A novel bone conduction implant (BCI): Engineering aspects and pre-clinical studies

Abstract

Percutaneous bone anchored hearing aids (BAHA) are today an important rehabilitation alternative for patients suffering from conductive or mixed hearing loss. Despite their success they are associated with drawbacks such as skin infections, accidental or spontaneous loss of the bone implant, and patient refusal for treatment due to stigma. A novel bone conduction implant (BCI) system has been proposed as an alternative to the BAHA system because it leaves the skin intact. Such a BCI system has now been developed and the encapsulated transducer uses a non-screw attachment to a hollow recess of the lateral portion of the temporal bone. The aim of this study is to describe the basic engineering principals and some preclinical results obtained with the new BCI system. Laser Doppler vibrometer measurements on three cadaver heads show that the new BCI system produces 0-10 dB higher maximum output acceleration level at the ipsilateral promontory relative to conventional ear-level BAHA at speech frequencies. At the contralateral promontory the maximum output acceleration level was considerably lower for the BCI than for the BAHA.This is an electronic version of an article published in:Bo Hakansson, Sabine Reinfeldt, Mans Eeg-Olofsson, Per Ostli, Hamidreza Taghavi, Johannes Adler, John Gabrielsson, Stefan Stenfelt and Gosta Granstrom, A novel bone conduction implant (BCI): Engineering aspects and pre-clinical studies, 2010, INTERNATIONAL JOURNAL OF AUDIOLOGY, (49), 3, 203-215.INTERNATIONAL JOURNAL OF AUDIOLOGY is available online at informaworldTM: http://dx.doi.org/10.3109/14992020903264462Copyright: Taylor & Francishttp://www.tandf.co.uk/journals/default.as

Implications for Contralateral Bone-Conducted Transmission as Measured by Cochlear Vibrations

“…An implantable BC hearing aid, here termed BCI, is under development and evaluation (13,14) and the planned position for this device is approximately at position 6. From the ipsilateral data in Eeg-Olofsson (10) combined with the results in this study a BCI in position 6 would improve sound transmission ipsilaterally and for bilateral application give a reduced cross over transmission, hence provide for better binaural hearing.…”

“…This conclusion has led to an ongoing project of developing a bone conduction implant (BCI) in order to avoid the Baha® percutaneous solution and in this way get a BC HA with equal or better amplification and less risk of skin problems (13,14).…”

Estimation of bone conduction skull transmission by hearing thresholds and ear-canal sound pressure

“…Recently, there have been several studies investigating sound transmission in the human skull, also known as bone conduction (BC) sound transmission, by measurements of skull vibrations (Eeg-Olofsson et al, 2011;Håkansson et al, 2010;Stenfelt and Goode, 2005a). The rationale for these studies is that the vibration of the cochlea is related to a hearing perception, and the measurement of cochlear vibration enables a fast estimation of the BC excitation with greater level and frequency resolution compared with the same measurements done by hearing thresholds.…”

Evaluation of Bone Tissue Formation in a Flat Surface Attachment of a Bone Conduction Implant: A Pilot Study in a Sheep Model

“…1, both MPI and TF decrease. It has been shown in cadavers [Håkansson et al, 2010] that a limited bone-to-implant contact is sufficient to transfer sound to the inner ear efficiently. The results in the current animal study confirm the findings by Håkansson et al [2010].…”

“…Typically, they will be lower, but also resonances can move/shift in frequency compared to an interface with a high BIC. Preclinical mechanical measurements of MPI and TF on human cadavers [Håkansson et al, 2010] have proven that a flat implant to bone contact is an effective method to transmit sounds to the cochlea. The next phase was to study the mentioned research questions in an animal model (sheep).…”