Summary: A Central Michigan University researcher is collecting data on ear size and shape to enhance hearing aid programming, aiming to provide better and safer amplification for individuals of all ages.
Takeaways:
- The research addresses discrepancies in hearing aid programming by gathering ear size data for different body types, aiming to avoid over- and under-amplification.
- The study will collect measurements from 300 adults and 336 children over several years to establish more precise programming guidelines for hearing aids.
- Funded by a $1.38 million NIH grant, the research has the potential to improve both over-the-counter and audiologist-prescribed hearing aids for adults and children.
A faculty member from Central Michigan University is gathering data on the size and shape of the outer ear to improve the programming and safety of hearing aids in hopes of helping people hear better.
Measuring the Inner and Outer Ear
Sarah Grinn, a faculty member of Central Michigan University’s communication sciences and disorders department, says hearing aids are programmed using two measurements. One measurement is from the inner ear, and one measurement is from the outer ear, which helps audiologists precisely program hearing aid amplification for patients, says Grinn.
While the inner ear measurement could be completed with an online hearing test or by the newest Apple iPhone hearing test feature, the outer ear measurement requires clinical training and equipment that only audiologists have, Grinn says. However, the high price tag of a typical prescription hearing aid is enough to cause some people to seek more budget-friendly alternatives.
Over-the-counter hearing aids are a cheaper option, but they are pre-programmed with a one-size-fits-all approach to the outer ear measurement, which is based on the size and shape of the average adult male ear. For male and female ears of any other size and shape than the “average adult male,” this approach can lead to a mismatch in the amplification the patient needs to hear accurately by avoiding under-amplification and hear safely by avoiding over-amplification.
Establishing Ear Size Averages
Grinn’s research intends to fix that discrepancy by establishing outer ear size and shape averages for male and female adults of all body sizes.
Right now, her research team is measuring the ears of 300 adults in six different height categories. They hope to wrap up this research within a year, after which her team will begin measurements on children’s ears.
That’s when the research will get more challenging.
Additional Pediatric Research
Grinn says they will recruit 336 children between the ages of 3 months and 15 years, and will measure each child’s outer ears once a year for four years. While adults’ outer ears stay the same, children’s outer ears change in size and shape as they age, which changes how amplification funnels through them.
Over-the-counter hearing aids aren’t currently available for children, Grinn says. All hearing aids for children are prescribed by an audiologist.
Audiologists often have to use an average estimate of a child’s outer ear size based on the child’s age when programming hearing aids, because the child cannot sit quietly during the measurement process, Grinn said.
Children of the same age can have different body sizes, so using an estimate of outer ear size based on age often results in a mismatch between what the child needs and what a hearing aid provides.
“This research will improve audiologist-prescribed hearing aids for children and over-the-counter hearing aids for adults,” Grinn says.
The research is funded by a competitive $1.38 million grant from the National Institutes of Health, and supported by graduate students in the CMU Doctor of Audiology program who work in Grinn’s research lab.
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