Normal values for distortion product otoacoustic emissions in children: a study using primary levels previously demonstrated to be optimum for identification of hearing loss.

No published data exist for normal values of distortion product otoacoustic emissions (DPOAE) in children at primary levels f1 = 65 dB and f2 = 55 dB SPL. These primary levels have been previously demonstrated to be optimal for identification of hearing impaired ears in adults. A total of 102 normal children underwent audiological assessment, including exclusion of middle ear disease, pure tone audiometry and DPOAE DP-grams (primaries L1/L2 = 65/55 dB SPL, f1:f2 = 1.22). There was a statistically significant decrease in DPOAE amplitude with increasing age. DPOAE amplitude was also dependent on the frequency of f2. However, there was wide inter- and intra-individual variation in DPOAE amplitude at different frequencies of f2. There was also a large overlap between the range of values of DPOAE amplitude between the adjacent age groups. Detailed assessment of DPOAE in children is feasible in the clinical setting. These normal values should prove invaluable in future studies; however, the large range of normal values means that cross-sectional studies may not be able to detect small variations in cochlear function.