Cochlear Implants: Where We’ve Been, Where We’re Going Amber M. Gardner, Ph.D., CCC-A University of Virginia Health System

Early Attempts… Alessandro Volta – early 1800s became the first to stimulate the auditory system electrically Two metal rods in his ears (approx. 50V) “a boom within the head” followed by a sound similar to that of boiling thick soup

Early Attempts… Realization made over the next 50-60 years that since sound is more of an alternating signal, stimulating with DC wasn’t going to produce an adequate hearing sensation Duchenne – 1885 – used an alternating current “the beating of a fly’s wings between a pane of glass and a curtain” Improving, but not there yet…

Early Attempts… Brenner – 1868 – published study that revealed hearing sensation was better using negative polarity. Also found that a reduction of unpleasant side effects could be achieved with correct placement of the electrodes

Early Attempts… 1930s – thermonic valve (vacuum tube) was introduced and this allowed greater precision in electrical stimulation Wever & Bray (1930)– electrical response recorded near the auditory nerve of a cat was similar (freq. & amplitude) to sounds to which the ear had been exposed

Early Attempts… Gersuni & Volokhov (1936) First to demonstrate that with electrical stimulation hearing sensation still remained after removal of tympanic membrane & ossicles – theorized the cochlea was the site of stimulation

Early Attempts… Stevens & Jones (1939) – Listed several mechanisms that produced hearing when the cochlea was stimulated electrically Electrical energy could be converted into sound by a direct effect on the basilar membrane that would vibrate maximally at a point determined by the frequency – these vibrations would stimulate the hair cells Direct stimulation of the auditory nerve produced a crude hearing sensation.

Early Attempts… 1940s & 1950s – Researchers began to realize that if more precise hearing sensations were to be produced stimulation of the auditory nerve fibers must be more localized vs. widespread current.

Early Attempts… 1950 – Lundberg stimulated the auditory nerve during a neurosurgical operation. Used a sinusoidal current - patient only heard noise. 1957 – Djourno & Eyries – placed a wire directly on the auditory nerve (cholesteatoma surgery). Initially pt. just heard “a roulette wheel” & “a cricket” but was eventually able to differentiate pitch and identify several words.

Getting Closer Doyle et al (1964) inserted an electrode array (4 electrodes) into the cochlea of a deaf patient Patient was able to repeat phrases Simmons (1966) inserted an electrode array into the cochlea with more precision (closer to the modiolus) Patient had ability to determine signal duration length and tonality was achieved

Almost There Early 1970s - Michelson and House - insertion of electrode array through scala tymani driven by implantable receiver stimulators. 1972 – speech processor developed to interface with the House 3M single electrode implant & was commercially marketed. Single channel devices - very poor speech understanding (especially in open set)

Multi-channel Cochlear Implant Rod Saunders – First multi-channel CI patient (1978) Courtesy: Cochlear

Increasing Channels - Speech Channels will increase from 1 to 2, 2 to 4, 4 to 8 to 32 – note the improvement in quality.

Increasing Channels - Music First you will hear the song with 4 channels, then 8, then 16, then 32 – finally you will hear the original. Demo

Trends in Candidacy 1985 1990 1998 Today Age of Implantation Adults age 18 or older Adults & Children age 2 years or older Adults & Children age 18 months + Adults & Children age 12 months + Onset of Hearing Loss Postlinguistic Postlinguistic Adults & Pre/Postlinguistic Children Pre/Postlinguistic Adults & Children Pre/Postlinguistic Adults & Children Degree of SNHL Profound Severe-to-Profound Adults Profound Children Severe-to-Profound Adults, Children > age 2 Profound children < 2 years old Adult Speech Scores (open–set) 0% 40% or less sentences in quiet 50% on sentences in quiet in ear to be implanted, with 60% or less in contralateral ear or binaurally Pediatric Speech Scores N/A Lack of auditory progress, Less than 20% pediatric word tests 30% or less on pediatric word tests

3 FDA Approved CI Manufacturers Cochlear – 1985 Advanced Bionics – 1996 MedEl – 2001 (1994 – European release)

Speech Processor (1978) Courtesy: Cochlear

Speech Testing (1978) Courtesy: Cochlear

Cochlear – Portable Speech Processor 1980 – 2nd Recipient (George Watson) Courtesy: Cochlear

Nucleus 22 Device Courtesy: Cochlear

Wearable Speech Processor (WSP) 1982 Courtesy: Cochlear

From WSP to Mini Speech Processor (MSP) 1986 Courtesy: Cochlear

CI22M (Mini 22 Implant) Magnet Flexible receiver antenna 1988 Courtesy: Cochlear

MSP to Spectra Introduced in 1988 to go with the CI22M Courtesy: Cochlear

CI24M 1997 Removable Magnet Monopolar electrodes Telemetry – can measure impedances Stimulation rates increased Courtesy: Cochlear

Spectra to Sprint 1997 Increased number of program slots More flexibility Courtesy: Cochlear

Esprit 1998 First BTE processor from Cochlear Courtesy: Cochlear

Esprit 3G 2002 (24 users) 2004 (22 users) Courtesy: Cochlear

Freedom 2005 - New internal & external devices Same processor for BTE, bodyworn options New “Smart Sound” features Courtesy: Cochlear Courtesy: Cochlear

System 5 Launched Sept. 8, 2009 Internal device – thinner, but same technology platform External – thinner, more water resistant, autophone, 2 way remote control Courtesy: Cochlear Courtesy: Cochlear Courtesy: Cochlear

Advanced Bionics History Company started by Al Mann in 1993 1996 - received FDA approval for adults 1997 - received FDA approval for pediatrics

Advanced Bionics 1.0 – 1994 (adults) 1.2 – 1996 (adults), 1997 (pediatrics) CII ~ 2000 Courtesy: Advanced Bionics

HiRes 90k 2003 Titanium (vs. ceramic) housing Removable magnet Courtesy: AB

AB – Body Worn Processors Courtesy: Advanced Bionics S-Series ~ 1999 PSP~ 2001 1.0 - 1994 1.2 - 1996

AB – BTE Speech Processors Courtesy: Advanced Bionics Auria & Harmony 2003 & 2006 Platinum BTE 1998 CII BTE 2000

MedEl History 1975 - Hochmairs begin development of cochlear implant 1977 - Multi-channel CI implanted in Vienna 1989 - MedEl is founded 1991 - Industry first BTE speech processor (trials) 1994 - European approval of MedEl system 2001 - FDA approval of MedEl system 2003 - FDA approval of MRI compatibility (.2 Tesla)

MedEl Internal Devices Combi 40+ Introduced 1996

Pulsar CI 100 and Sonata Pulsar – September 2005 (Ceramic Housing) Sonata – September 2007 (Titanium Housing) Magnet fixed Courtesy: MedEl 38

Tempo+ Speech Processor (1999) Lightest BTE Processor Up to 9 Programs One processor – multiple wearing options Courtesy: MedEl 39

Opus 2 Speech Processor 2007 Ergonomic switch free design Wireless FM Fine Tuner – bilateral support, volume, sensitivity & telecoil switches Courtesy: MedEl

Future Directions Greater number of bilateral recipients Hybrid/EAS cochlear implants Totally implantable cochlear implants

Bilateral CI Benefits Insurance Coverage - class action law-suits Improved localization Improved speech in noise performance Insurance Coverage - class action law-suits

Hybrid/EAS EAS - Electric-Acoustic Stimulation Combination of CI & HA High frequency information - shorter electrode array Low frequency information - HA (typically mild to moderate HL) Still in clinical trials in US Approved in Europe (2007) All 3 companies still in US trials MedEl Duet Courtesy: MedEl 43

Hybrid/EAS European & trial data indicates patients are performing significantly better with EAS than CI alone or HA alone Noted especially in music & speech in noise Points to consider Risk of damage to residual hearing acuity during original insertion of electrode array What is the course of action if hearing acuity changes and HA is no longer beneficial - additional surgery with new/standard array?

Totally Implantable Cochlear Implant (TICI/TIKI) Internal Components Rechargeable battery (lithium ion) Microphone (subcutaneous) Speech processor External Hardware Battery recharger On/Off Volume/Sensitivity

TIKI

Totally Implantable Cochlear Implant (TICI/TIKI) Benefits No external parts able to “hide deafness” no cables, mics... to break Able to hear 24hrs a day (in shower, while sleeping...)

Totally Implantable Cochlear Implant (TICI/TIKI) Disadvantages Larger internal device - more surgical time/larger incision Battery will have to be replaced (approx. 6yrs) Replace only battery or entire device? Hear “body noises” (breathing, swallowing). Some people are unable to adjust to these.

TIKI Results 3 patients implanted Melbourne Able to have “invisible hearing” or use 3G processor Hearing acuity TIKI - Mild to moderate HL (improving to mild HL after 6 months) 3G - Hearing WNL Speech discrimination - CNC Lists TIKI - 33% (Improved as compared to pre-op) 3G - 77%

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