Digital Cell Phones and Hearing Aids
- Part 2

Part one

Q: WHAT SHOULD BE CONSIDERED WHEN PURCHASING CELL PHONE SERVICE?
A: One website that is particularly helpful in sorting out wireless service providers is http://www.wirelessadvisor.com. By entering a zip code, the Wireless Advisor identifies which service providers operate in a particular area and the transmission technology each one uses.

Through anecdotal reports from hearing aid (HA) users, clinical experience, and research evidence, CDMA and iDEN transmission technologies seem to work better (although not necessarily interference free!) for HA users than GSM transmission technology. Of the largest carriers, Verizon Wireless and Sprint PCS use CDMA technology, and Nextel uses iDEN technology.

Once a service provider has been selected, the next step is to determine which cell phone handsets it supports. The service provider's website is the best way to find these phone models and their features and accessories.

A very important question to ask is how long one has to cancel the service and return a phone without penalty, if they don't work for a particular hearing aid wearer.

Q: WHAT SHOULD BE CONSIDERED WHEN PURCHASING A CELL PHONE HANDSET?
A: Generally speaking, it's a good idea to shop for cell phone handsets at the "full" retail telephone store of the service provider. The support personnel at the full retail telephone store are more likely to know about these issues than the personnel at electronics or office supply stores. Full retail service provider stores are also more likely than electronics stores to have phones that are "in service" which can be tried with the particular hearing aid of concern.

The design of the telephone handset may be important for hearing aid users. Look for a telephone that has a "clam shell" or "flip up" design, where the only part of the phone in the section that flips up is the speaker (where you listen to the other party). Once a carrier has been selected, see if they support handsets made with this design. This design provides some physical distance between the hearing aid and the components related to the cell phone's transmission technology that may potentially cause interference. For telecoil users, it also provides physical distance between the cell phone electronics (another potential source of interference) and the hearing aid. The greater the distance between the hearing aid and these electronics, the less potential there is for interference experienced by the hearing aid wearer.

Interference from backlighting, depending on the type of display, can be particularly bothersome for telecoil users. Backlighting is used to light the phone's display window so information can be easily viewed in low light conditions. Backlighting typically turns on when the phone is turned on and then when any of the buttons on the control pad are pushed, including the volume control buttons. The ability to control whether the display is illuminated or not, and the amount of time the backlight stays lit may be important considerations for telecoil users, especially if the phone provides otherwise interference-free listening.

The Cellular Telecommunications and Internet Association (CTIA), the trade organization for the wireless telephone industry, has a website on accessibility and wireless technology (http://www.accesswireless.org/index.htm ). The website lists wireless phones to try if you are a hearing aid wearer. The phones are listed by manufacturer, and information is provided on which handsets may have lower levels of RF emissions and which may have inductive coupling capability.

Finally, hearing aid wearers should consider their need with regard to ring signaling. Most cell phones have a choice of distinctive ring signals and a volume control for ring signaling. Many will even have a built-in vibratory alert. A "holster" can be used to clip the phone to clothing so incoming calls can be detected through vibration. If a vibratory alert is desirable, but not built-in, there are vibrating alerting accessories available, although their performance may be less consistent than phones with this option built-in.

Q: WHAT SHOULD BE CONSIDERED WHEN PURCHASING NEW HEARING AIDS?
A: When purchasing new hearing aids, hearing aid candidates should be sure to tell their audiologist that they want to be able to use a digital cell phone. The audiologist can talk to the hearing aid manufacturers to find out which of their hearing aids have some level of "built-in" immunity to cell phone interference. Hearing aid components, such as microphones and t-coils, are being developed that are more resistant to interference, but this needs to be stated as a requirement.

In addition to built-in immunity, audiologists may suggest that hearing aid candidates select hearing aids with telecoils. Telecoils are required in order to take advantage of many of the accessories, such as neckloops or other add-ons, developed by both the phone industry (e.g., neckloops by Nokia and Motorola) and third party manufacturers (e.g., CHAAMP by Audex, HATIS). When audiologists discuss accessories with hearing aid patients, it's important to consider the cost of the accessory and its ease of use and maintenance.

Most accessories increase the distance between the hearing aid and the phone's antenna, thereby reducing or eliminating the effects of the interfering EM field. Neckloops, for example, inductively couple to a hearing aid's telecoil and plug into the 2.5mm plug or proprietary connector on compatible phones. These loopsets include a built-in microphone and permit hands-free use of the phone and binaural listening if the user has two hearing aids with telecoils. The phone itself can be carried in a pocket or clipped on a piece of clothing, away from the hearing aids.

The Hearing Industry Association (HIA), the trade organization for hearing aid manufacturers, has committed to including written material with hearing aids on their anticipated performance with digital cell phones. HIA has also committed to offering a 30-day trial period for new hearing aids with a full refund if a customer is dissatisfied with its performance when coupled to a digital cell phone.