L'origine dei moderni metodi di esplorazione della periferia uditiva: Dall'onda viaggiante di von Békésy alla coclea attiva

In this study the Authors review knowledge on cochlear mechanics, especially in regards to modern diagnostic procedures of cochlear pathologies. Von Békésy's important intuitions and experiments, on which "pre-modern" knowledge on cochlear physiology was based, are shown, as well as the strong contradictions and the mistakes made in his experiments, mistakes that may appear banal today, but were unnoticed, at that time, by all the academic establishment. From the idea of a passive cochlea, exclusively based on mechanical and hydrodynamic processes of the Basilar Membrane (BM) and on the so-called "traveling wave", we have, during the years, reached what today is known as the "active cochlea": from completely linear mechanisms we acquired knowledge on highly non-linear physiologic mechanisms. The importance of studies conducted with Mössbauer technique and immunofluorescence on the BM and, most of all, on the outer hair cells (OHC) is emphasized. In the last ten years researcher's interest has focused on the OHC, since it is on their charge that most of the micromechanisms that can explain the complexity of sensibility, dynamics of hearing, and frequency analysis capability. Modern diagnostic procedures and methods regarding this particular part of the cochlea, and above all those that rely on Otoacoustic Emissions (OAE), are based on this knowledge.