Normal tympanometric gradient: a comparison of three methods.
Tympanograms were obtained from 166 ears of 83 college students with normal middle ear function. Three measures of gradient were determined for each tympanogram: Gdif, Gratio, and GdP. Each gradient measure was evaluated for its potential usefulness in discriminating between ears with and without effusion. Gdif was found to be a fairly poor choice for gradient. Because it correlated so highly with static admittance, little additional information would be gained about tympanogram shape. The two other measures, Gratio and GdP, appeared to be roughly equivalent and would be preferred over Gdif as measures of tympanogram shape.
D000158:Acoustic Impedance Tests / Q000379:methods*; D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D012016:Reference Values