Tympanometric characteristics of Chinese school-aged children

To investigate the tympanometric characteristics of Chinese school-aged children with normal middle ear function.

Measurements were made for four tympanometric variables [peak, compensated static acoustic admittance (peak Ytm); equivalent ear canal volume (Vec); tympanometric width (TW); and tympanometric peak pressure] from 278 Chinese children aged between 6 and 15 yrs. Data from the right ear were compared across age groups with those of Chinese young adults and with Western children of comparable ages. Data from the left ear were used to examine specificity using tympanometric screening criteria suggested in the present study.

The developmental pattern in tympanometric variables found with the Chinese school-aged children in the study was similar to that found with white children in Western studies. Increasing age was accompanied by an increase in peak Ytm and Vec values, a decrease in TW values, and less negative and less varied tympanometric peak pressure values. The lower limit of peak Ytm 90% range of the Chinese school-aged children in the study was lower and their TW values were wider than those of white children. Age-specific data also suggested that the upper Vec limits of children between 6 and 7 yrs of age differed from those of older children. Racial differences in peak Ytm and TW values were noted, in that the Chinese school-aged children had a lower peak Ytm limit and wider TW values than white children. The use of ASHA 1997 guidelines for identifying ears for referral with respect to Chinese school-aged children may therefore not be highly sensitive and specific. Gender differences noted in peak Ytm and Vec values were too small to be of clinical significance.

To increase the accuracy of tympanometry in determining ears to be referred for further assessment, the use of the tympanometric characteristics observed in the Chinese school-aged children in the present study (i.e., peak Ytm lower limit < 0.2 mmhos and Vec upper limit > 1.5 cm3) should be considered in addition to ASHA 1997 tympanometric screening guidelines.