3D imaging speeds ear-canal scans

The inventor Douglas Hart, an MIT professor of mechanical engineering, plans to market the technology to hearing-aid manufacturers first, but believes it could also be useful to build fitted earphones for MP3 music players, or custom-fit earplugs for military personnel and other people who work in noisy environments.

The new technology is similar to a commercial 3D scanning system that Hart developed for dentistry, designed to replace the silicone moulds traditionally used to make impressions for dental crowns and bridges. While Hart was working on that imaging system, hearing-aid manufacturers approached him to see what he could do to improve their fitting process.

’Getting a precise 3D scan of the ear canal is the Holy Grail of the hearing-aid industry,’ said Scott Witt, head of research and development for hearing-aid manufacturer Phonak. ’Taking these impressions is still the messiest, least exact part of the process,’ he said.

Patients who need a hearing aid usually have to spend about an hour with an audiologist, who fills the patient’s ear canal with a gooey silicone substance. After about 15 minutes, the gel hardens into a mould that is removed from the ear and shipped to a hearing-aid manufacturer, who scans the mould and builds a custom-fit hearing aid using a 3D printer.