D_Strom.jpg (8295 bytes)Gain Attention

Dispensers of hearing instruments know that it’s often the small things that count—especially when you’re talking about decibels of gain or the ability for patients to adjust their own gain. In this issue of HR, Gitte Keidser and Frances Grant of the National Acoustics Laboratory (NAL) in Australia address differences in prescriptive fitting strategies, and Sergei Kochkin uses his Knowles MarkeTrak data to shed light on the issue of volume controls and customer satisfaction. The two articles point to some very interesting results relative to gain that have important implications when fitting hearing instruments.

One can craft a fairly persuasive argument that wide dynamic range compression (WDRC) represents the most important innovation in amplification science since the transistor. Compression amplification (ie, making soft inputs sound soft and loud inputs sound comfortably loud) compensates for the recruitment problem found in most hearing-impaired people by squeezing incoming signals into their reduced dynamic ranges. In their article, Keidser and Grant compare two amplification strategies for accomplishing this feat: loudness normalization (represented by the IHAFF fitting approach) and speech intelligibility maximization (ie, the NAL-NL1 approach). What they find is that the two fitting rationales can yield fairly significant differences in the prescription of gain for flat or steeply sloping losses in a two-channel device—differences of 6-9 dB. Additionally, they find an overall user preference for the NAL-NL1 approach.

Likewise, Kochkin’s article (pages 26-35) takes on gain from a user control perspective. Many people in the industry have conjectured that experienced hearing instrument users who have become accustomed to a volume control (VC) will be satisfied only with hearing aids that retain the VC function. It’s more complex than that, says this study of more than 2,800 MarkeTrak subjects. Those experienced users who are fit with automatic gain control instruments actually have higher satisfaction rates (by 12%). Overall, it would appear that VCs can negatively impact customer satisfaction when listening in noise, comfort with loud sounds, and cell phone use. But there is an important caveat: if the wearer wants a volume control and considers the VC responsible in large part for his/her hearing satisfaction, then that person needs a VC. Statistically, this portion probably represents about 1/3 of the hearing aid user population.

• Generating some good news in anticipation of the new year, the Centers for Medicare & Medicaid Services (CMMS) set their Medicare reimbursement rates for cochlear implants at $19,173—slightly lower than the previous $19,280 but comfortably higher than the agency’s proposed rate of $15,137. The final reimbursement rate was the result of hard-fought efforts by the hearing industry (particularly Advanced Bionics, Cochlear Corp, and Med-El), professional organizations, and consumer advocacy groups led by SHHH founder Howard “Rocky” Stone. Had CMMS’s lower proposed rate been enacted, it would have had a devastating effect on the number of implants performed, and it is likely that many of the medical centers that currently lose money on Medicare implants would have stopped performing CI services altogether.

• This month’s issue—the first of the new year—sports a new look in its editorial features and departments. In reality, HR Art Director Mike Hirano, an affable Hawaiian who for some inexplicable reason is also a Minnesota Vikings fan, has been gradually inserting his talented touches to this magazine for the past 2 1/2 years. Once the Vikings’ season ended (sometime in early-September), he was able to get past his mourning and dedicate himself fully to the magazine’s redesign. I hope you’ll agree that his good work has increased the readability and improved the overall look of the magazine. Thanks, Mike.

Karl Strom
Editor-In-Chief