Auditory Brain Stem Responses to Air- and Bone-Conducted Clicks in the Audiological Assessment of At-Risk Infants

ABSTRACTAuditory brain stem responses [ABRs] to air and boneconducted clicks were used to assess the auditory status of 170 atirisk neonates. During the perinatal period, 20.6% [35/170 cases] of the at-risk infants failed ABRs to airconducted clicks at 30 dB nHL in at least one ear. Earspecific results indicated an initial failure rate of 15.0% [51/340 ears]. Approximately two-thirds (32/51 ears] of these initial failures showed purely conductive deficits, whereas the remaining one-third [I9/51 ears] involved suspected sensorineural components. Follow-up audiological evaluations were performed for 87.1% (148 cases] of these atirisk infants at 4 mo and/or 1 yr corrected age. Based on the initial tests and followup assessments, the tentative operating characteristics of ABRs to both air and boneconducted clicks for identification of sensor neural deficits in at-risk neonates were calculated. It was found that the ABR to boneconducted clicks yielded better specificity, predictive value of positive results, and overall efficiency. It is suggested that the ABR to boneconducted stimuli should be viewed as a valuable addition in the assessment of cochlear reserve in infants who fail a newborn auditory screening to airconducted stimuli.