Middle-ear function with tympanic-membrane perforations. II. A simple model

Area of Science:

• Biomedical Engineering
• Acoustics
• Otolaryngology

Background:

• Tympanic membrane (TM) perforations can cause hearing loss.
• The exact mechanisms and contributing factors to hearing loss from TM perforations require further quantitative modeling.

Purpose of the Study:

• To develop a quantitative acoustic model of the human middle ear with a TM perforation.
• To identify the primary factors influencing hearing loss due to TM perforations.

Main Methods:

• Acoustic measurements were performed on human cadaver ears.
• A quantitative model was developed incorporating sound coupling through the perforation.
• The model was constrained by experimental acoustic data.

Main Results:

• Perforation-induced transmission changes are primarily due to altered driving pressure across the TM.
• Changes in TM structure and ossicular coupling contribute less significantly.
• Hearing loss is primarily dependent on perforation diameter, sound frequency, and middle ear cavity volume.

Conclusions:

• The developed model accurately represents acoustic transmission changes in middle ears with TM perforations.
• Model predictions can help clinicians differentiate hearing loss causes.
• Understanding these factors aids in assessing the impact of perforations on hearing and potential additional pathologies.