Using a Dynamic Tracking Filter to Extract Distortion-Product Otoacoustic Emissions Evoked With Swept-Tone Signals

Abstract

Distortion-product otoacoustic emissions (DPOAEs) are sound energy generated by healthy inner ears when stimulated by two tones. Since DPOAEs are physiologically related with the functional status of the inner ear, they have been widely used as a clinical tool in hearing screening and diagnoses. Currently, almost all DPOAEs recording systems use pure tones as the stimuli and can test only one frequency at a time, resulting in low efficiency and insufficient resolution. In this study, conventional pure tones were replaced by swept tones with time-varying frequencies to overcome the limitation of current DPOAEs measurements. A tracking filter with dynamic center frequencies was proposed to extract the swept-tone DPOAEs from recorded signals with stimulus artifacts and background noises. The results of this study showed that the dynamic tracking filter had great performance in effectively extracting the swept-tone DPOAEs under different noise conditions for both the simulation and experimental data. The spectrogram of the extracted swept-tone DPOAEs could provide useful information to examine the functional status of the inner ear and to identify the detailed frequency regions of the hearing loss. These preliminary findings suggested that the swept-tone DPOAEs might be useful for developing a more efficient and accurate tool for hearing loss screening in the clinic.

Fatigue Modeling via Mammalian Auditory System for Prediction of Noise Induced Hearing Loss

“…The distribution of BM velocities is obtained by the TRNL filter (as shown in Figure 3 ). In this section, two noise signals, referred as impulse noise and sweeping chirp noise, were simulated and fed into the TRNL filter to demonstrate the response of BM in the cochlea [ 38 ]. Figure 5 shows the time-frequency ( T - F ) distributions of the BM velocities in the cochlea as the output of the TRNL filter, responding to the simulated noises.…”

“…In addition, instead of using the displacement of BM as the loads in [ 35 ], the velocity of BM is used as the complex loads on the organ of Corti in our proposed models [ 38 ]. The velocity of BM not only reflects the acoustic power flowing into the inner ear, but also highly correlated with strain and loads [ 37 , 39 ].…”