Printed in L ’ S A The Acoustic Reflex in Diagnostic Audiology: From Metz to

In 1946, Metz described what was probably the first practical impedance bridge for measurement of the acoustic reflex. Over the next four decades, diagnostic use of the acoustic reflex progressed in parallel with instrumentation refinements. Today, acoustic reflex threshold and decay testing are a routine com-ponent of the diagnostic audiology test battery. Recent advances in the measurement of suprathreshold latency and amplitude have further enhanced the diagnostic value of acoustic reflex measurement. In 1975, Sanders ( 1) summarized his experience with immittance audiometry by writing that “it is rapidly being recognized as one of the most significant contributions since the development of the pure tone audiometer ” (p. 122). One wonders if Otto Metz ever envisioned what was to become of his pioneering work in the clinical measure-ment of middle ear impedance. The story of modern clinical immittance audiometry began in Copenhagen in 1946 with Metz’s now classic monograph (2) on the use of impedance measurement in otological diagnosis. It progressed over the next four decades as the result of a fascinating blend of technological advancement and clin-ical intuition and implementation. It continues today with immittance audiometry enjoying the status of an integral and routine aspect of diagnostic audiology