Hearing screening--aspects of epidemiology and identification of hearing impaired children.

Mass screening of hearing in children is based on the concept of secondary prevention. In recognition of the importance of an early identification and intervention in children with congenital or early-acquired (i.e. neonatal period) hearing disability, numerous hearing screening programs have been introduced throughout the world. The devastating consequences of a congenital/early acquired hearing disability upon the speech, language, and social development of a child, and the estimated prevalence rates of at least 1-1.5/1000 live births of congenital permanent hearing impairment, represent an important health problem. The increase in the estimated prevalence of permanent hearing impairment in childhood, reaching at least 3.6-8.2% of live births at 5-9 years of age further emphasizes the importance of the problem. The delayed identification of children with congenital/early acquired hearing disability should result in the implementation of universal neonatal hearing screening, and the negative impact on the learning processes during school age from hearing impairment acquired throughout childhood seems to justify the introduction or maintenance of a hearing screening at school entrance. Implementation of efficient hearing screening programs throughout the neonatal period, infancy, or childhood should result in secondary prevention of this important health problem.