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

Imaging for Sound and Speech Perception in Cochlear Implant Users

Meeting Abstract

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  • corresponding author T. Kubo - Department of Otolaryngology, Osaka University School of Medicine, Japan
  • H. Nishimura - Department of Otolaryngology, Osaka University School of Medicine, Japan
  • Y. Ohsaki - Department of Otolaryngology, Osaka University School of Medicine, Japan

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. Doc05omci058

Die elektronische Version dieses Artikels ist vollständig und ist verfügbar unter: http://www.egms.de/de/meetings/omci2005/05omci058.shtml

Veröffentlicht: 31. Mai 2005

© 2005 Kubo et al.
Dieser Artikel ist ein Open Access-Artikel und steht unter den Creative Commons Lizenzbedingungen (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.de). Er darf vervielf&aauml;ltigt, verbreitet und &oauml;ffentlich zug&aauml;nglich gemacht werden, vorausgesetzt dass Autor und Quelle genannt werden.


Gliederung

Text

Introduction

The purpose of this study was to use positron emission tomography (PET) for the identification of the mode of auditory cortical activation in cochlear implant (CI) users by using when they hear sounds and speech or read sign language. Subjects were both congenitally deaf adults and post-lingual deaf adults, who were accustomed to reading sign language and hearing speech sounds with CI. Cerebral blood flow in auditory cortical areas was measured by PET scanner following the administration of H2 15O, during exposure to speech sounds or sign language, or simultaneous exposure to both stimuli. Different modes of auditory cortical activation were detected in response to these stimuli. One mode was seen in a post-lingual deaf adult who suffered brain infarction including the left auditory association area (AAA), and had developed speech perception over time after receiving CI. The PET study after one year revealed strong activation in the right and left auditory cortices while listening to speech sounds. Another mode was seen in a congenitally deaf adult whose primary communication mode was sign language, and whose AAA was not activated by speech sound but by sign language. Comparison of the mode of activation in the AAA of the short- and long-term CI users (one year vs 5 years) showed that it was weaker in the short-term than in the long-term user group when speech sounds and sign language were simultaneous presented. Mode of activation in the AAA was different for each CI recipient and reflected different ways of speech perception.

Materials and Methods

ACA was activated only by reading sign language, but not by speech sound. Competing information process of auditory and visual stimuli was found in short time CI users, but it disappeared in long time CI users which supported the evidence of speech perception i). Data were reconstructed into an images, which were analyzed with statistical parametric mapping software (SPM 96). Relative cerebral blood flow was measured after i.v. injection of H2 15O.

Results

ii) Exp 2) Post-lingually deaf CI users, three were short term and three long term users. iii) In experiment two, speech sound and sign language were simultaneously provided to short and long term CI users. The former group showed a competing information processing in AAA, but dominant auditory input was found in the later group. Two experiments were conducted, Stimulus modes were either speech sound or sign language. In experiment one, In experiment two, speech sound and sign language were simultaneously provided to short and long term CI-users. The former group showed a competing information processing in AAA, but dominant auditory input was revealed in the later group. Cross modal plasticity of auditory and visual inputs existed in AAA of CI-users. The dominance of two information depends on the time of auditory input. Auditory association cortex was activated by viewing SL, but not hearing words in congenitally deafned subjects. In this subject sounds hearing with CI activated only the primary auditory area (Hersch gyrus) of the contra-lateral side. Auditory association area was activated by watching sign language in a congenitally deaf CI subject. The result is to prove difficulty in understanding words with CI in congenitally deaf subjects.