부산대학교 도서관

Objective: Individuals with hearing within the normal range and presence of Distortion Product Otoacoustic Emissions (DPOAE), have a varied amplitude in the range of emissions when compared to each other or between the frequencies tested. Therefore, it is important to determine if DPOAE amplitudes are normal or abnormal. In some cases, a quick analysis leads to the confident conclusion that the findings are normal when noise floors are consistently low across the frequency region and the DPOAE amplitudes are reliably within a normative range defined by the 5th to 95th percentile lines. In other cases, the analysis will require a thorough examination of each of these response parameters, and their correlation with other audiologic findings. However, there is no literature on normative data on the expected DPOAE amplitude values performed using the ILO version 6, Otodynamics®, equipment and these data can be premeditated for further investigation in cases with present but reduced amplitude DPOAE response. Thus, the aim of the study was to analyze the DPOAE values in children with typical development and normal hearing. Methods: A total of 114 ears (57 individuals) between the ages of 7 and 15 years were evaluated, 29 female and 28 male. We used as inclusion criteria to constitute the study group, individuals without otologic symptoms, history of middle ear infection, ear surgery and with audiometry assessment within the normal range according to the criteria of the World Health Organization. Then, the individuals were submitted to research of DPOAE. In the DPOAE, the frequencies f1 and f2 were presented simultaneously, in the intensities of 65 dB and 55 dB, respectively, in the relation f2/ f1=1.22. The frequencies f2 investigated were 1; 1.4; 2; 2.8; 4 and 6 kHz To the realization these procedures, an otoacoustic emission analyzer model ILO version 6, Otodynamics®, was used. DPOAE were found to be present when the difference between amplitude and noise was greater than or equal to 3 dB, at frequencies of 1 and 1.4 kHz and when the difference between amplitude and noise was greater than or equal to 6 dB at frequencies of 2; 2.8; 4 and 6 kHz. Then, the collected data were tabulated and subjected to statistical analysis using the MINITAB 16 software. Descriptive analysis comprised measures of central tendency (mean and median), dispersion (standard deviation) and position (maximum and minimum). Results: When performing DPOAE in the 114 ears, all presented presence of response. The results obtained from the descriptive statistical analysis of the amplitude of the emissions for each frequency presented lower average for the frequency of 1000 Hz, being 21,068 with a con- fidence limit of 19,997 for 5th percentile and 22,139 for 95th percentile. The 1400 Hz and 2000 Hz frequencies presented similar position measurements, with an average of 1400 Hz equal to 24,705, with a confidence limit of 23,774 to 5th percentile and 25,636 to 95th percentile, while for the 2000 Hz frequency the average obtained was 24,751, with confidence limit from 23,918 to 5th percentile and 25,602 to 95th percentile. The same occurred with the frequencies of 2800 Hz and 6000 Hz, with an average of 23,682 and confidence limit of 22,787 to 5th percentile and 24,576 to 95th percentile at 2800 Hz and an average of 24,644 and confidence limit of 22,720 to 5th percentile and 24,567 to 95th percentile at 6000 Hz. The 4000 Hz frequency presented an average of 24,097 and con- fidence limit of 23,185 for 5th and 25,010 for 95th percentile. Conclusions: The results obtained related to DPOAE amplitude may contribute to a more accurate diagnosis of peripheral auditory system alterations. [ABSTRACT FROM AUTHOR]