15HLT03 Ears II: Metrology for modern hearing assessment and protecting public health from emerging noise sources

• Forschungsstelle: METAS
• Projektnummer: F-5259.30070
• Projekttitel Englisch: 15HLT03 Ears II: Metrology for modern hearing assessment and protecting public health from emerging noise sources

Schlüsselwörter (Englisch)

Hearing assessment, neonatal screening, hearing rehabilitation, ear simulator, hearing aids

Kurzbeschreibung (Englisch)

This project concerns two aspects of hearing assessment and conservation; the further development of the next generation of ear simulators that will provide measurement traceability for hearing tests on adults, children and neonates, and improvement in our understanding of human response to infrasound and ultrasound, including novel assessment methods for potential health risks.

 

Virtually everyone will have their hearing tested at stages throughout their life. It is essential for effective diagnosis that these tests are accurate and quality assured. Ear simulators provide the basis for measurement traceability, but in the past have been designed for adults only. The EMRP HLT01 EARS project made the first significant steps at specifying ear simulators for other age groups, and produced a prototype neonatal ear simulator. However the concept of a universal ear simulator needs further refinement and extending to cover all forms of audiological testing, before it can be adopted into clinical practice. One specific aspect is that new methods for transient calibration are needed, to replace the current, technically flawed methods. The move to the next generation of ear simulators is the ideal time to introduce new improved calibration methods for transient stimuli.

Another aspect of hearing conservation concerns environmental and industrial exposure to noise which represents a major public and occupational health issue. With urbanisation and industrial innovation often come undesirable consequences such as new types of noise hazard from infrasound and airborne ultrasound. Greater understanding of the human perception mechanisms is needed in order to tackle the risks posed by this emerging noise. Due to the inaudible nature of some of these noise sources, a multi-disciplinary approach is needed combining neuro-imaging and advanced audiological investigations. Alongside the development of this understanding, new methods and instrumentation are needed to measure and assess noise sources in both public and workplace environments.

 

This is a joint research project carried out in the framework of the European Metrology Programme for Innovation and Research (EMPIR) (see:http://www.euramet.org/research-innovation/empir/). The EMPIR initiative is co-funded by the European Unions's Horizon 2020 research and innovation programme and the participating states. METAS is one of the project partners in the Project.

Projektziele (Englisch)

The overall objective of this project is the improvement and further development of strategies and methods of metrology and calibration for hearing assessment, hearing diagnosis and safety. The specific objectives of the project are:

1. To finalise the universal ear simulator concept to fulfil the whole range of audiological requirements for traceability to sound pressure, including the development of an alternative approach to transient calibration based on impulse response and adaptors for the most common devices. A demonstrator will be realised for the novel ear simulator.
2. To generate robust normative reference threshold data (transfer and input impedance), calibrate devices across partners, quantify the degree of equivalence with currently established practices and provide a user guide summarising features, calibration and handling for application of the novel ear simulator in practice.
3. To exploit neuro-imaging and audiology to further develop understanding of perception as well as response and loudness thresholds for ultrasound (16 kHz – 80 kHz), infrasound (4 Hz – 16 Hz), and the influence of infrasound on sound within the normal hearing range; together with the development of instrumentation and measurement methods for the determination of noise and its hazards in those frequency ranges in both public and workplace environments.
4. To determine experimentally the impact of infrasound and ultrasound on hearing, mental health, cognitive abilities and general wellbeing, and their contribution to annoyance and loudness, including the study of individuals with particular sensitivity to noise.
5. To engage and work closely with stakeholders to establish the clinical protocols and international standards proposals for the use of the universal ear simulators in the calibration of audiometric equipment used for hearing assessment and hearing aid fitting for both children and adults; and to create the knowledge for future guidelines and policy framework to enhance the wellbeing of European citizens and protect them from health hazards associated with infrasound and ultrasound.

Abstract (Englisch)

Within the overall project, significant progress has been achieved regarding the assessment of non-audible sound. The acoustics and vibration laboratory at METAS conceived and implemented a prototype of a portable sound measuring instrument with an extended frequency range reaching far into the ultrasound region (up to 80 kHz). Another key achievement consists in the development of measurement capabilities for traceable secondary calibrations of quarter inch measurement microphones in the ultrasound range.
METAS has also contributed significantly to the development of a novel concept of a universal occluded ear simulator. We had the opportunity to investigate to what extent such a occluded ear simulator could also be applied in a wider context by means of simple adapters (to calibrate circum- as well as supra-aural headphones for audiometry applications rather than just in-ear headphones).

Umsetzung und Anwendungen (Englisch)

As laid out in the project description, general awareness of the presence of emerging noise sources within the infra- as well as ultrasound region is rising. As the national metrology laboratory of Switzerland, METAS is in charge to ensure that correct measurements can be made. The achievements reached within this project enable us to provide traceability also in the ultrasound region and to qualify measurement instrumentation which could be used to assess ultrasound noise pollution and related health risks caused by such sources. METAS has extended its range of calibration services in the area of reference instrumentation for the audiometer calibration.

Publikationen / Ergebnisse (Englisch)

IEC 60318-Y, 1^st working draft "Family of occluded ear simulators for different age groups". Submitted to IEC/TC29 WG21