Vestibular function is tested by
A. Galvanic stimulationB. Acoustic reflex
C. Fistula test
D. Impedance audiometry
E. Cold caloric test
Ans. (A) Galvanic test ; (C) Fistula test ; (E) Cold caloric test
• Fistula test: is done by pressing the tragus and alternately relasing it or by compression of air by Siegle’s speculum. Positive test is indicated by vertigo and nystagmus and signifies presence of fistulous communication between middle ear and labyrinth. Negative test signifies absence of fistula and fastula with dead labyrinth.
• Galvanic test is the only vestibular test which helps in differentiating an end organ lesion from that of vestibular nerve.
• Impedence Audiometryprovides a quick objective resistance measurement of tympanic membrane and middle ear and their compliance to sound pressure transmission.
• Acoustic reflex: is based on the fact that a loud sound, 70-100 dB above the threshold of hearing of a particular ear, causes bilateral contraction of the stapedial muscles which can be detected by tyrnpanometry. It is an objective test for
— Rough estimation of hearing ability
— Detection of non-organic hearing loss (Malitigerers)
— Demonstration of recruitment
— Localization of lesion of the facial nerve
— Assessment of hearing in neonates and children
