An optimal filtering technique to reduce the influence of low-frequency noise on click-evoked otoacoustic emissions.
There is a need for methods capable of increasing the detectability of transient-evoked otoacoustic emissions (TEOAE). Detection of an emission is based commonly on either visual inspection and cross-correlation between replicate recordings or cross-spectral analysis. Performance of these methods is obviously influenced by the residual noise level. Residual noise is often of low frequency and can be reduced by digital off-line filtering. For this purpose, an optimal high-pass filtering technique is proposed. Cross-correlation between replicates of TEOAEs was used to determine the cut-off frequency that maximizes the signal-to-noise (S/N) ratio. This is shown in a series of responses characterized by various S/N ratios. Data have been scored both visually and with quantitative methods before and after the use of high-pass filtering. The capability to detect the signal was increased with only a marginal decrease in the total power of the emissions.
Tognola
G
G
Center of System Theory (CNR), Polytechnic of Milan, Italy.
Ravazzani
P
P
Grandori
F
F
D000161:Acoustic Stimulation; D000328:Adult; D001309:Auditory Threshold / Q000502:physiology; D003638:Deafness / Q000209:etiology / Q000503:physiopathology*; D005583:Fourier Analysis; D006801:Humans; D017084:Otoacoustic Emissions, Spontaneous / Q000502:physiology*; D010040:Otosclerosis / Q000150:complications / Q000503:physiopathology