Pure-tone audiometric and impedance measurements in school-aged children in Finland

Pure-tone audiometric and impedance examinations were performed in 687 Finnish school children in the first, fourth and eighth grades (ages, 7, 10 and 14 years old) to study the sensitivity and usability of hearing and tympanometric screening examinations in schools. There were 138 children (20.1%) with a hearing loss > 15 dB in at least one frequency. Among these children, 103 were found to have pure sensorineural losses while 35 children had conductive losses. Of all the sensorineural losses, 118 of the cases involved slight high-frequency changes. Six children had hearing losses at speech range and all had been previously diagnosed. Six other children had 20–30 dB losses at 3–6 kHz, with 5 of these children diagnosed for the first time. Twenty-four of the children with conductive losses had middle ear effusions that were found at a 15 dB screening level for hearing. When the limit of normal tympanometric peak pressure was -150 daPa, 36 of 38 ears with middle ear effusions were found tympanometrically. Judging by the findings of the present study, we recommend that routine pure-tone audiometric screening for 7- and 10-year-old children in schools could be discontinued but should be continued for 14-year-old children. In contrast, tympanometry with a tympanometric peak pressure limit at -150 daPa should be used as a screening procedure for 7-year-old children on school entry.