Impedance audiometry is done using frequency probe of: (A) 220 Hz, (B) 555 Hz, (C) 440 Hz, (D) 1000 Hz
Answer is A. It consists of a probe which fits into the external acoustic canal and has 3 channels: To deliver a tone of 220Hz To pick up the reflected sound a microphone To bring about changes in air pressure in the canal from positive to normal and then negative Ref: Dhingra; 6th Edition; pg no 24