The ETS represents a modern version of the Toynbee tube. The ETS replaces the tube with sophisticated electronic equipment that amplifies and records the sounds of air entering the middle ear. The results of the test correlate well with the clinical behavior of the eustachian tube. The ETS does this by permitting the auditory tube to function in its normal state. It requires minimal patient response and does not require a soundproof room. It allows performance of the Toynbee, Politzer, and Valsalva maneuvers with the equipment in place and does not interfere with catheterization of the tubal orifice. Medications may be applied to the nose and nasopharynx or be given parenterally while the sonograph is in place. Thus far, it appears that the ETS is very useful in evaluating dysfunction of the eustachian tube.