Meta-Analysis-Correlation between Spiral Ganglion Cell Counts and Speech Perception with a Cochlear Implant.

Yew-Song Cheng,Mario A Svirsky

doi:10.3390/audiolres11020020

Abstract

The presence of spiral ganglion cells (SGCs) is widely accepted to be a prerequisite for successful speech perception with a cochlear implant (CI), because SGCs provide the only known conduit between the implant electrode and the central auditory system. By extension, it has been hypothesized that the number of SGCs might be an important factor in CI outcomes. An impressive body of work has been published on findings from the laborious process of collecting temporal bones from CI users and counting the number of SGCs to correlate those numbers with speech perception scores, but the findings thus far have been conflicting. We performed a meta-analysis of all published studies with the hope that combining existing data may help us reach a more definitive conclusion about the relationship between SGC count and speech perception scores in adults.

Highlights

Cochlear implants represent the most successful example of a neural prosthesis that replaces a human sense with an electronic device
The most important result of the present analysis was a negative one: no significant correlation between spiral ganglion cells (SGCs) count and speech perception scores was found shows the absence of a correlation
One possible explanation for the absence of correlation in our analysis is that a small number of SGCs may be sufficient to deliver the information conveyed via electrical stimulation by a cochlear implant, and speech perception is only affected at very low SGC counts

Summary

Introduction

Cochlear implants represent the most successful example of a neural prosthesis that replaces a human sense with an electronic device They do so by stimulating the auditory nerve directly, bypassing the normal mechanism that transduces sound into neural activity [1]. The number of remaining spiral ganglion cells (SGCs) is frequently cited as a potentially important factor [9,10]. This is a very reasonable hypothesis because SGCs (including the soma and the peripheral axons) are almost certainly the sole conduit by which electrical pulses generated by the cochlear implant can elicit activity in the auditory system. It is quite plausible that a healthier auditory nerve (indexed by a larger number of remaining SGCs) might be associated with better outcomes for cochlear implant patients

Methods

Results

Discussion

Conclusion