Spatial resolution of cochlear implants: the electrical field and excitation of auditory afferents

Andrej Kral, Rainer Hartmann, Dariusch Mortazavi, Rainer Klinke*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

228 Citations (Scopus)


This paper investigates the spatial resolution of electrical intracochlear stimulation in order to enable further refinement of cochlear implants. For this purpose electrical potential distributions around a conventional human intracochlear electrode (NUCLEUS-22) were measured in a tank, in cat cadaver cochleae and in living cat cochleae. Potential gradients were calculated where of importance. The values were compared to spatial tuning curves from cat primary auditory afferents in electrical mono-, bi-, and various tripolar stimulation modes. Finally, a lumped element model was developed to elucidate the single fiber data. Tank potential measurements show the principal features of the different stimulation modes but are not sufficient to explain all the features of experimental data from single fibers. Intracochlear potential measurements indicate an increase in spatial resolution in an apical direction. The single fiber data also confirm that a tripolar stimulus configuration provides significantly better spatial resolution than any other stimulation mode presently in use.

Original languageEnglish
Pages (from-to)11-28
Number of pages18
JournalHearing Research
Issue number1-2
Publication statusPublished - 1 Jul 1998
Externally publishedYes


  • Auditory single fiber
  • Cochlear implant
  • Electrical stimulation
  • Lateral inhibition
  • Spatial resolution


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