History of Cochlear Implants (implantables) Flashcards
What are CIs?
A surgically implanted device to help people with severe hearing loss
Works by directly stimulating the auditory nerve using electrical signals, bypassing the damaged parts of the inner ear
Are CIs considered electrical hearing?
Yes
Not acoustic
Has CI development been rapid?
Yes
It has also been labeled as the most successful and effective implantable prosthesis
Prior to the 18th century, how was hearing loss viewed?
Deafness was considered a serious sensory disability
Deafness means that the hair cells are damaged and because of this damage sound cannot reach the auditory nerve
There were no treatments available
Children were particularly disadvantaged
They led sheltered, restricted lives in institutions, and were often labeled “deaf and dumb”
When was the first attempt to stimulate the auditory system electrically start?
In the early 1800s by Alessandro Volta
Inserted metal rods into his ears and connected them to an electric circuit
He reported a jolt in the head followed by a strange crackling or bubbling sound
*Idea that electrical stimulation can lead to sound
What was the duchenne de boulogne experiment of 1855?
French neurologist stimulated the cochlea using an alternating current
He reported auditory sensations like buzzing, hissing, and ringing
Also experienced non-auditory effects, such as a metallic taste
When was the first cochlear implant attempt?
1957
André Djourno and Charles Eyries implanted a single electrode
The patient could hear some sounds and a few words, but the effect didn’t last
The device failed within weeks and was removed
A second patient was implanted, but that device also failed
After these setbacks, Eyries chose not to continue the project
Who was William F. House?
An American otologist who read about the early implant by Djourno and Eyries
He realized that electrical stimulation could create hearing sensations and began developing a hearing prosthesis for deaf individuals
When was Dr. House’s first implant?
1961
Developed a surgical method to place electrodes into the scala tympani of the cochlea with Dr. Doyle
Implanted Deaf adult volunteers using a single wire electrode or a 5-electrode array
Promising results, but issues related to biocompatibility and infections (needed to be removed)
He paused the project for several years
What was the initial reaction to CIs by auditory scientists and otologists?
Highly critical
There was no way to replace, even crudely, the exquisite structure and function of the cochlea
Many individuals though that implants had little (if any) chance of restoring useful hearing
When did House resume his work on CIs?
1968
Doyle did not resume his work
Due to the development and success of other devices, such as pacemakers and ventriculoperitoneal shunts
The long-term safety an efficacy of these devices suggested to House that a reliable and fully biocompatible CI could be made using the new techniques
Who else did Dr. House team up with during his work?
Jack Urban (engineer) in 1969 and 1970
Implanted 3 adults with multi-channel devices
Insulation material had been perfected in the 60’s for use with heart pacemakers
Sound perception was sustained
House & Urban continued focusing on single channel implants (didn’t see much difference between single-channel and multi-channel)
Others in the United States, France & Australia were working on multi-channel devices
Was House regarded as the father of CIs?
Yes
Was House’s experiment re-tested?
Yes
Tested by a team at the University of California at San Francisco
Investigated the feasibility and possible efficacy of single-electrode implants
A few patients were implanted and found similar results to those reported by House
Recognition of speech was not possible, but sound was produced
Who was professor Graeme Clark?
Australian otolaryngologist
Interested in CIs due to Deaf father
Left his surgical practice to try to develop a way to electrically stimulate the auditory nerve with the goal of improving speech understanding
Implanted his first 3 patients in 1978
He had difficulty obtaining funding for this research (opposition from physiologists and ENTs who felt the implant would damage the cochlea)
What was Bilger’s Report?
An NIH funded study to evaluate early CIs
Included all 13 of the patients who had been in implanted in the USA as of that date - tested both without use of the implant and with use
The CI devices all used a single site of stimulation in cochlea
Resulted in NIH support of CIs and funding
The results demonstrated that the CI improved quality of life for all study subjects
Where the initial CIs very large?
Yes
But these were among the first devices that could be used by patients outside of the laboratory
When was the first multi-channel implant?
1978
Implanted by Graeme Clark
reported really good outcomes
Started turning toward multi-channel devices rather than single channel
When was the speech processor of CIs made portable?
1980
Still very large, but they can move around with it
Did the NIH make a statement about multi-channel implants in 1988?
Yes
Suggested that multichannel implants were more likely to be effective than single-channel implants and indicated that about 1 in 20 patients could carry out a normal conversation without lipreading
Encouraged people to focus their efforts on multi-channel
Were there challenges and controversies surrounding CIs?
Yes
Several groups, such as the World Federation of the Deaf, fought against medical treatments of deafness and argued in favor of preserving the deaf culture
In the United States, opposition to CIs became commonplace in the 1990s, and opposition to implants in children who could not provide informed consent was especially vigorous
The test of time has alleviated most of these initial concerns as one can no longer argue that CIs are not safe and effective
What were the three major corporations manufacturing cochlear implants?
Cochlear nucleus
Advanced Bionics (American)
Med-El
What is the cochlear corporation?
Company created out of Greame Clark’s work at the university of melbourne
First FDA approved multi-channel devices
22 channels available for stimulation
Are they able to stimulate more frequencies in the cochlea with more channels?
Yes
