Twenty studies were included in the review: two for treatment efficacy; eight for screening efficacy; and 11 for safety of screening and treatment.
Treatment efficacy: one good-quality retrospective cohort study found that significantly more children who had undergone UNHS were diagnosed by the age of nine months than was the case for those not screened (p< 0.001). Children diagnosed before the age of nine months had statistically significant better adjusted mean scores on a majority of language outcome measures than those diagnosed later, corresponding to an increase of between 10 and 12 points of verbal intelligence quotient. Children who had undergone UNHS had statistically significantly higher scores on some language measures at school age. Another fair-quality study provided inconclusive evidence on relationships between age at diagnosis and language outcomes.
Screening efficacy: one large nonrandomised trial found that UNHS had a false positive rate of 1.5 per cent and a false negative rate of 4 per cent. Based on this, screening yield was estimated to be 90 cases per 100,000 of population, equivalent to 80 per cent of expected prevalence. UNHS resulted in an increase in referrals before six months of age of 71 per 100,000. This was accompanied by significantly higher odds of confirmation of diagnosis before 10 months (5.0, 95% CI: 1.2, 23.0), initiation of management before 10 months (8.0, 95% CI:1.2, 51.0) and higher detection rates (2.3, 95% CI: 1.1, 4.7).
Safety: there was some evidence from non-randomised studies and surveys of increased parental anxiety and worry associated with screening for children with positive tests. There was some evidence from case series of increased rate of bacterial meningitis in children with cochlear implants, particularly those in which positioners were used. None of these cases occurred in children aged under 12 months at implant.