Middle ear effusion: relationship of tympanometry and air-bone gap to viscosity.

Sixty cases comprising 95 ears were reviewed in which myringotomy with ventilation tube insertion had been performed for alleviation of middle ear effusion and for which tympanometric and pure-tone audiometric data had been collected within five days of surgery (mean = 1.0 days). Results suggest that types B and C tympanograms in combination with greater than 15 dB air-bone gaps are good indicants of thick fluid in children less than nine years old. No tympanometric patterns in combination with air-bone gap data systemactically predicted thin fluid. For all subjects, type C tympanograms with less than 15 dB air-bone gaps indicated an absence of significant fluid at surgery.