The freedom to move around – Hearing aid research takes a big step towards the real life
Stefan Klockgether – email@example.com
Diego Ulloa Sanchez
CH 8712 Stäfa
Popular version of paper 5aPPb1
Presented Friday morning, December 11, 2020
179th ASA Meeting, Acoustics Virtually Everywhere
One major aspect of hearing aid development is audiological performance. This describes the benefit in hearing a hearing impaired person can have from using a hearing aid.
Measuring audiological performance depends on the perception of individuals. To reduce the impact of individual behavior of subjects on measured results – a lack of experiment control, the degrees of freedom during an audiological study are usually strongly limited and important aspects of perception in real life are sacrificed in favor of control.
In recent years, efforts have been taken to substantiate the performance of hearing aids in real life situations. It is important to understand the listeners behavior in realistic acoustic environments, especially the potential differences between normal hearing and hearing impaired people.
The new “Real Life Lab” at Sonova brings the freedom to move around to controlled laboratory conditions. The lab provides a stage where persons can move around freely and interact with sound sources. The stage is surrounded by loudspeakers to present sound from all directions. Any motion by persons on the stage can be tracked in real time to regain the control. The motion data can be passively tracked or actively used to trigger audio and video reproduction.
Caption Figure 1: The Sonova Real Life Lab with loudspeakers at the sides, below the floor and at the ceiling.
The lab is also used to investigate the behavior in acoustic scenes. A pilot study has been done, to find differences between normal hearing and hearing impaired. The subjects had to find different acoustic targets in a complex scene (Video 1). Their motion as well as there performance was tracked with motion capturing (Video 2).
The subject has to find different acoustic targets (a crying baby, a barking dog or a ringing telephone). The subject wears a hairband to track head position and orientation, a vest to track the torso and a controller to point to the found target.
Motion capturing view of the task. The three tracked objects are the head position in pink, the torso in orange and the pointer in light blue with a pink beam indicating when and where a target has been found.
Five normal hearing (NH, age ≈ 27), five subjects with hearing loss wearing hearing aids (HL, age ≈ 74) and five age-matched persons with age-appropriate hearing (AA, age ≈ 71) participated in the study.
Number of found targets in an allowed time.
Weighted amount of head movements and accuracy.
The results show clear differences in the performance as well as in the search strategy. The young normal hearing were fast, accurate and moved their heads a lot. The age-appropriate hearing group was slower, but as accurate and moved their heads a lot. The hearing impaired were slower, less accurate and moved their heads less. Hearing impaired seem to benefit less from the gain in acoustic information which is provided by head movements and may therefore reduce the movements.