Extremely low birth weight infants are at high risk for auditory neuropathy

Evaluation of hearing loss after failed neonatal hearing screening

OBJECTIVE

We evaluated the causes of hearing loss found after failed universal newborn hearing screening and compared the results with the previously used behavioral observation test (Ewing/CAPAS).

STUDY DESIGN

Hearing loss in neonates, born between September 1999 and October 2007 and referred to our center after failed screening, was determined by audiologic testing and physical examination.

RESULTS

In 340 included neonates the results of hearing tests were as follows: normal hearing 21.2%, conductive hearing loss 20.3%, and sensorineural hearing loss (SNHL) 57.9%. Children referred from the neonatal intensive care unit were more at risk of SNHL (71%) than those from the well-baby clinics (54%). Hearing aids were provided at a median age of 8 months. The positive predictive value of SNHL screening was 54% for a child from a well-baby clinic and 71% for a child from the neonatal intensive care unit.

CONCLUSION

The use of universal newborn hearing screening results in a lower proportion of infants positive because of otitis media with effusion than the previously used Ewing/CAPAS test (20% vs 59-81%). Second, screening leads to identification of hearing loss and intervention at a younger age (8 months vs 15-18 months). Third, the positive predictive value for SNHL has improved (54% vs 2%).

[Quality evaluation of a neuro-development follow-up program of very low birthweight infants]

INTRODUCTION

Advances in perinatology have been associated with improved survival of very low birth weight (VLBW;<1500 g) infants. These children have an increased risk of future neurological and development handicaps. A set of quality indicators have been recommended for the neurodevelopment follow-up programs in this group of patients.

AIM

To analyze our neurodevelopment follow-up program according to these quality of care indicators in 5 post-discharge follow-up areas: general care; physical health; vision, hearing, speech and language; developmental and behaviour assessment; and psychosocial issues.

PATIENTS AND METHODS

Fifty-one VLWB patients born in 2000 who have completed our 6-year follow-up program have been retrospectively studied. The agreement between our program and the standard of quality is evaluated.

RESULTS

A copy of a discharge summary of the patient's neonatal course is present in the medical record in 92% of the cases. The inclusion of clinical data and general medical aspects in the medical summary is heterogeneous. Somatometric evaluation for the first two years of age is always present in a filled-in graphic. The international classification of the retinopathy of the preterm (RDP) is used in 100% of the patients. An ophthalmologic examination for RDP is performed in 72% (37/51) of the infants before hospital discharge; of the other 28%, only in 6 patients the date of the outpatient examination is present. Specific evaluations and interventions are performed within the recommended period of time in most of the children with suspected or neurosensory handicaps. More than ninety per cent of the patients are referred to the neurodevelopment specialist and most of them go to the visit (90.2% between 9 and 15 months and 78.4% between 21 and 30 months). Recommendations for a psycho-educational assessment are followed in the extremely premature (BW<1000 g and/or 28 weeks of gestational age) children. The number of patients who follow the program decreases with time. Psychosocial evaluation does not usually appear in the medical records of the patients.

CONCLUSION

We have a good adherence to most of the recommended indicators in our follow-up program. The evaluation of these indicators is a useful tool to analyze the quality of a developmental follow-up program and to improve it.

The frequency of auditory neuropathy detected by universal newborn hearing screening program

OBJECTIVE

Auditory neuropathy/auditory dyssynchrony (AN/AD) has become a well-accepted clinical entity. The combined use of oto-acoustic emissions (OAEs) and auditory brainstem response (ABR) testing in the universal newborn hearing screening (UNHS) has led to the easy recognition of this disorder. Although, we are now able to diagnose AN/AD reliably, little is known about its epidemiology, etiology, and especially the frequency of its occurrence. The primary goal of this study was to determine the frequency of AN/AD in the Western Anatolian region of Turkey. The secondary goal was to compare the detection rate of AN/AD before and after the implementation of the UNHS in the audiology department of Dokuz Eylul University Hospital.

METHOD

Between 2005 and 2007, among the 23,786 newborns who were screened by automated click evoked oto-acoustic emissions (a-CEOAE) and automated auditory brainstem responses (a-ABRs), 2236 were referred to our department. All necessary audiological tests were performed for all the referred newborns. Among them, babies with deficient or abnormal ABR in combination with normal OAEs were considered as having AN/AD. These babies were evaluated with additional diagnostic audiological tests. Furthermore, comparison of the incidence of children diagnosed with AN/AD before and after the implementation of UNHS in our audiology department was also performed.

RESULTS

Among the referred newborns, 65 had abnormal or deficient ABR test results. Ten of these 65 newborn babies (mean diagnostic age: 5.7 months) with hearing impairment showed electrophysiological test results that were consistent with AN/AD. The frequency of AN/AD in these 65 children with hearing loss was 15.38%. Moreover, the frequency of AN/AD within UNHS was found to be 0.044%. Seven of the 10 babies with AN/AD had hyperbilirubinemia as a risk factor, which is a high rate to be emphasized. On the other hand, the retrospective investigation of children diagnosed with AN/AD in the same audiology department between 1999 and 2005 (i.e. before the implementation of UNHS) revealed only 7 children, with an average diagnostic age of 34 months.

CONCLUSION

After implementing the UNHS, the incidence of AN/AD in the audiology department increased from 1.16 to 4.13. Furthermore, the age of diagnosis of AN/AD decreased from 34 months to 5.7 months. This study shows that AN/AD, when screened, is a comparatively common disorder in the population of hearing-impaired infants. While newborn hearing screening provides early detection of babies with hearing loss, it also helps to differentiate AN/AD cases when the screening is performed with both a-ABR and automated oto-acoustic emission (a-OAE) tests. Thus, the routine combined use of a-ABR and a-OAE tests in UNHS programs, especially for the high-risk infants, can provide better detection of newborns with AN/AD. Furthermore, hyperbilirubinemia is merely an association and maybe etiologically linked.