title: Initial clinical experience with a totally implantable cochlear implant research device.
abstract: OBJECTIVE
  To evaluate the effectiveness and issues associated with a research totally implantable cochlear implant (TIKI).
  
  
  METHODS
  Limited patient trial.
  
  
  METHODS
  Tertiary referral center.
  
  
  METHODS
  Three adult human subjects with severe-to-profound sensorineural hearing loss.
  
  
  METHODS
  Subjects were implanted with a research TIKI developed by Cochlear Limited and the Co-operative Research Centre for Cochlear Implant and Hearing Aid Innovation. The TIKI has a lithium ion rechargeable battery, a package-mounted internal microphone, and sound-processing electronics that enable the use of "invisible hearing" without the use of an external device. The TIKI also functions with an external ESPrit 3G sound processor as a conventional cochlear implant. The standard surgical technique was modified to accommodate the larger device package. Postoperatively, subjects used TIKI in both invisible hearing and the conventional ESPrit 3G modes.
  
  
  METHODS
  Device use was recorded in both invisible hearing and ESPrit 3G listening modes. Performance of the internal battery and microphone was assessed over time. Psychophysical MAP data were collected, and speech perception was measured at 1, 3, 6, and 12 months postoperatively in both listening modes.
  
  
  RESULTS
  There were no surgical or postoperative complications. All subjects use both invisible hearing and conventional ESPrit 3G modes. Speech perception outcomes for all patients showed improvement from preoperative scores. As a consequence of the reduced sensitivity of the implanted microphone, speech perception results using the invisible hearing mode were significantly lower than the ESPrit 3G mode. Subjects reported some body noise interference that limited use of the invisible hearing mode; however, all continue to use the invisible hearing mode on a limited daily basis. The rechargeable battery functioned well, with a cycle time indicating the low-power implant design is effective and will deliver long battery life.
  
  
  CONCLUSIONS
  This study demonstrates that the challenges in developing a safe and effective TIKI can be overcome. Three subjects implanted with the research TIKI all reported benefit from routine use. For each subject, hearing outcomes using invisible hearing mode were not as good as when using the external ESPrit 3G sound processor in the conventional mode.
authors: Department of Otolaryngology, University of Melbourne, East Melbourne, Victoria, Australia. rjbriggs@netspace.net.au
authors: Robert J S
authors: RJ
authors: Briggs
authors: Helmut C
authors: HC
authors: Eder
authors: Peter M
authors: PM
authors: Seligman
authors: Robert S C
authors: RS
authors: Cowan
authors: Kerrie L
authors: KL
authors: Plant
authors: James
authors: J
authors: Dalton
authors: David K
authors: DK
authors: Money
authors: James F
authors: JF
authors: Patrick
mesh_terms: D000328:Adult; D019929:Cochlear Implantation; D003054:Cochlear Implants / Q000009:adverse effects; D005260:Female; D006319:Hearing Loss, Sensorineural / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000453:epidemiology; D012984:Software; D013067:Speech Perception / Q000502:physiology; D013672:Technology; D016896:Treatment Outcome