Relations between notched-noise suppressed TEOAE and the psychoacoustical critical bandwidth.

Narrow-band transitory evoked otoacoustic emissions (TEOAE) were recorded for nine normal hearing subjects in the presence of a broadband tone complex suppressor. Introducing a spectral notch at the frequency of the narrow-band stimulus causes the suppression effect to decrease, the more so the wider the notch. This decrease in suppression permits an estimate of the size of one critical band. One advantage of this approach is that no active participation of the subjects is required. The estimated critical bandwidth is then compared with independent estimates based on a simultaneous masking experiment, using the same stimuli. The two measures of the critical bandwidth coincide well for those six subjects with spontaneous otoacoustic emissions. However, the bandwidth estimate based on the OAE measurements is too large for the other three subjects without spontaneous emissions. Simulations of the suppression effect with a driven van der Pol oscillator with moderate undamping produce critical bandwidth estimates consistent with those observed in the psychoacoustical experiments. This allows an estimate of the "effective" amount of undamping on the basilar membrane that is required to produce the critical bandwidth observable in psychoacoustic experiments.