The auditory brainstem response in pediatrics.

Abstract

When properly recorded and interpreted, the auditory brainstem response (ABR) serves as a powerful, noninvasive tool for the diagnosis of pediatric auditory disorders. The detection of eighth cranial nerve and brainstem dysfunction relies primarily on the comparison of wave latencies to normative data and between ears of the same patient. The description of peripheral hearing sensitivity thresholds by ABR relies primarily on the determination of the weakest stimulus intensity at which the ABR can be elicited. Differential diagnosis of sensorineural versus conductive loss is assisted by analysis of latency-intensity relationships and by bone-conducted ABR findings, whereas description of the frequency contour of the audiogram is possible using band-limited tone burst stimuli as well as other methods. From the caveats and case examples reported here, it should be clear that the ABR cannot be measured or interpreted from a patient in a "black box" fashion. Suprathreshold ABR recordings for neurotologic analysis are influenced by cochlear dysfunction, which can affect both absolute and interpeak wave latencies, and by conductive hearing loss, which affects absolute wave latencies, in such a way that the patient's audiogram must be known for proper test administration and interpretation. Interpretation of suprathreshold ABR data to infer hearing threshold sensitivity has extremely limited utility and can "clear" a child who indeed has substantial hearing loss. Threshold ABR recordings represent the most accurate means available to estimate the audiogram in the very young infant or difficult-to-test child, yet can be influenced by retrocochlear dysfunction, and require concurrent knowledge of outer and middle ear status as well as careful interpretive statements of the actual frequency range for which the audiogram has been estimated. The diagnosis of hearing impairment by ABR in a child is accomplished best when it is performed in the context of concurrent audiologic and otologic workups, with availability (on site or by referral) of a team of hearing health care professionals to evaluate and support the whole child and family. In the case of a newly diagnosed significant hearing impairment in an infant or toddler, input is needed from various professionals including those involved in education of the hearing-impaired, speech-language pathology, developmental psychology, social service, genetics, and ophthalmology, as well as the primary care pediatrician.(ABSTRACT TRUNCATED AT 400 WORDS)