Impedance screening for middle ear disease.

Pure tone audiometry has hitherto been employed as the sole means of indentifying ear pathology. During the last decade it has been demonstrated that even hearing which is normal according to pure tone sweep check screening audiometry (20 dB) can be associated with middle ear pathology. With the intention of identifying cochlear as well as middle ear pathology, a study was initiated in which pure tone testing was combined with impedance measurements as a screening test. The intention has been to determine a screening level at which pathology is identified and the number of false-positive is minimized. A combination of tympanometry (less than or equal to -150 mm H2O) and pure tone screening at 0.5 and 3 kHz is recommended as a screening procedure for the identification of cochlear as well as middle ear pathology.