DPOAE growth function in schoolchildren with impaired temporal ordering skills

To investigate whether the cochlear responses of a group of children with normal temporal ordering tests would be different from those children with abnormal results in the same tests.

25 children aged 8 to 13 years participated in the study, all with normal range pure-tone audiometry thresholds, type A tympanometry and distortion product otoacoustic emissions (DPOAE) present in both ears. Of these, 13 children formed the Study Group and 12 the Control Group. The Study Group differed from the Control Group by presenting changes in temporal auditory tests. In addition to the tests to verify the inclusion criteria, the DPOAE growth function were recorded for three different f2 frequencies, respectively 2002, 3003 and 4004 Hz. The stimuli were presented at level f2 (L2) from 20 to 65 dB SPL in steps of 5 dB and the stimulus level f1 (L1) followed the formula: L1=0.4L2+39 dB. The data were analyzed statistically, adopting a significance level of 5%.

The groups did not differ in relation to conventional DPOAE values (DP-Gram). The Study Group differed from the Control Group by exhibiting both the threshold (p=0.034) and the higher slope (p=0.043) in the 2000 Hz DPOAE growth.

Children with alterations in temporal ordering tests require greater intensity to reach the DPOAE threshold at a frequency of 2000 Hz when compared to children without complaints, also presenting a more linear cochlear amplification at this same frequency, indicated by the increase in the value of slope.