The Milan Project: a newborn hearing screening programme.

AIM: Since 1997 a newborn hearing screening programme has been implemented by the U.O. Neurologia-Neurofisiopatologia and Dipartimento di Neonatologia of the Istituti Clinici di Perfezionamento ICP in Milan for both babies with no risk and those at risk of hearing impairment. This programme was named the Milan Project.

METHODS: The protocol for no-risk babies consisted of three stages: in the first two stages, newborns were tested with transient click-evoked otoacoustic emissions (TEOAE), in the third one with conventional auditory brainstem responses (ABR). The first TEOAE test was performed by 36 h of age, before discharge, the second one after 15-30 d in case of referral, and the third one, by ABR, for those babies who failed the second TEOAE stage. Newborns at audiological risk were submitted to conventional ABR before the third month of corrected age. Some of this latter population was also submitted to the TEOAE test. The entire tested population (no-risk babies and newborns at audiological risk) consisted of 19 777 babies: 19 290 without risk ("no risk") and 487 at risk ("at risk").

RESULTS: During the course of the Milan Project, hearing impairment (ABR threshold equal to or greater than 40 dB nHL) was identified in 63 newborns (19 from the no-risk and 44 from the at-risk population), with a prevalence of 0.32%. Bilateral hearing impairment (BHI) was found in 33 newborns (10 from the no-risk and 23 from the at-risk population), corresponding to 0.17%. Among infants with bilateral hearing impairment, 30.3% had no risk factors. The prevalence of hearing impairment was determined on days 15-30 after birth.

CONCLUSIONS: The results show that the implementation of a hospital-based, universal neonatal hearing screening programme for babies with and without audiological risk is feasible and effective. The effectiveness of the programme has increased as a function of the years since its inception, with a strong decrease in the referral rate. Further improvement is obtained if the TEOAE measurements are repeated in cases of referral scoring before discharge.