Question
What is the best communication system for hearing impaired people communicating with telephones? Please address ''Blue-Tooth'' and T-coil systems, and any other recommended technologies.
Answer
It's way too early to say if Blue Tooth technology will work efficiently and effectively with hearing aids or even FM systems and other ALDs. As of this date (September, 2001), too much current is required to power the Blue Tooth system with tiny, button cell, hearing aid type batteries. According to some hearing aid designers I've spoken with, you'd have to strap a battery to your leg to run Blue Tooth technology (in its current state) with today's hearing aids. But maybe someday......
In general, there are no quick and easy answers concerning the best telephone system for people with hearing loss. The answer depends on several factors: (1) degree and configuration of loss, (2) speech recognition ability, (3) lifestyle, (4) personal preference (5) others.
Additionally, if a person has no usable speech recognition ability, then we must consider visual technology. This could be a VCO (Voice Carry Over) or ''read and talk'' phone.
Using the relay system, the user speaks into the phone as usual (understandable speech is needed) and the person on the other end speaks through a communication assistant. The assistant types text, and the text is read on a small screen on, or near the phone. This type of device is generally used by people who are post-lingually deaf. That is; they began their lives with normal hearing and developed significant hearing loss over time.
TTYs and computers containing TTY software are also used by people with limited speech recognition ability. Probably the most exciting technology to come along is the ''Instant Message'' function of most new PCs, which enables two or more people to read and write text to each other via PC, and the Wyndtell Pagers [www.wynd.com]
which allow provide personal, portable two-way communication, as well as a chat functions. These devices are akin to portable TTYs, fax machines, and pagers and are wildly popular with busy people with normal hearing as well people with hearing loss.
For people who want to use a ''voice phone'', a deeply inserted CIC hearing aid (necessary to prevent acoustic feedback) can be used with a regular phone and an amplified handset or portable, battery-powered amplifier. However, many people cannot wear such deeply inserted devices. Thus, ITC hearing aids are often recommended. In my opinion, ITC hearing aids pose several challenges. First of all, they are too large to be cosmetically discreet. Second, their shallow fit often produces feedback. Finally, they don't have enough ''real estate'' to be equipped with a sensitive enough telecoil. For the best telecoil reception, I recommend an ITE or BTE hearing aids. To boost the sensitivity of a telecoil, you can order it equipped with a pre-amplifier. Also, in ITE hearing aids you should specify how the telecoil will be placed inside the hearing aid case. For BTE hearing aids, the telecoil is usually placed vertically (one end facing the ground and the other facing skyward). This is because vertical placement works best with room and neckloops. However, the best placement for telephone reception is horizontal (one end facing into the ear canal and the other facing outward). Keep in mind that most people who need a telecoil may also need a way to couple their hearing aids to assistive listening devices (ALDs). In that case, order a vertical placement with a pre-amp. The person can compensate when using the phone by slightly angling the receiver AND they will still be able to use ALDs. In fact, some BTE companies install their telecoils at an oblique angle as a compromise solution.
When ordering a telecoil, you should verify that its performance is satisfactory. ANSI 1996 (S3.22) calls for greater magnetic field strength than the old 1987 standard did. It also requires that an entire frequency response be measured, rather than a response at only 1000Hz. Make sure you have your hearing aid measurement system upgraded to this standard. Some systems provide a Telewand that can be held in position near the hearing aid just like a telephone handset. This allows ''in situ'' measurement. Another neat measurement is the simulated telephone sensitivity. This estimates how much the hearing aid volume control would have to be raised when switching from microphone mode to telecoil mode. The ideal situation would equal a value of zero (0) and your client would not have to practice the extremely annoying drill of turning up the hearing aid every time they need to use the telecoil.
To enhance telephone reception, handset and portable amplifiers can be recommended. Most produce 20 to 30 dB of gain. If more is needed, an amplified phone might be a better idea. Several companies make such phones (Walker, Ameriphone, Williams Sound). Some of them produce in excess of 55 dB of gain and can be used with telecoils, DAI and even implants. It's also a good idea to have clients try out various phones. Telephones have minimal standards when it comes to hearing aid compatibility and sometimes several must be tried before settling on one.
One thing to watch out for in the workplace is electromagnetic inference from computer monitors and fluorescent lighting. In these cases, telecoil coupling may not be possible. However, BTE hearing aids can be coupled to the phone using DAI. Stand-alone hardwired devices (e.g. Audex SounDirector, Williams Sound PockeTalker) can be coupled to any modular phone and used with DAI. If electromagnetic interference is not an issue, then these devices can be used with a neckloop or silhouette inductors.
For your clients with reduced speech recognition ability, you might want to try providing them with diotic telephone reception, as this may be the difference between being able to use a voice telephone and having to switch to VCO. A couple of neat solutions include using any of the stand-alone devices coupled inductively or via DAI to BOTH hearing aids. The Oticon TA-80 C also can be used this way. This device is an acoustic-to-magnetic adapter that simply straps onto the telephone earpiece. However, a thin cord connected to a silhouette adapter can be added and used at the opposite ear, thus providing a telephone signal to both ears.
Another option important to many clients is hands-free telephone reception. Walker Plantronics' (contact: Sandra.mills-doyle@plantronics.com) M12 amplifier can be used with an H51 headset and a special interface that connects to a hearing aid via DAI or a neckloop (PNSSP1109-01).
Individuals with mild hearing loss might do very well with acoustic coupling of the hearing aid. Feedback often can be reduced via the use of a telepads (foam rings or squares that attach to the earpiece to increase distance between the phone and the hearing aid microphone). Plastic versions are also available and are more portable (the foam variety stick to the phone, making them impractical for temporary use on other phones). Also, before recommending this solution, make sure you know what type of phone your client will be using. Some pads and most plastic couplers make it difficult to hang up the phone (unless it is of a desk type that allows you to place the handset upside down). Some clients simply use a paperweight to hold down the interrupter switch.
Some new technologies are also available such as the Touchless Telecoil, which is available in Micro-Tech and some Starkey models. The Touchless T-coil allows the stationary magnetic field of the telephone receiver to trigger the hearing aid's telecoil by simply positioning the hearing aid near a hearing aid compatible phone. This device might be a great solution for clients who cannot flip an M/T switch or who would rather not have to. This device cannot be used with ALDs but the manufacturer is attempting to remedy the situation with an additional device that can be worn over the ear.
A word (actually several paragraphs) about digital cell phones and hearing aids . . .
Digital Cell phones currently account for about 75-80% of the US cellular phone market and this technology is accelerating fast. Digital cell phones offer many great features unavailable through most analog phones. However, digital cell phones interfere with hearing aids. The interference, which is generally heard as a distorted buzzing sound, differs from hearing instrument to hearing instrument and is generally worse for older/larger models. Interference can be so severe that conversation is not possible and it matters little whether the hearing instrument is in the M or T position - but it is usually worse in the T position. The systems found to cause the greatest amount of interference is the TDMA (GSM) system. The CDMA system causes the least interference. Consumers cannot always choose between the two transmission systems since the carrier chooses them. Also, the further away from the cell (transmitting tower) the greater the interference will be. This is due to the automatic power increase of the cell phone as it senses an increase in transmitting distance to the cell.
The problem of digital cell phone compatibility with hearing instruments is worsening. As cellular phones become smaller they may use ceramic rather than magnetic speakers. This means no induction field at all and hence, no T-coil. Interestingly, the same thing happened with land-line phones awhile back and was remedied by legislative action mandating that all land-line phones sold in the U.S. (since 1991) be hearing aid compatible.
Several hearing aid companies have been working toward eliminating digital cell phone interference problems. Many newer model hearing instruments are partially ''immunized'' for this type of interference
For example, in Oticon's newer Technical Data sheets you will notice a new measurement called ''EMC (Electro Magnetic Compatibility) Immunity, dB SPL.'' The dB SPL figure refers to IRIL (Input Related Interference Level). The dB SPL figure for IRIL should be interpreted as follows:
Since most analog cell phones were replaced by digital units some 10 years ago in Scandinavia and in Europe, some hearing instrument companies have offered silver-nickel plated casing shells for category III BTEs. According to Preben Brunved of Oticon Corporation, the use of this technology will bring the IRIL level down to approx. 15 dB SPL.
In the meantime, you might want to recommend a ''hands-free interface'' for your clients who want to use their hearing aids with cell phones. You can find information on the various cell phone websites. Word has it that at least one of the cell phone manufacturers (Motorola) is interested in making a device that will couple a BTE hearing aid to their hands-free earbud kit. In addition, Nokia is talking about introducing a device, CHAAMP, that will make their 5100, 6100 and 7100 series digital cell phones compatible with all hearing instruments that are equipped with T-coils. Audex [vbeatty@iamerica.net] also sells hands-free devices.
References:
For contact information for the products mentioned above, you can view Gallaudet's Assistive Devices Center website [https://aslp.gallaudet.edu/aslpweb/business/ald/ald_desc.html]. My colleague (both at Gallaudet and at City University of New York where we attend school) Linda Kozma-Spytek wrote a fantastic article on cell phones that you might want to read. ''Digital Wireless Telephones and Hearing Aids'' by Linda Kozma-Spytek, M.A., Research Audiologist, Gallaudet University Technology Access Program, Washington, D.C. /newroot/resources/Article/article.cfm?tid=93. Catherine Palmer also recently wrote a very nice ''Page Ten'' article on telephone solutions which appears in the current (September) issue of The Hearing Journal.
BIO:
Cindy Compton is a professor of Audiology at Gallaudet University's AuD program and directs the Gallaudet Assistive Devices Center. A graduate of Rutgers and Vanderbilt Universities, Cindy has published extensively in the area of assistive technology. She recently defended her dissertation at the Graduate Center of the City University of New York and will be graduating in May. Her dissertation focuses on the development and validation of a multiple-speaker technique for evaluating the real world performance of directional microphone hearing aids. Her committee includes Drs. Arlene Neuman (Professor) and Harry Levitt of CUNY (Distinguished Professor Emeritus), and Dr. Mead Killion of Etymotic Research (adjunct professor at Northwestern University, Rush University, and CUNY). In her spare time, she is an avid sailor of the Chesapeake Bay.