Tympanometry in the detection of hearing impairments associated with otitis media with effusion.

The monitoring of children with otitis media with effusion ties up considerable resources in audiology departments. Impedance audiometry is frequently used when investigating these children. It has been shown to be highly sensitive in detecting middle ear effusion, but its value in identifying those children with a significant hearing impairment secondary to this is in question because of the wide range of hearing impairments possible with a type B tympanogram. This study quantified the sensitivity and specificity of impedance audiometry in detecting a hearing impairment greater than or equal to 25 dB HL due to otitis media with effusion. The subjects were 285 children of whom 20% had hearing thresholds greater than or equal to 25 dB HL. A peaked tympanogram (types A or C) virtually eliminated the possibility (98% confidence) of such a hearing impairment. A flat type B tympanogram was satisfactorily sensitive (93%) in detecting a hearing impairment, but non-specific (76%). The positive predictive value was 49%, i.e. 51% of ears with this type of tympanogram had hearing within acceptable limits. Assuming that a sensorineural impairment has been excluded and a population is being monitored for hearing impairment associated with otitis media with effusion, it is suggested that the presence of a peaked tympanogram indicates normal hearing, whereas those children with a flat tympanogram would require their hearing to be evaluated. Increased use of impedance audiometry to monitor children with otitis media with effusion would reduce the number requiring full pure-tone audiometry with a subsequent reduction in the workload of an audiology department.