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77th Annual Meeting of the German Society of Oto-Rhino-Laryngology, Head and Neck Surgery

German Society of Oto-Rhino-Laryngology, Head and Neck Surgery

24.05. - 28.05.2006, Mannheim

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Electrophonic and electroneural hearing with combined electric/acoustic stimulation (EAS) of the cochlea

Elektrophones und elektroneurales Hören bei kombinierter elektrisch/akustischer Stimulation (EAS) der Cochlea

Meeting Abstract

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  • author presenting/speaker Maike Vollmer - University of California, San Francisco, San Francisco, USA
  • corresponding author Jochen Tillein - J.W. Goethe University, Frankfurt/Main, Germany
  • Ben H. Bonham - University of California, San Francisco, San Francisco, USA

German Society of Otorhinolaryngology, Head and Neck Surgery. 77th Annual Meeting of the German Society of Otorhinolaryngology, Head and Neck Surgery. Mannheim, 24.-28.05.2006. Düsseldorf, Köln: German Medical Science; 2006. Doc06hno024

The electronic version of this article is the complete one and can be found online at: http://www.egms.de/en/meetings/hno2006/06hno024.shtml

Published: September 7, 2006

© 2006 Vollmer et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.

Outline

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In an animal model we studied the central neuronal encoding of combined electrical and acoustical stimulation (EAS) of the cochlea in the presence of intact hair cells.

Under general anesthesia normal hearing cats were implanted with a scala

tympani electrode array. For acoustic stimulation an earphone was sealed to the ipsilateral auditory meatus. Neuronal responses to pulsatile and sinusoidal stimuli were recorded simultaneously at 16 sites along the tonotopic gradient of the contralateral inferior colliculus (IC).

At low intensities, electric probe frequencies activate IC locations

that correspond to the probe frequency. These electrophonic responses have acoustic-like response patterns (shallow growth function and large dynamic range) and are masked when the electric signal is preceded by acoustic stimuli of the same frequency.

At higher electrical intensities, additional IC locations are activated that

correspond to the cochlear site of the stimulating electrode(s). These electroneural responses are based on the direct activation of the auditory nerve and typically demonstrate a steep growth function and a narrow dynamic range. Electroneural responses are masked by acoustic frequencies that correspond to the cochlear site of electrical stimulation.

The findings indicate that electrical stimulation of the hearing cochlea can produce two different kinds of auditory responses: low-threshold acoustic-like electrophonic responses and higher-threshold electroneural responses of the auditory nerve. The interactions between these two response patterns may influence the efficacy of combined stimulation in EAS patients.

(Supported by NOHR, NIH N01 DC-2-1006, NIH N01 DC-3-1006 and MedEl)