Ear Impressions for the New Laser Shell Technology

ABSTRACT

A new hearing aid shell technology has been introduced: A laser scans the impression taken by an audiologist and the data are used to create a 3D image of the impression on the computer screen. This image is used to design a shell with a vent and the receiver bore. When the design is finished, another computer builds the shell from nylon powder or liquid.

This technology duplicates the shape of the impression into the shell with extreme accuracy. It would be expected that hearing aids made with such a shell would have the perfect fit and would not require modifications and remakes. However, such an assumption would be incorrect. In fact, all the problems common with the traditional shells also are plaguing the new electronic shell: acoustic feedback, loose fit, discomfort, and lack of secure fit. This article explains how the accuracy of an ear impression taken by the audiologist contributes to the fitting of the shell, and concludes that ear impressions taken with a higher viscosity silicone and the patient's mouth open are the most appropriate to build e-shells.

KEYWORDS

Human ear - ear impression - hearing aid shell

REFERENCES

• 1 Data gathered from research assignments submitted by doctoral students. Pennsylvania College of Optometry, School of Audiology, Course ACD 602, 2000-2002
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