Week 1 History of CI Flashcards
1
Q
Andre Djourno
A
(1904-1996)
- French physiologist
- interested in neuroprosthesis and transcutaneous stimulation (across skin)
- –used induction coils to stimulate the rabbit’s sciatic nerve
- –best signal for muscle contraction=400-500 Hz within speech range
- —-high freq failed to create contraction and low freq were painful
- –so attempted to trigger muscle contraction using his voice
- no tissue damage after 2 yrs repetitive stimulation for the rabbit
- he suggested using induction coils as an option for treating deafness in a paper he published in 1954
2
Q
Charles Eyries
A
(1908-1996)
- French surgeon
- neuroanatomy and embryology of the VII nerve was his interest
- did VII nerve repair
- had a lab in the medical school associated with the hospital at which Djourno was working for
3
Q
Djourno and Eyries Collaboration
A
- Eyries had a 57 yr old pt with large bilat cholesteatomas
- –temporal; bone resection had been performed, causing ablation of the labyrinth and facial nerve and total loss of hearing on both sides
- Eyries wanted to find a graft for the VII nerve from cadavers in the med school, where he met Djourno. Then Djourno convinced him of the additional procedure to stimulate hearing
- –surgery on this pt on 2/25/1957
- —-right side facial nerve was grafted and proximal cochlear nerve stump was shredded so the electrode was seated in the remaining stump and the induction coil into the temporalis muscle
- –intraoperative monitoring: pt can detect 100 Hz tone
- –after surgery: good intensity recognition, poor frequency recognition, no speech recognition
4
Q
what happened with the 1st Djourno and Eyries Pt?
A
- after therapy, pt could differentiate high freq from low freq
- could appreciate environmental sounds and some words, but not speech
- several months later the implant quit working. A solder joint connecting the wires to the ground electrode broke
- –surgery was repeated with a new device which ended the same way, the Eyries refused to do it a third time
- Djourno has another implant done with another otologist but pt lost to follow up
- Djourno then lost funding
5
Q
What happened when Eyries and Djourno’s work got to the US?
A
- didnt get to the US until a year later
- –the New York Times published a translation (in 1958) of the original article that was published in a French Journal in March 1957
- in 1959 a pt showed William F. House a summary of the work
6
Q
William House and The Doyles–Los Angeles
A
- House is an otologist who worked with John Doyle, a neurosurgeon, and his brother James Doyle, an electrical engineer
- while doing stapes surgery, House and Doyle placed a needle electrode on the promontory or into the open oval window to try to induce hearing
- –square wave stimuli wee used and pts reported hearing them with no discomfort
- –this inspired the use of a hard wired system
7
Q
House and Doyles: 1st pt
A
- in 1961 a 40 yr old pt with severe otosclerosis and deafness volunteered
- –on 1/5/1961, pt had consistent responses to promontory stimulation
- –so on 1/9/1961 a gold wire was implanted in the round window
- —-poor loudness tolerance which resulted in wire removal
- re-implanted on February 1st 1961 with a 5 wire electrode array and induction system under the skin
- –pt heard square wave stimulation, and needed higher current/intensity over time
- –after several weeks, device had to be removed due to swelling and possible infection
- —-which raised possible bio-compatibility problem
8
Q
House and Doyles: 2nd pt
A
- 2nd pt was implanted in the same period (around 1961)
- –pt heard square wave stimulation, with time a higher current was needed to induce a response
- –for fear of infection, wire was removed
9
Q
Doyle patent for multielectrode device
A
- James Doyle and Earle Ballentyne submitted a patent in 1961 for a multi-electrode device. Patent was not granted until 1969
- after the 2 implants, the press reported about “artificial ear” to restore hearing
10
Q
House and Doyle disagreement
A
- House and the Doyles disagreed an how aggressively to market the device, and House was concerned about bio-incompatibility
- the Doyle bros kept implanting pts until 1968 when they couldn’t gt any more funding
11
Q
pacemaker technology in the late 1960s
A
- in 1967 william house became interested in CIs again after the improvements in medical prosthesis and collaborated with Jack Urban (electrical engineer)
- in 1969 House implanted several pts with Urban
12
Q
House and Urban’s 3 pts
A
1: implant removed due to tissue rejection
1: lost to follow up
1= Charles Grazer who became a longitudinal study
13
Q
Charles Grazer
A
- stimulus levels and results were found to be stable over many years in Grazer’s implant
- Grazer was an excellent subject and many improvements in signal processing came as a result of his cooperativeness
- House focused on the single electrode device, later became House/3M
14
Q
Single Channel Device and FDA
A
- House continued with the single channel device developed by him and Jack Urban. House/3M single channel device gained FDA approval in 1984 and was the 1st approved CI
- 1981 House implanted 1st preschooler who was age 3 and deafened from meningitis
15
Q
F. Blair Simmons–Stanford University
A
- 1962: Simmons stimulated the auditory nerve intraoperatively at Stanford
- –18 yr old pt with cerebellar tumor
- –During surgery (awake) pt discriminated sounds up to 1k Hz
- 1964 Simmons implanted 60 yr old man with multiple disabilities with a 6 electrode array ( inserted about 3-4mm)
- –different pitches were detected with different electrodes
- –outcome was poor, further human implantation at Stanford was discontinues pending animal studies
16
Q
Robin Michelson and Michael Merzenich–University of California San Francisco
A
- 1st implant was a single channel for a congenitally deaf woman (1970)
- –obtained auditory sensation from stimulation
- –pitch perception below 600 Hz
- –could differentiated square vs sine wave
- –the implanted gold wire broke and the implant was removed
- several more pts received single wire devices (1971)
- –pts had pitch perception based on stimulus frequency
- –could recognize speech but had no word understanding
- –all lost residual hearing
17
Q
Controversies and Doubts with CI
A
- in 1970, the NIH created the Neural Prosthesis Program with the National Institute of Neurological Diseases to promote research, and fund research, in CIs
- in 1973/1974, concerned expressed at several CI related meetings:
- –remaining nerve fiber population in deafness is not sufficient
- –electrical stimulation could deliver signal that is not part of speech (very high freq)
- –the dynamic range of loudness is only 6 dB with CI as opposed to 100 dB in normal hearing
- –intracochlear manipulation that would occur with cochlear implantation would result in significant damage to cochlear structure
18
Q
1974 Meeting
A
- Dr. Francis Sooy (UCSF) with support of the NIH assembled the implant devotees meeting in 1974 to evaluate the progress and define the research goals
- –2 decisions:
- —-1) implant criteria
- ——-fully informed
- ——-no useful hearing
- ——-willing to participate
- ——-adult
- —-2) stop implanting single channels until completing an objective eval of the already implanted pts with single channel devices
- ——-in 1975, NIH funded a team for university of pittsburg led by Robert Bilger to conduct the assessment study
19
Q
The Bilger Report (1977)
A
assessment study of all those previously implanted led by Robert Bilger
- 13 adult single channel implant subjects (11 by House, 2 by Michelson)
- –poor speech understanding with implant alone
- –improved lip reading scores
- –improved quality of life
- –improved speech perception
- this helped to push forward and justify funding research efforts toward a multichannel device
20
Q
Graham Clark
A
- Australian otolaryngologist at University of Melbourne
- realized that single-channel device is limited (1969), so he worked on:
- –speech strategies
- –optimizing electrode array (about 20-25mm)
- –safe reliable implantable receiver-stimulator
- formed what is now known as Cochlear, Inc
- 1978-1st commercial multichannel implant
- –by 1981 Clark demonstrated speech understanding with a multichannel implant (open speech set and no lip reading)
- 1985- FDA approval for adult implantation with Nucleus device
21
Q
Merzenich and Research Triangle Institute in North Carolina
A
- the CI team at UCSF lead by Merzenich collaborated with Blake Wilson and Charles Finley team at Research Triangle Institute in NC
- –the team developed an 8 channel CI with independent power sources for each channel
- –in 1986, UCSF formed an agreement with a company owned by entrepreneur Alfred Mann, who provided significant financial support
- –Mann then developed Advanced Bionics (AB)–first FDA approved device for adults in 1996
22
Q
Ervin Hochmair
A
- a team of researchers led by Ervin Hochmair at the Technical University of Vienna started pursuing CI in early 70s
- –in 1977 they implanted a pt with an 8 electrode device
- –this group also collaborated with Blake Wilson at the Research Triangle Institute to improve their signal coding strategy
- –1990 Ervin and Ingebrog Hochmair left the university to form Med-El company
- –FDA approval was received in 2001
23
Q
Claude Chouard
A
- a Djourno student from France attempted the following in 1972:
- –1976 he implanted several pts with an 8 electrode device
- –starting with mapping the frequencies along the cochlea in pts with unilateral HL (compare CI side to normal hearing side)
- –the French group continues to develop a 12 electrode device which was later sold to the French companu MXM Neurelec
- –MXM Neurelec was then sold to Oticon, and doesnt yet have FDA approval for any device
24
Q
CIs for children timeline
A
- 1986: pediatric clinical trials led to a workshop sponsored by Cochlear, Inc. to discuss factors that impact success:
- –post-lingual deafness
- –pre-lingual deafness of short duration
- –commitment by family to oral education
- 1990 approval as young as 2 years. Nucleus 22 was the 1st system approved for this population
- –AB in 1997
- –Med-El in 2001
- 2000 approval for children as young as 12 months
25
Q
Blake Wilson and the Research Triangle Institute
A
- this group had significant impact on what is called “coding strategies”
- –Wilson and colleagues developed continuous interleaved sampling (CIS) strategy and the n-of-m strategy in the late 80s and early 90s
- –they also developed the current steering concept which is now used for creating virtual channels
- –the use of different stimulus rates at low frequencies
- –explored the electroacoustic stimulation
26
Q
FDA as of December 2012 number of CI recipients
A
- approximately 324,000 people worldwide have received implants
- in the US, roughly 58,000 adults and 38,000 children have received implants
27
Q
tuning curves for electrical vs acoustic stimulation
A
- acoustic stimulation= sharp tuning curves
- electrical stimulation= will fire to whatever frequency as long as there is the correct amount of current provided to cause firing
- –lead to the loss of ability to distinguish frequency
28
Q
firing rate for electrical vs acoustic stimulation
A
- acoustic= firing rate increases slowly with increase of intensity of acoustic signal
- electric= just a small change in intensity will cause a large change in firing rate of neurons
- –makes dynamic range very small (about 10 dB
- –also with electric stimulus there is no plateau of the neurons as they dont saturate as they do with an acoustic signal
29
Q
electrical stimulation results in a more synchronous neural response leading to:
A
- steeper amplitude growth (input-output) function
- larger evoked response amplitude
- shorter evoked response latency
30
Q
what are the 2 major components of a CI?
A
- external sound processor
* internal receiver
