AREA CHANGE AND VOLUME DISPLACEMENT OF THE HUMAN TYMPANIC MEMBRANE UNDER STATIC PRESSURE

Direct measurements are presented of the area change and volume displacement of a human tympanic membrane under static pressures in the range of - 1.6 KPa to + 1.6 kPa. The area change is given separately for the pars tensa and the pars flaccida. For the pars tensa a strong asymmetry in area change under positive and negative pressure is observed. The volume displacement is also given separately for the pars tensa and the pars flaccida. The volume displacement of the entire TM agrees very well with volume displacement data in literature on tympanometry. It is shown further that a linear relationship between umbo displacement and volume displacement exists. The compliance of the tympanic membrane under static pressure load is compared to acoustic compliance measurements at low frequencies, and found to be a factor 2.5 higher than the compliance at 500 Hz.