A Digital World

In this issue of The Hearing Review, Chester Pirzanski, BSc, and Brenda Berge, AuD, present data from the fitting of hearing instruments by experienced dispensing professionals, and examine this information in the context of how digital shell-making—a promising new technology being developed by many manufacturers—will impact the hearing care field relative to feedback. Specifically, they ask the question, “Is the end near for acoustic feedback?” It may not surprise you to learn that acoustic feedback—which has been around since at least the advent of portable hearing aids in the 1930s—isn’t printing up its funeral notice yet. Pirzanski and Berge point out that digital shell-making and ear-scanning technology represent huge promise for increasing the efficiency and effectiveness of the hearing instrument fitting process. However, they also note that this technology is likely to be limited by the same factors that today’s impression-taking technology is limited by: the dynamic ear canal and the fact that, in general, “no two ears are alike” when it comes to canal movement. Interestingly, they found that about 20% of all ears are mobile or soft, which correlates fairly well with the historic 20% return rate for in-the-ear (ITE) hearing aids. In fact, Pirzanski and Berge believe that the hearing care field today has the ability to eliminate more than half of the current returns for credit by employing the 2-step impression-taking reform they promulgate: namely, an open-mouth ear impression and the use of a higher-viscosity impression material. If this is true, hearing care professionals and the industry would be very wise to adopt this impression-taking practice: avoiding more than 300,000 returned aids each year would make for a lot more satisfied consumers and a lot less money down the drain.

This issue also contains technical reviews of three new digital hearing instruments, all of which incorporate directional microphone technology. Thomas A. Powers, PhD, and Volkmar Hamacher, PhD, summarize four recent articles in the audiological literature pertaining to the use of adaptive directional microphone systems. They suggest that the studies speak for themselves: these types of systems hold tremendous promise for those consumers who regularly find themselves in complex, adverse listening environments. Mark Flynn, PhD, details a new digital hearing instrument that uses a new kind of processing technology for employing an adaptive directional system, among other functions. One of the more unique features this product is reported to offer is the ability to maintain separate polar patterns for up to 4 different frequency bands (eg, the low-frequency band might automatically set itself for a greater level of attenuation to reduce a noise source, while the other 3 higher-frequency bands maintain their own separate polar patterns). C. Mike Hall, MA, who has recently returned to the field of audiology and is now a volunteer-consultant for Sebotek, relates his clinical experience of using a new style of hearing aid for those patients who have highly active ear canals. Hall believes that this hybrid BTE/CIC device has, among many benefits, the ability to provide a deep, secure seal within the ear canal and alleviate problems associated with a highly active temporomandibular joint.

The digital realm also has greatly influenced the hearing aid battery industry. The article that starts on page 26 shows how battery manufacturers have responded to the digital challenge and are striving to create new power standards for these hearing instruments.

Next month is Better Speech and Hearing month, a time when dispensing professionals typically tout new technology and their ability to help people through amplification and aural rehabilitation. It’s clear from this issue and recent editions of HR that there is a lot to talk about.

Karl Strom