Presentation on theme: "Cochlear Implants: Where We’ve Been, Where We’re Going"— Presentation transcript:
1Cochlear Implants: Where We’ve Been, Where We’re Going Amber M. Gardner, Ph.D., CCC-AUniversity of Virginia Health System
2Early Attempts…Alessandro Volta – early 1800s became the first to stimulate the auditory system electricallyTwo metal rods in his ears (approx. 50V)“a boom within the head” followed by a sound similar to that of boiling thick soup
3Early Attempts…Realization made over the next years that since sound is more of an alternating signal, stimulating with DC wasn’t going to produce an adequate hearing sensationDuchenne – 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…
4Early 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
5Early Attempts…1930s – thermonic valve (vacuum tube) was introduced and this allowed greater precision in electrical stimulationWever & 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
6Early 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
7Early Attempts…Stevens & Jones (1939) – Listed several mechanisms that produced hearing when the cochlea was stimulated electricallyElectrical 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 cellsDirect stimulation of the auditory nerve produced a crude hearing sensation.
8Early 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.
9Early 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.
10Getting CloserDoyle et al (1964) inserted an electrode array (4 electrodes) into the cochlea of a deaf patientPatient was able to repeat phrasesSimmons (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
11Almost ThereEarly 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)
12Multi-channel Cochlear Implant Rod Saunders – First multi-channel CI patient (1978)Courtesy: Cochlear
13Increasing Channels - Speech Channels will increase from 1 to 2, 2 to 4, 4 to 8 to 32 – note the improvement in quality.
14Increasing Channels - Music First you will hear the song with 4 channels, then 8, then 16, then 32 – finally you will hear the original.Demo
15Trends in Candidacy 1985 1990 1998 Today Age of Implantation Adults age 18 or olderAdults & Children age 2 years or olderAdults & Children age 18 months +Adults & Children age 12 months +Onset of Hearing LossPostlinguisticPostlinguistic Adults & Pre/Postlinguistic ChildrenPre/Postlinguistic Adults & ChildrenPre/PostlinguisticAdults & ChildrenDegree ofSNHLProfoundSevere-to-Profound AdultsProfound ChildrenSevere-to-Profound Adults, Children > age 2Profound children< 2 years oldAdult Speech Scores(open–set)0%40% or less sentences in quiet50% on sentences in quiet in ear to be implanted, with 60% or less in contralateral ear or binaurallyPediatric Speech ScoresN/ALack of auditory progress,Less than 20% pediatric word tests30% or less on pediatric word tests
163 FDA Approved CI Manufacturers Cochlear – 1985Advanced Bionics – 1996MedEl – 2001 (1994 – European release)
29Freedom 2005 - New internal & external devices Same processor for BTE, bodyworn optionsNew “Smart Sound” featuresCourtesy: CochlearCourtesy: Cochlear
30System 5Launched Sept. 8, 2009Internal device – thinner, but same technology platformExternal – thinner, more water resistant, autophone, 2 way remote controlCourtesy: CochlearCourtesy: CochlearCourtesy: Cochlear
31Advanced Bionics History Company started by Al Mann in 1993received FDA approval for adultsreceived FDA approval for pediatrics
36MedEl History 1975 - Hochmairs begin development of cochlear implant Multi-channel CI implanted in ViennaMedEl is foundedIndustry first BTE speech processor (trials)European approval of MedEl systemFDA approval of MedEl systemFDA approval of MRI compatibility (.2 Tesla)
41Future Directions Greater number of bilateral recipients Hybrid/EAS cochlear implantsTotally implantable cochlear implants
42Bilateral CI Benefits Insurance Coverage - class action law-suits Improved localizationImproved speech in noise performanceInsurance Coverage - class action law-suits
43Hybrid/EAS EAS - Electric-Acoustic Stimulation Combination of CI & HA High frequency information - shorter electrode arrayLow frequency information - HA (typically mild to moderate HL)Still in clinical trials in USApproved in Europe (2007)All 3 companies still in US trialsMedEl DuetCourtesy: MedEl43
44Hybrid/EASEuropean & trial data indicates patients are performing significantly better with EAS than CI alone or HA aloneNoted especially in music & speech in noisePoints to considerRisk of damage to residual hearing acuity during original insertion of electrode arrayWhat is the course of action if hearing acuity changes and HA is no longer beneficial - additional surgery with new/standard array?
47Totally Implantable Cochlear Implant (TICI/TIKI) BenefitsNo external partsable to “hide deafness”no cables, mics... to breakAble to hear 24hrs a day (in shower, while sleeping...)
48Totally Implantable Cochlear Implant (TICI/TIKI) DisadvantagesLarger internal device - more surgical time/larger incisionBattery 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.
49TIKI Results 3 patients implanted Melbourne Able to have “invisible hearing” or use 3G processorHearing acuityTIKI - Mild to moderate HL (improving to mild HL after 6 months)3G - Hearing WNLSpeech discrimination - CNC ListsTIKI - 33% (Improved as compared to pre-op)3G - 77%