Resonance Frequency in Stiff Tympanic Membrane
Tympanic Membrane Mechanics and Resonance
- The resonance frequency of a stiff tympanic membrane typically ranges from 226 Hz to 1,000 Hz, with 226 Hz being the standard frequency used for tympanometric assessment in adults and children over 6 months of age, while 1,000 Hz is more appropriate for infants under 6 months due to their naturally stiffer tympanic membranes 1, 2
- Tympanometry, which measures tympanic membrane mobility and middle ear function, typically uses a 226 Hz probe tone as the standard frequency for assessment in adults and children over 6 months of age 3, 1
- For infants younger than 6 months, a higher frequency probe tone of 1,000 Hz is recommended as the 226 Hz tone is insensitive to middle ear effusion due to the naturally stiffer tympanic membrane characteristics in this age group 1, 2
Factors Affecting Tympanic Membrane Resonance
- Pathological stiffening of the tympanic membrane (as seen in conditions like tympanosclerosis or otitis media) can alter the normal resonance patterns and affect hearing 3, 4
Clinical Assessment of Tympanic Membrane Stiffness
- Pneumatic otoscopy evaluates tympanic membrane mobility, with distinctly impaired mobility being highly predictive of middle ear effusion and increased stiffness 3
- Tympanometry provides objective measurement of tympanic membrane mobility by creating graphs showing how energy is reflected back while canal pressure varies from negative to positive 5
- Type A tympanograms (high-peaked) indicate normal tympanic membrane mobility, while Type B (flat) suggests increased stiffness due to middle ear effusion or perforation 1