Liden-Jerger classification of tympanometric shapes

Type A tympanograms are indicative of normal middle ear pressure. Type A_D (deep) tympanograms demonstrate increased compliance, as seen with ossicular chain discontinuity. Type A_S (shallow) tympanograms show decreased compliance, suggesting a stiff middle ear system, which can be caused by myringosclerosis or otosclerosis. Type B tympanograms with little or no mobility of the tympanic membrane are suggestive of middle ear effusion. Type C tympanograms indicate negative middle ear pressure and a retracted tympanic membrane. Type D tympanograms are notched, suggesting a hypermobile or scarred tympanic membrane.