cochlear implant ok print

8/12/2019 Cochlear Implant OK Print

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LITERATURE READING

Oke Kadarullah

Department of Otorhinolaryngology-Head and Neck SurgeryHasan Sadikin Hospital

Medical Faculty Padjadjaran University2012


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INTRODUCTION

Hearing loss poses a monumental obstacle ofeffective communication skills.

The perception and the production of speech arehighly dependent on the ability to processauditory information.

Early identification

An appropriate sensory aid recommended.

Conventional amplification is initial choice.cochlear implants or other implantable hearingaids.

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Anatomy & Physology of Hearing

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Preview animasi


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Component CI system

Microphone.

Speech processor.

Electrode array.

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Role of The Cochlea

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The Cochlea (Spiral Ganglion)

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Otte et al : We Need

10.000 ganglion

cells with 3.000

apically to have agood speech

discrimination


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How CI Works

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Implant Selection

Nucleus

Clarion/Bionic

MedEl

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Selection & Evaluation of Patients

Children

12 months or older

Bilateral severe-to-profound sensorineural hearingloss with PTA of 90 dB or greater in better ear

No appreciable benefit with hearing aids (parentsurvey when 5 yo)

Must be able to tolerate wearing hearing aids andshow some aided ability

Enrolled in aural/oral education program

No medical or anatomic contraindications

Motivated parents

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Contraindications

Incomplete hearing loss

Neurofibromatosis II, mental retardation, psychosis,organic brain dysfunction, unrealistic expectations

Active middle ear disease CT findings of cochlear agenesis (Michel deformity) or

small IAC (CN8 atresia)

Dysplasia not necessarily a contraindication, but

informed consent is a must H/O CWD mastoidectomy

Labyrinthitis ossificansfollow scans

Advanced otosclerosis

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Classification of Cochlear Implant Recipients

1. Postlingually deafened adults and children:

deaf at or after age 5 years

High level of success

2. Congenitally or early deafened children:

most frequently encountered type of profound SNHL

variable results

3. Congenitally or early deafened adolescents and adults:patient who has had little or no experience with sound

low level of success

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General Workup

Audiologic exam with binaural amplification

CT scan/MRI of temporal bones

Trial of high-powered hearing aids

Psychological evaluation

Medical evaluation

Any necessary tests to discover etiology of hearing

loss

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Surgical Anatomy

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Mastoidectomy

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Posterior Tympanotomy

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Cochleostomy

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SURGICAL IMPLANTATION

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Step by step surgery

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Preview film


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Special Circumstances

Cochlear Ossification

Cochlear Malformation

Bilateral Implantation

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Postoperative Management

Initial Stimulation & Device Programming

Post operative Rehabilitation

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Complication

Infrequent Wound infection

Facial nerve injury

Tinnitus Infected foreign body

Electronic malfuction

Delayed mastoiditispostauricular abscess.

Meningitis Further degeneration of the central auditory

system

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Result

Wide range of outcomes

(subjective & objective measurements)

Adult outcome

Pediatric outcome

Spoken word recognition

Speech production and language outcomes

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Other Implantable Hearing Devices

Implantable Hearing Devices (IHDs) that couple with theossicular chain in the middle ear

Advantages of IHDs :

(1)elimination of acoustic feedback

(2)a wider frequency response

(3)elimination of a tight-fitting external ear canal mold

(4)improved perception of the auditory signal.

Devices : Vibrant Soundbridge

Direct System

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Vibrant Soundbridge

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Components:

(1)A surgically implanted internal receiver that

includes the floating mass transducer, which is

crimped onto the long process of the incus(2)External processor, which picks up sound from

the environment and transmits the signal to

the implanted receiver. The implant is

positioned through a mastoid-facial recess

approach


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Vibrant Soundbridge

Appropriate for moderate sensorineural hearing loss

Not appropriate for conductive hearing loss or

retrocochlear hearing loss

Speech discrimination must be at least 50%. A stable middle ear should be present and the tympanic

membrane must be intact.

Average functional gain of 10 to 15 dB across thefrequency spectrum

Aided speech recognition scores comparable with

conventional hearing aids31


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Direct System

consists of : a neodymium-iron-boron (Nd-Fe-Bo) magnet

implanted at the incudostapedial joint via a transcanal

procedure

An external processor produces an electromagnetic fieldthat sets the implanted magnet into motion.

Average functional gain of 10 to 15 dB for all tested

frequencies lower than 6 Hz.

There was no significant change in average residual hearing

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HIGHLIGHTS

Cochlear implants (multichannel design)sound information : intensity, timing, andfrequency.

Postlinguistically deafened adultsthemost predictable beneficiaries of cochlearimplants.

Ossified or congenitally deformed cochleas(i.e., Mondini deformity) do notcontraindicate cochlear implantation.

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HIGHLIGHTS

A detailed hearing-aid trial with training isrequired to compare hearing-aid performance

with that expected with a cochlear implant.

The standard surgical approach is through the

mastoid and facial recess, providing access to

the round window.

Detailed longitudinal studies are now clearly

demonstrating improvements in speech

perception and speech production.34


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Cumming otolaryngology HNS 4thed Elsevier 2007

Bailey BJ, Head & Neck Surgery - Otolaryngology, 4th Edition

Lippincott Williams & Wilkins 2006

Snow, JB., Ballenger JJ, Otorhinolaryngology Head and Neck

Surgery, sixteenth Edition, BC Decker 2003

Dhingra PL, Diseases of Ear, Nose and Throat, 4thedition,

Elsevier, 2005

Moller, A.R, Cochlear and Brainstem Implants, Karger, 2006

Ulug T., Atlas of Temporal Bone Surgery, 1stedition,Thieme, 2010

Niparko J.K, CochlearImplants: Principles and Practice, 2nd,

Lippincott, 2009

cochlear implant ok print

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