Probst R, Harris FP. Arch Otolaryngol Head Neck Surg. Coronavirus Resource Center. Our website uses cookies to enhance your experience. By continuing to use our site, or clicking "Continue," you are agreeing to our Cookie Policy Continue. Twitter Facebook. This Issue. August Harris, PhD. Access through your institution.
Add or change institution. Save Preferences. Privacy Policy Terms of Use. Introduction: The correlation between the transient TEOE and distortion product DPOAE evoked otoacoustic emissions may be useful for the neonatal auditory screening, mainly in premature infants, who have risk indicators for hearing deficiency.
There is need for deepening the knowledge regarding this population cochlea features. But one method compliments the other and both may be used in the TAN. Since then, several studies were carried out and the results found in the INHI identification of neonatal hearing impairment were described.
However, it is necessary to go on with these works, mainly in special population, such as the premature neonates. The mean age of the diagnosis occurs at about 3 years of age 1. The neonates are considered to be premature when they are born with gestational age lower than 37 weeks and for presenting special characteristics, and they also need specific cares 2.
Due to the long period of permanence in the Neonatal Intensive Care Unit NICU , the premature neonates are exposed to an inadequate environment of stimuli and amongst which the excessive noise. In the uterus, the fetus is protected from external noises for the joint action of the uterine wall, the amniotic liquid and also for listening only by osseous way.
In the other hand, by losing uterine protection and starting airway hearing, the preterm infant remains exposed to high levels of noise in the NICU.
On average, the bottom noise is a NICO of From the hypothesis that the transient evoked otoacoustic emissions TEOAE are more used, but have a large number of "failures" in the premature newborns and a number of these "would pass" the distortion product evoked otoacoustic emissions DPOAE , as observed empirically in the clinical practice, this research aims at carrying out the TEOAE and DPOAE and compare their outcomes in a sample of premature neonates and verify the correlation of both tests.
In addition to this, the premature newborns have a number of risk indicator for hearing loss, and the scientific community needs to deepen the knowledge regarding the features of the cochlea in this population. Then the correlation between the TEOAE and DPOAE may raise new information for the accomplishment of the INHI, especially in premature neonates for they present with particularities such as a reduced size of the external auditory meatus, the high physiological noise, and the presence of risk indicators of hearing loss.
After the babies were discharged from the NICU, they remained with their mothers in a joint lodging called intermediate bed, and in this occasion the procedure was applied only to newborns for whom the parents signed the Term of Free and Clarified Authorization. During the period from April through August , 50 premature babies were selected at random and consecutively, 23 of feminine sex and 27 of masculine sex, with the presence of one or more of the following criteria of hearing loss risk: disease or state requiring admission in the ICU for 48 hours or longer; mechanical ventilation; use of ototoxic medication.
Patients with other risk factors for hearing loss were excluded from the study because they could present with hearing loss due to factors not related to the prematurity and permanence in the NICU. Patients with nasogastric probe were excluded from the study for being susceptible to otitis media 3. The babies remained during the exam n the cradle in postprandial sleep, beside the mothers' beds.
The initially ear to be tested was selected at random. The exams with suitable response in three frequency out of the five tested were considered to be "approved", and the exams that did not present the pattern adopted were considered to be "failure".
The data descriptive analysis was made: frequency, central trend average and variance measures standard deviation , presented by means of tables. The mean age was of 34 weeks d. All were suitable to the gestational age GA with average weight of However, with the frequency band of 4kHz we verified a significant difference Table 1.
In the reproducibility study we observed a higher average in the frequency of 3kHz, in the statistical analysis we verified a significant difference with the frequency bands averages of 2kHz and 4kHz Table 1.
In the gender comparison we verified? The analysis of amplitude per frequency band in the DPOAEs showed that the highest averages occurred in the frequency of 2kHz and 8kHz respectively Table 2. In the other frequency bands we verified significant differences between the averages Table 2. All Issues. Year: Vol. Original Article. PDF in Portuguese. PDF in English. Text in Portuguese.
How to cite this article. Author s :. Key words:. Because the DPOAEs presented less noise interference, whether physiologically or environmentally of the newborns, there is a lower number of failures, which was also verified in this study. By evaluating 70 neonates coming from NICU, about It is worth standing out that this difference was confirmed in studies with a higher number of participants and suggests anatomic differences between genders with the possibility of occurring a higher quantity of external hair cells in the female gender's cochlea and factors related to the efferent activity of the right ear.
Therefore, we may infer that this study did not find any significant difference between genders and between ears possibly because of the number of participants. It is worth remarking that despite the frequency band of 3kHz presents a performance better than the others, upon the execution of the statistical analysis between frequencies, there was no significant difference between the averages of the frequency band amplitude of 3kHz and 2kHz.
The fact that the frequency band of 3kHz has response values higher than the other frequencies on average is opposed to our studies 8,9,13,14,15 KORRES and col. In the scientific literature we may observe a growing interest in the studies of the DPOAEs in the INHI, mainly for the frequency specificity 19, 20, 21, 22, 23, 24, In the statistical analysis no significant difference was observed between genders and the side of the ears; this finding was also verified in other researches 19, 20, Upon performance of the comparison by frequency band, no statistically significant difference was observed between the amplitude averages of the frequency bands of 2kHz and 8kHz.
GORGA and col. However, there was no statistically significant difference in the comparison of the frequency bands averages of 2kHz and 3kHz. In the same study the authors compared the outcomes from the DPOAEs with the region in which the exams were carried out: room without acoustic treatment and room with acoustic treatment.
The fact that "failure" occurs more in the TEOAEs than in the DPOAEs may be explained by the difference between the obtainment technique and the frequencies that were tested in each of the tests.
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