Dennis Van Vliet, AuD, is Director of Education and Professional Relations, Audio-Sync Hearing Technologies. Readers may contact Dr. Van Vliet at Dennis_VanVliet@AudioSyncHearing.com.
Our home in the hills of Los Angeles isn't very big, less than 2,000 square feet on two levels. As a consequence, sound in one area of the house is often easily heard in another.
Figure. Dennis Van V...Image Tools
We have a couple of clocks that chime to announce the progress of the day. One is a 100-year-old grandfather clock that has been in my wife's family for that long. The other, a smaller, table top glass and cloisonné design, came from her mother's estate and is probably about as old. The grandfather clock chimes every 15 minutes, and the smaller one every 30 minutes.
If the chimes of the two old clocks aren't closely aligned, I feel compelled to adjust one or the other to make things right. Sometimes, just moving a minute hand a bit will do it. Other times, I'll need to make a slight adjustment to a screw on the bottom of a pendulum to lengthen or shorten the arc of the swing to slow or speed up the clock. All this is to say that I'd likely be a terrible hearing aid patient if I'm that bothered by such a little acoustic event.
Some patients may be able to adapt to things that don't sound exactly right. That's why we use our counseling skills to encourage them to stick it out and put up with the unfamiliar sounds so that their brains will learn to recognize them as components of speech that have meaning. We have to rely on their reports, our objective measures, and clinical experience to know when to pat them on the back and encourage, and when we have to make adjustments.
Others, due to personality and individual characteristics, cannot easily adapt. In those cases it is up to us to determine what it is that is bothering them, and then decide what can be done by way of programming or other modification to make the sound acceptable to the patient.
It might be an echo, a perceived distortion, or other element of sound quality that is disturbing to the patient. Initially, the patient will need to communicate not only that he objects to the sound, but what the characteristics of the sound are that he objects to. This is not always easy for patients and as a consequence not easy for us to interpret what they mean.
I remember a patient who was insistent that voices were “reedy” with his new hearing aids. I'm not a musician, but can generally recognize whether a musical instrument uses a reed, a string, lips, or column of air as the vibrating body. In the case of his complaint, however, I had a very difficult time understanding what he meant, and an even harder time figuring out how to resolve his complaint. Although these situations are not typical, they occur often enough, and create enough angst for us and the patient, that the bad memories remain with us.
A look at our best practice protocols might be in order, especially with patients for whom sound quality is a big issue. Some elements of sound quality are addressed with subjective assessment of audibility, comfort, and tolerance, but patients may have residual sound quality complaints when we are satisfied that audibility and comfort goals have been met.
The typical patient will volunteer objections whether or not we ask for his opinion, but we might want to consider documenting a judgment of sound quality as a general rule for all patients. While I hate to ask for trouble, a formal step-by-step protocol that encourages a patient to describe sound quality, in terms of acceptability and general characteristic might be useful. Probably the reason we don't have several of these protocols available is that the term “sound quality” encompasses many domains and terminology.
There are standards and descriptors used in telecommunications that refer to things like signal distortion, background intrusiveness, and overall mean opinion score. Those might be useful for engineers and researchers, but difficult for our typical patient to relate to. J. Poggenburg, obviously an engineer, notes that phonetic descriptions of sound are “Not useful for engineering work.” He asserts that “Objectivation of the subjective judgment is necessary.” (www.headacoustics.de) His approach suggests that context is important and that a general approach will not be useful because of the many underlying dimensions and aspects.
Bentler et al (J Speech Hear Res 1993;36:820-831) in a study of subjective measures of hearing effectiveness used bipolar pairs of sound quality dimensions based on the work of Gabrielsson and Lindstrom (J Aud Eng Soc 1985;33:33-53) which included loud/soft, clear/hazy, harsh/mellow, distinct/blurred, rough/smooth, pleasant/unpleasant, quiet/noisy, treble/bass, and near/far. Some of these have the potential to be actionable in programming or modification of a fitting, and might be helpful in the fine tuning aspect of the process.
The Final Word? Sound quality, while difficult to define, is important to hearing aid users and may require more than a “How does that sound?” approach. Manufacturers have started to come to the market with tools that allow the patient to participate in the fine-tuning process with improvement of sound quality as the ultimate goal. That's a good start. Our responsibility should be to develop protocols to document patients' quality perceptions and facilitate any corrective adjustments.
© 2011 Lippincott Williams & Wilkins, Inc.