How are induction loops better than infra-red (IR) or FM systems?

Neither Infrared or Radio systems can replace induction loop systems.  Other technologies do have their advantages, however induction loops systems are the most versatile technology available, suitable for the broadest range of applications.

Infrared has the specific advantage that the signal does not cross walls and hence provides a very high level of confidentiality. It can also be used in multi-channel systems for simultaneous translation, where it is used purely as a communications system.

It suffers quite badly from shadowing, offering many situations in rooms where the signal is lost. Special receivers have to be issued which draw attention to the hearing disability. There are also very serious concerns about the standards of hygiene; have the receivers really been cleaned and disinfected? The cost of these processes is a significant expenditure for the operator of the facility.

Radio systems are even less attractive. Apart from the negative user response noted above, there is a major problem with signal loss. Professional radio microphones use diversity reception to reduce signal loss due to reflection of the radio signals from walls, etc.. This is not possible with the radio receivers used for assistive listening. Furthermore, there is a major problem with shortage of frequencies and confidentiality is totally non-existent.

In comparison, induction loops have the following advantages:

  • Uses built-in T coil in hearing aid
  • Utilises internal tonal correction
  • No additional receiver needed
  • Hygiene problems eliminated
  • No loss of special receivers from venues
  • Will work in conditions of bright light and outside

Are all hearing aids compatible with induction loops?

Sadly, not all hearing aids are fitted with the loop facility. In the UK, almost all NHS aids are equipped with a 'T' position, as are many privately sold aids. In the UK private sector, it is often the audiologist who decides whether to offer the loop reception facility, but generally they do offer aids with a 'T' setting. At present, about 95% of hearing aids in the UK are said to have the loop receiving function.

In the USA, audiologists do acknowledge the benefit of the 'T' facility, however up to 50% of aids sold in the USA are without the 'T' coil facility.

Digital hearing aids work in exactly the same way as ordinary analogue aids in terms of induction loop use but you must make sure that the digital hearing aid has a 'T' switch position. As far as we are aware, all digital hearing aids supplied by the NHS (National Health Service) in the UK have a 'T' coil facility. Privately dispensed digital aids may or may not have a 'T' coil. As policies over 'T' coil provision in hearing aids vary around the world - check with your audiologist about this before you buy, as it may affect what they offer to you. Many digital hearing aids allow the option of setting the relative levels between microphone and 'T' coil inputs to be adjusted by the audiologist. If the loop signal is quiet / loud relative to normal microphone use, ask your audiologist to adjust it for you.

The international standard governing the use of induction loops (IEC60118-4) requires that the loop coil be vertically orientated to pick up the magnetic signal. Regretably, IEC60118-1 which applies to hearing aids, does not define any orientation. Some hearing aids are available with a pick up coil adjusted for reception of horizontal magnetic fields and these may give poor results even when used in a correctly installed loop system unless you bow your head forwards to face the floor. Ampetronic are currently researching this effect and would welcome your comments if you have experienced this problem. Please let us know the hearing aid manufacturer, model number and date of purchase for our records together with a brief description of the exact circumstances under which the problem arose.

Always check with your audiologist BEFORE purchasing a hearing aid to ensure compatibility with induction loop systems.

Do induction loops interfere with pacemakers?

There has never been a technical study on whether a hearing loop could have any negative effect on a pacemaker or interfere with its operation.

Studies have reached  the ‘Proposal’ stage before but have been rejected by the experts as the magnetic field strength produced by a hearing loop system could not in all practical reality affect a pacemaker, and so the study would be rendered pointless.

However the concern is understandable and it is a sensible question considering how a pacemaker functions.

Although there is no evidence to state that the magnetic field produced by a hearing loop can effect a pacemaker, in order to alleviate any doubt Ampetronic simply suggest that a distance of 150mm or 6’’ separation between loop cable and pacemaker is maintained.

This would imply that a neck loop is not placed directly across the chest and that a person with a pacemaker should not lean against a counter or portable loop system”.

What is AGC (automatic gain control) and why is it important?

Automatic Gain Control is standard in all Ampetronic equipment. AGC automatically adjusts the output level of a loop amplifier to retain a constant level while retaining normal dynamics of speech and music. AGC provides a dynamic range that can be comfortably received by the hearing aid, and provides excellent intelligibility for the hearing aid wearer over a wide range of input levels. AGC is a fundamental part of creating an assistive listening system that is beneficial to the hearing impaired. The international standard for induction loop systems IEC60118-4 does not mandate the use of AGC, however it is practically not possible in normal circumstances to meet the requirements of this standard without gain control.

What is a Hearing Loop, Induction Loop or T-Loop?

An Induction Loop, also known as a Hearing Loop or T-Loop, is an assistive listening system that provides access to facilities for those with a hearing impairment. It takes a sound source and transfers it directly to a hearing aid via a magnetic field without background noise interference or distortion.

The presence of an Induction Loop should always be indicated by the internationally recognised hearing impaired sign with a T symbol.

Over the last 25 years Hearing Loops have become the default assistive listening solution in Europe, Scandinavia and Australasia, and are now becoming increasing prevalent in America. Due to their benefits and ease of use, hard of hearing groups are mandating their installation in locations as diverse as taxis, kiosks, schools, houses of worship, concert halls and stadiums.

Isn’t this what hearing aids are for?

Hearing aids enhance sound in close conversational settings, or where there is little background noise or distance to the source. Many modern digital hearing aids can filter out a great deal of background noise, however this does not resolve the issue of distance between the sound source and the hearing aid user.

A Hearing Loop magnetically transfers the sound from a microphone, TV or audio signal directly to hearing aids and cochlear implants without interference, background noise or distrotion, regardless of distance.

How much does a hearing loop cost?

The cost of a Hearing Loop system is proportional to the size and complexity of the loop design, the associated amplifier(s) and the accessories required.

A ‘fit-for-purpose’ retail/reception desk or home TV room loop should typically be less than £300 plus any installation fees, whereas a professional system for a large venue may cost thousands of pounds proportional to the size of the venue and other audio visual equipment that may be installed.

It is worth remembering that the cost of installing a Hearing Loop in a medium size venue, such as a place of worship, will often be less than the cost a single user has paid for their professionally fitted hearing aids.

Do all hearing aids have a telecoil?

The increasing popularity of Hearing Loops has seen a steady increase in the inclusion of telecoils in hearing aids. At present just under 70% of hearing aid models in active use are fitted with them.

This number is as high as 95% in countries where Hearing Loops are already established.

All new model cochlear implants now offer telecoils with manufactures stating that 95% of all new hearing aids are to offer telecoils, although some Audiologists do not activate them as standard, especially in the United States.

Hearing aids usually have an active life of around 5 to 10 years before a person’s hearing degeneration dictates a replacement. It is therefore reasonable to assume that by 2020 almost all hearing aids will have a telecoil installed.

If you would like more information about your model of hearing aids please contact your Audiologist.

Can people without hearing aids and/or telecoils use a hearing loop?

All assistive listening systems, including hearing/induction loops, can be used with portable receivers and headsets.

Don’t wireless technologies like Bluetooth offer an easier and less costly solution?

Wireless technologies are not suitable for assistive listening solutions that directly utilise the hearing aid in their current form as they cause significant battery drain and have a limited range.

In the case of Bluetooth, as an example, the area cover is between 5-100 square meters (depending on type), the technology can only support the connection of up to 7 users at the same time and also requires the ‘pairing’ of devices in order to connect them.

What sort of places can a Hearing Loop be used in?

Although Hearing Loops have traditionally been used in places such as houses worship and conference rooms, advances in technology have allowed the spread of the technology to areas including:

Stadiums, theatres, cinemas, concert halls, sports halls, courts, lecture halls, school classrooms, video concerning suites, meeting rooms, museum exhibits, fairground rides, taxis, help points, nursing homes, domestic TV rooms, retail counters, receptions, transport stations, waiting rooms, boats, minibuses, cars and trains.

Contact us or look at our products to gain some insight in the the applications available.

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