Hearing loss in early infancy: incidence, detection and assessment.

Auditory evoked potential techniques have revitalized programs for early detection, quantification, and management of hearing loss. Some issues underlying the need for such programs, and their structure, are reviewed with reference to recently-published guidelines. The prevalence of hearing loss in infancy is poorly understood; estimates depend on the type and degree of loss, the tests used, and their timing. Evidence that significant hearing loss can escape early detection continues to accumulate; delays are attributable to many factors, including insufficient awareness and deficiencies in conventional tests. High-risk registers are valuable but imperfect tools, and should not be the sole avenue of early detection. Electrophysiologic tests, especially the auditory brain stem response, have a major role in early assessment. Attention to many technical and patient-related factors is required, and frequency-specific testing is feasible and informative.