Distortion-product otoacoustic emission input/output characteristics in normal-hearing and hearing-impaired human ears.
Distortion-product otoacoustic emission (DPOAE) input/output (I/O) functions were measured in 322 ears of 176 subjects at as many as 8 f(2) frequencies per ear for a total of 1779 I/O functions. The f(2) frequencies ranged from 0.7 to 8 kHz in half-octave steps. Behavioral thresholds (BTs) at the f(2) frequencies ranged from -5 to 60 dB hearing loss (HL). Both linear-pressure and nonlinear, two-slope functions were fitted to the data. The two-slope function describes I/O compression as output-controlled self-suppression. Most I/O functions (96%) were better fitted by the two-slope method. DPOAE thresholds based on each method were used to predict BTs. Compared to estimates based on linear-pressure functions, individual BTs predicted from DPOAE thresholds based on the two-slope model had lower residual error and accounted for more variance. Another advantage of the two-slope method is that it provides an estimate of response growth rate (RGR) that is not tied to threshold. At all frequencies, the median low-level RGR (across I/O functions of the same f(2) and BT) usually increased as BT increased, while high-level compression decreased. The observed characteristics of DPOAE I/O functions are consistent with the loss of cochlear compression that is typically associated with mild-to-moderate HL.
Neely
Stephen T
ST
Boys Town National Research Hospital, 555 North 30th Street, Omaha, NE 68131, USA.
Johnson
Tiffany A
TA
Kopun
Judy
J
Dierking
Darcia M
DM
Gorga
Michael P
MP
D000161:Acoustic Stimulation; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001309:Auditory Threshold; D002648:Child; D006309:Hearing / Q000502:physiology*; D034381:Hearing Loss / Q000503:physiopathology*; D006801:Humans; D016014:Linear Models; D008875:Middle Aged; D017711:Nonlinear Dynamics; D017084:Otoacoustic Emissions, Spontaneous; D011312:Pressure; D055815:Young Adult