screening (Sininger, 2002). Infants with late-onset hearing loss will be missed in the newborn screening; and constant surveillance is needed by the medical community to find these infants and begin remediation as soon as possible (Joint Committee on Infant Hearing, 2000).
The screening and diagnostic testing process is designed to expedite intervention for children with hearing loss and maximize the opportunity to provide audition during critical learning periods (Sininger, Doyle, and Moore, 1999; Yoshinaga-Itano et al., 1998). The goal of early hearing detection and intervention programs is to identify hearing loss and begin intervention including fitting of hearing aids at or before 6 months of age.
Assessment of hearing loss in infants requires age-appropriate procedures. Infants under 6 months of age cannot give an accurate response to sounds at threshold levels, regardless of their ability to detect them. These infants require an audiological test battery based on objective physiological tests that reveal threshold-level responses, as well as information regarding the functioning of the peripheral auditory system.
General agreement exists in the United States regarding the essential elements of an appropriate protocol for diagnostic audiological assessments of infants and young children. An audiologist with appropriate state licensure or equivalent credentials must perform such assessments. The complete battery includes a history and parent interview, evaluation of middle ear function, OAE testing, and an age-appropriate assessment of auditory behaviors. The core of the diagnostic evaluation protocol is an estimate of audiometric thresholds using auditory brainstem response or other proven electrophysiological assessment with frequency-specific stimuli. According to the American Academy of Pediatrics (2000, p. 804):
Audiologists providing the initial test battery to confirm the existence of a hearing loss in infants must include physiological measures and developmentally appropriate behavioral techniques… For infants birth to six months of age, the test battery … must contain an electrophysiological measure of threshold such as ABR or other appropriate electrophysiological test using frequency-specific stimuli.
Unlike vision, human auditory sensitivity is adult-like within a few days of birth (Adelman, Levi, Linder, and Sohmer, 1990; Klein, 1984; Sininger, Abdala, and Cone-Wesson, 1997). Consequently, hearing loss degree and configuration are judged by the same standards for newborns as for adults.