Michal Feręczkowski1,2, Tobias Neher1,2
1Institute of Clinical Research, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark
2Research Unit for ORL – Head & Neck Surgery and Audiology, Odense University Hospital, Odense, Denmark; University of Southern Denmark, Odense, Denmark
In current practice, hearing aids (HAs) are typically fitted based on audiometric thresholds only, even though research suggests that suprathreshold factors play a role for HA outcome. Measurements based on stimuli with linear frequency-specific amplification (‘aided’) carried out at above-conversational levels may provide estimates of suprathreshold hearing deficits that are largely independent of the effects of audiometric thresholds. In some listeners, high presentation levels may lead to a performance decrease, i.e., rollover in the performance-intensity function. Here, we investigated potential links between word recognition scores (WRS) measured at above-conversational levels, uncomfortable levels (UCL) for narrowband noise stimuli, and aided outcome as assessed using the Hearing-in-Noise Test (HINT) as well as the International Outcome Inventory for Hearing Aids (IOI-HA). The participants were 37 experienced HA users with symmetrical, sensorineural hearing losses. Unaided and aided WRS were measured monaurally under headphones with monosyllabic words presented between the most comfortable and uncomfortable level of each participant. The aided HINT measurements were analyzed using a linear mixed-effects model with the unaided and aided WRS, rollover presence, the UCL data, pure-tone average hearing loss, and age as predictors. The IOI-HA scores were analyzed using a multiple linear regression model with the unaided and aided WRS, pure-tone average hearing loss, and age as predictors. The aided WRS data predicted the two outcomes more effectively than any other considered predictor. Additionally, rollover presence was a significant predictor of HINT outcome. Overall, these results imply that suprathreshold deficits as captured by aided WRS measurements performed at higher-than-normal levels can be useful for developing more individualized HA fitting strategies.