By Stephen Hallenbeck, Au.D
This week, I’ll be posting a number of blog posts about the science behind Remote Microphone Technology and the patient benefits in terms of localization, directivity and wind noise reduction.
Remote Microphone Technology works by leveraging the natural effects of the pinna and external ear.
The pinna carries out an important function by shaping the acoustic properties of sound entering the ear. These modifications serve to enhance the frequencies important for speech understanding as well as provide cues which allow our brain to decode, analyze and orient ourselves in the environment. When hearing is impaired, the natural boost in sounds provided by the pinna is often insufficient to ensure audibility of these essential cues. The obvious solution to this problem is to amplify those frequency regions important for speech perception to restore audibility. Hearing instruments, in general, do a good job of this, but often disrupt the cues provided by the pinna depending on the location of the sound inlet. As a result, the altered pinna cues can add to a perception that hearing instruments provide unnatural sound.
Remote Microphone is a new design technique that places the microphone in the external ear near the concha cymba, with the body of the device in the ear canal to improve device retention and cosmetic appeal in comparison to a BTE. This technique removes the microphone from the body of the instrument. The externalized microphone is housed in a plastic capsule attached to the body of the hearing instrument via thin wires encased in a flexible translucent plastic tube seated in the superior portion of the wearer’s concha near the crus of the helix. The remaining components of the hearing instrument, including the battery, microprocessor and the receiver are encased in a plastic housing which sits in the ear canal. This design also allows for venting around the in-the-ear component to provide open comfort similar to that of an open BTE.
Check back on Wednesday to learn about the microphone location effect.