Analysis of parameters for the estimation of loudness from tone-burst otoacoustic emissions

There is evidence that tone-burst otoacoustic emissions (TBOAEs) might be useful for estimating loudness. However, within-listener comparisons between loudness and TBOAE measurements are an essential prerequisite to determine appropriate analysis parameters for loudness estimation from TBOAE measurements. The purpose of the present work was to collect TBOAE measurements and loudness estimates across a wide range of levels in the same listeners. Therefore, TBOAEs were recorded for 1- and 4-kHz stimuli and then analyzed using a wide range of parameters to determine which parameter set yielded the lowest mean-square-error estimation of loudness with respect to a psychoacoustical, cross-modality-matching procedure and the inflected exponential (INEX) loudness model. The present results show strong agreement between 1-kHz loudness estimates derived from TBOAEs and loudness estimated using cross-modality matching (CMM), with TBOAE estimation accounting for almost 90% of the CMM variance. Additionally, the results indicate that analysis parameters may vary within a reasonable range without compromising the results (i.e., the estimates exhibit some parametric robustness). The lack of adequate parametric optimization for TBOAEs at 4 kHz suggests that measurements at this frequency are strongly contaminated by ear-canal resonances, meaning that deriving loudness estimates from TBOAEs at this frequency is significantly more challenging than at 1 kHz.