We describe a laser Doppler system (LDS) that can be used clinically f
or the measurement of tympanic membrane (TM), malleus and prosthesis h
ead displacement in response to sound inputs of 80- to 100-dB sound-pr
essure level (SPL). It also has the potential for use in the operating
room to perform measurements of prosthesis and stapes displacement. T
he information provided by such testing gives the otologist knowledge
of TM and ossicular function that is unique in evaluating middle ear f
unction; it should help select the best type of reconstruction in a gi
ven case and direct us toward new and better methods of TM and ossicul
ar reconstruction. The results of umbo displacement measurements in 95
human ears are reported. Examples are provided of LDS measurements in
representative ears and how they can be of help to the clinician. The
potential of multisite TM-displacement testing is demonstrated in two
temporal bones, including before and after partial ossicular replacem
ent prosthesis (PORP) insertion.