Click- and chirp-evoked human compound action potentials.
In the experiments reported here, the amplitude and the latency of human compound action potentials (CAPs) evoked from a chirp stimulus are compared to those evoked from a traditional click stimulus. The chirp stimulus was created with a frequency sweep to compensate for basilar membrane traveling wave delay using the O-Chirp equations from Fobel and Dau [(2004). J. Acoust. Soc. Am. 116, 2213-2222] derived from otoacoustic emission data. Human cochlear traveling wave delay estimates were obtained from derived compound band action potentials provided by Eggermont [(1979). J. Acoust. Soc. Am. 65, 463-470]. CAPs were recorded from an electrode placed on the tympanic membrane (TM), and the acoustic signals were monitored with a probe tube microphone attached to the TM electrode. Results showed that the amplitude and latency of chirp-evoked N1 of the CAP differed from click-evoked CAPs in several regards. For the chirp-evoked CAP, the N1 amplitude was significantly larger than the click-evoked N1s. The latency-intensity function was significantly shallower for chirp-evoked CAPs as compared to click-evoked CAPs. This suggests that auditory nerve fibers respond with more unison to a chirp stimulus than to a click stimulus.
Department of Hearing and Speech, University of Kansas Medical Center, Kansas City, Kansas 66160, USA. mchertof@kumc.edu
Mark
M
Chertoff
Jeffery
J
Lichtenhan
Marie
M
Willis
D000161:Acoustic Stimulation; D001300:Audiometry, Evoked Response / Q000295:instrumentation; D001301:Audiometry, Pure-Tone; D001309:Auditory Threshold; D003051:Cochlea / Q000294:innervation*; D003056:Cochlear Nerve / Q000502:physiology*; D005071:Evoked Potentials; D005260:Female; D006801:Humans; D008297:Male; D011930:Reaction Time; D012815:Signal Processing, Computer-Assisted; D013997:Time Factors; D014159:Transducers