Comparing otoacoustic emissions evoked by chirp transients with constant absorbed sound power and constant incident pressure magnitude.
Human ear-canal properties of transient acoustic stimuli are contrasted that utilize measured ear-canal pressures in conjunction with measured acoustic pressure reflectance and admittance. These data are referenced to the tip of a probe snugly inserted into the ear canal. Promising procedures to calibrate across frequency include stimuli with controlled levels of incident pressure magnitude, absorbed sound power, and forward pressure magnitude. An equivalent pressure at the eardrum is calculated from these measured data using a transmission-line model of ear-canal acoustics parameterized by acoustically estimated ear-canal area at the probe tip and length between the probe tip and eardrum. Chirp stimuli with constant incident pressure magnitude and constant absorbed sound power across frequency were generated to elicit transient-evoked otoacoustic emissions (TEOAEs), which were measured in normal-hearing adult ears from 0.7 to 8 kHz. TEOAE stimuli had similar peak-to-peak equivalent sound pressure levels across calibration conditions. Frequency-domain TEOAEs were compared using signal level, signal-to-noise ratio (SNR), coherence synchrony modulus (CSM), group delay, and group spread. Time-domain TEOAEs were compared using SNR, CSM, instantaneous frequency and instantaneous bandwidth. Stimuli with constant incident pressure magnitude or constant absorbed sound power across frequency produce generally similar TEOAEs up to 8 kHz.
Boys Town National Research Hospital, 555 North 30th Street, Omaha, Nebraska 68131, USA.
Douglas H
DH
Keefe
National Center for Rehabilitative Auditory Research, VA Portland Health Care System, 3710 SW US Veterans Hospital Road, Portland, Oregon 97239, USA.
M Patrick
MP
Feeney
Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, Ohio 45229, USA.
Lisa L
LL
Hunter
Boys Town National Research Hospital, 555 North 30th Street, Omaha, Nebraska 68131, USA.
Denis F
DF
Fitzpatrick
D000161:Acoustic Stimulation / Q000379:methods*; D000162:Acoustics / Q000295:instrumentation*; D000328:Adult; D003051:Cochlea / Q000502:physiology*; D004424:Ear Canal / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017084:Otoacoustic Emissions, Spontaneous; D011312:Pressure; D012815:Signal Processing, Computer-Assisted; D013016:Sound; D013997:Time Factors; D014160:Transducers, Pressure; D055815:Young Adult