1. Recent Advances in Cochlear
Implant Candidacy
BY: DR AMIRA EL
SHENNAWY
ASSISTANT PROFESSOR
OF
AUDIOLOGY
CAIRO UNIVERSITY

2. History Of Cochlear Implantation
 1800 Alessandro Volta
 1957 Djourno & Eyries
 1961 Dr Wiliam F House
 1970s
 1984 FDA approved single channel device in adults

3. What is a
Cochlear
Implant ?

6. Evolution of Cochlear implant

7. Current Implant Technology
Three companies currently have FDA approved implants
Advanced Bionics (California) —HR90 K
Cochlear (Australia) —Nucleus 5
Med-El (Austria) —Sonata ti100

8.  Candidacy for CI has changed gradually but
significantly since the first multichannel devices
were implanted in the late 1970s .
 Due to increasing experience, improvement of
technology and the proven reliability, the selection
criteria are broadened with shifting borders.
 Main extensions are related to age, additional
handicaps, residual hearing & special etiologies of
deafness.

9.  The obvious goal for careful selection of CI
patients is to never have a single patient
perform more poorly with their CI than they
did with their hearing aids (Gifford,H 2011).

10. Stages in Patient Selection
 I. Questionnaire
Age - Aetiology
Onset of HL ( pre , peri , postlingual )
Duration of sensory deprivation ( plasticity )
Hearing aid use
II. Audiological investigations
III. Language assessment
IV. Radiological examination

11.  V. Psychological assessment
IQ testing
 VI. Vestibular testing
 VII. Medical & Otological examination
 VIII. Electrical stimulation of the cochlea
Counseling…………..

12. Pediatric CI Candidacy

13. Team Approach
Teacher
Surgeon &
Psychologist
Pediatrician
Child
SLP Caregivers
Audiologist

14.  FDA approval for implanting children:
1990 > 2 years
1998 = 18 months
2000 = 12 months

15.  Changes in age of implantation are due to:
1.Better / early identification of HL (universal
hearing screening )
2.Increased public awareness
3. Increased professional awareness
4.Changes in technology :
Electrode array – Programming – Processors
Telemetry

16.  The literature has demonstrated that in terms of
speech development and language acquisition , the
best results come from children implanted under the
age of 2 years similar to normal hearing children
(Sharma et al ., 2002 ).
 All CI devices can be safely indicated for children 12
months or older .
 However, implanting children younger than 12
months remains controversial.

17.  Further reductions in age at implantation are currently
limited by the nature of audiologic testing in very young
children.
 In cases of HL due to meningitis or hereditary hearing loss ,
implantation should be considered before the age of 12
months.

18. Audiological evaluation
 Behavioral audiometry ( age appropriate )
 Tympanometry & acoustic reflexes
 ABR , ear specific & frequency specific
 ASSR
 OAE
 Aided free field testing
 Special tests : EABR , EMLR , ESR, Electrical late
event related potentials.

19. Audiometric Thresholds
For children aged 12-23 months hearing threshold
for both ears should equal or exceed 90 dB.
 For individuals older than 24 months hearing
threshold should equal or exceed 70 dB.
 Speech detection with best fit hearing aids in a sound
field equal to or worse than 55 dB.

20.  Hearing aid trial for 3 months.
 During HA trial , child should be making at least
month to month auditory progress as well as speech
and language progress. If this is not the case then, CI
evaluation should be considered ( Gifford, H 2011 ).
 Teenagers ???

21.  Speech & Language assessment
 Psychological assessment , IQ testing
 Counseling , family support , motivation & realistic
expectations.
 Medical and Otological examination

22. Radiological assessment:
CT scan traditionally is the gold-standard imaging modality
Superior visualization of the bony structure of the otic capsule
and the course of the facial nerve .
 Weakness: can miss cochlear fibrosis, retrocochlear pathology, CNS
abnormalities, and cochlear nerve hypoplasia/absence
Magnetic resonance imaging (MRI)
 More effective at identifying cochlear fibrosis
 Able to identify presence/absence of cochlear nerve and caliber
 Weakness: inferior visualization of bony anatomy, inability to detect
the presence of the round window, oval window, or an enlarged
vestibular aqueduct; often requires anesthesia for young patients

24. Vaccination
 Children with cochlear implants are at higher risk for
meningitis, though overall rate is low (<0.6%)
 Streptococcus pneumoniae has been the most common
organism isolated in the children with cochlear implants who
developed meningitis
 Current vaccine recommendations:
 Patients <2 years old
 Prevnar (7-valent) only
 Patients 2-5 years old
 Prevnar and Pneumovax (23-valent)
 Patients >5 years old
 Pneumovax only
 Additionally, all patients <5 year old should receive the Hib vaccine
 Vaccination should be completed at least 2 weeks prior to
surgery

25. Adult CI Candidacy criteria

26.  History :
 Onset & course of hearing loss
 Duration (plasticity)
 Aetiology ( fever , trauma )
 History of HA use
 Means of communication
 Education
 Motivation , realistic expectations
Prelingual adults ???????

27. When to refer an Adult for a CI?
• Bilateral severe to profound sensorineural hearing
loss
• Limited benefit from appropriate hearing aids i.e.
poor speech recognition
• Telephone use is difficult, limited or impossible
• Patient relies heavily on speech reading or note
writing to understand speech
• Patient is distressed by the inability to communicate
efficiently on a daily basis
• No medical contraindications

30.  Speech recognition testing is the cornerstone in adult
CI patient selection,
 Where the best-aided scores on open-set sentence
tests of <50% in the ear to be implanted and <60%
in contralateral ear is considered as an indication for
implantation.

31. Choosing the most appropriate ear
 Audiological factors :
1. Residual hearing
In the early years of CI , the audiologically worse ear was
chosen so that (un) expected iatrogenic cochlear damage
would have fewer consequences.
In the late 1990s the better ear with the most residual
hearing was preferred as studies had shown that better
preserved peripheral neural pathways would lead to better
results after CI.

32. 2. Duration of HL
It is generally accepted that duration of deafness has
a negative effect on CI performances.
Most clinicians choose the ear with the shortest
duration of deafness.
3. Only functioning labyrinth

33.  Surgical Factors
1.Anatomic variations : cochlear ossification,
cochlear malformation and cochlear nerve
malformation.
2.Otological medical history : otitis media ,
cholesteatoma and temporal bone fracture.
Personal factors
Handedness , (right ear advantage)

34. Contraindications for implantation
 Completely atretic VIII nerve
 Small internal auditory canal syndrome
 Agenesis of cochlea: Michel deformity
 Active middle ear/mastoid infection
 Tympanic membrane perforation
 Severe organic brain dysfunction
 Severe mental retardation
 Psychosis, unrealistic expectations

35. Hybrid CI (Electro Acoustic Stimulation)
 The expanded criteria have led to research questions
centering on advanced uses of the technology.
 Specifically, could an implant benefit other users
previously not considered to be a candidate?
A group that was felt to be underserved with
conventional amplification were those patients with
the following audiometric profile

37.  Audiogram
Below 1.5 kHz – No or moderate HL
Above 1.5 kHz – Severe to profound sensorineural
hearing impairment.
Dead regions of the cochlea (elderly) .
 Speech scores
The patient's monosyllable word score should be ≤
60% at 65dB SPL in the best aided condition.

38.  Hearing preservation surgery
 Two methods are commonly used for inserting the
electrode into the cochlea:
Round-window insertion VS
Cochleostomy insertion.
 Round-window insertion has found a wider
acceptance because it is considered to be less
traumatic (controversial).

39.  EAS electrodes for cochlear implants :
 Long-term research has shown that mechanical flexibility
of the electrode array is one of the key factors for
preserving residual hearing.
 Studies with different lengths of electrodes have shown that
an insertion depth of 10 mm has a good chance of
preserving residual.
 Electrodes that can be inserted to a depth of 18–
22 mm are a good compromise.

40. EAS audio processors
 Combines cochlear implant technology with a digital
hearing aid. This device uses one microphone for the
input, but has two separate digital sound processors
for differentiated processing.
 The parallel processing of these signals, however, is
performed separately and optimized for both
acoustic hearing (focusing on low-frequency hearing)
and cochlear implant stimulation (focusing on high-
frequency hearing).

41. The hearing aid is integrated in the ear hook and the
amplified signals are forwarded to the auditory
pathway via an ear mould.
 The ear mould used for the acoustic component is
similar to a conventional hearing aid ear mould and
can be exchanged.

42. Bilateral CI
 Recent Trend towards BILATERAL use of CI/s
-- 1992: 0-1%
-- 2007: 14-15%
 70% of bilateral CI usage is among 18 years and under age
group.
 Simultaneous CI
 Sequential CI

43.  Advantages of bilateral implantation
 Improved hearing in quiet (binaural summation)
 Improved hearing in noise (binaural squelch, head shadow
effect, and binaural redundancy)
 Improved sound lateralization
 Improved sound localization
 Assurance that the ―better hearing ear‖ is
implanted/‖captured‖
 Qualitative listening improvement (more ―balanced‖;
―richer quality‖; more ―confident‖ feeling; and less fatigued)

44. Disadvantages
Increased costs (2 devices, batteries, etc.)
 Multiple pieces of equipment to manage
 Surgical and medical risks
 Future developments
 No or limited ―natural‖ hearing remaining
 Different processing strategies & speech
processors (with sequential bilateral CIs)

45. Bimodal stimulation
CI in one ear and HA in the other.
 Binaural stimulation
 Residual hearing in contralateral ear
 After established electrical stimulation
 Balancing between the two ears
 Future technology
 Cost effectivness

46. Special Etiologies

47.  Meningitis:
9% of childhood deafness.
Commonest organism to cause HL is S pneumoniae.
Labyrinthitis ossificans.
Implantation before 12 months of age.
Trauma:
BILATERAL OTIC CAPSULE FRACTURES ARE
UNCOMMON
Intraluminal fibrosis or ossification may occur which
makes electrode insertion difficult.

48.  Hyperbilirubinemia
risk of auditory neuropathy.
Auditory neuropathy /dyssynchrony:
Many clinicians have been conservative about the
outcome.
Sydney CIC has the most experience.
They reported variable outcome due to wide
variability of impairments.

49. Many of the children had successful implantation
with a smaller number failing to gain significant
benefit.
75 % of the patients benefited from the CI due to
surviving OHCs when IHCs are compromised.
Patients who did not benefit ,may have dysfunction
in afferent neural synapses, CN or higher auditory
systems.
During patient selection, electrically evoked CAP
should be tested .

50. Usher Syndrome
 Most common cause of blindness in humans.
 Autosomal recessive
 Type I (USH1) most severe 30- 40 % :
 Severe to profound congenital HL , motor
developmental delay & progressive retinopathy.
 Early implantation is critical to developing
effective oral – auditory skills prior to visual loss.

51. Autosomal syndrome.
Hyperplasia of
eyebrow,
heterochromia iridis,
white forlock,
Variable SNHL.
Increased incidence
of auditory Waardenburg Syndrome
neuropathy

52.  Keratitis Icthiosis Deafness Syndrome (KID)
Rare congenital disorder of the ectoderm.
Heterogeneous mutation in the Connexin 26 gene
Autosomal dominant.
Congenital icthyosis , vascular keratits , SNHL ,
alopecia and squamous cell carcinoma may occur.
CI produces good audiological results BUT Wound
complications are very common , failure to heal,
partial extrusion of the implant.

53. Multi handicapped
 Patients with additional disabilities such as mild
motor disability, cerebral palsy , cognitive
disabilities, specific learning disabilities, behavioral
disorders and sight impairment have been
implanted.
 Multi-handicapped children receive benefit from
cochlear implantation. The rate of this improvement
is slow but offers better quality of life due to better
auditory-communication skills, better self-
independence and social integration.

54. Recent Trends
 RECENT TRENDS

55. C I in Unilateral Deafness
 Up to now treatment modalities for single sided
deafness are; NO treatment , Conventional
contralateral routing of signal or BAHA.
 CI makes a new treatment modality for those
patients.
 Study done by Arndt et al., 2011 revealed that CI
improved hearing abilities in single sided HL &
superior to alternative options. CI didn’t interfere
with speech understanding in the normal ear.

56. CI in Unilateral deafness and tinnitus
 Tinnitus is a frequent often disabling condition.
 In patients who are deaf with tinnitus in the affected
ear, treatment based on acoustic input are
impossible.
 Tinnitus suppression using electric stimulation has
been reported to be successful (Buechner et
al.,2010).
 Several studies (Kleinjung 2009: Van de Heyning et
al., 2008 and Moller 2003 ) concluded that CI may
represent a chance for complete suppression of
tinnitus in selected cases.

57. CHALL
ENGES

58. Audiological
 Mapping very young children:
difficulty in obtaining behavioral results’
evolution of recent technology helps assist in
mapping through the use of ECAP measurements.
 Mapping the multi handicapped.

59. Surgical Challenges
Implanting very young children
 Children below 12 months usually have poorly pneumatized
mastoid bones leading to greater intraoperative blood loss
and risk of facial nerve injury.
 Greater anesthesia risk ,size of airway & difficulty
maintaining cardiovascular fluid & temp homeostasis.
 Thin scalp : care in drilling well for body of device.
 Increased incidence of otitis media
 Fortunately, cochlea is adult size at birth.

60. Hearing preservation surgery
 A special surgical technique to preserve the residual
hearing of the patient (in most routine cochlear
implant surgeries, any residual hearing will likely be
destroyed).
 This is a very realistic goal for many patients with
sloping hearing loss (EAS ).
 Achieved by performing ―Soft surgery‖

61. Dysplastic Cochlea
Due to increased knowledge of temporal bone
anatomy and improved imaging techniques more
patients with Mondinin dysplasia , Common
cavity, hypoplastic cochlea and large vestibular
aqueducts are implanted.
Modifications in surgical techniques.
Likelihood of CSF gusher .

62. Labyrinthitis Ossificans
Consequence of meningitis
Ossification partially or completely block the lumen
of scala tympani & or scala vestibuli.
Several techniques:
Drilling a basal tunnel , circum-modiolar drill-out,
use of double or split electode array.

63. Bilateral Implantation
Lengthy, bilateral loss of vestibular function ,
contamination of the field.
Monopolar cautery can not be used for the second
side

64. New Devices
If and when the totally implantable cochlear
implant (TICI) becomes a reality, it will
require a modification of current surgical
techniques to implant a microphone and
possibly adding hardware to the ossicles.

65.  Overall the selection criteria have
been broadened with increasing
experience and technological
improvement.
 This development may continue
and the borderline between HA &
CI will shift further.
 However, the basis for success
still remains good rehabilitation,
a team approach and the
willingness of the patient to
undergo the whole process of CI.