Related Experiment Video
Updated: Feb 11, 2026

The Measurement of Unsteady Surface Pressure Using a Remote Microphone Probe
Published on: December 3, 2016
Predicting bone conduction device output using a forehead surface microphone: comparison with promontory motion and
Tobias Mair1, Ivo Dobrev1, Christof Röösli1
1Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
Objective:
To evaluate the accuracy of output predictions made by a custom prototype forehead-mounted surface microphone (SM) when used with different bone conduction devices (BCDs).
Design:
Experimental study comparing SM measurements with three-dimensional cochlear promontory motion (VPROM) and intracochlear pressure in response to stimulation by various BCDs.
Study Sample:
Six fresh-frozen human cadaver heads with three BCDs (one ADHEAR and two BONEBRIDGE devices implanted at separate positions). A stepped sine stimulus (0.1-10 kHz) was applied.
Results:
Strong linear relationships were observed between forehead surface sound pressure, promontory motion, and differential intracochlear pressure across all BCDs, particularly between 400 Hz and 2 kHz. At higher frequencies, SM sensitivity declined-above 2 kHz for the ADHEAR and above 3 kHz for the BONEBRIDGE-limiting predictive accuracy.
Conclusions:
The prototype surface microphone reliably measured device output at low to mid frequencies, indicating its potential for dynamic range estimation in clinical settings by normalising SM output to hearing thresholds. However, reduced sensitivity at higher frequencies suggests that further development is needed to enable reliable output prediction across the entire clinically relevant frequency range.
Related Concept Videos
Hydrostatic Pressure Force on a Plane Surface
Hydrostatic Pressure Force on a Curved Surface
The Sense of Self: Reflected Self-Appraisal and Social Comparison
Cardiac Output II: Effect of Stroke Volume on Cardiac Output
Preload
Preload refers to the initial elongation of the cardiac myocytes before contraction and is related to the volume of blood filling the heart at the end of diastole, or end-diastolic volume. The...
Local Anesthetics: Clinical Application as Surface, Infiltration, and Conduction Block Anesthesia
Cardiac Output I:Effect of Heart Rate on Cardiac Output
Cardiac output (CO) refers to the total amount of blood ejected by one of the ventricles in liters per minute (L/min). In a resting adult, CO ranges from 5 to 6 L/min, adjusting according to the body's metabolic requirements.
Effect of Heart Rate on Cardiac Output
Cardiac output adapts to metabolic demands during stress, physical activity, or illness. The autonomic nervous system regulates heart rate via the sinoatrial node. The parasympathetic nervous system decreases heart...

