Ear Simulators and Hearing Aids
Measurements of hearing by pure tone audiometry are made traceable through the calibration of ear simulators. These are transfer standard devices that enable acoustic earphones to be measured when connected to an appropriate acoustic load. However, new techniques such as oto-acoustic emission and evoked response audiometry are increasingly being used alongside pure-tone audiometry. Such objective techniques are particularly appropriate for use in screening (e.g. the NHS Newborn Hearing Screening Programme) and diagnosis of hearing defects, and are revolutionising hearing measurement on a national scale.
New calibration devices simulating these modalities are currently being researched.
In addition to maintaining standards and measurement services for audiometry, NPL also provides input to the working groups of international and national standards bodies, including WG21 on Ear simulators and WG10 on Audiometric equipment in IEC TC29 and WG1 on Hearing thresholds in ISO TC43.
For more information, please contact Richard Barham