Download Cochlear Implantation

Cochlear Implant Technology
Presented to Carleton University
By Bob Baillargeon,Thursday November 11th 2010
Did you know that…
• Hearing Loss is the 4th Most Prevalent Disability in
Canada after Mobility, Pain and Agility.
(Source: Statistics Canada, Participation and Activity Limitation Survey, 2001)
• 40% of Persons over the age of 65 Report a
Significant Hearing Loss (Source: Statistics Canada (December 2002))
• Today’s Youth are also at Risk of Significant Hearing
Loss
– At 85 dB, you can listen to music for 8 hours with no
damage. But for every 3 dB increase, cut that time in half.
•
•
•
•
•
4 hours for 88 dB
2 hours for 91 dB (subway, lawnmower)
½ hour for 97 dB (motorcycle)
15 minutes at 100 dB (school dance)
for a concert which can be 110 dB and above… less than a
minute!
(Source: Ontario Association of Speech-Language Pathologists and Audiologists (2005))
Who motivates the hearing impaired
adult to seek help?
•
•
•
•
•
•
Self
Spouse
Physician
Children
Friend
Other
30%
25%
19%
12%
10%
4%
Adam, 1999
Anatomy of the Ear
• Outer ear
• Middle ear
Normal Inner Ear
• Inner ear - cochlea
Damaged Ear
Inner
Hair Cells
Outer
Four primary styles of
Hearing Aids
•
•
•
•
Completely In the Canal (CIC)
In The Canal (ITC)
In The Ear (ITE)
Behind The Ear (BTE)
Completely in the Canal (CIC)
•
•
•
•
•
Fits deeper in ear canal (custom
made)
Mild to moderate or sloping
high-frequency hearing losses
Not usually for children
Advantage:
– Smallest size (least visible)
Disadvantages:
– Small size can be difficult to
handle
– Small batteries are changed
more often
– Cannot be used with some
accessories
– Can be damaged by earwax
& ear drainage
In The Canal (ITC)
•
•
•
•
•
Fits in ear canal (custom made)
Mild to moderately-severe hearing loss
Not usually for children
Advantage:
– Smaller size (barely visible)
Disadvantages:
– Small size can be difficult to handle
– Cannot be used with some
accessories
– Can be damaged by earwax & ear
drainage
In The Ear (ITE)
•
•
•
•
•
Fits completely in the outer ear
(custom made).
Mild to severe hearing loss
Not usually for children
Advantages:
– Small size
– Can be used with add-on
accessories
Disadvantages:
– Small size can be difficult to
handle
– Can be damaged by earwax
& ear drainage
Behind The Ear (BTE)
•
•
•
•
•
Fits behind the ear with custom
earmold or slim tube in outer ear
Mild to profound hearing loss
Can be used by all ages
Advantages:
– Durable
– Larger size easier to handle
& maintain
– Separate earmold can be
easily replaced
– Easy to use with assistive
listening devices
Disadvantage:
– Larger size (highly visible)
What all hearing aids have in
common?
• A battery
• A microphone
• An amplifier
• Loudspeaker
Cost of hearing aids
• Some coverage offered: ADP(Assistive Device
Program) in Ontario = $500/3 years/ear.
• Patient still has to pay between $600 to $2500 per
ear after ADP contribution.
• The cost is the same for adults and children
Facts about Hearing Aids
• Hearing aids do not completely correct a
hearing loss 100%
• Hearing aids amplify all sounds
• Hearing aids will help hearing in many
situations
• Benefits of hearing aids depend on several
factors
• Two hearing aids are better than one
• Adjusting to hearing aid(s) is a long process
Some simple communication strategies:
• Face the hearing impaired person so
lipreading is possible
• Speak more slowly and distinctly, do not
shout!
• Rephrase instead of repeating
• Write down a few key-words if necessary
Other possible options
Bone Anchored Hearing Aid
Titanium fixture/external abutment/sound processor
Typically for congenital atresia or chronic
ear infections
•Implantable Hearing Aid
BAHA
– Alternative to an acoustic hearing aid, for mild to severe
sensorineural hearing loss
•Cochlear Implant
Vibrant Soundbridge
What is a Cochlear Implant ?
•Surgically implanted device.
• Electrode Array and a Receiver-Stimulator
•But it works only if used with:
• External components:
• Speech Processor, Headpiece & Battery
•To work, it needs:
• Programming with a computer
•To work even more optimally:
• Rehabilitation sessions necessary
External components: Speech
Processor, Headpiece & Battery
What does it look like?
Illustration from Advanced Bionics
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
Children Candidacy
• Severe to profound sensorineural hearing
loss in both ears
• Lack of benefit from hearing aids and therapy
• No medical contraindications
• High motivation and appropriate expectations
for child and family
• Placement in educational program that
emphasizes auditory skills
• 12 months and up; may be indicated earlier
for special cases
Other considerations
•
•
•
•
•
•
Age
Duration of deafness
Language
Mode of Communication
Other handicaps
Motivation
How is a Cochlear Implant
Different from a Hearing Aid?
• Hearing Aids:
– acoustically amplify sound
– rely on the responsiveness of surviving hair cells
• Cochlear Implants:
– bypass damaged hair cells
Convert the acoustic input signal into electrical impulses
to stimulate the auditory nerve fibers in the cochlea.
The resulting electrical sound information is sent
through the auditory system to the brain for
interpretation.
How does it work?
• Sound Processor
•
•
•
captures sound from the environment
processes sound into digital information
transmits to the implant.
2. Implant
• converts transmitted information into
electrical signals
• delivers signals to the electrodes for
stimulating the hearing nerve.
3. Hearing Nerve
•
carries the sound information to the brain,
where it is interpreted.
Evaluation Process
•
•
•
•
•
Audiological
Medical
Psychological & Social Worker (children)
Auditory-Verbal Therapy (children)
Speech Language Pathology (for adults,
when required)
Audiological Assessment
• Diagnostic testing:
–
–
–
–
Audiogram
Tympanometry & Acoustic Reflexes
Auditory Brainstem Response
Otoacoustic Emissions
• Speech perception tests with appropriate
amplification
• Counseling re: types of implants &
expectations
Medical Assessment
• Otologic history & examination
• General medical health
• Pneumococcal meningitis vaccine:
Pneumovax
• Diagnostic Imaging
• Computed Tomography (CAT)
• Magnetic Resonance Imaging(MRI)*
• Electronystagmography ENG(Adult only)
Electronystagmography (ENG) is a diagnostic test to record involuntary movements of the eye
caused by a condition known as nystagmus. It can also be used to diagnose the cause of
vertigo, dizziness or balance dysfunction by testing the vestibular system.
Surgery Risks and/
or Adverse Effects
• Facial nerve injury (less than 1/300 to 1/500)
• Small possibility of infection
• The small amount of hearing in the operated ear
will be lost.
• Some discomfort or numbness around the
implanted ear after the surgery
• Temporary dizziness, tinnitus or taste disturbance
• MRI precautions after surgery
Surgery
• Inpatient procedure
• Requires general
anesthesia
• Duration ~ 3-4 hours
Behind-The-Ear/Device Marking Template
The Behind-the-Ear/Device
Marking Template is used to
allow adequate clearance
between the pinna, the speech
processor and the headpiece.
From Advanced Bionics
Device Coil Gauge
After placing the Device
Coil Gauge, an outline is
drawn around the template.
From Advanced Bionics
Incision Line
Note: The surgeon will
determine the length of the
incision line.
A conventional postauricularscalp incision approximately
5.0-6.0cm in length for
children may be used.
The incision may be longer
in adults if the scalp needs to
be thinned.
From Advanced Bionics
Recess Marking Template
The Recess Marking
Template is used to
determine the location of
the recess bed and channel
for the electrode lead.
From Advanced Bionics
Mastoidectomy-Facial Recess Approach
After completion of a
mastoidectomy-facial
recess approach, the
implant-receiver well/recess
bed and electrode lead
channel are drilled.
Suture tie-down holes to
stabilize the implant are
placed.
A standard cochleostomy is
used.
From Advanced Bionics
Electrode Insertion
The insertion tool is used to
insert the electrode array in the
usual fashion.
The Insertion Tube is placed just
inside the cochlea toward the
basal turn of the scala tympani,
with the insertion tube slot
directed toward the modiolar (or
inner) wall.
From Advanced Bionics
Closure
The skin incision is closed
in layers.
From Advanced Bionics
Electrode Array Placement
Within the Cochlea
Illustration courtesy of Cochlear Corporation
Audiological testing in the OR
• Impedance
check on all
electrodes
• Neural response
testing to help
estimate
required levels
X-Ray to confirm position
of internal device
Courtesy of Cochlear Corporation
After the surgery
•Initial stimulation: 4-6
weeks post surgery
•Adjustments made
regularly based on
feedback from patients,
parents, therapists and
educators
•Rehabilitation to meet
specific patient needs
•Regular follow-up
appointments
Positive psychological
& social benefits
• Decline in:
-Loneliness
-Depression
-Social isolation
• Increase in:
– Self-esteem
– Independence
– Social integration
– Vocational prospect
Negative psychological
& social impacts
• Concerns about the maintenance and/or
malfunctioning of the Cochlear Implant
• Difficulty in background noise
• Unreasonable expectations of aural-only
benefit on the part of the implant user or
their family and friends
Potential Benefits
1.
2.
3.
4.
5.
6.
7.
Better speech understanding compared to a hearing aid
Awareness and responsiveness to environmental sounds
Less dependence on family members for day to day living
Reconnection with the world of sound
Facilitation of communication with family and loved ones
Ability to talk on the phone
Better appreciation of music
Advanced Bionics
28515 Westinghouse Place
Valencia, CA 91355