Feedback analysis in percutaneous bone-conduction device and bone-conduction implant on a dry cranium

Area of Science:

• Audiology
• Biomedical Engineering
• Otolaryngology

Background:

• Percutaneous bone-conduction devices (PBCD) are standard for conductive hearing loss and single-sided deafness.
• PBCD systems can have limitations, particularly with insufficient high-frequency gain.
• Bone-conduction implant (BCI) systems offer an alternative with intact skin and reduced feedback potential.

Purpose of the Study:

• To compare the gain headroom of a bone-conduction implant (BCI) with a conventional percutaneous bone-conduction device (PBCD).
• To evaluate the potential for higher amplification in BCI systems due to reduced feedback oscillations.

Main Methods:

• Loop gains of the Baha Classic 300 (PBCD) and a BCI were measured across 100–10,000 Hz.
• Measurements were conducted using a Skull simulator and a dry cranium.
• Both devices were tested at full-on gain settings.

Main Results:

• The BCI demonstrated 0–10 dB greater gain headroom at higher frequencies compared to the Baha.
• When normalized to the cochlear level, the BCI provided a 10–30 dB improvement in gain headroom.
• BCI systems allow for significantly higher gain settings before feedback occurs.

Conclusions:

• Bone-conduction implants (BCI) enable higher gain settings without feedback issues compared to percutaneous bone-conduction devices (PBCD).
• BCI technology offers improved high-frequency amplification potential for hearing restoration.
• This suggests BCI as a potentially superior alternative for specific hearing loss profiles.