An electronic instrument used to evaluate the functional condition of the middle ear by changing the air pressure in the external auditory canal to measure and graph the mobility characteristics of the tympanic membrane. It identifies abnormalities in tympanic membrane mobility due to stiffness, flaccidity, or the presence of fluid in the middle ear cavity. The device is also used to measure the acoustic reflex threshold from contractions of the stapedial muscle, to monitor healing of tympanic membrane grafts or stapedectomies, or to monitor follow up treatment for inflammation of the middle ear.