Diagnostic Measurements and Imaging Technologies for the Middle Ear

Clinical diagnostic tools and imaging technologies can be used to quantify both the physical and functional status of the middle ear in humans. Four fundamental measurement approaches provide quantifiable information. Behavioral measures are the primary, oldest, most common and least invasive and are based on controlled acoustic signals and voluntary responses. Physical measures were developed later and are based on a controlled acoustic signals and controlled static air pressure in the external ear canal while simultaneously measuring the resultant sound pressure. Physiological measures include a variety of involuntary responses that result from controlled acoustic signals that induce specific involuntary physiological activity including reflexive contractions of the middle ear muscles, acoustic signals generated by the cochlear structures, and neural activity from the peripheral auditory neural system detected from electrical signals measured with surface electrodes on the head. Imaging technology, currently undergoing many new developments, is becoming available clinically and being adapted specifically for clinical use. This chapter will outline the current status of these clinical technologies and define how they interact and can be analyzed to provide very precise, repeatable, and quantifiable measures of the structure and function of the entire middle ear and its components in a living human.