Virtual time-variant model of the Eustachian tube

In contrast to most of the clinical examinations, the sonotubometric assessment of the Eustachian tube function allows the registration of the tube opening at the perforated, as well as at the intact eardrum in physiological conditions. In this paper, a new procedure is introduced which performs a measurement of the transmission path nose/ear. With digital signal processing algorithms the generation of a new feature relevant for medical diagnostics is made accessible. The method is based on techniques known from speech processing: the acoustic tube model, the normalized least-mean-square (NLMS) algorithm with so-called perfect sequence (PSEQ) (Luke, 1992 and Luke and Schotten, 1995) excitation and the Levinson-Durbin algorithm. Within the framework of an interdisciplinary cooperation we developed a new real-time acoustic measurement prototype which opens up entirely new possibilities in otological diagnostics