HEARING FACULTY TESTING AND APPARATUS THEREFOR

摘要

A hearing faculty test and apparatus therefor is based on the finding that sound input to the ear gives rise to a returned wave from and related to the condition of the inner ear, this wave being detectable as an echo from the ear drum. The apparatus preferably comprises a sealing aural probe housing transducers respectively to project a repetitive transient sound by pulse generator activation and to pick-up for detection successive echoes by time-gating. Detected echoes are preferably averaged during processing for display. The echo occurs about 5-20 ms after its sound and a maximum operating frequency of about 50 Hz is appropriate. A continuous sound input can be used with consequent echo interference detectable as rapid changes of acoustic impedance with sound input frequency. Another alternative can involve detection of the ear drum movement by returned waves.