Training in ABR
Evaluating auditory brainstem responses to different chirp stimuli
Description
This paper describes how the ABR amplitude is dependent of Chirp duration (sweeping rate) and stimulus level. A standard Click and five Chirps of different durations are presented at three levels of stimulation (20, 40 and 60 dB nHL) in 20 normal hearing adult ears. It is found that all the Chirps (except the longest one at 60 dB nHL) always produce larger ABR amplitudes than the Click. It is also found that the shorter Chirps are most efficient at higher levels whereas the longer Chirps are most efficient at lower levels. The paper concludes that two mechanisms appear to be involved: (1) upward-spread-of excitation at higher levels, and (2) an increased change of the cochlear-neural delay with frequency at lower levels. The observed changes in ABR amplitude and latency from the different chirp stimuli are consistent with this conclusion.
