Early detection of hearing impairment: what role is there for behavioural methods in the neonatal period?

A survey of the use of behavioural methods for neonatal hearing screening in 1985 (1) concluded that the future for automated methods was quite promising. Since then several studies have assessed the two main automated behavioural tests: the Auditory Response Cradle (ARC) and the Crib-o-Gram (COG). As a screen targeted at neonatal intensive care unit (NICU) babies and other high risk groups (at present the most cost-effective form of neonatal hearing screening), the ARC is shown to have low sensitivity, even for severe hearing impairments, and the COG has an unacceptably low specificity. Any future for behavioural testing during this period must therefore rely on new implementations flowing out of a fundamental understanding of (a) the way in which neonates respond to sound and (b) the ways in which a behavioural test might complement screening with Auditory Brainstem Responses (ABR) or Evoked Oto-acoustic Emissions (EOAE). A clearer understanding of the relative benefits of detecting different degrees of hearing impairment at birth in both the NICU population and the unrestricted population is urgently needed. To determine what role should be played by specific screening programmes such benefits need to be balanced against the total costs of screening assessment and rehabilitation, in which false positives (low specificity) play a large part.