Transcutaneous and percutaneous bone conduction sound propagation in single-sided deaf patients and cadaveric heads

Abstract

Objective

To investigate transcranial transmission (TT) and the dampening effect of the skin in patients and cadaver heads.

Design

In patients a pure tone bone conduction audiogram for ipsilateral and contralateral stimulation was performed. The TT was defined as the difference between ipsilateral and contralateral hearing thresholds. In cadaver heads ipsilateral and contralateral promontory motion was measured using a three-dimensional Laser Doppler Vibrometer system.

Study sample

Seven single-sided deaf patients fitted with a Baha^® Connect, fifteen single-sided deaf patients without a bone conduction hearing aid and five Thiel-embalmed cadaver heads were included.

Results

The TT decreased with increasing frequency in patients and cadaver heads. No significant difference was seen between patients and cadaver heads. Measurements on patients and cadaver heads showed increasing skin attenuation with increasing frequency. However, the dampening effect was 3–12 dB higher in patients than in cadavers at all frequencies.

Conclusion

The TT was not significantly different for patients compared to cadaver heads. The value of promontory motion to estimate TT in patients need to be further evaluated. The skin attenuates a BC stimulus by 10–20 dB in patients and by a smaller amount in cadaver heads, probably due to changes in the properties of the Thiel-conserved skin.

Keywords:

• Transcranial transmission
• skin dampening
• bone conduction
• unilateral hearing loss
• promontory motion

Acknowledgements

Thanks to Dr. rer. biol. hum. Bernd Strauchmann, Head of CI-Center Audiology at the University Hospital Zürich, for his technical support. Thanks to Maggy Kunz, audiometrist at the University Hospital Zürich, for the logistical support.

Disclosure statement

The authors declare that there are no conflicts of interest.

Additional information

Funding

The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by the Swiss National Science Foundation [grant number 325230-166377].