When the NIH Consensus Development Conference recommended that all babies be screened for hearing loss before discharge from the hospital, many people questioned whether it was practical for hospitals to implement such programs. Although the rapid increase in hospital- based programs in the last five years provides clear evidence about the practicality of such programs, many questions remain about the efficiency and effects of such programs (slide #34). Many such issues could be addressed, but only four are discussed briefly here.
The first issue relates to how successful programs have been in screening all babies prior to discharge and what types of referral rates are typically achieved. Slide #35 shows the results of a survey of 120 universal newborn hearing screening programs, all of which used either OAE or ABR as a screening tool. Fifty-five of the 64 OAE-based programs used TEOAE, and 54 of the 56 ABR-based programs used the Natus automated ABR. These data show that the percentage of babies screened prior to discharge is about 95% for both OAE and ABR-based programs. Less than 10% of babies do not pass the screen prior to discharge, with referral rates for AABR about half the referral rates (4% on average) as compared to the referral rate of OAE-based programs (about 8%). These numbers are very different from the percentages published about the original Rhode Island Hearing Assessment Program in which 27% of the infants were referred for additional screening at the time of discharge. With changes in equipment and procedures for doing screening, referral rates have come down dramatically for OAE-based programs. Referral rates for AABR-based programs have also been reduced, even though they were never as high as 25%. With the newest equipment, it is not unusual to have referral rates for AABR-based programs of 2% or 3%.
In spite of the fact that most hospitals are discharging babies at an average of about 24 hours after birth, coupled with frequent reports of referral rates of less than 10% at the time of hospital discharge, there is still a persistent belief that referral rates will be very high for OAE- based programs when babies are less than 24 hours of age. An article by Maxon and her colleagues provides data showing how it is possible to obtain very low refer rates for babies within the first few days of life (see slide #36). The article also makes many concrete suggestions for how to achieve acceptably low referral rates in TEOAE-based newborn hearing screening programs.
Questions have also been raised about whether UNHS programs really do reduce the age at which children with hearing loss are identified. Some people have felt that because of the difficulties in follow up and diagnosis of very young children, we could go to a great deal of work and still not substantially reduce the age of identification. Data addressing this question were reported recently by Parving and Salomon (slides #37 and #38), in which three different five-year cohorts of all births in Copenhagen County beginning in 1970, 1980, and 1990 were analyzed for the age at which a bilateral hearing loss greater than 25 dBHL was identified. For the 1970-74 cohort, no specific procedures were in place for early identification of hearing loss. Beginning in 1975, a home-based behavioral screening program was used with more than 95% of all the children. From 1990 to 1994, an OAE newborn hearing screening program was implemented for approximately 20% of all of the births. There were approximately 37,000 births in each five-year cohort, and procedures for diagnosis and follow up were essentially the same for all of the cohorts. As shown in slide #38, the average age at which children with hearing loss were identified dropped substantially for each of the cohorts. Even though universal newborn hearing screening had not been implemented county-wide in 1990, more than 60% of the children with hearing loss were identified before 12 months of age. The prevalence of hearing loss in each of the three cohorts was about the same. The data from Parving and Salomon provide good evidence that hospital-based universal newborn hearing screening programs will substantially reduce the age of identification compared to a home-based behavioral screening program.
A third issue related to the efficiency of newborn hearing screening programs is whether such programs create unacceptable levels of parent anxiety or disruption of family functioning. Ellen Clayton has summarized some of the possible negative consequences of different screening outcomes (slide #39). To assess how frequently such problems occur, Tluczek et al. (1992) gave questionnaires to 104 parents of children who had failed a screening test for cystic fibrosis. A similar study was done by Uzcategui (1997) of 171 parents of children who failed the initial newborn hearing screening test (slide #40). In both cases, a Likert-type scale was used to assess parent feelings on a number of dimensions related to anxiety. Slide #41 shows the results from both studies. Although the level of concern/fear, shock, anger, and confusion are substantially less for the newborn hearing screening sample than for the cystic fibrosis sample, it is clear that issues related to parent anxiety need further investigation. Other results from the Tluczek study emphasized the need to make sure parents are appropriately informed about the intent to do screening and the results of the screening process (slide #42).
A study by Barringer and Mauk (slide #43) showed that virtually all parents would give their permission to have their baby screened if they were asked, and the majority would be willing to pay for it out of their own pocket. Almost 90% said that any anxiety caused by the baby not passing the initial screen would be outweighed by the benefits of early detection if hearing loss was found to be present.
Similar results were found by Watkin and his colleagues (1995) when they surveyed 208 parents of children with sensorineural loss (slide #44). The majority wished their child had been identified earlier; 89% preferred having a newborn hearing screening program instead of what they had; and most were dissatisfied with the age at which their child's hearing loss was identified.
A final issue related to the efficiency of newborn hearing screening programs has to do with tracking babies who are referred from the initial screen through the diagnostic process and making sure they receive appropriate early intervention. Most operational programs identify tracking and follow up as the biggest challenge related to early identification of hearing loss. As shown in slide #45, many programs are unable to obtain conclusive diagnostic information on as many as half of the children who failed the screening process. Not surprisingly, programs with the highest prevalence rate are those that are most successful at following children through to a conclusive diagnosis. Clearly, finding ways to keep better track of children until a diagnosis is obtained is one of the most important challenges that needs to be addressed by programs whose goal is early identification of hearing loss. Screening itself has proven to be relatively easy, but completing the process through diagnosis and appropriate early intervention remains a substantial challenge. It appears that how successful we are at tracking children through the diagnostic process is partly a function of geographical and socio-economic circumstances. Clearly, programs that don't work hard at keeping track of children will not be successful. However, many programs that have been working very hard still lose track of a substantial number of children.
These data emphasized the need for better tracking and follow-up systems and integrating those tracking and follow-up systems with other public health information databases. It is also important to point out, however, that even in those programs which are having difficulty tracking the majority of children through a conclusive diagnosis, the prevalence of children with hearing loss being identified is substantially higher than has historically been the case. Thus, it is clear that universal newborn hearing screening programs are efficient in identifying children with hearing loss at an early age, but improvements are still necessary.
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