title: Percutaneous versus transcutaneous bone conduction implant system: a feasibility study on a cadaver head.
abstract: OBJECTIVE
  Percutaneous bone-anchored hearing aid (BAHA) is an important rehabilitation alternative for patients who have conductive or mixed hearing loss. However, these devices use a percutaneous and bone-anchored implant that has some drawbacks reported. A transcutaneous bone conduction implant system (BCI) is proposed as an alternative to the percutaneous system because it leaves the skin intact. The BCI transmits the signal to a permanently implanted transducer with an induction loop system through the intact skin. The aim of this study was to compare the electroacoustic performance of the BAHA Classic-300 with a full-scale BCI on a cadaver head in a sound field. The BCI comprised the audio processor of the vibrant sound bridge connected to a balanced vibration transducer (balanced electromagnetic separation transducer).
  
  
  METHODS
  Implants with snap abutments were placed in the parietal bone (Classic-300) and 15-mm deep in the temporal bone (BCI). The vibration responses at the ipsilateral and contralateral cochlear promontories were measured with a laser Doppler vibrometer, with the beam aimed through the ear canal.
  
  
  RESULTS
  Results show that the BCI produces approximately 5 dB higher maximum output level and has a slightly lower distortion than the Classic-300 at the ipsilateral promontorium at speech frequencies. At the contralateral promontorium, the maximum output level was considerably lower for the BCI than for the Classic-300 except in the 1-2 kHz range, where it was similar.
  
  
  CONCLUSIONS
  Present results support the proposal that a BCI system can be a realistic alternative to a BAHA.
authors.affiliation: Department of Signals and Systems, Chalmers University of Technology, Göteborg, Sweden. boh@chalmers.se
authors.forename: Bo
authors.initials: B
authors.lastname: Håkansson
authors.forename: Måns
authors.initials: M
authors.lastname: Eeg-Olofsson
authors.forename: Sabine
authors.initials: S
authors.lastname: Reinfeldt
authors.forename: Stefan
authors.initials: S
authors.lastname: Stenfelt
authors.forename: Gösta
authors.initials: G
authors.lastname: Granström