Acoustic Reflex Testing

Measuring the stapedius muscle response to loud sound

Overview

When a loud sound reaches the ear, the tiny stapedius muscle in the middle ear contracts on both sides, slightly stiffening the ossicular chain. Acoustic reflex testing, usually performed with the same probe used for tympanometry, measures the sound level that triggers this contraction and whether it occurs in each ear. Because the reflex pathway runs through the middle ear, cochlea, auditory nerve, brainstem, and facial nerve, patterns of present, raised, or absent reflexes help pinpoint where a problem lies. It is a routine part of the immittance test battery.