Tympanometric asymmetry.

Tympanometric asymmetry was investigated in 17 normal adult subjects. Experimental variables included transmission quantity, probe frequency, direction of pressure change, and type of probe tip. Tympanograms were characterized by systematic asymmetries that appeared to be related predominantly to middle-ear effects, although ear canal effects probably contributed to the asymmetries as well. Implications for the standardization of measurement procedures are discussed.