Cytochrome P450 enzyme activities in the Australian brushtail possum trichosurus vulpesula: a comparison with the rat, rabbit, sheep and chicken

630 neonates with risk factors of perinatal hearing impairment were screened of hearing loss by means of registration of transient otoacoustic emissions before discharge from the newborn nursery. Neonates were screened additionally by means of brainstem evoked response audiometry, if they had bilateral negative emissions. 810 healthy neonates were screened as control group. The investigations were carried out in incubator after the feeding of neonates. The prevalence of a bilateral negative cochlear response was 5.2% in the risk babies and 1.7% in healthy neonates. Neonates are high risk patients for hearing loss if they show craniofacial anomalies including alcohol embryofetopathy, connatal infections, or very low birth weight babies with additional risk factors. The pedaudiological control investigations of the babies with a negative bilateral cochlear response delivered in the risk group 15 cases (2.4%) with an important hearing impairment and in the healthy neonates 2 cases (0.25%) respectively. Prevalence and importance of perinatal hearing impairment explains the necessity of detection in the neonatal period.