Noise suppression of transient-evoked otoacoustic emissions. II. Derived narrow-band contributions.
Transient-evoked otoacoustic emissions (TEOAEs) were decomposed into cochlear place specific components using high-pass noise suppression. This was performed using high-pass filtered noise with cut-off frequencies between 0.7 and 5.6 kHz in 0.5-octave steps. Subtraction of the TEOAEs obtained in the presence of two high-pass noise suppressors with 0.5-octave difference in their cut-off frequencies, f(A) and f(B), should theoretically result in TEOAE components with frequencies between f(A) and f(B). The reconstructed wide-band emission power spectrum obtained by summing the narrow-band emission power spectra, was nearly identical to the power spectrum of the original wide-band emission. This suggests that no phase-cancellation occurs and that the individual narrow-band TEOAEs are uncorrelated, and thus that their generators are potentially independent. About 66% of the derived narrow-band emissions had spectral components that extended below the cut-off frequency of the lower high-pass noise filter. These tail components were interpreted as resulting from high-frequency side suppression of the high-pass noise on the click emission and potentially distortion product components from the TEOAE.
Molenaar
D G
DG
Departments of Physiology and Biophysics, and Psychology, University of Calgary, Calgary, Alta., Canada.
Shaw
G
G
Eggermont
J J
JJ
D000161:Acoustic Stimulation / Q000379:methods; D000328:Adult; D006801:Humans; D009622:Noise; D017084:Otoacoustic Emissions, Spontaneous / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D013997:Time Factors