Schairer et al. [J Acoust Soc Am 133, 1560–1573 (2003)] demonstrated that cochlear nonlinearity is reflected in psychometric function (PF) slopes for 4-kHz forward-masked tones. The goals of the current study were to use PF slopes to compare the degree of compression between signal frequencies of 0.25 and 4 kHz in listeners with normal hearing (LNH), and between LNH and listeners with cochlear hearing loss (LHL). Forward-masked thresholds were estimated in LNH and LHL using on- and off-frequency maskers and 0.25- and 4-kHz signals in three experiments. PFs were reconstructed from adaptive-procedure data for each subject in each condition. Trends in PF slopes across conditions suggest comparable compression at 0.25 and 4 kHz, and potentially a wider bandwidth of compression in relative frequency at 0.25 kHz. This is consistent with other recent behavioral studies that revise earlier estimates of less compression at lower frequencies. The preliminary results in LHL demonstrate that PF slopes are abnormally steep at frequencies with hearing loss, but are similar to those for LNH at frequencies with normal hearing. Overall, results are consistent with the notion that PF slopes reflect degree of cochlear nonlinearity, and can be used as an additional measure of compression across frequency.

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Overall, the findings support other recent studies that suggest the development of CI guidelines that may standardize programming and follow-up practices of CI audiologists. This could prove valuable for the continual improvement of CI outcomes, particularly in the pediatric population.