The Cochlear Implant

Figure 1. A Sample Cochlear Implant (Source)

Brief: The cochlear implant is a surgically implanted electronic device that provides a sense of sound to someone who is deaf or hard of hearing in both ears. They work with a microphone and a series of electronics that bypass the regular hearing pathway. The electronic components trigger electrodes placed in the cochlea and stimulate the cochlear nerve. However, there is a small level of controversy associated with the devices especially within the deaf community. They feel that it is insulting to people who learned sign language as their first language. It consists of 5 main parts: the microphone, a speech processor, a transmitter, a receiver/simulator, and an electrode array embedded in the cochlea.

Figure 2. A Sample Installation of a Cochlear Implant (Source)

In the late 18th century, Alessandro Volta discovered that electrical signals can be transmitted through the cochlea to generate the illusion of sound in his head. This information went undeveloped until 1930 when Stevens and Jones thought that the electrical signal could be transduced to into sound vibrations in the inner ear known as the electrophonic effect. In 1964 the first cochlear implant was installed into a patient with total perceptive deafness. The patient demonstrated the ability to discern the length of signal duration, and some tonality was observed. Later on, the implant became safe enough that it could be placed on patients aged 2 and older. This device seeks to restore partial hearing to those with loss.

Use: The implant is usually inserted under general anesthesia. As a result, the patient is then able to hear a single tone and its duration. The implant works as long as the battery powering the implant has power. Replacing the battery allows continued usage.

Additional Information: General Info, General History