Newborn hearing screening has positively affected childhood developmental outcomes. However, limitations remain, including;
- high false positive and negative rates of detection for progressive and late onset deafness
- multi-tiered testing is routinely required as symptoms develop
- there is no focus on differentiating non-genetic causes, genetic predisposition to ototoxic drugs, and genetic causes of hearing loss.
Molecular genetic testing could address these weaknesses by providing a specific diagnosis not dependent on phenotype and not requiring confirmatory follow-up testing.
Despite these limitations the prevalence of childhood hearing loss (HL) has declined in an era of vaccinations and less ototoxic drugs. Still genetic causes of HL represent 40-50% of cases. Most are non-syndromic (NSHL), and not associated with other clinical features. Despite eliminating HL due to congenital rubella andHaemophilis sepsis/meningitis, congenital NSHL continues to affect 1/1,000 newborns. By adulthood, an additional 1/1,000 will develop HL. It is interesting that the incidence is higher than most metabolic disorders which are included in mandatory newborn screening programs. Early diagnostic detection of congenital NSHL is critical since early auditory stimulation by 6 months of age is required for age apprpriate speech and language development1,2. The costs associated with special education for the affects of a late diagnosed child range from $38,000-240,0003 per life. Consequently, screening for NSHL became a national priority in 1993 when NIH endorsed universal screening by 3 months of age4-6. The American Academy of Pediatrics and American College of Medical Genetics also endorsed screening7,8. Currently there are 2 approaches to screening: high-risk and universal. High-risk screening detects ~50% of affected infants. Development of physiological screening tests suitable for testing newborns led to universal screening. More recently focus has shifted to development of more efficient cost-effective technologies and methodologies. In our next blog we will discuss these methodologies; Audiometric Newborn Screening, Cytomegalovirus (CMV), GJB2 and GJB6 Mutations, Mitochondrial (MT) mutations, Syndromic Deafness, Usher syndromes
There are also misconceptions about hearing loss screening;
- One is that parents will know if their child has a hearing loss by the time their child is 2-3 months of age. Prior to the universal hearing screening, the average age at which children were found to have a HL is 2-3 years.
- Another, frequent misconception is that HL does not occur often enough to justify the use of universal screening programs. At 2-4 per 1000 live births it has been estimated to be one of the most common congenital anomalies.
- Parving A. The need for universal neonatal hearing screening - some aspects of epidemiology and identification. Acta Paediatr Suppl. 1999: 88; 69-72 [PMID: 10626584].
- Löhle E, Holm M, Lehnhardt E. Preconditions of language development in deaf children. Int J Pediatr Otorhinolaryngol. 1999: 47; 171-175 [PMID: 10206366].
- Mahr PE, Feldman JJ, Dunbar JL. The societal costs of severe to profound hearing loss in the United States. Policy Anal Brief H Ser. 2000: 2; 1-4 [PMID: 11763878].
- NIH Consensus Development Conference Statement Early Identification of Hearing Impairment in Infants and Young Children. Int J Pediatr Otorhinolaryngol. 1993: 27; 215-227 [PMID: 8270361].
- Screening for Hearing Impairment. US Preventive Task Force. In: Guide to Clinical Preventive Service. 2nd Ed. Alexandria, VA. Int Med Publishing. 1996:933.
- Kemper AR, Downs SM. A cost-effective analysis of newborn hearing screening strategies. Arch Pediatr Adolesc Med. 2000: 154; 484-488 [PMID: 10807300].
- American Academy of Pediatrics Joint Committee on Infant Hearing 1994 Position Statement. Pediatrics. 1995: 95; 152-156 [PMID: 7770297]. Statement of the American Board of Medical Genetics on Universal Hearing Screening. Published January 2000. https://www.acmg.net/StaticContent/StaticPages/Universal_Hearing.pdf . Accessed 11/29/2013.