All are tests to check Eustachian tube patency except

The basis of this test is to induce nystagmus by producing pressure changes in the external canal which are then transmitted to labyrinth. Its stimulation causes nystagmus and veigo. Normally the test is negative. Fistula test: This test is used for assessment of vestibular function. The basis of this test is to induce nystagmus by producing pressure changes in the external canal which are then transmitted to the labyrinth. Valsalva test: It is a eustachian tube functional test. The principle of this test is to build positive pressure in the nasopharynx so that air enters the eustachian tube. Toynbee's test: It is a eustachian tube functional test. This test causes negative pressure. It is performed by asking the patient to swallow while the nose had been pinched. Frenzel test: It is a eustachian tube functional test. It is used to open the eustachian tube and ventilate the middle ear by contracting muscles of the floor of the mouth and pharynx while nose, mouse and glottis are closed. Reference: Diseases of Ear, Nose and Throat, PL Dhingra, 7th edition, pg no. 43, 62, 63, 508