Exploring the impact of force direction and phase on bone conduction hearing with bone conduction actuator

Area of Science:

• Biomechanics
• Auditory Neuroscience
• Computational Modeling

Background:

• Understanding bone conduction (BC) hearing mechanisms is crucial but challenging due to difficulties in controlling BC transducer input forces.
• Existing research has limited exploration of how varying input forces affect BC hearing outcomes.

Purpose of the Study:

• To investigate the effects of unilateral and bilateral bone conduction (BC) input forces on human head mechanics and auditory system responses.
• To analyze the influence of input force direction and phase differences on BC hearing using a computational model.

Main Methods:

• Developed a three-dimensional finite element (FE) model of the human head to simulate BC input forces.
• Investigated 16 distinct unilateral input force directions and applied phase differences (0°, 90°, 180°) for bilateral inputs at the mastoid positions.
• Compared promontory and basilar membrane velocities to assess the impact of input force parameters.

Main Results:

• Unilateral BC input force direction variations showed magnitude differences within 10 dB, with anti-resonance shifts observed between 1 and 3 kHz.
• Bilateral BC input analysis revealed complex interactions influenced by phase differences between the applied forces.
• The FE model allowed precise manipulation and analysis of input forces, overcoming experimental limitations.

Conclusions:

• Input force direction significantly influences BC hearing, particularly around the anti-resonance frequency range.
• Phase differences in bilateral BC stimulation critically affect auditory system responses.
• This FE modeling approach provides valuable insights into BC hearing mechanisms and transducer design.