Robert L. Martin

How much low frequency gain do you use

Adding gain in the lower frequencies is like putting cayenne pepper in your favorite food dish: caution and experience are both needed. If you use too much low-frequency (LF) gain the patient says the amplified sound is noisy and they stop wearing the hearing aids. If we don’t give patients enough LF sound, they believe the hearing aids are not doing any good. Selecting the best amount of amplification is a learned skill; it is as much art as it is science. People need to be treated as individuals, not types of hearing loss. Two people with identical hearing may have different life styles (noisy vs. quiet) and need different amounts of LF gain. In this column I usually discuss gain in the higher frequencies, but this month I want to focus on the lower frequency zone. These sounds are associated with mellowness and richness rather than brightness and clarity. Let’s look at six people and discuss how to best help these patients without over or under amplifying the lower frequencies.

Gene therapy for hearing loss: An update

Genetic research has made amazing advances as scientists have decoded most of the genetic information that is stored in our chromosomes. For many years, geneticists focused largely on identifying genes responsible for inherited diseases and conditions, including hearing loss. Their research helped us understand the modes of inheritance of these genes and to counsel patients affected by genetic forms of hearing loss. More recently, hearing scientists have increasingly focused on identifying genes that might be used to restore lost hearing. Using gene therapy to treat hearing loss has produced encouraging results in animals and holds great promise for future treatments in humans. It’s no wonder that hard-of-hearing people are excited when they see news reports on this topic. In this column, we offer you a brief update to help you give your patients a realistic idea of the prospects of using gene therapy to restore lost hearing.

Some practical ideas on hearing aid fittings

Young practitioners fresh out of graduate school are zealous in their approach to hearing aid fittings. They have studied fitting guidelines and real-ear targets and they attempt to implement them religiously. Professionals with 10 or 20 years of practice under their belts, see the world from a very different perspective. The young professional understands theory and the step-by-step processes used to match an insertion gain curve to a real-ear target. The old-timer understands that target recommendations are important, an integral part of practice, but also that target fitting guidelines are only suggestions—suggestions that often should be overridden when clinical judgment suggests a different course of action. Most real-ear fitting guidelines refer to the pure-tone hearing thresholds to see how much hearing has been “lost,” then they recommend specific amounts of real-ear gain to “correct” the loss. Let’s call this the “hearing loss correction” approach or the “match the target” approach to fitting hearing aids. Young practitioners learn this approach in school. Another point of view in fitting hearing aids is to look at what hearing the patient still has rather than at what has been lost. This approach, which attempts to maximize the patient’s residual hearing, is more practical and more adaptable than the “correct the loss” approach. Clinicians who use this approach have, undoubtedly, earlier in their careers attempted to put huge amounts of gain into “dead zones” only to encounter endless problems with feedback, lack of improvement in word understanding, and angry patients. If you ask some veteran dispensers, “How do you fit hearing aids?” they often answer, “I just do what works.” I believe what they are saying is, “I have attempted to follow strict hearing aid fitting protocols, have had limited luck, and, through trial and error—a lot of error—I have learned to avoid the typical problems of feedback and exposing the patient to too much output. I make patients happy and they communicate fairly well.” This is the “art” of dispensing, refined over thousands of fittings.