Implications of deep electrode insertion on cochlear implant fitting

Article Article scientifique Article Implications of deep electrode insertion on cochlear implant fitting eng 2007-01-11 2007-03 author Gani Mathieu 135566 author Valentini Grégory 920893 author Sigrist Alain 763272 author Kos Izabel 105443 author Boex Colette 0000-0002-9374-4791 28086 69-83 10.1007/s10162-006-0065-4 17216585 1438-7573 PMC2538415 Using long Med-El Combi40+ electrode arrays, it is now possible to cover the whole range of the cochlea, up to about two turns. Such insertion depths have received little attention. To evaluate the contribution of deeply inserted electrodes, five Med-El cochlear implant users were tested on vowel and consonant identification tests with fittings with first one, two, and up to five apical electrodes being deactivated. In addition, subjects performed pitch-ranking experiments, using loudness-balanced stimuli, to identify electrodes creating pitch confusions. Radiographs were taken to measure each electrode insertion depth. All subjects used each modified fitting for two periods of about 3 weeks. During the experiment, the same stimulation rate and frequency range were maintained across all the fittings used for each individual subject. After each trial period the subject had to perform three consonant and three vowel identification tests. All subjects showed deep electrode insertions ranging from 605 degrees to 720 degrees. The two subjects with the deepest electrode insertions showed significantly increased vowel- and consonant-identification performances with fittings with the two or three most apical electrodes deactivated compared to their standard fitting with all available electrodes activated. The other three subjects did not show significant improvements in performance when one or two of their most apical electrodes were deactivated. Four out of five subjects preferred to continue use of a fitting with one or more apical electrodes deactivated. The two subjects with the deepest insertions also showed pitch confusions between their most apical electrodes. Two possible reasons for these results are discussed. One is to reduce neural interactions related to electrodes producing pitch confusions. Another is to improve the alignment of the frequency components of sounds coded by the electrical signals delivered to each electrode to the overall pitch of the auditory perception produced by the electrical stimulation of auditory nerve fibers. Adult Cochlear Implantation / methods Cochlear Implants Deafness / diagnostic imaging Deafness / surgery Electrodes, Implanted Humans Loudness Perception Middle Aged Pitch Perception Radiography Speech Perception Dewey 616.8 61 Département des neurosciences cliniques 226 false Journal of the Association for Research in Otolaryngology 8 1 8494b2ee-eed6-49d8-b1b9-073f6e482251 Article (Published version) Restricted Article-scientifique-from-europePmc.pdf 777764 application/pdf CC BY restrictedAccess Faculté de médecine / Section de médecine clinique / Département des neurosciences cliniques

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Implications of deep electrode insertion on cochlear implant fitting	Journal of the Association for Research in Otolaryngology			2007	192	0

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Gani, Mathieu