and future possibilities

“…However, a large gain in the number of independent sites may well require a fundamentally new type of electrode or a fundamentally different placement of electrodes. The many issues related to electrode design, along with prospects for the future, are discussed elsewhere [15][16][17][18][19][20][21][22][23][24][25]. Figure 2 shows a complete presence of hair cells (in the labeled organ of Corti) and a pristine survival of cochlear neurons.…”

“…Such growth of neurites would bring the target to the electrodes. Another possibility is to implant an array of electrodes directly within the auditory nerve (an intramodiolar implant) through an opening made in the basal part of the cochlea [19][20][21][23][24][25]. In this case, the electrodes would be placed immediately adjacent to axons of the auditory nerve.…”

Characterization of microglial attachment and cytokine release on biomaterials of differing surface chemistry

“…Implantable electrode technology is a clinically effective treatment for a number of disorders including deafness [1] and for symptoms associated with Parkinson's disease [2]. In addition, increasing evidence suggests that such technology may be applicable in brain-machine interface (BMI) applications to control limb prostheses [3][4][5][6].…”