Testing of Eustachian tube functioning via strain gauge measurement of tympanic membrane movement

Abstract

So far, there is no method for monitoring the operability of the Eustachian tube in a physiological situation. The existing tests display either only momentary or nonphysiological characteristics of the tube functioning, so sparse information can be gathered in order to predict long-term normal operation. This paper presents a new approach to monitor the effect of the pressure compensation function of the tube on the tympanic membrane. When pressure differences are equalized, the tympanic membrane moves in- or outward; these movements are detected, using a highly flexible film strain gauge sensor. The new strain gauge design takes into account the anatomy of the tympanic membrane with stapes and the areas of maximal movement. The film adheres to the tympanic membrane via wet adhesion forces. A new measurement system was engineered to improve data acquisition and pressure chamber compatibility. The new strain gauge design and measurement system was tested on probands in a pressure chamber. The measurement system detected both strong deflections during Valsalvamaneuvers as well as slight motion during active tube opening, without causing discomfort for the proband. © 2009 Springer-Verlag.