gms | German Medical Science

Fourth International Symposium and Workshops: Objective Measures in Cochlear Implants

Medical University of Hannover

01.06. bis 04.06.2005, Hannover

Responses to electrical stimulation in individuals with residual hair cell function

Meeting Abstract

  • corresponding author P.J. Abbas - University of Iowa, Iowa City, IA , USA, 52242
  • C. Etler - University of Iowa, Iowa City, IA , USA, 52242
  • K. Nourski - University of Iowa, Iowa City, IA , USA, 52242
  • C. Brown - University of Iowa, Iowa City, IA , USA, 52242
  • C. Miller - University of Iowa, Iowa City, IA , USA, 52242

Medical University of Hannover, Department of Otolaryngology. Fourth International Symposium and Workshops: Objective Measures in Cochlear Implants. Hannover, 01.-04.06.2005. Düsseldorf, Köln: German Medical Science; 2005. Doc05omci053

Die elektronische Version dieses Artikels ist vollständig und ist verfügbar unter: http://www.egms.de/de/meetings/omci2005/05omci053.shtml

Veröffentlicht: 31. Mai 2005

© 2005 Abbas et al.
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Gliederung

Text

Implantation of individuals with residual hearing allows for the possibility of interactions between acoustic and electric stimulation. We have addressed this issue using acute recordings of the electrically evoked compound action potential in experimental animals with relatively normal hearing. In addition, we have made recordings of NRT measures in patients who have significant low frequency hearing and have been implanted with a short electrode array in the base of the cochlear in order to preserve that residual hearing. The measures in experimental animals have shown that typically an electrophonic response (Moxon, 1970) with a latency of approximately 1.5 ms is observed in addition to the short latency direct neural response. In animals, we consistently observe both a clear interaction between acoustic noise and electrical stimulation during the noise presentation as well as residual effects after the offset of the noise stimulus. Our measures in human implant users consistently show the normal direct response but show no evidence of an electrophonic response. We also have not observed any interaction between acoustic noise and the response to electrical stimulation. We interpret these results to mean that, in this group of implant users, there are separate populations of neurons carrying acoustic and electric stimulation. In addition, however, we have made measures of channel interaction for the 6-electrode array using our standard two-pulse paradigm (Abbas et al., 2004). Those measures show differential masking among electrodes within the basal array suggesting that there are separate channels of information effectively transmitted through the array.