Fretz RJ, Fravel RP. Design and function: a physical and electrical description of the 3M House cochlear implant system. Ear Hear 1985 May-Jun;6(3):14S-19S

This image is taken from an article about the 3M/House cochlear implant design. Note that the “Bandpass Filter”, as shown above, would limit the output so that the person wearing the device would not be able to hear about 35% of the information (high frequencies) necessary for the understanding of standard English.

If someone is not being provided with all the information they need, how can they possibly do well as compared with those who are being provided with that information? If, for example, one were to compare a group of patients using a hearing aid that has the above frequency limits with a group of patients using a hearing aid that did not have those limits, the second group is essentially guarenteed to excel, in comparison.

It is not surprising, therefore, that patients using these processors did poorly... What is astonishing is that they did so well.

Back to “Low-cost CI page”..