Silence is not always golden

IEC International Standards help hearing-impaired people live a more comfortable life

By Morand Fachot

Hearing loss reportedly affects the lives of hundreds of millions in the world. Hearing aids help those suffering from this disability live a nearly "normal" life, but still far too few people benefit from these aids. IEC TC 29: Acoustics, has prepared more than a dozen International Standards to ensure hearing aids and related equipment, such as audiometers, meet the needs of users and practitioners.

There are actually hundreds of individual parts inside a hearing aid, such as this Siemens Motions S BTE device (Siemens-Press Image) There are actually hundreds of individual parts inside a hearing aid, such as this Siemens Motions S BTE device (Siemens-Press Image)

Not a minor disability

According to the WHO (World Health Organization) over 360 million people in the world have disabling hearing loss, which it defines as loss greater than 40dB (decibels) in the better hearing ear in adults and greater than 30dB in the better hearing ear in children.

There are four categories of hearing loss, with severities ranging from mild to profound. It can affect one ear or both ears, and leads to difficulty in hearing conversational speech or loud sounds.

The categories include "hard of hearing" people who suffer from mild, moderate or severe hearing loss, and "deaf" people who have profound hearing loss, implying very little or no hearing. Over 90% of those affected are adults and 9% are children. Elderly people have a higher incidence of hearing loss. The human impact of hearing impairment is severe; it affects social and emotional interaction and academic achievement as well as employment and career prospects .

Staggering economic cost

Hearing impairment also has severe adverse economic and societal consequences. A 2006 report estimated that some 16% of EU citizens suffered from hearing loss. It set the total cost for (the whole of) Europe to over 210 billion euros per year at the time. Surveys in the US and other developed economies produced similar conclusions: societies incur costs in the hundreds of thousands of dollars over the lifetime of each individual suffering profound to severe hearing loss, and households with one or more individuals affected by hearing loss have a lower than average income.

Help is at hand

The WHO estimates that half of all cases of hearing loss can be prevented by primary intervention mechanisms such as immunization against certain diseases and reducing exposure to loud occupational and recreational noise. Early diagnosis of hearing problems through screening of individuals at risk and appropriate management can help prevent more serious problems occurring.In spite of its economic cost to society and individuals hearing loss itself is relatively inexpensive to treat. Wearing two modern digital hearing aids makes all the difference in terms of economics for society and quality of life for individuals, yet they are worn by only about one in six of those in developed economies who would benefit from their use.

Improved hearing thanks to IEC International Standards

The public’s overall perception of hearing aids is that of rather conspicuous yet often ineffectual devices that sit behind or within someone's ear. However, modern hearing aids are now often unobtrusive and very effective, thanks in no small measure to work by experts from WG (Working Group) 13: Hearing aids, of IEC TC (Technical Committee) 29: Electroacoustics. WG 13 experts have so far prepared 13 International Standards in the IEC 60118 series. These cover measurements of electroacoustical and performance characteristics for various types of hearing aids, as well as methods of measurement, and other specifications. TC 29 has also prepared IEC 60601-2-66, Particular requirements for the basic safety and essential performance of hearing instruments and hearing instrument systems, in the Medical electrical equipment series of International Standards, and IEC 62809, a Technical Report that provides an overview of the requirements and tests for the latter.

Other TC 29 WGs prepare standards for equipment intended for hearing impairment issues. They include, among others, WG 10: Audiometric equipment, which prepares International Standards for machines used for evaluating hearing loss, and WG 22: Audio-frequency induction-loop systems and equipment for assisted hearing, that allows wearers of specially equipped hearing aids to get a wireless signal transmitted directly to their ear. In the UK, for instance, these systems are installed in the back seats of all London taxis, in 18 000 post offices, in most churches and cathedrals, and in many museums and public building .

More flexible, efficient and less obtrusive

Hearing aids include an internal microphone, amplifier and receiver as well as various control buttons and a battery.

DSP (digital signal processing) has vastly improved the sound quality and sound processing ability of hearing aids, allowing them to be tailored to each individual's acoustic and environmental needs. This flexibility allows audiologists to "tune" and "retune" hearing aids to the user’s preferred sound quality and most needed sound processing characteristics.

Hearing aids are available in several main styles to meet most or all categories of hearing impairment.

Patients have the choice between the following categories, depending on a number of factors and the degree of severity of their impairment:

  • BTE (behind-the-ear) models, which are available for all degrees of hearing loss
  • RIC (receiver-in-canal) can be worn comfortably behind the ear but are smaller than standard BTE models; they are available for mild to severe hearing loss
  • ITE (in-the-ear) models are made specifically to fit the shape of a wearer's ear canal for maximum benefit and the best possible comfort. They are suitable for mild to severe hearing loss, are less conspicuous and very effective
  • CIC (completely-in-the-canal) hearing aids are defined by the location of their faceplate, 1-2 mm inside the aperture of the ear canal. They are very unobtrusive
  • IIC (invisible-in-canal) is the most recent category of hearing aids to be made available. It fits to the second bend of the ear canal and offers users a truly invisible solution

In addition to their aesthetic advantages CIC and IIC aids offer many acoustic benefits. They retain some aspects of the ears’ natural filtering of sounds, as compared to the microphone placement of BTE-style hearing aids, and are much closer to the eardrum.

Bright prospects for growth

Considering that only a minority of hearing impaired people uses hearing aids, even in developed countries, prospects for the hearing aids market are bright.

If the human, societal and economic costs of hearing impairment are huge, so are the potential benefits for the global hearing aid devices industry. Valued at USD 7,2 billion in 2011, the market is forecast to reach USD 11,3 billion by 2018, growing at a 7% CAGR (compound annual growth rate), according to a recent GBI Research report.

This growth, driven by the development of more efficient and reliable devices, will benefit millions of people. It is being made possible by through the efforts of IEC TC 29 experts.

There are actually hundreds of individual parts inside a hearing aid, such as this Siemens Motions S BTE device (Siemens-Press Image) There are actually hundreds of individual parts inside a hearing aid, such as this Siemens Motions S BTE device (Siemens-Press Image)
Maico digital diagnostic audiometer (Photo: Maico Diagnostic GmbH) Maico digital diagnostic audiometer (Photo: Maico Diagnostic GmbH)
There are actually hundreds of individual parts inside a hearing aid, such as this Siemens Motions S BTE device (Siemens-Press Image) There are actually hundreds of individual parts inside a hearing aid, such as this Siemens Motions S BTE device (Siemens-Press Image)