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.