The document provides information about cochlear implants, including: 1) Cochlear implants bypass damaged parts of the inner ear to electrically stimulate the auditory nerve. They allow access to sound and can help develop speech recognition and communication. 2) The history of cochlear implants dates back to the 18th century but modern multi-channel implants were developed in the 1980s and have improved performance. 3) Over 100,000 people worldwide have received cochlear implants, including over 6,000 procedures annually in the US. The number of recipients is growing as criteria have expanded to include milder and unilateral hearing losses.

1. Cochlear Implants
Chih-Hung Wang, MD, PhD
Department of Otolaryngology-Head & Neck Surgery
Tri-Service General Hospital, National Defense Medical Center
王智弘
三軍總醫院耳鼻喉部 國防醫學院耳鼻喉學科

2. Photo source: U. S. Food and Drug Administration

3. Biologic Application of
Electricity
has driven the development of a wide
range of medical treatments,
past and present,
use electricity.

5. Outer Ear Structure

6. Middle Ear Structure

7. Middle Ear Structure

8. Middle Ear Function

9. Middle Ear Function

13. What Is A Cochlear Implant?
 A surgically implanted medical device that
bypasses the damaged part of the inner ear
to electrically stimulate the remaining neural
fibers of the auditory nerve
 Electrical current stimulates the remaining
auditory nerve fibers in the damaged inner
ear to generate sensations of hearing

14. What are the potential
benefits of CI?
 Access to sound
 Environmental sounds
 Speech sounds
 High frequency sounds
 Soft sounds
 Development of speech
recognition and speech
communication

15. History of
Cochlear Implants
 1790, when Alessandro Volta (the developer of the electric battery)
placed metal rods in his own ears and connected them to a 50-volt
circuit, experiencing a jolt and hearing
a noise "like a thick boiling soup".
 Djourno and Eyries(1957) - direct stimulation by placing a wire on the
auditory nerve
 House and Doyle(1961) – approaching the auditory nerve through scala
tympani electrode implantation tympani approach
( hearing sensation that were “pleasant and useful”)
 Simmons(1964) - modiolar stimulation
 House and Michelson - implantation of electrodes driven by implantable
receiver-stimulators

16. History of
Cochlear Implants (cont.)
 House(1972) - first speech processor was developed to interface with the
House 3M single-electrode implant, 1972~1980: > 1000 implanted,
In 1980, age criteria were lowered form 18 to 2 years )
 1984 – multiple-channel devices, enhanced spectral perception and speech
recognition capabilities (Australia, Nucleus)
 1990s – changes in implant technology and in clinical approaches, speech
processor designs have evolved to produce higher performance levels strategies
 1995 - Clarion CI, ABC applied in USA
 1998 – MedEl, Austria entered the US market

17. How many people are
implanted?
 1980 - 1,000
 1990 - 5,000, 90% adults
 1997 - 20,000
 2002 - 45,000, 50% children
 2006 - >100,000
 2009 - >188,000
 approximately 6,000 procedures take place annually in the
United States. (adult/child: 41,500/25,500)
 Approximately 100 cases annually in Taiwan

18. Van Naarden et al:
 An overall prevalence rate of serious hearing impairment of 1.1
cases per 1000 children aged 3-10 years.
 By age 75 years, 360 of 1000 adults have a disabling hearing
loss.
1996, National Institute on Deafness and Other
Communications Disorders survey
 More than 28 million Americans are deaf or hearing impaired.
 This statistic may reach 40 million by the year 2020.

20. ++++
+++

21. The indication for cochlear
implantation
 Congenital hearing loss and prelingual
deafness
 Acquired hearing loss and postlingual
deafness
 Severe hearing loss that can be aided and
that deteriorates to profound loss in
childhood, adolescence, or adulthood
(perilingual) and coexists with various
degrees of language development

22. The contraindication for
cochlear implantation
 deafness due to lesions of the eighth cranial nerve or brain stem
 chronic infections of the middle ear and mastoid cavity or tympanic
membrane perforation
 The absence of cochlear development as demonstrated on CT scans
remains an absolute contraindication
 Certain medical conditions that preclude surgery (eg, specific
hematologic, pulmonary, and cardiac conditions) also may be
contraindications
 The lack of realistic expectations regarding the benefits of cochlear
implantation and/or a lack of strong desire to develop enhanced oral
communication skills poses a strong contraindication for implant
surgery

23. Evolving Audiologic Criteria
May, 1995 NIH Consensus Development Conference on Cochlear Implants
 Profound bilateral sensorineural hearing loss (>90dB)
 Minimal speech perception under best aided conditions.
April, 2001: Balkany T, et al: Cochlear Implants in Children.
Otolaryngologic Clinics of North America 34:455-62.
 Severe (70-90dB) or profound bilateral sensorineural hearing loss
 Those with some residual amplified hearing are still candidates

24. Expanding Age Criteria
May, 1995 NIH Consensus Development Conference on Cochlear Implants
 Minimum age of 2 years
April, 2001: Balkany T, et al: Cochlear Implants in Children.
Otolaryngologic Clinics of North America 34:455-62.
 Recommend minimum age to be 12 months.
 Provides child with auditory input during critical period of language
development

25. Candidacy- ADULTS
 Health adult over 18 Y/O
 Severe to profound hearing loss in both ears
(PTA  70 dBHL)
 Post-lingual onset of severe to profound hearing loss
(after age 6 y/o)
 Limited benefit from hearing aids
(SDS  50%)
 Desire to improve hearing and realistic expectations
 No medical contraindications

26. Candidacy- CHILDREN
 12 months to 17 years of age
 Bilateral profound hearing loss
(PTA  90 dBHL)
 Negligible functional hearing aid benefit
(6 months at least)
 In USA
Children  4 y/o
PBK word score 0-12% or HINT-C score  30%
Children  4 y/o
MLNT word score  20% or IT-MAIS score  2 on questions 3, 5, 6

27. January 2005
 Medicare guidelines as of January 2005 allow
for cochlear implantation in patients with
50% aided sentence discrimination scores
and allow for 60% sentence scores in clinical
trials.
 Clearly, the trend over time is that relaxed
guidelines are better, and better implant
performance and outcome have been
demonstrated.

28. How to evaluate the candidate
 Measures the patient's hearing with and without hearing aids.
 Evaluation with pure-tone audiometry (PTA) and auditory brainstem
response (ABR) testing (in the case of children) often is performed.
Otoacoustic emission (OAE) testing complements these studies; OAE
results often indicate the need for a trial of newer and sometimes
stronger hearing aids.
 A CT scan is obtained to evaluate the status of the cochlea and to
establish the presence of a patent (nonossified) cochlea or to identify a
common cavity, Mondini dysplasia, enlarged vestibular aqueduct, or an
ossified cochlea.
 In children and young adults, speech and language evaluation and
educational placement discussions are performed next.
 Finally, a psychosocial evaluation is completed. Once a patient has
been evaluated, a team meeting commences to recommend
implantation advice.
 If the patient is cleared for implantation, the patient proceeds with
preoperative medical clearance, chooses an implant device, and
proceeds with surgery

29. How many surviving neuron
should be left
 The number of surviving neuron populations
needed for successful implantation remains unclear.
 In 1991, Linthicum et al:
successful speech understanding in a patient who
demonstrated less than 10% of the normal
complement of neurons via a temporal bone study

30. Speech Audiometry
1950, USA: Speech sound , words or sentences
 Speech reception threshold (SRT):
spondee words: 50% repeat
SRT-PTA< 6~8 dB, if >12 dB, repeat SRT or PTA
SRT-speech detection threshold< 8 dB
 Speech discrimination score(SDS):
phonetically balanced words:
SRT + 40 dB=PB-MAX

31. Speech discrimination score
(SDS)
Score Disability
90-100% Normal
75-90% Mild
60-75% Moderate
50-60% Severe
<50% Profound

32. The Cochlear Implantation
Team
 Interdisciplinary team
 Otologist
 Audiologist
 Aural rehabilitation specialist
 Speech pathologist
 Clinical psychologist

33. Age & Outcomes
 Younger age at implantation is generally
associated with better outcomes.
 Children implanted after age 5 show
improvement over those with hearing aids, but
less improvement than children implanted under
age 5.
 Children over age 10 should be screened
carefully, as they are more likely to have poorer
outcomes.

34. Central Neural Plasticity
 Children older than 7 y/o with
prelingual hearing loss are typically not
considered as good candidates for CI

35. Radiologic Evaluation
 Computed tomography of the temporal
bones
 Mastoid aeration
 Facial nerve position
 Patency of cochlea
 Middle ear status
 Evaluate IAC

36. Mondini Dysplasia

37. Radiologic Evaluation
 Indications for Magnetic Resonance Imaging
 IAC <1.5mm on CT
 Evaluate presence of cochlear nerve
 Hx of Meningitic Deafness
 Evaluate degree of cochlear ossification
 Cochlear aplasia or auditory nerve aplasia are
contraindications to cochlear implantation
 High-resolution T2-weighted fast spin echo
MRI is complementing and even replacing CT
scanning because of its increased ability to
reveal cochlear ossification

38. Normal Cochlear CT

39. Psychosocial Factors
 Patient and family motivation are critical
 Must be prepared for extensive period
of aural rehabilitation
 Initial postoperative rehabilitation may
require daily sessions for up to two weeks.
 Realistic expectations

40. Cochlear Implantation Procedure
 2-3 hours under general anesthesia
 The internal device is placed under the skin
behind the ear into a well created in the mastoid
bone
 The electrode array is inserted into the cochlea
 Patient usually discharged the following day
 Device is activated 4 weeks later

41. Determine the side of the
implant
 Implanting the better-hearing ear, allows for
a greater population of surviving spiral
ganglion cells to receive electrical stimulation
and, hence, potentially results in a better
outcome.
 However, some patients, especially those
who have progressive bilateral sensorineural
hearing loss and are experiencing
asymmetric deafness bilaterally , the
poorer-hearing ear may be implanted

44. Components of All Cochlear Implant Systems
• Headpiece (HP) with HP
Microphone (and Transmitter
Antenna), Cable SP
• Speech Processor (SP)
• Internal Cochlear Stimulator HP
(ICS) Package (with Receiver
Antenna) SP
• Electrode Array
ICS
ICS

45. Cochlear Implant Components
 Internal Device
 Surgically implanted under the
skin
 Electronics package (receiver-
stimulator) with magnet
 Electrode array placed inside the
cochlea
 External Device
 Worn on the body or at ear level
 Sound/speech processor
 Microphone
 Coil with magnet

47.  The external components of the CI
system pick up sounds, analyze
them, and convert them into an
electrical signal that is sent to the
internal device located under the
skin
 Internal and external components
are held close to each other by a
pair of magnets and communicate
via transcutaneous transmission of
a radio-frequency signal

48.  The internal device decodes the
signal and sends electrical current
to each electrode
 When the electrodes stimulate the
nerve fibers of the auditory nerve,
the signal is received by the brain
and interpreted as sound

49. Nucleus 24 Contour Array

50. Facial Recess Width
Oval Window: 5.4  0.9 mm
Round Window: 4.5  1.3 mm
Robert H.R. Bettman et al. ORL 2003

51. Dr. Wang’s Lab 2006

52. Basilar membrane
cochleostomy
RW

53. Medel

58. 人工電子耳 帶來一線「聲」機
三總耳鼻喉頭頸外科部
部主任 王智弘
 說人工電子耳是現代醫學中的一項”奇蹟”，一點也不為過，它不僅實現聽障患者對於聆聽聲音的渴
望，也破解了亙古以來老祖宗們所謂“聾即是啞”的一貫魔咒，為先天性聽障孩童與後天性失聰的患
者，帶來了一線「聲」機。
 人工電子耳的原理是利用植入的電極線，纏繞於我們已經受損的聽覺接受器官-耳蝸，進而取代受
損的耳蝸器官並發揮其刺激聽覺神經纖維的功能; 當環境中的聲音訊息透過掛在耳朵上微小麥克風
的接收與語言處理器的信號轉換後，這些聲音的編碼信號就會傳輸到耳蝸的電極線，就如同正常
的耳蝸器官接受到聲音訊號的刺激一般，植入的電極線收到訊號後立即執行其刺激聽覺神經纖維
的功能，聲音的接收從此不再受限於耳蝸的罷工而中止傳遞，這就是人工電子耳的奧妙，而這樣
的巧思竟是來自1790年代左右，有人嘗試將鐵線放入耳道後給予電壓通電，竟然聽到猶如濃湯煮
沸的噪音聲所揭櫫。
 值得注意的是，有兩項新進的發展讓整個植入系統的表現有了重大提升: 一是兩耳均植入人工電子
耳；另一為合併助聽器使用與人工電子耳植入所產生的效應。 兩耳植入有助於將兩耳間的音量差
與時間差作某種程度的恢復，提供植入者分辨聲音方向的線索，有了兩耳的刺激，頭影效應(head
shadow effect)的存在會讓兩耳感受到不同的音量，於是加強了音源位置的辨識。至於合併助聽器
與電子耳的使用，是讓戴助聽器的低頻殘存聽力得以保存，結合電子耳所提供的高頻聽力，整體
的頻率辨識度表現將更趨理想。
 如果聽障患者配戴助聽器能得到助益，人工電子耳的植入就不太必要，這是最簡單的分辨與取捨
方式，畢竟人工電子耳的植入是一項需要開刀的侵入性治療模式，不過，手術的安全性很高，經
術前評估的適合植入者，都可藉由這項醫學科技產品來重新體驗“聆聽聲音”的感覺。

59. 人工電子耳手術術前評估
人工電子耳手術雖然可恢復聽障患者的聽力，但是術前的評估卻必須小心謹慎。不良的術前溝通
和評估，可能會造成手術本身成功、但是個案失敗的情況。是以對於醫療團隊來說，完善的
術前評估常需耗費心力、花上數個月的時間，經醫師綜合考量檢查的結果、預期的成效和家
屬及病人的期望值等因素後，才能了解患者是否真的適合。
術前評估包括了許多檢查，可分為以下幾類：
 病史詢問：透過詳細的病史詢問來初步排除罹患遺傳疾病或智能障礙的孩童個案，使之儘早
接受早期療育。後天性失聰患者則須了解其病因以及聽障發生的時間。
 聽力檢查：包含了純音聽力圖、聽性腦幹反應與耳聲傳射檢查。並非所有聽障個案都需要人
工電子耳手術，若評估透過助聽器輔助後可使個案聽力進步、語言發展獲得改善，或是對成
年案例的生活品質有所助益者，則以助聽器輔助改善聽力即可。
 身體檢查：包含全身理學檢查、耳鼻喉科方面的檢查以及放射影像學的檢查。透過這些檢查
，醫師才能知道患者是否可以進行全身麻醉、有無影響電子耳手術的非適應症或疾病。藉由
影像檢查才能得知患者的內耳構造是否適合植入電極，包括耳蝸發育不全、前庭大腦導水管
擴大等畸形變化。
 語言評估：對於幼兒來說，術前評估語言的發展極為重要，因為改善聽力即是為了能發展健
全的語言。定期的觀察幼兒語言發展情況，且互相對照語言評估和聽能評估的結果，可得知
患者對於人工電子耳的需求。
 其他支持系統的評估：人工電子耳手術前後的聽語評估及復健，對於患者日後聽力的改善有
很大影響。故此必須有詳盡的聽語復健計畫和日後患者家庭對於教育的安排等後續的支持體
系，方能收得最大療效。三總耳鼻喉部目前均有專業合格的聽力師與語言治療師，來專責評
估並訓練幼兒的聽能與語言復健。

60. 人工電子耳適應症及禁忌症
人工電子耳的植入，目前健保並未給付此品項，以下為適應症的說明。
 成年聽障者：
1. 年齡大於18歲以上、且身體狀況無明顯開刀禁忌症的患者。
2. 兩側重度到極重度的感音性聽力障礙。
3. 經傳統式助聽器輔助效果不佳、或語言辨識能力不足者。
4. 若患者語言發展前即失聰、且未曾配戴助聽器輔助者，不建議接受植入手術。
 幼兒聽障者：
1. 雙耳極重度聽障確定者，經配戴適當之助聽器六個月以上，語言發展仍無明
顯進步時，建議3歲前進行植入。
2. 若因腦膜炎引起之聽障，為避免發炎後耳蝸骨化增加此手術的困難度，更可儘早施行手術。
3. 無其他接受手術之禁忌症或無法配合術後復健訓練者。
4. 有完整的術後教育計劃。
若重度聽障患者有以下情況，則為人工電子耳植入的禁忌症，不建議接受此手術：
 （1）持續進行之中耳炎。
 （2）併有自閉症。
 （3）併有重度智障。
 （4）中樞聽覺系統病變 (如: 核黃疸所致的聽神經病變) 。
 （5）上全身麻醉可能有風險者，如：嚴重之心臟疾病。
（6）內耳畸形(如耳蝸發育不全)、經評估後不適合手術者。

61. 人工電子耳手術後照護
 接受人工電子耳手術後，術後一週即可拆線，於術後三至四週，確定手術傷口癒
合良好時，聽力師即可透過電腦、為患者量身訂作出一套個人的「電子耳音量與
舒適度的調整圖」。這個過程通常不會一次就決定好，大約三個月內需每個禮拜
一次回門診進行調整。若患者是幼兒，還必須透過聽語治療師一系列課程，配合
語言復健，如聽音訓練、讀唇技巧、發聲方法等課程，方能使聽障幼童開始辨識
新的語音訊息。由此可見，人工電子耳植入術的成功，不單是指手術的順利完成
，更需配合術後聽能復健的完整課程。
 另外人工電子耳的手術亦有併發症的可能，故術後必需注意是否有如下的症狀出
現，並做好傷口照護。併發症包括：
（1）傷口皮瓣發炎、感染，嚴重時需移除人工電子耳植入物。
（2）腦膜炎。
（3）植入電極放置不當或折壓傷。
（4）術後持續頭暈疑有外淋巴液漏或廔管時。