specificity and sensitivity of transient otoacoustic emission in neonatal hearing screening compared with diagnostic test of auditory brain stem response in Tehran hospitals

Since early detection [specially before 6 months of age] of deaf people leads to better hearing and speech outcome after treatment, several clinical trials have been performed in order to find a cost effective, short duration screening test for diagnosis of neonatal hearing impairment. The aim of this study was to assess the sensitivity and specificity of Transient Otoacustic Emission [TEOAE] test in newborns comparing with auditory brain stem response [ABR] in the age of 3 months and to analyze the association between risk factors and hearing loss in neonates. A cross-sectional study was conducted January 2008 - May 2009 in Tehran. 1000 newborns [526 boys and 474 girls] were assessed. First, all of neonates were evaluated by TEOAE 24h after birth. If responses of OAE were failing, they were retested 10 to 15 days after birth by TEOAE. Also, All Neonates were assessed by ABR in the age of 3 months. Descriptive Statistics was used to analyze data. Eighteen out of 1000 neonates failed double-checked TEOAE tests, of which 6 were confirmed by ABR test [12 false positive results]. Nine out of 1000 neonates had impaired ABR tests, from these patients, 6 had failed OAE as well, but 3 had normal OAE [3 false negative results]. From these 9 patients 2 had profound hearing loss and received cochlear implantation. We found that OAE has 66.7% sensitivity and 98.8% specificity in diagnosis of neonatal hearing impairment. Its positive and negative predictive value was 33.3% and 99.7% respectively. Also we did not find statistically significant relationship between hearing loss and risk factors. TEOAE as a simple, non-invasive, short duration and cost effective method, is a suitable test for neonatal hearing screening. Even though only two thirds of patients were detected by this method, 99.7% negative predictive value makes it a good screening test. We recommend OAE as a suitable primary neonatal hearing screening all over the country

model portraying experimental loss of hair cell: the use of distortion product otoacoustic emission in the assessment of rat's ear

The use of rats in research academies to study deafness is widespread, meanwhile medicinal methods to eliminate hair cells is also increasing. Thus, aminoglycosides and loop diuretics have grasped more attention. This study aimed at establishing an animal model in which a rapid distortion of the hair cell of cochlea administering amikacin and furosemide and using distortion product otoacoustic emission [DPOAE] the functioning of rat's ear would be assessed. Forty-eight male Sprague-Dawley rats [mean weight 200-250g] were randomly divided into six equal groups. Except the control group the rest received 0.5mg/g, 0.75mg/g, 1mg/g, 1.25mg/g, and 1.5mg/g, of subcutaneous amikacin respectively. 30 minutes later every rat received 0.1mg/g of furosemide intrapritoneally. DPOAE of rats was measured before these injections and 72 hours later. Then tissue sections of the rat's cochlea were prepared. All the cases had a significant decrease in their DPOAE with the frequencies 2KHz-8KHz [p