Lots of hearing aids are "Telecoil (T-coil) equipped." T-coils are designed to pick up electromagnetic signals, as opposed to microphones which register acoustic signals.
Certain telephones, cell phones, and assistive listening systems in public places (theaters, museums, etc.) produce electromagnetic signals. T-coil equipped hearing aids are supposed to "inductively couple" with such electromagnetic devices/systems to provide clear, amplified sound through the hearing aids. If you want to learn more about the technology, click here.
Few in North America know much about T-coils -- Europeans are said to know and use them more. My audiologist knew virtually nothing about the technology, and she has a Au.D.
Few of the hearing-impaired in the USA are using their T-coils. In my own case, I initially tried to use the T-coils in my new hearing aids with several different telephone handsets at home and at work. In each case, when I switched my hearing aids to T-coil from microphone, I couldn't hear the caller.
In retrospect, my hearing aides were not coupling inductively, probably because the electromagnetic signals in the ear cups were too week. At the time, I didn't know better; I just thought that T-coil technology sucked.
When I questioned my audiologist about my experience, she gave me a small, rare-earth magnet to put in the ear cup which she said would boost the electromagnetic signal. Not! It turns out that what the magnet is supposed to do is switch certain automatic hearing aids from microphone mode to T-coil mode, not boost the telephone's electromagnetic signal.
In spite of the misadventures and misinformation, I struggled on, albeit with lowered expectations. Based a few glowing testimonials that I came across in the course of my research, I decided to try an inductive loop. Luckily, my new cell phone is a Nokia 6086 (remember the Europeans know about T-coils). Furthermore Nokia makes an inductive loopset (LPS-4) that fits the cellphone model I have. Online, people are selling the Nokia LPS-4 for anywhere between $35 - $100. I paid $35, which included shipping.
When the unit arrived, there was a fat instruction book, with 3-4 pages of instructions written in just about every language on earth. The device is very simple; almost idiot-proof. Plug it into the cellphone, put the loop around your neck, and it should work. Switch your hearing aids to T-coil (one ear or two), place a call and the sound comes through loud and clear. A voice pick-up and call-answer button are located on the loopset, so your phone can stay in your pocket, except to dial.
My cellphone has a radio on board so I can listen to it during meetings and nobody is the wiser. While I can listen to music on my cell phone, the loopset only plays monaural sound.
In certain places, electromagnetic interference caused by certain electronic devices and/or machinery is a problem. Interference creates a buzzing sound in the ears which ranges from barely audible to somewhat distracting, depending on the call.
I was in love with my new Nokia 6086 cellphone before because of the Hotspot@Home feature. Now with my inductive loop, I am ready to marry it.