The handicap due to hearing loss is well known. In neonates it will impair speech learning and education. Early detection of hearing loss will help with a correct treatment. The prevalence of congenital hearing loss is as high as 3 for 1000 normal births. Prevalence is higher in at risk neonates in neonatology. Risk factors are known: history of familial hearing loss; intra uterine infection (cytomegalovirus, rubella, herpes, toxoplasmosis); bacterial meningitis ; ototoxic drugs (aminosids, diuretics) ; birth weight lower than 1500g ; hyperbilirubinemia treated by blood exchange or phototherapy; Apgar's score ranging from 0 to 4 after 1mn or 0 to 6 after 5mn ; and assisted ventilation for more than 5 days.

      In a publication of June 1999, the French Health Agency ANAES (Agence Nationale d'Accreditation et d'Evaluation en Sante) recommended a generalized newborn hearing screening using otoacoustic emissions recordings. Such a screening is widely used in England and in the United States but not in France except in Lyon. In 1993 we started a hearing screening program of at risk neonates in a neonatology unit. This program is still in progress. Recently we studied the feasibility of a generalized hearing screening in a maternity hospital of Lyon. Screening is based on the recording of transient evoked otoacoustic emissions (TEOAEs). Presence of TEOAEs in the newborn ears shows that outer hair cells of the organ of Corti function properly. Absence of TEOAEs needs to be confirmed with at least 2 successive recordings. If certain, a hearing loss is suspected. It is then confirmed with a clinical examination by an otorhinolaryngologist and by the recording of brain stem evoked potentials (BAER). BAER will assess hearing loss, determine its origin and measure its depth. A treatment (cochlear implant or hearing aids) may then be started.

      We published our results of hearing screening of 1531 at risk neonates: "Auditory screening in high-risk pre-term and full-term neonates using transient evoked otoacoustic emissions and brainstem auditory evoked potentials" T. Morlet, C. Ferber-Viart, G. Putet, F. Sevin, R. Duclaux. Int. J. Pediatric ORL, 45 (1998) 31-40. In 1361 newborns (89%) TEOAEs were normally present, but they could not be recorded in 170 newborns (11%). After BAER and clinical examination, severe hearing loss has been diagnosed in 14 neonates (0,9%). 22 (1.6%) had a unilateral or a bilateral but moderate hearing loss. These results show that hearing loss is far more frequent in newborns at risk in the neonatology units than in normal neonates. For this reason we are trying to extend hearing screening in other neonatology units of Lyon. However, it is well known that hearing screening of at risk populations will miss up to 50% of congenital hearing losses in newborns. On a public health point of view it is necessary to implement a generalized hearing screening in maternity hospital.

       We studied the feasibility of such a program in a maternity hospital of Lyon. Our results show that the recording of TEOAEs is well accepted by the mothers ("Depistage systematique de la surdite en maternite par otoemissions acoustiques provoquees: aspects pratiques et attitudes parentales": A. Moulin, C. Ferber-Viart, M. Berland, C. Dubreuil et R. Duclaux . Archives de Pediatrie, 8, 1-8, 2001). In our study, 200 newborns have been recorded in 2 months. No profound hearing loss has been diagnosed. In 6 newborns (3%) TEOAEs could not be recorded. They had normal BAERs. Hearing was subsequently normal.

       In order to implement the screening in a maternity hospital the necessary equipment costs about 100 000 FF (15 150 Euro). In a maternity hospital with 3000 births a year a full technician 7 days a week is necessary in order to record TEOAEs every day. As a whole, hearing screening of 1 newborn costs about 100 FF.

       Generalized hearing screening in newborns is recommended by the French Health Agency. As shown by our studies it is possible to implement such a screening in maternity hospitals in France. However, investments in equipment as well as in medical and technical staff are necessary. In French maternity hospitals, the cost of hearing screening would be about 100 FF (15.15 Euro) per newborn.

Contact : Pr. Duclaux and Dr. Ferber-Viart, Hospices Civils de Lyon et UMR CNRS Neurosciences et Systèmes Sensoriels, Service d'Exploration Fonctionnelle Neurosensorielle, Centre Hospitalier Lyon Sud et Hôpital Debrousse, 69 310 PIERRE BENITE, France.

e-mail : roland.duclaux@chu-lyon.fr
chantal.ferber-viart@chu-lyon.fr