The development of impedance audiometry during the past decade had added new scope and dimension to clinical audiology. After introduction of the impedance audiometry, the measurement of sound conducting system in combination with the development of otoneurology and microsurgery played an important role in diagnosis of hearing disturbance. Based on the pionering efforts of Metz (1946), who first introduced the concept of impedance. audiometry, Ter kiIdsen and others pioneered the application of the electroacoustic approach, culminating in the present commercially available electroacoustic bridge (Madsen ZO 70, 72).
In Korea, still there is no report about this, so we measured the normal value of Korean by using Madsen ZO 70 and afford it as a base of further study in sound conduction system of middle ear.
The results are as follows;
1. The tympanograms in normal and sensori-neural ´hearing loss_ cases were mostly in type A curves.
2. The range of acoustic impedances in normal cases were 6215 to 4320Q (mean. 197251), and the range of static compliances in normal cases were 0. 2 cc to 1.4ce (mean. 0.69cc).
3. Stapedial reflex, thresholds were 96dB at 500Hz, 97dB at 1000Hz, 99dB at 2000Hz, and 96dB at 4000Hz in normal and sensori-neural hearing loss cases in mild and moderate degrees. S.R was mostly absent in sensorineural hearing loss cases in severe degree.
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