There is a consistently high false-positive rate for infants tested in the newborn nursery—between 3.5% and 10%.5-9,20 This is in part because of matter (vernix) in the newborn ear, the background noise in the nursery, and fluid in the middle ear. The fluid and vernix clear spontaneously during the first few days of life. As a result, most studies repeat the failed newborn screens at the age of 2 to 8 weeks. Infants who fail the second screen are referred for diagnostic auditory brain response testing. The overall failure rate after the second screen was 1% or even less in the referenced studies.59,20 The actual rate of sensorineural hearing loss in these studies is 1 to 2 per 1000. Thus, for every 1000 infants tested, approximately 10 were referred for diagnostic auditory brain testing. The rate of true sensorineural hearing loss was 1 to 2 per 1000. Therefore, 5 to 10 diagnostic auditory brain response tests were done to find each infant with hearing loss. The positive predictive value (PPV) for infants who failed the second screen was 16% in the Rhode Island study and between 5% and 19% in Colorado.8,9 In comparison, the PPV for hypothyroidism screening is 3% and is 80% for phenylketonuria screening.8
Cost-Effectiveness
It appears universal screening will be cost effective, but no studies have been done to prove this. In our study the cost was just higher than $22,000 dollars to find 1 low-risk infant with hearing loss (Tables 2 and 3). Costs in other studies have ranged from $4000 to $17,500 per child identified with hearing loss.6-8 The significant factor when comparing these costs is the actual incidence of hearing loss. Studies with lower costs per identified child had a higher incidence of hearing loss. For example, if our study had found 2 children with sensorineural hearing loss, the cost per child diagnosed would have been just higher than $11,000. This cost of hearing screens can then be compared with the cost of identifying infants with phenylketonuria disease (~$10,000) and hypothyroidism (~$40,000) per child given the diagnosis.8,10 There is a clear cost benefit with phenylketonuria and hyperthyroid screening, but a cost benefit has not been proved with universal hearing screening. The potential for cost savings relies on fewer children requiring special education and fewer adults on long-term disability. The state of South Dakota provides an in-residence school for the deaf at no cost for state residents but charges approximately $15,000 per year for patients who are residents of other states. In-residence schooling in other states can cost as much as $30,000 per year.10 This is approximately 4 times the cost of regular schooling. If only a portion of the early-identified infants attended 12 years of regular school, universal screening would be cost-beneficial. A study comparing schooling costs in early-identified infants versus late-identified infants has not been done.
Is it feasible for rural states to implement a universal hearing screening program? Our study found infants could be successfully screened at a specified time rather than waiting for the infant to be perfectly quiet. Therefore, otoacoustic emission testing lends itself to being taken on the road, and the same equipment and personnel can be used to test infants at a number of hospitals within a 100-mile radius. The software is user friendly, and the cost of otoacoustic emission devices has dropped to approximately $7000. Wyoming began implementation of a universal hearing screening program in 1994, and as of 1998 that program has been fully implemented. In 1998, 95% of all infants born in Wyoming were successfully screened.23 Universal hearing screening can be done, and has been done in rural states and communities.
Conclusions
Testing only high-risk newborn infants results, at best, in early identification of only half of the infants with hearing loss.1 Universal screening is the only effective way to identify the majority of newborn infants with hearing loss. Early identification and treatment has been shown to significantly improve expressive and receptive language skills in infants and children with hearing loss. For this reason, it is clearly worthwhile to pursue universal screening. However, long-term patient outcomes and cost benefits should be studied.
Acknowledgments
We would like to thank the Children’s Miracle Network at Rapid City Regional Hospital, which provided funding of $13,562.50 to purchase the otoacoustic testing equipment.
We also thank Douglas A. Bright, MD, program director, Rapid City Regional Hospital Family Practice Residency, for his guidance and support with our project.