Predicting severity of cochlear hair cell damage in adult chickens using DPOAE input-output functions.
Distortion product otoacoustic emissions (DPOAE) were recorded from the ear canal of aged broiler chickens which have been shown to present with age-related cochlear degeneration [Hear. Res. 166 (2002) 82]. We describe the relationship between the shape of the DPOAE input-output (I/O) function and the type of hair cell damage present at and between the cochlear frequency places of the DPOAE primary tones (f1 and f2). The mid stimulus level compressive growth of the mean DPOAE I/O functions is reduced in a graded fashion relative to the severity of hair cell damage. However, individual DPOAE I/O functions within most hair cell damage groups show large variability from this characteristic. Various least squares regression models were used to predict hair cell density from indices derived from the DPOAE I/O function (area, threshold and slope). The results showed that no simple linear relationship exists between hair cell density and the DPOAE I/O function indices. Multivariate binary logistic regression used DPOAE I/O function indices to predict membership in hair cell damage groups. The logistic model revealed that DPOAE threshold can be used to predict the occurrence of severe/total hair cell damage with good specificity though poor sensitivity.
Lichtenhan
Jeffery T
JT
Department of Hearing and Speech, University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, KS 66160, USA.
Chertoff
Mark E
ME
Smittkamp
Susan E
SE
Durham
Dianne
D
Girod
Douglas A
DA
D000375:Aging / Q000473:pathology / Q000502:physiology*; D000704:Analysis of Variance; D000818:Animals; D002645:Chickens; D005260:Female; D006198:Hair Cells, Auditory / Q000473:pathology / Q000503:physiopathology* / Q000648:ultrastructure; D016015:Logistic Models; D008855:Microscopy, Electron, Scanning; D015588:Observer Variation; D017084:Otoacoustic Emissions, Spontaneous / Q000502:physiology*; D011304:Presbycusis / Q000473:pathology / Q000503:physiopathology*; D012720:Severity of Illness Index