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More than 1 out of every 1 000 children are born with permanent hearing impairment that calls for habilitation. Early detection of hearing loss and commencement of habilitation can improve the language development of such children. Most industrialized countries have programs for detecting hearing impairment in infants. The most common approach is for children to undergo a screening test just before the age of 1. Swedish child health centers have used two distraction methods - BOEL (Gaze Orientation By Sound) and Baby-test 3000. But flaws have emerged in these screening approaches and it has been shown that only 5.4 percent of all hearing impairment in Sweden is detected before the age of 6 months. Otoacoustic Emissions (OAEs) and automated Auditory Brainstem Response (aABR), two methods that offer fresh opportunities for hearing screening of the newborn, can be performed while the baby is still at the maternity ward. A two-stage screening is often employed, i.e., a second test is performed within a few days unless the initial results give a bilateral pass. Habilitation measures - such as the fitting of hearing aids, support for the family and sign language training - can commence as soon as hearing loss is detected. The potential target group for newborn hearing screening consists of the approximately 100 000 children born in Sweden each year.
A number of studies and reviews of the literature indicate that screening during the neonatal period (the first month of life), using OAEs and/or aABR, results in earlier detection of congenital hearing impairment than traditional distraction tests. The only controlled (non-randomized) trial, which included 54 000 children, compared newborn with traditional screening. The number of children with bilateral hearing impairment (40 dB or greater hearing loss in the better ear) who were referred to further examination before the age of 6 months was 94 per 100 000 in the group screened during the neonatal period, as opposed to 32 per 100 000 with traditional screening. The number of false negatives was significantly lower for neonatal (4 percent) than traditional (27 percent) screening. Habilitation commenced before the age of 10 months for 59 per 100 000 of the children who underwent neonatal screening, as opposed to 25 per 100 000 of those who were screened in the traditional manner. A number of studies based on thorough observations suggest that early detection and commencement of habilitation measures improved communicative and linguistic development. There is no evidence that the actual screening of hearing has a negative impact on the child.
For screening to be ethically acceptable, any hearing impairment that is detected must be followed up by an organization that can provide rapid, effective habilitation. False positive screening results, and even early diagnosis, can upset parents during a sensitive period in the relationship with their child. Proper information, short assessment periods and the fewest possible number of false positives can minimize that risk.
Universal screening of the newborn, including diagnostic assessments, costs approximately SEK 240 per child. The adoption of such a program throughout Sweden would add approximately SEK 19 million to annual healthcare costs, ie, SEK 300 000 per additional case detected. Since hearing impairment is detected with traditional screening methods in a considerably smaller percentage of children than in Britain - the country from which the data for making the calculation was taken - the estimated cost in Sweden is approximately 30 percent less. To assess the program´s cost effectiveness, the costs of providing earlier habilitation must also be taken into consideration, as well as the financial resources that society frees up by virtue of better language development among the children affected and improved health-related quality of life for both them and their parents. No data is currently available for calculating either the lifetime costs or the health benefits of universal screening.
There is scientific evidence that newborn screening, using either OAEs or aABR, results in earlier detection of congenital hearing impairment and commencement of habilitation (Evidence grade 2)*. Limited evidence exists that earlier detection and commencement of habilitation promotes improved communication and language development in the child (Evidence grade 3)*. The evidence is satisfactory with respect to costs per case detected but insufficient when it comes to the method´s cost effectiveness.
*Grading of the level of scientific evidence for conclusions. The grading scale includes four levels; Evidence grade 1 = strong scientific evidence, Evidence grade 2 = moderately strong scientific evidence, Evidence grade 3 = limited scientific evidence, Evidence grade 4 = insufficient scientific evidence.
This summary is based on a report prepared at SBU in collaboration with Assoc. Prof. Leif Hergils, Linköping University Hospital, Linköping. It has been reviewed by Prof. Ulf Rosenhall, Karolinska University Hospital, Stockholm and Inger Uhlén, MD, Karolinska University Hospital, Stockholm.
The complete report is available only in Swedish.
SBU Alert is a service provided by SBU in collaboration with the Medical Products Agency, the National Board of Health and Welfare, and the Federation of Swedish County Councils.