Problems of audiologic evaluation in infants and children

Abstract

With the expansion of universal newborn hearing screening, otolaryngologists are increasingly being expected to evaluate and treat infants and very young children with hearing loss. However, audiologic evaluation in infants and children has several inherent limitations. Both distortion product otoacoustic emission (DPOAE) and auditory brainstem response (ABR) are widely used as adequate methods for universal newborn hearing screening. The presence of DPOAEs provides strong evidence of a normally functioning auditory periphery. ABR is considered to have high accuracy and a negligible false-negative rate. However, there is the possibility of congenital hearing loss not being identified by either test. Auditory neuropathy spectrum disorder (ANSD) cannot be detected by DPOAE screening. ABR screening is preferred for infants admitted to the NICU who are at a risk of neural hearing loss. Since the click-evoked ABRs lack frequency-specificity, they may underestimate the degree of hearing loss when the audiogram is sloping or unusual in shape. “Over-referral” rate of DPOAE screening is about 5%, mainly due to middle-ear effusion and a narrow external ear canal. NICU-treated or Down's syndrome infants have immature auditory pathways in some cases, resulting in a high threshold of ABR seen in the initial test. The combined use of objective testing and behavioral testing is recommended for pediatric audiologic assessment.