Laboratory and Field Study of the Potential Benefits of Pinna Cue-Preserving Hearing Aids

Abstract

The potential benefits of preserving high-frequency spectral cues created by the pinna in hearing-aid fittings were investigated in a combined laboratory and field test. In a single-blind crossover design, two settings of an experimental hearing aid were compared. One setting was characterized by a pinna cue-preserving microphone position, whereas the other was characterized by a microphone position not preserving pinna cues. Participants were allowed 1 month of acclimatization to each setting before measurements of localization and spatial release from speech-on-speech masking were completed in the laboratory. Real-world experience with the two settings was assessed by means of questionnaires. Seventeen participants with mild to moderate sensorineural hearing impairments completed the study. An inconsistent pinna cue benefit pattern was observed across the outcome measures. In the localization test, the pinna cue-preserving setting provided a significant mean reduction of 22° in the root mean square (RMS) error in the front-back dimension, with 13 of the 17 participants showing a reduction of at least 15°. No significant mean difference in RMS error between settings was observed in the left-right dimension. No significant differences between settings were observed in the spatial-unmasking test conditions. The questionnaire data indicated a small, but nonsignificant, benefit of the pinna cue-preserving setting in certain real-life situations, which corresponded with a general preference for that setting. No significant real-life localization benefit was observed. The results suggest that preserving pinna cues can offer benefit in some conditions for individual hearing-aid users with mild to moderate hearing loss and is unlikely to harm performances for the rest.

Extended High-Frequency Bandwidth Improves Speech Reception in the Presence of Spatially Separated Masking Speech

“…The use of a TM microphone location might have improved the ability to use spatial cues provided by the pinna in the unaided condition (Jin et al 2002). A recent study comparing a pinna cue-preserving microphone position with a position that did not preserve pinna cues showed benefit for front-back sound localization for the former but no benefit for spatial release from speech-on-speech masking (Jensen et al 2013). Also, in the diffuse configuration, the TM microphone location used in the unaided condition would have provided some shielding from the masking sounds towards the rear of the head, leading to a better TMR.…”

Impact of Hearing Aid Technology on Outcomes in Daily Life III: Localization

“…When using a BTE style hearing aid (including receiver-in-the-canal [RIC] hearing aids), incoming sounds are picked up by the hearing aid microphone without filtering by the pinna. As a consequence, monaural spectral cues provided by the pinna are missing, resulting in poorer front/back discrimination performance with BTEs compared to hearing aid styles with microphone locations in the ear (e.g., Best, et al, 2010; Jensen et al 2013; Van den Bogaert et al 2011). Furthermore, acoustical evidence has shown substantial binaural directivity advantages at frequencies above 1000Hz when the microphone is located at the entrance of the ear canal compared to above the pinna (Sivonen 2011).…”

An open development platform for auditory real-time signal processing

“…However, in order to develop algorithms that have potential to be implemented in a future generation of auditory devices, they must be tested in many possible situations, but testing real-time algorithms in real-life situations is difficult or impossible for many researchers. The evaluation of real-world benefits of signal processing algorithms has been investigated and described by several research groups [1], [2].…”

“…However, in order to know if the algorithm works in real-life, we want to know about interactions between algorithm, environment and participant in real-life situations; only then the algorithm can be fully evaluated for its usefulness. In fact, most algorithms that have shown benefit in laboratory situations were either never further evaluated in real-time environments or failed to live up to their promise if they have [1], [2]. Real-time processing of environmental sounds means giving up control of most environment parameters, but gaining highest possible 'ecological validity', that is to test the participant in unpredictable situations as they would face in real life.…”