Open community platform for hearing aid algorithm research: open Master Hearing Aid (openMHA).

(openMHA) was developed and provided to the hearing aid research community as an open-source software platform with the aim to support sustainable and reproducible research towards improvement and new types of assistive hearing systems not limited by proprietary software. The software offers a flexible framework that allows the users to conduct hearing aid research using tools and a number of signal processing plugins provided with the software as well as the implementation of own methods. The openMHA software is independent of a specific hardware and supports Linux, macOS and Windows operating systems as well as 32-bit and 64-bit ARM-based architectures such as used in small portable integrated systems.

Self-motion with Hearing Impairment and (Directional) Hearing Aids.

When listening to a sound source in everyday situations, typical movement behavior is highly individual and may not result in the listener directly facing the sound source. Behavioral differences can affect the performance of directional algorithms in hearing aids, as was shown in previous work by using head movement trajectories of normal-hearing (NH) listeners in acoustic simulations for noise-suppression performance predictions. However, the movement behavior of hearing-impaired (HI) listeners with or without hearing aids may differ, and hearing-aid users might adapt their self-motion to improve the performance of directional algorithms.

Development and evaluation of video recordings for the OLSA matrix sentence test.

Objective: The aim was to create and validate an audiovisual version of the German matrix sentence test (MST), which uses the existing audio-only speech material.

Design: Video recordings were recorded and dubbed with the audio of the existing German MST. The current study evaluates the MST in conditions including audio and visual modalities, speech in quiet and noise, and open and closed-set response formats.

Review of Self-Motion in the Context of Hearing and Hearing Device Research.

The benefit from directional hearing devices predicted in the lab often differs from reported user experience, suggesting that laboratory findings lack ecological validity. This difference may be partly caused by differences in self-motion between the lab and real-life environments. This literature review aims to provide an overview of the methods used to measure and quantify self-motion, the test environments, and the measurement paradigms.

The Virtual Reality Lab: Realization and Application of Virtual Sound Environments.

To assess perception with and performance of modern and future hearing devices with advanced adaptive signal processing capabilities, novel evaluation methods are required that go beyond already established methods. These novel methods will simulate to a certain extent the complexity and variability of acoustic conditions and acoustic communication styles in real life. This article discusses the current state and the perspectives of virtual reality technology use in the lab for designing complex audiovisual communication environments for hearing assessment and hearing device design and evaluation.

The Quest for Ecological Validity in Hearing Science: What It Is, Why It Matters, and How to Advance It.

Ecological validity is a relatively new concept in hearing science. It has been cited as relevant with increasing frequency in publications over the past 20 years, but without any formal conceptual basis or clear motive. The sixth Eriksholm Workshop was convened to develop a deeper understanding of the concept for the purpose of applying it in hearing research in a consistent and productive manner.

Evaluation of the Influence of Head Movement on Hearing Aid Algorithm Performance Using Acoustic Simulations.

Head movements can improve sound localization performance and speech intelligibility in acoustic environments with spatially distributed sources. However, they can affect the performance of hearing aid algorithms, when adaptive algorithms have to adjust to changes in the acoustic scene caused by head movement (the so-called maladaptation effect) or when directional algorithms are not facing in the optimal direction because the head has moved away (the so-called misalignment effect). In this article, we investigated the mechanisms behind these maladaptation and misalignment effects for a set of six standard hearing aid algorithms using acoustic simulations based on premade databases; this was done so we could study the effects as carefully as possible.

Movement and Gaze Behavior in Virtual Audiovisual Listening Environments Resembling Everyday Life.

Recent achievements in hearing aid development, such as visually guided hearing aids, make it increasingly important to study movement behavior in everyday situations in order to develop test methods and evaluate hearing aid performance. In this work, audiovisual virtual environments (VEs) were designed for communication conditions in a living room, a lecture hall, a cafeteria, a train station, and a street environment. Movement behavior (head movement, gaze direction, and torso rotation) and electroencephalography signals were measured in these VEs in the laboratory for 22 younger normal-hearing participants and 19 older normal-hearing participants.

Effects of directional hearing aid settings on different laboratory measures of spatial awareness perception.

Hearing loss can negatively influence the spatial hearing abilities of hearing-impaired listeners, not only in static but also in dynamic auditory environments. Therefore, ways of addressing these deficits with advanced hearing aid algorithms need to be investigated. In a previous study based on virtual acoustics and a computer simulation of different bilateral hearing aid fittings, we investigated auditory source movement detectability in older hearing- impaired (OHI) listeners.

Influence of Multi-microphone Signal Enhancement Algorithms on the Acoustics and Detectability of Angular and Radial Source Movements.

Hearing-impaired listeners are known to have difficulties not only with understanding speech in noise but also with judging source distance and movement, and these deficits are related to perceived handicap. It is possible that the perception of spatially dynamic sounds can be improved with hearing aids (HAs), but so far this has not been investigated. In a previous study, older hearing-impaired listeners showed poorer detectability for virtual left-right (angular) and near-far (radial) source movements due to lateral interfering sounds and reverberation, respectively.

Binaural model-based dynamic-range compression.

Objective: Binaural cues such as interaural level differences (ILDs) are used to organise auditory perception and to segregate sound sources in complex acoustical environments. In bilaterally fitted hearing aids, dynamic-range compression operating independently at each ear potentially alters these ILDs, thus distorting binaural perception and sound source segregation.

Design: A binaurally-linked model-based fast-acting dynamic compression algorithm designed to approximate the normal-hearing basilar membrane (BM) input-output function in hearing-impaired listeners is suggested.

Sensitivity to Angular and Radial Source Movements as a Function of Acoustic Complexity in Normal and Impaired Hearing.

In contrast to static sounds, spatially dynamic sounds have received little attention in psychoacoustic research so far. This holds true especially for acoustically complex (reverberant, multisource) conditions and impaired hearing. The current study therefore investigated the influence of reverberation and the number of concurrent sound sources on source movement detection in young normal-hearing (YNH) and elderly hearing-impaired (EHI) listeners.

Acoustic and perceptual effects of magnifying interaural difference cues in a simulated "binaural" hearing aid.

Objective: To investigate the influence of an algorithm designed to enhance or magnify interaural difference cues on speech signals in noisy, spatially complex conditions using both technical and perceptual measurements. To also investigate the combination of interaural magnification (IM), monaural microphone directionality (DIR), and binaural coherence-based noise reduction (BC).

Design: Speech-in-noise stimuli were generated using virtual acoustics.

Virtual acoustic environments for comprehensive evaluation of model-based hearing devices.

Objective: Create virtual acoustic environments (VAEs) with interactive dynamic rendering for applications in audiology.

Design: A toolbox for creation and rendering of dynamic virtual acoustic environments (TASCAR) that allows direct user interaction was developed for application in hearing aid research and audiology. The software architecture and the simulation methods used to produce VAEs are outlined.

Spatial Acoustic Scenarios in Multichannel Loudspeaker Systems for Hearing Aid Evaluation.

Background: Field tests and guided walks in real environments show that the benefit from hearing aid (HA) signal processing in real-life situations is typically lower than the predicted benefit found in laboratory studies. This suggests that laboratory test outcome measures are poor predictors of real-life HA benefits. However, a systematic evaluation of algorithms in the field is difficult due to the lack of reproducibility and control of the test conditions.

Perceptual consequences of different signal changes due to binaural noise reduction: do hearing loss and working memory capacity play a role?

Objectives: In a previous study, ) investigated whether pure-tone average (PTA) hearing loss and working memory capacity (WMC) modulate benefit from different binaural noise reduction (NR) settings. Results showed that listeners with smaller WMC preferred strong over moderate NR even at the expense of poorer speech recognition due to greater speech distortion (SD), whereas listeners with larger WMC did not. To enable a better understanding of these findings, the main aims of the present study were (1) to explore the perceptual consequences of changes to the signal mixture, target speech, and background noise caused by binaural NR, and (2) to determine whether response to these changes varies with WMC and PTA.

Do hearing loss and cognitive function modulate benefit from different binaural noise-reduction settings?

Objectives: Although previous research indicates that cognitive skills influence benefit from different types of hearing aid algorithms, comparatively little is known about the role of, and potential interaction with, hearing loss. This holds true especially for noise reduction (NR) processing. The purpose of the present study was thus to explore whether degree of hearing loss and cognitive function modulate benefit from different binaural NR settings based on measures of speech intelligibility, listening effort, and overall preference.

Multicenter evaluation of signal enhancement algorithms for hearing aids.

In the framework of the European HearCom project, promising signal enhancement algorithms were developed and evaluated for future use in hearing instruments. To assess the algorithms' performance, five of the algorithms were selected and implemented on a common real-time hardware/software platform. Four test centers in Belgium, The Netherlands, Germany, and Switzerland perceptually evaluated the algorithms.