| Hearing handicaps are common defects of newboms and do harm to human health heavily. However, the key to ensure remedy effects is to discover hearing handicaps earlierly. Auditory screening of newboms can make the ones who have hearing impairment be clearly diagnosed in 3 months, which significantly benefits the remedy and convalescence. Distortion product otoacoustic emission ( DPOAE) test is quick and harmless, and so on, so it is the main way in auditory screening of newboms presently. In screening, the best time is so important because many destructive results should be caused if the test be carried untimely. However, in national, studies about it are scarce and argued. Furthermore, most are investigated in transiently evoked otoacoustic emissions ( TEOAE). So the best time in DPOAE test is undefinite. In order to find it, a continuous observation of passing rates of DPOAE in newboms was carried in our study. It would be hoped that auditory screening of newboms be done scientificly.Materials and Methods100 newboms (200ears), male 54 and female 46, (bom range from January 1 to April 19 in 2003 ) , from gynecotokological ward of Shengyang city medical and hygienic center of women and children were examined in auditory room by CJY - OAE - 2000 - I . Circumstances of newboms and their parents were registered in detail. Everyone was examined for 9 times namely 1 2 3 4 5 6 7 15 and 30 after born in quiet situation. The results were processed by SPSS.Results1. The passing rates of DPOAE rose by days. Through approximate half in 1st days, over 70% in 2nd day and over 90% in 4th day, it approached 100% in 15 day. Nobody was found deaf.2. The curve of passing rate - day was steep on the 1st 2nd and 3rd points, and the later section was pretty flat. Untill the 15th day, it became linear and the passing rate approached 100% .3. Comparing the adjoining passing rates, it was found that the time is longer, x2 is less. "P"of the first 3 groups are less than 0. 05, and there were differences in it. But the later is reverse.Discussion1. The intensity of two pure tones in DPOAE is less and the time is short, so middle and inner ears would not be damaged. It is evidenced that DPOAE test is more sensitive than pure tone audiometer test and the amount of it is reduplicated and steady. Furthermore, DPOAE test could endure noises better, so the special room is not necessary for it. Because DPOAE test has so many advantages including cheapness and easiness for schlepping, it is very fit for auditory screening of newboms.2. Otoacoustic emission (OAE) comes from cochlea and approaches external acoustic meatus through ossicula chain and tympanic membrane. So only cochlea and middle ear are healthy, like acoustic neuroma, can DPOAE be normally derived, but ABR could not. It is not proved that cochlea be bad when DPOAE could not be educed, too, because secretory otitis media can prevent it. So do it when newboms have some fat in external acoustic meatus and amniotic fluid in tympanic cavity. Actually, DPOAE test can only be used in first screening, and in final diagnosis auditory brainstem respons(ABR) and acoustic im-mittance measurement are necessary.3. Selecting the best time is considered important when DPOAE test is carried . If it is done more early, too many mistakes will be made, which may result in two bad effects; the one is to spend much money on the later screening, the other is that the parents might be frightened. But later screening would embarrass language learning and reduce the screening rates. In our study, it is found that the passing rates of DPOAE are high and steady when four days or more time after born, approximately over 93.5%. So the best time in auditory screening of newborns is not earlier than the fourth day after born.Conclusion1. DPOAE test is very fit for auditory screening of newborns, especially for the first screening.2. DPOAE test can not be used as a golden level in clinical auditory diagnosis , and should be combined wi...
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