Low-Admittance Pathologies: Otitis Media with
Effusion, Middle Ear Tumor, Ossicular Fixation,
Tympanosclerosis
Low static admittance of the middle ear is produced by space-occupying
lesions in various ways. A lesion that displaces air in the middle ear space
causes low admittance by reducing the middle ear volume. The lesion also
may interfere with the vibration of the ossicular chain, contributing to the low
admittance. If the lesion is in contact with the eardrum, low admittance
results from interference with eardrum vibration.
Otitis Media with Effusion (OME)
Tympanometric characteristics of patients with OME typically include one or
more of the conditions illustrated in Figure 30. In advanced cases, OME
results in flat tympanograms (low static admittance). In intermediate stages
of OME, the peak height may be normal, but the gradient may be too wide.
Low Peak Ya Tympanogram Too Wide
Figure 30
A-34
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