By Dr. Max S. Chartrand Ph.D.

In Part I of this series published in the January-February 2000 issue of The Hearing Professional, we discussed the prevalence of severely hearing impaired (SHI) patients within the Hearing Instrument Specialists's practice, and introduced a true "total communication concept" with which to supplement the communicative needs of SHI patients who need more than amplification alone.

Indeed, though these patients constitute only about 15 percent of the average practice patient base, they also comprise the most challenging group to satisfy with amplification (Aural Rehab Concepts, 1997). Part of the challenge is that expectations exceed the ability of such damaged cochleae to efficiently process sound no matter how much amplification is used.

THE HEARING PROFESSIONAL

Hence, many SHI sufferers experience diplacusis, critical bandwidth distortion, extreme loudness growth abnormalities and severely limited functional dynamic ranges. These are dimensions usually little understood, and even less frequently assessed, by both patients and hearing care professionals. But they are real and may significantly limit the effectiveness of hearing instrumentation as the sole strategy for many SHI patients.

This segment will concern itself with some of the non-amplification compensation strategies available to the patient, which may require active promotion by their Hearing Instrument Specialists. It is not, however, a complete or exhaustive exposition on the topic, by any means, but an introduction and review of some of the most proven approaches.

Visual Compensation Modes

The most obvious human sense to supplement a marked lack of audition is vision. The human mind has an amazing ability to compensate for critical sensory shortcomings (via the diencephalon or "homunculus"), allowing one to compensate in lieu of the more appropriate sense. Hence, the blind are known for developing extraordinary auditory and spatial mapping abilities to^compensate for their lack of vision.

The same may be said of the deaf in developing superior, almost uncanny, visual and vibrotactile abilities. Visual compensation strategies such as speechreading, gestures, facial expressions and signing can be essential considerations in visually compensating for a severe hearing impairment.

Speechreading

Probably no other sensory compensation strategy for SHI patients should be stressed more than speechreading. Up to 40 percent of speech communication clues may be discerned through speechreading alone. Of course, that means that 60 percent of verbal communication may still be absent, making speechreading only a supportive or secondary communicative strategy. Coupled with amplification, the SHI patient can achieve total communication (Shimon, 1992). However, the utilization of speechreading skills exclusive of audition (without amplification) can hamper one in developing good listtning skills (Dodd and Burnham, 1988). Therefore, speechreading should be considered an adjunct to,rather than replacement of,the auditory function for SHI patients.

Basic skills in speechreading are easily developed over time by both post-linguistic children and adults alike (Hardman et al, 1993). Resources in speechreading include several excellent videotape programs, books, and, of course, volunteer and professional community courses. Every specialist should survey the resources available to their patients within their community. If resources are not readily available, the specialist may desire to provide such services through the auspices of their private practice. Here are a few resources to consider:

Local speechreading classes/instructors:  The Alexander Graham Bell Association will provide a list of speech-reading instructors throughout the United States. Contact A. G. Bell Association, 3417 Volta Place, N.W, Washington, D.C., 20007, or call 202.337.5220.

Self-Help Resources:  Consumer organizations such as Self Help for Hard of Hearing Persons (SHHH) and publications such as Hearing Health magazine offer information and materials for hearing impaired persons and professionals.

In-office speechreading program:  An in-house program may easily be developed at the hearing aid office by setting up a room with a VCR and color monitor for viewing from a library of videotaped lessons on speechreading. (This would, incidentally, also be an excellent place for display of assistive listening devices (ALDs).) SHI hearing aid users may be assigned weekly private sessions as part of their aural rehabilitation program, which is included in the purchase of new hearing instruments.

Contextual, Circumstantial Compensation

The utilization of contextual and circumstantial clues over actual word discrimination is auditory closure. In this way, the severe and severe-to-profound patient is able to put together whole words, phrases and even sentences derived from incomplete auditory clues. This assists in maintaining spontaneity in conversation.

Here are a few examples of arriving at whole meaning out of missed key words (easily misunderstood words are in parentheses):

• When two people greet each other, the one responding says, "I'm doing vine (fine)."
• In talking about an obstacle to completing a task, the speaker explains, "I tried in pain (vain), to get the door open."
• When going to the store, his wife's request was, '"Would you please pick up ten pound(s) of apple(s)?"
• The time/temperature recording on the phone said, "The time is ten-seven-ty (seventeen)."
• In the punchline of a joke, "...when the boss found out, boy, did he get the kink ship (pink slip)!"

By considering the time of day, circumstances, persons involved and relationship to each other,weather, purpose of the activity, momentary matters affecting the spirit of things, and surrounding environment, the impaired person may "fill in the gaps" much more readily. Spontaneity, again, is the key. Most human communication revolves around spontaneous action and reaction, give and take, questions and answers, a stated opinion and a response and a greeting and its return.

Visual and Peripheral Awareness

A game that is sometimes played at parties presents a good way to increase one's visual awareness. The group is divided into pairs and instructed to notice everything they can about that person (clothing, hairstyle, facial expression, etc.). After about 10 seconds of studying each other, they are to look away and name 10 items they remember about the other's appearance. An object lesson from this simple game is to increase awareness of things about the other person that would normally be overlooked. In actuality, one is increasing their comprehension or cognitive awareness.

Another important practice is to extend one's peripheral vision (or "side vision"). Since the ears of the deficient hearing system are no longer the "safety radar" they should be, the eyes are able to compensate a great deal by increasing their peripheral awareness of activities and objects around them (Chartrand, 1999). An exercise: Practice following one's own hand as far as possible until out of view. To do this, hold the hand directly in front of the face and then swing the hand over to the side, almost out of the range of visibility. Looking straight ahead, one should be able to note location of the hand until it is about 80-95 degrees azimuth.

Next, practice by making a mental list of things seen, in detail (colors, shapes, names, etc.), at the periphery of one's sight range. The increase of this ability will provide greater safety, better spatial mapping and, consequently, fewer surprises.

Using the Whole Body in Tactile Compensation

Many parts of the human body are particularly useful as a tactile sensory interface: the feet for detecting ground movement; the arms and legs resting against furniture or guard rails; the back against the back of a chair; the cheek-bones and sinuses for vibrations in the open air; the teeth, via trimgeminal and facial nerves, can detect slight vibrations; and the fingers against a speaker or other resonating surface. By redirecting one's attention to vibrotacrile information one can develop a keen ability to perceive and utilize such information in conjunction with auditory clues.

Currently, there are some credible theories about the vibrotactile receptors of the human body, especially in the ultra-hearing frequencies (above 20KHz). It is expected that more will be learned in the future, and that new technologies will develop that will enable the hearing impaired and deaf to more effectively utilize this little understood communicative route.

Development of Tactile Compensation

Apart from acoustic reception, the human ear is extremely receptive of tactile information, especially at the tympanicplexus, a virtual consortium of interconnecting motor and sensory neurons located in the center portion of the tympanic membrane (TM). Upon first blush, this detour from the usual auditory pathway of sound transmission may seem unuseful, but user experience and reports tells us volumes, especially among cochlear implant users who continue to wear a hearing aid in their non-implanted ear.

An effective approach to counseling may help the SHI hearing aid user who has a sharp precipitous loss with little or no residual hearing after 1KHz. Such an individual may be alarmed, after the fitting of new instruments and all the promises (expectations) raised by advertising claims that they are still unable to hear the squeak of a rusty door hinge, the squeal of the car's fanbelt, or the coach's whistle at a ballgame. There are many situations in which it would

be enormously helpful to be aware of such signals without actually "hearing" them. The specialist, then, must help the patient develop "tactile awareness." The sequence and dialogue of this counseling approach may consist of the following example.

Patient: After I received my new hearing aids, I went home expecting to hear things I haven't heard in a long time. But I was disappointed to find out that I could not hear the squeaking door hinge my wife had been trying to get me to fix for months.

Specialist: Well, then, you'll need to learn to use your tactile sense to "hear" such sounds since your hearing threshold is completely off the chart in the high frequencies. What I'd like you to do is tell me if you hear this sound. (The specialist then produces a pulsing 2KHz signal @ 60dB via the bone oscillator which should resonate against another surface, the test tabletop). Now, tell me, do you hear that?

Patient: I hear nothing. What should I be hearing?

Specialist: OK, now I'd like you to close your eyes and concentrate. See if you don't "feel" a tickling or slight vibratory pulsation on your eardrum. (The pulsed signal is given again, allowing the patient sufficient time to note the pulsation.)

Patient: I feel something, a fine vibration going like this (describes sound by moving finger in rhythm with pulsation). Is that the sound you're talking about?

Specialist: Yes, it is. What you must learn to do is begin to "feel" the sounds you cannot hear. This will take time and practice, as well as focus, but it can be done.

Imagery Compensation

This concept in aural compensation is a little more elusive to describe, for it involves utilizing substitution to fill the gaps where actual speech discrimination is absent. This is particularly helpful in cases where complete aural correction is not possible. Imagery compensation allows the individual to utilize such expressive clues as:

Voice Inflection:  When a question is asked, the voice tends to rise in pitch. More importantly, the ending of the question is left "hanging," begging for a return answer by virtue of suspension. The answer, then, tends to pick up at the level of pitch where the question left off, making its meandering trail back to the starting pitch for finality. In music this is comparable to starting the question at the tonic (I) and ending the question on the dominant (V).

Then, the answer begins at the dominant (V) and ends at the tonic (I) to show finality.

Voice inflection often belies the meaning behind the words, the uncertain statement inflected like a question (i.e., I'm not going to the show?), a pseudo-gratuitous question, which sounds more like a stern warning than a question (i.e.. You think you're something, don't you?}. By noting the rise and fall, the nuances of coloration and social ambiance, the listener will receive valuable clues through voice inflection that will help complete the auditory information accompanying it.

Elimination and Deduction:  By taking each missing word and supplanting in its place several possibilities, the listener may "piece together" the whole message in its broader context. Example: "Today, we're going to (meet) (eat) (visit) (talk) at Luby's." Similar to a "multiple choice" test, the SHI individual may develop an intellectual form of compensation.

A good practice while listening to a lecture or speaker is to take written notes. Write down what you "think" was said, analyze it and then make corrections only as the need becomes apparent. When in doubt, ask a normal hearing individual near you to help fill in the missing words or concepts.

By redirecting one's attention to vibrotactile information one can develop a keen ability to perceive and utilize such information in conjunction with auditory clues.

Syllabic Matching:  This involves the same mental acrobatics found in solving crossword puzzles, except that one is finding the word with proper number of syllables or phonemes. The fact that three syllables could be heard in the word "processor" indicates that the word was not protest, protect, or prospect which have only two syllables. However, it could have been protector, professor, prospector or hairdresser, each of which has three syllables. Since the topic is food making, processor would be the logical choice. By narrowing the possibilities and using substitution, one may come closer to correct communication.

Timbre:  Each word, or combination of words, presents various inflections of "brightness," such as in the major musical chord, and "darkness," as in the minor chord. The word "ate" is certainly brighter sounding than, say, "art." The "long vowels" provide brighter intonation than the "short vowels" and darker "diphthongs." The fluctuation between bright and dark syllables, if noticed, will begin to display an identifiable coloration that may be associated with certain words and expressions. If one were to analyze the spectral content of vowel sounds in speech, they would find distinct and measurable differences in the harmonic frequencies, both at the fundamental level and at each formant.

Notice the changes of timbre in the following sentence as it is spoken aloud: "Today is the day (bright timbre) for all good men and women to come (darker timbre) to the aid of their nation (bright again)." The fluctuation of bright and dark timbre would then provide another auditory clue.

Consonant/Vowel Structure:  While some words literally ricochet with fricatives and plosives, others are just as characteristic with their liquids and vowels. Witness the distinctive contrast between the words "certificate" and "lullaby," or "racketeer" and "animal." Through focused awareness and practice the individual begins to associate these consonantal structures and coloration with the words themselves. In fact, this mathematical and rhythmical approach, coupled with logic and context, will enable the user a greater measure of speech understanding through imagery and substitution.

Summary

This installment of the series involved a review of visual and nonauditory coping strategies that are available to the severely hearing impaired. Some of these are developed out of necessity by the patient, without specialized counseling. But to achieve maximal benefit, it is incumbent upon dispensing professionals to become well-grounded in these principles so that they may direct the rehabilitative process of their patients, and to connect them with community services that otherwise might not ever be utilized.

References

Aural Rehabilitation Concepts, Study of the severely hearing impaire population in the U.S., Gainesville, TX (1997).

Chartrand, M. S., "Transcranial or Internal CROS fittings," The Hearing Journal, September (1991).

Chartrand, M. S., Hearing Instrument Counseling, 2nd ed., Livonia, MI:

International Institute for Hearing Instruments Studies (1999).

Dodd, B. and Burnham, D., "Processing speechreading information," Volta Review, 90, pp. 45-60 (1988).

Hardman, M. L. et al.. Human Exceptionally: Society, School and Family, Boston: Allyn and Bacon, pp. 231-309 (1993).

Shimon, Debra A., Coping with Hearing Loss and Hearing Aids, San Diego: Singular Publishing Group (1992).