A Psychophysics experimental software to evaluate electrical pitch discrimination in Nucleus cochlear implanted patients

María Teresa Pérez Zaballos ,Matthijs Killian ,Ángel Ramos De Miguel ,Ángel Ramos Macías

doi:10.1088/1742-6596/689/1/012030

Abstract

Multichannel electrode array design in cochlear implants has evolved into two major categories: straight and perimodiolar electrodes. When implanted, the former lies along the outer wall of the scala tympani, while the later are located closer to the modiolus, where the neural ends are. Therefore, a perimodiolar position of the electrode array could be expected to result in reduced stimulus thresholds and stimulating currents, increased dynamic range, and more localized stimulation of the neural elements. However, their advantage for pitch discrimination has not been conclusively stated. Therefore, in order to study electrode independence, a psychophysical software has been developed, making use of Nucleus Implant Communicator tools provided by Cochlear company under a research agreement. The application comprises a graphical interface to facilitate its use, since previous software has always required some type of computer language skills. It allows for customization of electrical pulse parameters, measurement of threshold and comfort levels, loudness balancing and alternative forced choice experiments to determine electrode discrimination in Nucleus© users.

Highlights

The level of hearing rehabilitation obtained through cochlear implants has increased dramatically since its introduction
Multichannel electrode array design in cochlear implants has evolved into two major categories: straight and perimodiolar electrodes
A perimodiolar position of the electrode array could be expected to result in reduced stimulus thresholds and stimulating currents, increased dynamic range, and more localized stimulation of the neural elements

Summary

Introduction

The level of hearing rehabilitation obtained through cochlear implants has increased dramatically since its introduction This is the result of developments that include advanced signal processing, higher stimulation rates, greater numbers of channels, and the development of more efficient electrode arrays [1]. The selectivity of the electric fields about the neural stimulation depends on a number of factors apart from the electrode-nerve proximity These include: patterns of neuronal survival population, stochastic variability characteristics of individual nerve fibers, cochlear anatomy, signal characteristics and design features of the electrode [7]. An exception to the limitations of these platforms is APEX, a software application built and distributed under contract by the Experimental Audiology Department in Leuven [12] This platform supports psychoacoustic experiment design both for acoustical and electrical stimuli by means of a cochlear implant, and even the combination of both.

Platform Description

Findings

Conclusion