By Dr. Max S. Chartrand Ph.D.

The question "What if these hearing aids don't work?" is asked with the implication that there are no finite limitations to correcting one's hearing loss; just limitations in hearing aids. More often than not, though, for the severely hearing impaired patient, the question should be: "What if I need more than hearing aids to meet my needs?"

Of course, the informed answer is the application of the appropriate Assistive Listening Devices (ALDs) to fill communicative/auditory gaps. In practice, however, it's reportedly rare that assistive devices are even recommended during the evaluative or counseling stages of dispensing.

Whereas hearing instruments provide continuously wearable auditory correction for all-around function, in comparison to assistive devices they can perform poorly in auditoriums, on the telephone and in other communicative and signal-to-noise situations. This points to an undeniable need for assistive devices to complete the aural rehabilitative picture for those with the more serious hearing losses. Poor signal-to-noise ratio, distance and room reverberation come to the forefront when weighing the benefits of hearing aids versus ALDs in specific acoustic applications, the latter providing the needed advantage.

Specialists should be well acquainted with all available devices, their care, application and sources of supply. Recent professional journals and other sources are replete with information about currently available devices. For that reason, we will provide only an introductory treatment of the topic to acquaint dispensing professionals with appropriate counseling information as it pertains to ALDs.

Many Hearing Instrument Specialists have ALD displays in their offices. In some practices, a separate room has been designated with a display of demonstration models. Others keep a sampling of basic units in their counseling or fitting room for demonstration when needed. At the very least, most specialists will have the catalogs of various sources of supply.

In addition to hearing aid and cochlear implant users, the "culturally" deaf population, the immobile and those with central auditory processing difficulties (such as receptive aphasia) may also benefit from appropriate assistive devices.

However, many specialists and audiologists do not actively promote ALDs. Perhaps the principal reasons are the relatively low margin of profit and a perceived competitive factor to hearing aid amplification. There are a number of important reasons for actively promoting assistive devices into the financial model of a profitable dispensing practice:

1. Supplementing hearing instruments and cochlear implants with assistive devices can reduce over-expectation and credit returns.
2. ALDs do not require the same level of evaluation, counseling and adaptation as hearing instruments.
3. Patient and third-party loyalty will be enhanced by offering a more holistic hearing service.
4. The severely impaired hearing aid user's lifestyle and opportunities for growth will be enhanced.

These rehabilitative devices have enabled their users to mainstream into society in ways that hearing aid amplification and cochlear implantation cannot. It is suggested that the specialist utilize a "Communicative Assessment Form" to help determine the special and individual needs of their severely impaired patients and, where possible, to work with an aural rehabilitation counselor who specializes in assistive devices.

Following is a brief overview of some of the available devices that may effectively supplement and extend the usefulness of hearing instruments and cochlear implants:

• Closed caption television (CC) has lifted many hearing impaired individuals from virtual boredom and frustration while watching television and movies to joining with their normal hearing counterparts as part of the audience. Far more effective than a hearing aid for those with poor aided speech discrimination, the CC decoder projects dialogue and pertinent subtext onto the screen, while scrolling in relative synchronization with the spoken message.
  
  Since 1993, the Americans with Disabilities Act (ADA) has mandated that every television set 13" or larger sold in the US. must include a closed captioning decoder. Some people may not be aware of this because the option is programmed into the set-up controls. Too often, severely hearing impaired patients do not use this feature, or are unaware of its existence until advised by their Hearing Instrument Specialist.

Infrared TV amplifiers provide an acoustic benefit for the hearing impaired. The clarity, fidelity and convenience of these wireless devices make them superior considerations to external speakers for many hearing impaired persons who still enjoy reasonable residual hearing. The range of broad-cast is usually within 20 to 30 feet of the sound source.

• Infrared reception is received in the direct visual pathway of the transmitter, while the signal travels on light waves within the room. Hence, some lighting will be needed while viewing the television with the infrared system or a disturbing "hissing" and/or distortion may occur.
  
  Recent commercially available infrared systems with their attractive display materials, have made this a profitable device for specialists to sell in their waiting rooms. As patients enter for their appointments, they are given a demo headset with which to watch a hearing health-related video.
  
  Often the receptionist the most active promoter these devices, because of its ease of sale and continuous demonstration in the waiting room. Infrared transmitting and receiving sets are also available for wide-area listening situations (see Figure 3).
• Wireless frequency modulation (FM) auditory systems are also invaluable for difficult listening situations, such as in large auditoriums, church meetings, classrooms and one-on-one conversations in noisy restaurants or while traveling. Many churches, schools, amusement parks and some theaters provide these devices to the public at no charge, though too often they go underutilized by those who need them.
  
  Unique advantages of FM auditory systems are numerous. Broadcast and reception range is much longer than infrared, horizontally up to 1,000 feet, vertically by several miles; it will transmit through most building materials (except metal), and several channels can be used simultaneously without cross-interference. Sound quality can be very high fidelity (see Figure 4). 
  
  FM systems can be found in three user modes:

1. Personal FM auditory systems are used by individuals who purchase an entire auditory kit containing the microphone transmitter unit and a personal receiver. The receiver unit is used either directly with an acoustic coupler onto the ear, or by transmission through the hearing aid with a neckloop, direct auditory interface (DAI) or boot connection. Also available are ear-level FM receiver units, usually as part of an amplification array.
2. Large area and group listening systems are featured in many schools, churches, auditoriums and some theaters and amusement parks. In these cases, the transmitter is usually built into a public address or large area broad-casting system, while users simply check out the receiver units for personal use. The availability of various channels is very important in these systems, especially when several broadcasts (or classrooms) are using FM at once. Again, users may interface by direct coupling, DAI or hearing aid boot.
3. FM classroom soundfield systems, although a recent development, have proven to be helpful for a wide array of students: hearing aid and cochlear implant users who wish to be "mainstreamed" in the class room, developmentally-delayed students (particularly those with CAPD, ADD, or history of chronic OME) and normal hearing students who must listen in poor acoustic classroom settings.

• Hardwired systems are simply hard-wired assistive listening systems, which reduce the distance between thespeaker and listener or teacher and student. For years, hardwire systems were all that were available for the hearing impaired, and then only in large area listening situations such as auditoriums or chapels and sometimes schools. Nearly all modern buildings have replaced hardwired systems with wireless systems (i.e., FM, infrared). One reason these systems have fallen out of favor with hearing professionals is because of their lack of spectral and loudness growth functions. While hardwire systems are probably adequate for those with conductive losses or flat configurations, they certainly leave much to be desired for the much larger number of sensorineural losses. Additionally, they restrict the user to a specific location and usually require the use of bulky headphones.
• Loop Systems are hard-wired systems that provide a magnetic field or leakage that can be picked wirelessly by a hearing aid user's induction telecoil. These, also, are falling out of favor as few new structures today accommodate induction loop systems. Besides being severely limited in range, there have been reports of electromagnetic interference in some buildings. In regard to fidelity, the main drawback has been the very limited F2 range of the hearing aid induction coil itself, often topping out at 1.5-2.0KHz. Some of the newer amplified telecoils (with pre-amp) show responses near 4KHz. This is more acceptable, but is still quite limited compared to the 10KHz sensitivity ranges of their FM counterparts.
  
  Loop induction technology gained in popularity in the 1950s in Europe and later came to the U.S. in the 1960s. Consumer groups' recent push for telecoils on hearing aids has caused a mini-revival of the technology; however, fewer than 20 percent of hearing aids in use today feature telecoils, generally for users of BTE and some larger ITE products. Nearly always these are power class instruments for more severe losses. Consumer demand for smaller and less visible instruments has caused a continuing decline in the number of telecoil options offered. While the author, a hearing impaired consumer himself, sympathizes with those who wish to change current trends, the fact remains that FM is taking over and loop systems are on their way out. As far as telephone use, most mild and moderate users have better sound reception through the newer acoustic microphones and low-distortion amplifiers.
• Special signal devices include flashing light alarm clocks and flashing lamps for telephone calls, the doorbell or even a knock at the door. These devices serve to put the impaired individual in touch with the signals around them. Several new devices that have recently been introduced to the market involve multiple signal devices, allowing the user to wear a box no larger than a pager on their belt to be alerted of knocks on the door, monitoring of the baby, ringing of the telephone and, in some cases, built-in FM communication or direct amplifier (see Figures 5 and 6).
• Telephone amplifiers include built-in or add-on receiver amplifiers, special ringers and frequency selectors to accommodate various hearing loss configurations. Also, there are user-operated amplifiers on pay telephones at airports, hotels and other public places with high levels of activity. Under the ADA, specific mandates have been instituted that require a certain number of amplified phones per standard public telephones. For an individual at home or work, there are a host of add-on or re- placement telephone devices to add low-distortion amplification on the telephone. One often overlooked piece of equipment is the speakerphone, designed to give "hands free" utilization to the normal person but, more importantly, to allow an increased and lower-frequency acoustic signal for the hearing impaired without feedback. Furthermore, the severe or profound hearing impaired person may use an interpreter in calls (lipreading, written messages, etc.) while using the speaker phone, allowing for a "conference call" type setting (see Figure 7).
• Teletypewriter (TTY) or telecommunications device tor the deaf (TDD) equipment is indispensable for those who have little or no aidable speech discrimination. Just as important to these patients are their State Relay Services, which provide direct Relay Agent assistance when calling normal hearing persons. More recently the voice carry-over feature (VCO) was added, allowing the patient to speak into the telephone while the agent types the other party's end of the conversation via the TDD monitor screen. The purpose of TDD Relay Services is to provide the same level of telecommunications services to the deaf and hearing impaired as that afforded their normal hearing customers.
• Today there are many local, state and federal programs, including some private programs, that provide TDDs for the deaf and their close family members either free of charge or at reduced costs. Since 1985, there has been an aggressive effort in some community organizations, in co-operation with private telephone companies, to install these devices in more homes and businesses throughout the U.S. Moreover, it is becoming more commonplace for many hearing and speech clinics to have TTY/ TDD telephone numbers for their clientele. It is strongly recommended that all ENT medical, audiology and dispensing practices keep a TDD at their front desk, and to advertise the availability of the device next to their advertised phone number. Such wording may be displayed in the following manner: 817.555.5555 (Voice/TDD).
• A recent development with TDD technology involves the new microprocessor models that provide printed text of calls and interface with computers and other communications devices. Most of these have internal memory, instant conversion or translation of various TDD baud rates and languages. One of the most popular versions of the TDD is a small, compact TDD operating on rechargeable or alka-line batteries.
• The ADA mandates that all businesses and public accommodations provide some way for effective communication for the deaf. At hotels, US. federal regulations require one "ADA Compliance Kit" for every sixty hotel rooms. Foremost in that kit is the TDD. In addition, they are to have a TDD at the front desk so that deaf and hearing impaired guests may communicate with hotel personnel and services. In many cases, it has been reported that few hearing impaired individuals take advantage of the mandated services. Therefore, it is advisable for specialists to encourage their patients to take advantage of these services. As in any other market endeavor, services only rise to the level of demand if there is indeed a demand.

Conclusion

The very essence of aural rehabilitation is the empowerment of the hearing impaired individual to be given opportunities and insights that will help them to stretch higher, reach further and enlarge their vision. By reaching beyond the apparent capabilities they will, at a minimum, achieve the possible. This will take constant encouragement from the specialist, loved ones and other professionals.

It is imperative that the specialist customize the program for each patient. Some individuals will need assistive devices, some will not.

Furthermore, it is imperative that the specialist customize the program for each patient. Some individuals will need assistive devices, some will not. Some will need to utilize tactile compensation, while others may have to rely on speechreading as the only additional consideration be- yond amplification. In customizing each patient's hearing health care program, the specialist will be acting more as an aural rehabilitation counselor, and less as a commercial hearing aid dispenser. This approach maximizes the ultimate benefit of the caregiving.

References

Benoit, Robert, "Home use of FM amplification-systems during the early childhood years," Hearing Instruments, Vol. 40, No. 3, pp. 8-12 (1989).

Chartrand, M. S., From in-class surveys to more than 3000 hearing professionals attending the "Wholism in Hearing Healthcare" series lectures, National Institute for Hearing Instruments Studies, Livonia, MI (1992-94).

Chartrand, M. S., "The Unreported Story: Schools Still Failing in Hearing Healthcare," Hearing Health, May/June, pp. 12-13, 49 (1997).

Crandall, C. C., "Classroom Acoustics: A Failing Grade," Hearing Health, September/October, pp. 11-16, 59 (1998).

Kaplan, Harriet, "Assistive Devices for The Hearing Impaired," The Hearing Journal, pp. 13-18, May (1987).

Lightfoot, R. K., and Vaughn, G. R., "Assistive Listening Devices and Systems for Adults Who Are Hearing Impaired," Aural Rehabilitation:

Serving Adults and Children, 3rd edition, R. H. Hull, ed., San Diego: Singular Publishing, Inc., pp. 227-250 (1997).

Morris, B., "Assistive devices plus hearing aids: A winning combination," Hearing Journal, March (1998).

Redmon, J., Survey in use of ALDs in the dispensing practice, Unimax Hearing Instruments (1990).

Stach, Brad A., "Hearing Aid Amplification and Central Processing Disorders," Robert E. Sandlin, ed.. Handbook of Hearing Amplification, Volume II, Boston: College-Hill Press, pp. 103-104 (1990).

Vaughn, G. R., "Bill of rights for listeners and talkers," Hearing Instruments, no. 37, p. 8 (1986).