3D scanner could make hearing aids more comfortable, effective
A new digital scanning technique, developed at the Massachusetts Institute Technology (MIT), could offer a much better fit for future hearing aids, according to an article in the MIT Technology Review.
Douglas P. Hart, PhD, a mechanical engineering professor at MIT, developed the approach uses the absorption and emission spectra of light to capture a 3D picture of the inner ear.
Approximately 36 million American adults suffer from some form of hearing loss, according to the National Institutes of Health (NIH). However, only one in five people who could benefit from using a hearing aid wear one. One problem is that "hearing aids often just don't fit well enough, and are either uncomfortable or don't perform well enough because of the poor fit," according to David Copithorne, a technology consultant familiar with the hearing aid industry and a wearer of hearing aids.
The average hearing aid costs $1,500, but prices can go up to $5,000 each. Creating each aid typically involves a silicon-based material that hardens to create a mold for the aid. The researchers said that the process is imperfect, though: molds can deform or even damage the ear during extraction, and if the resulting hearing aid does not fit perfectly, it can lead to irritation, scratching or infection. This can also decrease the sound quality for the wearer.
Hart developed the scanning technique "completely by accident" while experimenting with emission reabsorption laser-induced fluorescence (ERLIF) as a way to measure the film thickness of engine oils. In the process, he figured out that he was getting very accurate 3D measurements of the films. "It's so accurate," he said, "you can measure anything in 3D."
ERLIF works on the principle that light is scattered differently depending on the depth of a liquid. Hart uses a fiber-optic camera inserted into the ear and wrapped by a liquid-filled balloon that expands to conform to the ear's shape. Measuring the light absorption of dyes in both the liquid and the balloon yields a 3D picture of the ear's shape and dimensions. ERLIF analyzes a light path from fluorescence, according to Davide Marini, a research fellow at Children's Hospital Boston, who worked with Hart on the technique.
The authors said that the camera's fast imaging rate means that it can measure how the ear canal changes shape as a patient chews or talks, and how it expands due to pressure--qualities that differ for every person, with some ears softer or more resilient than others. Silicon molds, on the other hand, typically require a patient to sit with her mouth hanging open for 10 minutes while the goop sets, Hart noted.
Copithorne said that the infrastructure is already in place for making molds from digital scans. Audiologists are increasingly choosing to scan the molds that they make, rather than hand-tooling a shell for their manufacturers.
The next step for Hart's team is to test its scanning technique with audiologists and make actual hearing aids. The team expects to work out the last technical issues this summer.
Douglas P. Hart, PhD, a mechanical engineering professor at MIT, developed the approach uses the absorption and emission spectra of light to capture a 3D picture of the inner ear.
Approximately 36 million American adults suffer from some form of hearing loss, according to the National Institutes of Health (NIH). However, only one in five people who could benefit from using a hearing aid wear one. One problem is that "hearing aids often just don't fit well enough, and are either uncomfortable or don't perform well enough because of the poor fit," according to David Copithorne, a technology consultant familiar with the hearing aid industry and a wearer of hearing aids.
The average hearing aid costs $1,500, but prices can go up to $5,000 each. Creating each aid typically involves a silicon-based material that hardens to create a mold for the aid. The researchers said that the process is imperfect, though: molds can deform or even damage the ear during extraction, and if the resulting hearing aid does not fit perfectly, it can lead to irritation, scratching or infection. This can also decrease the sound quality for the wearer.
Hart developed the scanning technique "completely by accident" while experimenting with emission reabsorption laser-induced fluorescence (ERLIF) as a way to measure the film thickness of engine oils. In the process, he figured out that he was getting very accurate 3D measurements of the films. "It's so accurate," he said, "you can measure anything in 3D."
ERLIF works on the principle that light is scattered differently depending on the depth of a liquid. Hart uses a fiber-optic camera inserted into the ear and wrapped by a liquid-filled balloon that expands to conform to the ear's shape. Measuring the light absorption of dyes in both the liquid and the balloon yields a 3D picture of the ear's shape and dimensions. ERLIF analyzes a light path from fluorescence, according to Davide Marini, a research fellow at Children's Hospital Boston, who worked with Hart on the technique.
The authors said that the camera's fast imaging rate means that it can measure how the ear canal changes shape as a patient chews or talks, and how it expands due to pressure--qualities that differ for every person, with some ears softer or more resilient than others. Silicon molds, on the other hand, typically require a patient to sit with her mouth hanging open for 10 minutes while the goop sets, Hart noted.
Copithorne said that the infrastructure is already in place for making molds from digital scans. Audiologists are increasingly choosing to scan the molds that they make, rather than hand-tooling a shell for their manufacturers.
The next step for Hart's team is to test its scanning technique with audiologists and make actual hearing aids. The team expects to work out the last technical issues this summer.