2017 Volume 27 Issue 2 Pages 111-117
Tympanometry is used to evaluate the presence of middle ear effusion in otitis media with effusion (OME). Recently, it has been recommended to use 1000 Hz tympanometry for newborn infants to evaluate OME. Accurate measurement by 226 Hz tympanometry is difficult in infants owing to their soft external auditory canals. In this study, we investigated the usefulness of high-frequency tympanometry in infants using Easy Tymp (MAICO, Germany), and compared it with the results of 226 Hz tympanometry.
The subjects were 98 infants aged 2 to 50 months (average 23.4 months) who visited our hospital from 2014 to 2015. Among these, 78 infants had cleft palate. Easy Tymp with 1000 Hz probe-tone frequencies and RS-22 (RION, Japan) with 226 Hz frequencies were used for the examination.
Of all the infants, 48 showed a type A tympanogram on 226 Hz tympanometry, while 43 showed “clear peak (type A)” on 1000 Hz tympanometry. In addition, 51 infants showed a type B tympanogram with 226 Hz, while 56 infants showed “flat (type B)” tympanogram with 1000 Hz. In infants less than 12 months of age, especially, 226 Hz tympanometry showed type B tympanogram in 57% of the ears, while 1000 Hz tympanometry showed flat tympanogram in 85% of the ears. In eight infants aged less than 18 months, the 226 Hz tympanometry yielded type A tympanograms and 1000 Hz tympanometry yielded “flat” tympanogram. Six among these eight infants had cleft palate, and they were less than 12 months old. These results were consistent with the previous reports.
The percentage of 1000 Hz tympanometry that yielded “flat” tympanograms in infants aged less than 12 months was significantly higher than the percentage in infants over 12 months old. Moreover, the percentage of 1000 Hz tympanometry that yielded “clear peak” tympanograms in infants aged less than 12 months was significantly lower than the percentage in infants aged over 12 months. Therefore, 1000 Hz tympanometry seems to reflect middle ear effusion more precisely than does 226 Hz tympanometry.
Many infants with cleft palate showed poor tympanic membrane findings and type B tympanograms. It is desirable to perform endoscopic or microscopic visual inspection and hearing evaluation according to the age, assuming the presence of effusion, even if infants showed type A on 226 Hz tympanometry.
The results of 226 Hz and 1000 Hz tympanometries were comparatively investigated. It is difficult to diagnose the presence of effusion even by visual inspection using pneumatic otoscopy. High-frequency tympanometry is useful for evaluating OME in infants with cleft palate, especially in those less than 12 months old.
