Question
What type of stimulus should be used for bone-conduction ABR, for assessment of infant hearing?
Answer
It's possible to use tone bursts for bone conduction ABR as well as for air conduction ABR measurement. The limitation is usually how much time is available for ABR recording before the child wakes up. I definitely want to estimate thresholds for low to high frequencies using air conduction.
My approach is to use only click stimulation in bone conduction ABR recording because my main goal is to simply determine if there's an air bone gap and the likelihood of a conductive loss. Or, if I already have a clue about middle ear dysfunction from history or from tympanometry, the bone conduction ABR confirms the presence of a conductive hearing loss. With that information, the child is referred to an otologist for further evaluation and possible medical management. I'll make the referral regardless of the pattern or extent of conductive hearing loss.
I suggest that you find some of the articles by David Stapell and his colleagues, like Susan Smartt, on bone conduction ABR because they do attempt to record frequency-specific bone conduction ABRs.
For an in-depth discussion of this topic, please view Dr. Hall’s recorded course on AudiologyOnline, Application of ABR in Objective Assessment of Infant Hearing
