POLAR NOTATION TYMPANOGRAM AS A DIAGNOSTIC TOOL FOR OSSICULAR ANOMALIES
1983 Volume 86 Issue 5 Pages 511-517
Details
1983 Volume 86 Issue 5 Pages 511-517
The routine tympanogram appears not to be sensitive for the diagnosis of ossicular chain disorders. This may be due to the facts that the probe tone frequency is fixed to around 220Hz and impedance of the middle ear is figurized as an equivalent air volume. A new device has been developped in order to improve the diagnostic value.
This device produces a sweep frequency probe tone of 220Hz to 2000Hz and can measure both the sound pressure and the phase in the external canal as the probe tone frequency sweeps. The microcomputor in the device calculates the difference in sound pressure or in phase between conditions of -200mmH2O an 0mmH2O of air pressure in the canal, and figurizes these values as a polar notation diagram.
Ten patients with ossicular anomalies were tested by this device. Preoperative diagnosis agreed with the operative finding. Results indicate that this test can be of great value in the evaluation of ossicular anomalies.
