Spatial design of hearing AIDS incorporating multiple vents

Area of Science:

• Biomedical Engineering
• Audiology
• Anatomy

Background:

• Hearing aid design is influenced by the complex 3D geometry of the human ear canal.
• Effective venting is crucial for hearing aid acoustics and user comfort, but ear canal variations pose challenges.

Purpose of the Study:

• To investigate human ear canal shape variations and their impact on hearing aid venting.
• To assess the feasibility and design flexibility of multiple venting options for hearing aids.

Main Methods:

• A statistical shape model was developed using principal component analysis on 109 human ear scans.
• Modal variations were analyzed to identify narrow ear canal regions.
• 3D models of hearing aid shells with single and multiple vents were created for comparison.

Main Results:

• The first three modes of the statistical shape model explained over 50% of ear canal shape variation.
• The narrowest predicted ear canal area was 36.4 mm², with a mean minimum area of 48 mm².
• Multiple small vents (0.4 mm) can provide venting equivalent to a single 2 mm vent, fitting within the ear canal's physical space.

Conclusions:

• The human ear canal's shape variations accommodate feasible multiple vented hearing aid shells.
• Multiple venting strategies offer enhanced design flexibility by allowing small vents to navigate around internal hearing aid components.