![]() 8, 11, 12 When comparing either test alone, pneumatic otoscopy has a better sensitivity and specificity than tympanometry for the diagnosis of OME. Determining the presence of obstructing cerumen in the canal, perforation or ventilation tubes in the tympanic membrane, and characteristics of the tympanic membrane (e.g., color, mobility, position, translucency) are helpful in correlating tympanometry findings with clinical disease. 6 Using pneumatic otoscopy with tympanometry improves the accuracy of diagnosis because many abnormalities of the eardrum and ear canal that might cause an abnormal tracing can be visualized. A pneumatic otoscopic examination of the tympanic membrane should be performed before tympanometry. The graphic display of this data is the tympanogram. ![]() The handheld tympanometer is a device that provides quantitative information on the function of structures and the presence of fluid in the middle ear. A type C curve may be useful when correlated with other findings, but by itself it is an imprecise estimate of middle ear pressure and does not have high sensitivity or specificity for middle ear disorders. According to the Agency for Healthcare Research and Quality guidelines on otitis media with effusion, the positive predictive value of an abnormal (flat, type B) tympanogram is between 49 and 99 percent. Tympanogram tracings are classified as type A (normal), type B (flat, clearly abnormal), and type C (indicating a significantly negative pressure in the middle ear, possibly indicative of pathology). Tympanometry is not reliable in infants younger than seven months because of the highly compliant ear canals of infants. It also can provide useful information about the patency of tympanostomy tubes. Its use has been recommended in conjunction with more qualitative information (e.g., history, appearance, and mobility of the tympanic membrane) in the evaluation of otitis media with effusion and to a lesser extent in acute otitis media. Tympanometry provides useful quantitative information about the presence of fluid in the middle ear, mobility of the middle ear system, and ear canal volume.
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