Intraoperative round window recordings to acoustic stimuli from cochlear implant patients

Baishakhi Choudhury, Douglas C. Fitzpatrick, Craig A. Buchman, Benjamin P. Wei, Margaret T. Dillon, Shuman He, Oliver F. Adunka

Research output: Contribution to journalArticle

43 Scopus citations

Abstract

HYPOTHESIS: Acoustically evoked neural and hair cell potentials can be measured from the round window (RW) intraoperatively in the general population of cochlear implant recipients. BACKGROUND: Cochlear implant performance varies greatly among patients. Improved methods to assess and monitor functional hair cell and neural substrate before and during implantation could potentially aid in enhanced nontraumatic intracochlear electrode placement and subsequent improved outcomes. METHODS: Subjects (1-80 yr) undergoing cochlear implantation were included. A monopolar probe was placed at the RW after surgical access was obtained. The cochlear microphonic (CM), summating potential (SP), compound action potential (CAP), and auditory nerve neurophonic (ANN) were recorded in response to tone bursts at frequencies of 0.25 to 4 kHz at various levels. RESULTS: Measurable hair cell/neural potentials were detected to 1 or more frequencies in 23 of 25 subjects. The greatest proportion and magnitude of cochlear responses were to low frequencies (<1,000 Hz). At these low frequencies, the ANN, when present, contributed to the ongoing response at the stimulus frequency. In many subjects, the ANN was small or absent, whereas hair cell responses remained. CONCLUSION: In cochlear implant recipients, acoustically evoked cochlear potentials are detectable even if hearing is extremely limited. Sensitive measures of cochlear and neural status can characterize the state of hair cell and neural function before implantation. Whether this information correlates with speech performance outcomes or can help in tailoring electrode type, placement or audiometric fitting, can be determined in future studies.

Original languageEnglish (US)
Pages (from-to)1507-1515
Number of pages9
JournalOtology and Neurotology
Volume33
Issue number9
DOIs
StatePublished - Dec 2012

Keywords

  • Auditory nerve neurophonic
  • Cochlear electrophysiology
  • Cochlear implant
  • Cochlear microphonic
  • Electrocochleography
  • Hearing preservation
  • Intraoperative monitoring

ASJC Scopus subject areas

  • Otorhinolaryngology
  • Sensory Systems
  • Clinical Neurology

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    Choudhury, B., Fitzpatrick, D. C., Buchman, C. A., Wei, B. P., Dillon, M. T., He, S., & Adunka, O. F. (2012). Intraoperative round window recordings to acoustic stimuli from cochlear implant patients. Otology and Neurotology, 33(9), 1507-1515. https://doi.org/10.1097/MAO.0b013e31826dbc80