Round window electrocochleography just before cochlear implantation: Relationship to word recognition outcomes in adults

Douglas C. Fitzpatrick, Adam T. Campbell, Baishakhi Choudhury, Margaret P. Dillon, Mathieu Forgues, Craig A. Buchman, Oliver F. Adunka

Research output: Contribution to journalArticle

44 Scopus citations

Abstract

HYPOTHESES: Electrocochleography (ECoG) to acoustic stimuli can differentiate relative degrees of cochlear responsiveness across the population of cochlear implant recipients. The magnitude of the ongoing portion of the ECoG, which includes both hair cell and neural contributions, will correlate with speech outcomes as measured by results on CNC word score tests. BACKGROUND: Postoperative speech outcomes with cochlear implants vary from almost no benefit to near normal comprehension. A factor expected to have a high predictive value is the degree of neural survival. However, speech performance with the implant does not correlate with the number and distribution of surviving ganglion cells when measured postmortem. We will investigate whether ECoG can provide an estimate of cochlear function that helps predict postoperative speech outcomes. METHODS: An electrode was placed at the round window of the ear about to be implanted during implant surgery. Tone bursts were delivered through an insert earphone. Subjects included children (n = 52, 1-18 yr) and postlingually hearing impaired adults (n = 32). Word scores at 6 months were available from 21 adult subjects. RESULTS: Significant responses to sound were recorded from almost all subjects (80/84 or 95%). The ECoG magnitudes spanned more than 50 dB in both children and adults. The distributions of ECoG magnitudes and frequencies were similar between children and adults. The correlation between the ECoG magnitude and word score accounted for 47% of the variance. CONCLUSION: ECoGs with high signal-to-noise ratios can be recorded from almost all implant candidates, including both adult and pediatric populations. In postlingual adults, the ECoG magnitude is more predictive of implant outcomes than other nonsurgical variables such as duration of deafness or degree of residual hearing.

Original languageEnglish
Pages (from-to)64-71
Number of pages8
JournalOtology and Neurotology
Volume35
Issue number1
DOIs
StatePublished - Jan 2014
Externally publishedYes

Keywords

  • Auditory nerve neurophonic
  • Cochlear microphonic
  • Hearing preservation
  • Intraoperative monitoring
  • Prediction of outcome
  • Residual hearing

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