What Devices Did Bell Invent to Help the Deaf?

​In 1879, Bell invented the audiometer to measure the amount of a person’s hearing loss. It was the first device designed to measure different levels of sound, and is the reason that sound is now measured in “decibels.”

Bell long dreamed of an electronic way to help the deaf to hear, a vision that has now become real with cochlear implants. He believed there should be a way to “produce the sensations of hearing by direct communication with the brain, through the bones of the head,” Bell told an interviewer in 1893 (who felt the idea was farfetched.)

“The brains of deaf people are usually in a perfectly healthy condition, and the only thing which prevents them from hearing is some defect in communication with the vibrating air,” he pointed out. “If their brains could be excited artificially in the same way that the brains of ordinary persons are excited by vibrations communicated through the various chambers and passages of the ear, then the deaf would hear in the same way that other persons do.”