Utility of categorical loudness scaling to estimate the outer- and inner-hair-cell-loss-related components of hearing impairment.

Abstract

Sensorineural hearing loss is mainly accompanied by a reduction or dysfunction of outer hair cells (OHCs) and inner hair cells (IHCs) in the cochlea. A dysfunction of OHCs is often assumed to correspond to an expansive component and a dysfunction of IHCs to an attenuating component of hearing loss. This study presents a method for assessing OHC and IHC losses from categorical loudness curves using adaptive categorical loudness scaling (ACALOS). A loudness model was used to fit modeled loudness curves to measured loudness curves by adjusting a model parameter HLOHC that quantifies the amount of hearing loss related to the dysfunction of OHCs relative to total hearing loss. This parameter HLOHC was compared to corresponding parameters extracted using temporal masking curves (TMCs) in 16 listeners with different audiometric thresholds. The results showed that both ACALOS and TMCs estimated HLOHC consistently, whereas ACALOS offers much more time-efficiency and about the same accuracy as TMCs. Since ACALOS is an easy and natural task for inexperienced listeners and because of the high time-efficiency, ACALOS appears to be a good candidate for the assessment of this part of the suprathreshold processing of sensorineural hearing-impaired listeners in clinical practice. [Work supported by the DFG (Grant No. SFB TRR31).]