Examination of the eardrum
The eardrum and the chain of ossicles must be mobile in order to be able to absorb a sound vibration and pass it to the cochlea, where this vibration is converted into an electric signal. A tympanometry measures this mobility in an objective way.
The smallest muscle of the human body is the musculus stapedius. This muscle pulls reflexively together with loud noises and provides relative protection against a noise trauma. Measuring this reflex is called step-dement reflex measurement.
With normal hearing, the stapedius reflex will usually be measurable. Absence of the reflex indicates a larger hearing loss.