Auditory Brainstem Response Thresholds to Air- and Bone-Conducted CE-Chirps in Neonates and Adults

Abstract

Purpose The purpose of this study was to compare auditory brainstem response (ABR) thresholds to air- and bone-conducted CE-Chirps in neonates and adults. Method Thirty-two neonates with no physical or neurologic challenges and 20 adults with normal hearing participated. ABRs were acquired with a starting intensity of 30 dB normal hearing level (nHL). The lowest stimulus intensity level at which a wave V was identifiable and replicable was considered the ABR threshold. Results ABR thresholds to air-conducted CE-Chirps were 9.8 dB nHL for neonates and adults. ABR thresholds to bone-conducted CE-Chirps were 3.8 and 13.8 dB nHL for neonates and adults, respectively. The difference in ABR thresholds to bone-conducted CE-Chirps was significantly different ( p < .0001, η p 2 = .45). Adults had significantly larger wave V amplitudes to air- ( p < .0001, η p 2 = .50) and bone-conducted ( p = .013, η p 2 = .15) CE-Chirps at a stimulus intensity of 30 dB nHL. At the same intensity, adults evidenced significantly shorter wave V latencies ( p < .0001, η p 2 = .49) only with air-conducted CE-chirps. Conclusion The difference in ABR thresholds and wave V latencies to air- and bone-conducted CE-Chirps between neonates and adults may be attributed to a disparity in effective signal delivery to the cochlea.