[Automated infant auditory screening using the Natus-ALGO 2e in the NICU]

Further examination of infants referred from newborn hearing screening

OBJECTIVES

Universal newborn hearing screening (UNHS) is considered beneficial and is accepted worldwide. However, some problems remain, and administrative systematization has yet to be established in many countries. This study assessed the hearing screening of referred newborn infants and discusses the problems that remain.

MATERIALS AND METHODS

Over the two years from July 2001 to June 2003, 98 ears of 49 infants were judged as a "referral" from a newborn hearing screening program, and were subsequently referred to our hospital for further examination using conventional ABR and other audiological tests. The methodology used for hearing screening varied between practitioners and hospitals that utilized both different recording apparatus for AABR and/or automated DPOAEs and independent protocols.

RESULTS

Conventional ABR identified 21 infants with bilateral normal hearing, 12 with unilateral hearing loss, and 16 with bilateral hearing loss, and a total correspondence rate of 40.8% (20 out of 49 infants). In a comparative analysis, 26 ears out of 98 (26.5%) were determined as false-positive, seven out of 98 as false-negative (7.1%), and there was a total correspondence rate of 66.3% (65 out of 98 ears). Five of the seven false-negative cases who were referred with unilateral hearing loss exhibited moderate to profound bilateral hearing loss (moderate; one infant, severe to profound; four infants). Of the 16 infants with bilateral hearing loss, nine with more than moderate loss had hearing aids fitted at our hospital or related educational institution before most were six months old.

CONCLUSIONS

Our results suggest the accuracy of newborn hearing screening remains an issue, but may be improved by an experienced examiner and better protocols including a two-stage process and altered timing of screening. Other ongoing health care programs need to monitor for signs of hearing loss even in the "passed" infants because of possible false-negatives and delayed-onset hearing loss. Improvement is needed in both the intervention systems and diagnostic follow-up of hospitals. Early public support is also required for infants with either severe to profound or moderate hearing loss. From the viewpoint of test conditions and puerperal parental psychological problems, it is considered that the timing of screening needs further discussion. Here it is suggested that screening should be performed within the first three months of infant's life but not be limited to before hospital discharge, and incorporated into the routine health care program for one-month-old infants without reducing efficiency.