INTRODUCTION

The implantation and maintenance of a newborn hearing screening program (NHS) in Maternity Hospitals have stimulated interest and worry of ENT (ear, nose and throat) doctors, child and speech doctors by the importance of guaranteeing precocity of diagnosis of a possible hearing loss and its rehabilitation.

Hearing development follow complexity gradual steps, which begins intra-uterus. Thus, in order that a child acquire a language and develop its speech, he/she should be able to detect a sound, pay attention to it, distinguish it, situated it, memorize it, recognize it and eventually understand it (1-4). Any of these steps, specially the first ones, are very important for the process conclusion.

The interruption of this sequence, which may occur because of either presence or absence of Hearing Loss Indicators Risk (HLIR), will consequently lead to functional losses on child development (2, 3, 5). On the other hand, it is known that the Central Nervous System has great plasticity when early stimulated, mainly up to 6 months of age. This increases connections in the nervous system and successively better rehabilitation of hearing pathways (6). Thus, the first 6 months are much important in the future development of a deaf child. All theses reasons justify the worry of ENT, child and speech doctors, who have raised conscious campaign for ordinary people and health professionals.


Touched by all this, Discipline of Otorhinolaryngology, Department of Pediatrics (Nursery), Speech Therapy Service of Clinical Hospital of São Paulo University (HCFMUSP) and the Department of Physiotherapy, Phonoaudiology and Occupational Therapy of São Paulo University (USP) have developed, in 2003, a Newborn Hearing Screening program as well as clinical follow-up in ENT Ambulatory of HCFMUSP in order to trace new-born audiologic profile in a high risk Nursery of HCFMUSP.

PATIENTS AND METHODS

From March to November of 2003, 1127 newborn (NB) were submitted to Newborn Hearing Screening (NHS) in the Nursery of the Clinical Hospital of São Paulo University. In general terms, this Nursery is said to be a high risk one.

Firstly, a questionnaire on possible Hearing Loss Indicators Risk (HLIR), secondly Joint Committee on Infant Hearing (7) was filled up by a child´s doctor for each of NB.

On NB discharge day, with at least 48 hours of life, all NB were submitted to Otoscopic Exam made by the ENT doctor, followed by external auditory meatus cleaning when needed.

After that, it was made an evaluation of presence of distortion product otoacustic emissions (DPOAE) using ERO SCAN DPOAE TEST SYSTEM - MAICO equipment, type C, when 6 (2 Khz to 4 Khz) auditive frequencies / hearing frequencies were tested with intensity of F1 of 65 dB SPL and of F2 of 55db SPL. The positivity criterion of (DPOAE) was automatically determined by the presence of OAE in three frequencies at least.

Together with DPOAE, it was made a behavior evaluation through a research of eye blink reflex, using "agogô" (a Brazilian percussion instrument) as sound instrument.

All the results were recorded in the same questionnaire and filled up by a child´s doctor. The NB who succeeded in the exams and did not present HLIR were discharged from hospital. The NB who succeeded the exams but presented HLIR were sent to Otorhinolaryngology (ENT) Ambulatory of HCFMUSP in order to have their hearing tested followed; the ones who did not succeed the exams were submitted to a new test for a second time through DPOAE and Eye Blink Reflex. The NB who did succeed neither the first test nor the second were sent to Ambulatory to be diagnosed.

The tests were made by a Speech and ENT Doctors during feeding breaks, as long as the child was in a quiet condition.

RESULTS

From March to November of 2003, there were 1840 NB in the Nursery of Clinical Hospital of São Paulo University. 1127 out of those (61.2%) were submitted to Newborn Hearing Screening Program (NHSP) in the same period (9 months). 581 NB (51.5%) were female and 546 (48.5%) were male.

1020 (90.5%) out of 1127 NB who were assisted, presented suitable Hearing Screening, but 107 (9.5%) presented changes in either one of the evaluations or in both (Graph 1). 44 NB (41.1%) presented lack of DPOAE in left ear, 24RN (22.4%) presented lack of DPOAE in right ear and 35RN (32.7%) presented lack DPOAE in both ears. Eye Blink Reflex was present in 1097 NB (98.2 %). Because of technical problems, ten of the cases were not tested. The Otoscopy followed the normal standard in 1124 NB (99.7%); only one case needed intervention of the ENT Doctor for external auditory meatus cleaning. In one of cases the patient presented agenesis of external auditory meatus and in another, presented synechia in external auditory meatus.

23 (21.5%) out of 107 cases (9.5%) having unsuitable screening were directly sent to the ambulatory for a hearing diagnosis. 84 cases (78.5%) were sent to a new test; from these, only 32 NB (38.1%) attended it. In the retest, 21 NB (65.6%) presented suitable exams, while 11 NB (34.4%) did not. From 21NB who succeed the retest, 2 of them (9.5%) presented HLIR, and were sent to the ambulatory in order to have their hearing test follow-up.

In total, 166 NB (14.7%) presented HLIR, and were sent to the ENT ambulatory to have their hearing development follow-up. 36 NB (3.2%) from these 36 NB were sent to the ambulatory for a diagnosis. From 36 patients, only 32 searched infant deafness investigation ambulatory, then they were sent to Brain Evoked Reflex Auditory (BERA), with the following results: 9 presented exams without any changes; 5 presented exams which suggested conductive hearing loss, 1 patient presented profound bilateral sensorineural hearing loss, 1 patient presented retrocochlear disfunction; while 16 patients did not bring their exams back. Thus, up to the moment, from 1127 patients who were submitted to Hearing Screening Program, only one, female, premature, with parieto-occipital meningoencephalocele, was diagnosed as a deafness case (0.09%), what means, she belonged to the hearing loss risk group. In this way, from 166 patients sent to the ambulatory, only 113 were assisted from May 2003 to June, 2004. This represents a 31.9% loss (53) of patients.

The most hearing loss indicators risk (HLIR) found during Screening, was congenital infection, followed by low Apgar (appearance, pulse, grimace, activity, and respiration), ototoxics, low weigh, congenital malformation, hyperbilirubinemia with exsanguinotransfusion levels, family hearing loss history, syndroms associated to hearing loss, neurological disorders, long-term mechanical ventilation, bacterial and consanguineous meningitis.

DISCUSSION

It is known that for the hearing lack low risk NB, the incidence of bilateral and expressive hearing loss is estimated between one and three in each thousand (8, 9, 10), what can be increase from two to five in each 100 NB coming from Intensive Care Unit (9,11). According to the Census made in 2000 by Brazilian Institute of Geography and Statiscs (IBGE), hearing loss (HL) incidence, in Brazil, achieved 16.7% in São Paulo State (12). Hearing loss is the most frequent congenital disorder, which prevails the others routinely screened, and it prevails 100 times more than phenylketonuria and 10 times more than hypothyroidism (5).

Newborn Hearing Screening Program (NHSP) consists of one or more audiologic exams (otoacustic emissions, brain stem audiometry, impedanciometry, eye-blink reflex), if it is possible, in newborn babies to detect and early treat hearing loss. When NHSP is done only in children who present HLIR, a fail is caused in identifying about 50% of deaf people (7, 13), and that's why it is recommended its accomplishment in universal way, that is, in 95% in NB from the nursery (7). Many of the children without hearing loss risk are not diagnosed before 18 months of age.

World Health Organiztion (WHO) data point out that about 1,5% of Brazilian people present some (HL), what may vary from mild to profound (1). The ideal is to do NHSP in the first month of life, to identify such children before three months of age and begin intervention up to 6 months (5, 7). In Brazil, the diagnostic average age for HL is from three to four years of age (1), and it can take two years to be completed, what can cause incurable damage to the child and tax costs to Society. In 1994, in Nóbrega's dissertation (4), it was concluded that the HL diagnostic confirmation, up to two years of age, occurred only in 13% of the studied patients, however 56% were suspected in this period. Thus, there was waste time in more than 2 years between clinical suspicion and HL confirmation (4, 14, 15).

Although the current study authors wanted to make universal NHSP, they faced some work difficulties, what prevent more than 95% of NB assistance, what meant only 61.2 of NB was assisted.

Although children bigger than 6 months of age can be tested through behavior tests, NB do not present the same easiness (16). Thus, two physiological measure of hearing function can be used: otoacustic emissions (OAE) and brain evoked reflex auditory (BERA) (16). Both have advantages and disadvantages, what means, they are able detect low degree hearing loss (16). So, NHSP has as main target to accurately separate the majority of NB with good hearing from the ones with hearing loss (16).

It is recommended that the NB should be quiet, preferably sleeping (16), in order to have a good exam, what may occur after been fed. In that way, the responsible people for the exam should suit themselves to the Nursery routine to do the tests during the breast-feeding breaks. The people who make the exams have about 2 hours for it, so it is good to keep in mind the feeding time, which happens every three hours, and the fetching time (taking then to their mothers and back to the Nursery).

The exams should be carried out in quiet places and many of the times this becomes difficult, as the collective crying of the NB cannot be avoided. So, the ideal is to make use of an isolated room where the people who make the exams remain alone with the NB.

After the tests done, it will be possible only one discharge procedure, ENT ambulatory guiding to following-up and/or hearing diagnosis if HLIR were correctly filled. It is essential to mention the importance of a multi disciplinary job, which child's doctors as well as nurses should know the ENT and Speech doctors' job. According to Joint Commitee on Infant Hearing (7), HLIR are: NB weighing less than 1500g; small size for gestational age; serious perinatal asphyxia, intracranial hemorrhage orleukoencephalomalacia, suspected or confirmed congenital infection; family history of hearing loss; consanguine parents or syndrome associated to HL; NB with bacterial meningitis; ototoxics; hyperbilirubinemia next to exsanguinotransfusion indication or leukoencephalomalacia; craniofacial malformation; NB who needed ICU for more than 48 hours. One of the difficulties found was on HL family history, as long as the mother was not nearby all the time, the others, could be checked in the NB record

It is important to understand that "SUCCEED" the test means, the results were consistent to normal hearing in the moment of the test (16). In the course of childhood, acquired losses can occur as otitis with secretion, infections, ototoxics, genetic or traumatic causes producing permanent hearing loss (16). Thus, from 166 sent to the Ambulatory, 32 were under diagnostic investigation, while the remained ones were under hearing following-up. According to Joint Committee on Infant Hearing (7), children who present hearing loss risk factor should be attended every 6 months for a period of three years to detect a possible progressive or late hearing loss (7, 16). It is important to pay attention to the instructions given to parents in relation to normal hearing, language development and behavior of a child, so parents will inform the doctor at any sign of changing (16) and also will be prevented from psychological stress (5). According to Fortnum et al (17), the superiority of permanent hearing loss can increase up to 9 years of age, reaching 205 in 100.000 patients. If such information is correct, it is thought that a possible progressive hearing loss is highly underestimated, and this reinforce the need of an attendance of these children.

It is expected that 2-4% of the NB in low risk Nurseries does not succeed the first test. This number can go up to 5-7% in patients who are ICU (16). Some of the factors which may cause failure in the tests are: noisy places, cell desquamation in external auditory meatus (EAM), secretion in medium ear and NB with permanent hearing loss (16). In the current study, there was only on intervention from the ENT doctor for external auditory meatus cleaning. The authors' impression is that at the beginning of the Program failures were more often, probably because of difficulty of technique, which, in the course of the study, was more frequent because of either the outdoor noise or the child excitement.

For lacking available people to make the tests during weekends, the NB who were discharged from hospital in that period had their appointments for the weekdays, this caused a impossibility problem of doing tests and retests during the first month of life, as ideally recommended (16). As the patients (children) got bigger and more excited, it became more difficult to do DPOAE, causing failure increase. For many times, patients did not come back to test, what meant that 52 patients did not come back to retests.

From 166 patients sent to the Ambulatory, only 113 (68%) were present up to the current moment. The same sequence loss rate was obtained by WEICHBOLD AND WELZL-MUELLER (18). Sequence loss can be assigned to unsuitable appointment systems, lack of phone contact, transportation difficulties and lack of communication between doctors and patient's family, in relation to the attendance to detect late hearing loss (19). WITTMAN-PRICE and POPE (20) abserved that when a 20-minute-eduacional-section is applied, during pre-natal period, in relation to NHSP and its importance in language development, 100% of the families came back to follow-up appointment. One of the arguments against NHSP is related to a high rate of a false positive of the test, what increases the number of retests and consequently patients and their family transportation to hospital (5,17).

Profound Bilateral Sensorineural Hearing Loss diagnosis was done in 1 NB out of 1127 evaluated, according to data found in the literature. Late researches appoint that the language of children aging between 3 and 8 years with hearing loss is similar to the ones from the same age without hearing loss if intervention is done up to 6 months of life and if there is an active commitment from parents. In the current study, the diagnosis of sensorineural hearing loss was done at 8 months of life, having the child sent to prosthesis ambulatory. The late identification leads to a late language development, what can result learning and emotional problems (6). Although diagnosis has not been done up to 3 months and intervention up to 6 months of age, as recommended (7), this patient diagnosis was earlier than Brazilian statistics shows, usually occurring between 3 and 4 years of age (1). On the other hand, according to WAKE et al (21), there was no difference in language development between the children's group with early intervention (before 6 months) and the group submitted to intervention between 6 and 12 months of life.

This study's authors also faced problems of charge procedures. NHSP is compulsory in all Maternity hospitals in the city of São Paulo by the Law number 12556 of May 8, 1998, published in DOM (Municipal Document) in Sep 1, 1998. According to Portaria 432 14/11/2000, the followed procedures in NHSP are highly complex and must be charged by APAC, which should be filled up in the ambulatory and not in the nursery of the institution. So, despite being a Municipal Law, the costs on the current project were not repaired. HALL AND DAVIS (22) had the same difficulty, though there were no government funds to apply and extend Newborn Hearing Screening Program.

In the current study, NHSP could be done in the ambulatory as an option, so the charge could be accomplished; on the other hand, absence rate could be high, as observed in retests. The exam could even be damaged by outdoor noise and, besides it could have happened ambulatory appointment overloading.

CONCLUSION

ENT doctors should understand the importance of NHSP to early patient insertion in Society. It is important to be universal, so it will avoid failure in hearing loss perception. It should be a multi disciplinary Program with help of speech, children doctors and nurses. Although it is application is difficult, it must be stimulated and made in all Nurseries. NHSP should be considered as a first step to handle hearing loss, what it is extremely important if it is done, from the diagnosis, its family treatment and orientation. Sensorineural Hearing Loss diagnosis was done in only one patient in this study, in the same incidence found in the literature.


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Picture 1. Newborn Hearing Screening chart in the Nursery of Clinical Hospital of São Paulo Univerty.

Graph 1. Newborn Hearing Screening (NHS) Results.