Comparison of Wave V Latencies of Auditory Brainstem Responses by Bone Conduction and Air Conduction in Normal Hearing Infants and Toddlers

Lim, Eun Jung; Kwak, Ki Hwan; Lee, Jin Geol; Lee, Jun Ki; Kim, Tae Hoon; Park, Jun Ho; Kim, SungHee

Abstract

BACKGROUND AND OBJECTIVES
Bone conduction (BC) auditory brainstem response (ABR) is an important factor in determining the type of hearing loss especially in infants and other difficult-to-test populations. However, multiple constraints including technical difficulties make evaluating BC ABR less feasible in the clinic, and there is also lack of information that guides clinicians how to evaluate it. The purpose of this study is to compare the latency of wave V in BC and air conduction (AC) ABR in normal hearing infants and gather reference values for wave V latency of BC ABR.
SUBJECTS AND METHOD
A total of 210 ears of normal hearing, of those not belong to the hearing loss risk group, were included. All the infants underwent ABR evoked by clicks via AC (3A insert phone) and BC (Radioear B-71, vibrator positioned on the mastoid) under sedation. The latency of wave V at 30 dB nHL by BC and AC was compared and analyzed according to age.
RESULTS
The results revealed that in every age group in the study, wave V latency at 30 dB nHL of BC ABR was shorter than that of AC ABR. There was a significant decrease in BC and AC latencies with age, but among each consecutive age group, significant latency change was not identified after 6 months old.
CONCLUSION
The latency of BC ABR in young children was shorter than that of AC ABR, and it decreased significantly as age increased. However, the reference data should be considered by taking each laboratory's test parameter into consideration.