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Differential diagnosis of Hearing loss

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Differential diagnosis of Hearing loss 1.Conductive Hearing loss 2.Sensorineural Hearing loss 3.Mixed Hearing loss Surgical Technique Postoperative Management ... – PowerPoint PPT presentation

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Title: Differential diagnosis of Hearing loss


1
Differential diagnosis of Hearing loss
  • 1.Conductive Hearing loss
  • 2.Sensorineural Hearing loss
  • 3.Mixed Hearing loss

2
DIAGNOSIS AND Assessment of hearing loss
  • HISTORY
  • Screening test-Behavioural tests
  • Speech test
  • Tuning fork test
  • Pure tone Audiometry
  • Speech audiometry
  • Impedence Audiometry
  • ABLB, SISI, TD
  • Electrocochleography
  • Auditory brain stem response
  • Otoacoustic emissions

3
Causes of conductive loss
  • Congenital
  • Meatal Atresia
  • congenital cholesteatoma
  • ossicular discontinuity
  • Fixation of malleus
  • Fixation of stapes

4
Acquired Causes of conductive loss
  • Acquired causes
  • EXTERNAL EAR
  • meatal aresia
  • wax
  • foreign body
  • furuncle
  • tumour
  • acquired atresia

5
Acquired Causes of conductive loss
  • Middle ear
  • Serous otitis media
  • Otosclerosis
  • Ossicular discontinuity
  • Adhesive otitis media
  • Tympanosclerosis
  • Csom
  • ASOM
  • TUMOUR
  • Trauma

6
MANAGEMENT OF CONDUCTIVE LOSS
  • SURGERY
  • Hearing aids

7
HEARING AIDS
1.Microphone 2.Amplifier 3.Receiver
8
Hearing aids
  • Sounds-----microphone volume control
  • battery amplifier
  • receiver
  • amplified
    sounds

9
TYPES OF HEARING AIDS
  • BODY WORN AID

10
bte
11
In the canal
12
Completely in the canal
13
Electroacoustic properties of the hearing aid
  • Acoustic gain
  • Frequency response
  • Maximum output
  • Distortion

14
ASISTED LEARNING DEVICE
  • FM
  • Hard wire system, class room amplification
  • Telecommunication device for the deaf
  • Alerting device for the deaf

15
Cochlear implants
  • Electronic devices designed to detect mechanical
    sounds and convert it into electrical signals
    that can be delivered to cochlear nerve and
    interpreted by the patients to provide useful
    hearing.

16
History of Cochlear Implants
  • Volta
  • Djourno and Eyries
  • House, Doyle, Simmons
  • 1972 Single-channel implant
  • 1984 FDA approval
  • 1990s
  • Beyond

17
Anatomy
18
Anatomy
Scala tympani Scala vestibuli Cochlear
duct Basilar membrane Vestibular
membrane Tectoral membrane Hair cells
(outer/inner) Cochlear nerve fibers
19
Anatomy-micro
20
Physiology of Hearing
21
(No Transcript)
22
Anatomy
23
Pathologic Anatomy
24
Components of Cochlear Implant
25
Implant Components
  • Microphone
  • amplification
  • External speech processor
  • Compression
  • Filtering
  • Shaping
  • Transmitter (outer coil)
  • Receiver
  • Electrode array
  • Neural pathways

26
Types of Cochlear Implants
  • Single vs. Multiple channels
  • Audio example of how a cochlear implant sounds
    with varying number of channels
  • Monopolar vs. Bipolar
  • Speech processing strategies
  • Spectral peak (Nucleus)
  • Continuous interleaved sampling (Med-El, Nucleus,
    Clarion)
  • Advanced combined encoder (Nucleus)
  • Simultaneous analog strategy (Clarion)

27
Anatomy of a Cochlear Implant
28
Indication for Cochlear Implant
  • Adults
  • 18 years old and older (no limitation by age)
  • Bilateral severe-to-profound sensorineural
    hearing loss (70 dB hearing loss or greater with
    little or no benefit from hearing aids for 6
    months)
  • Psychologically suitable
  • No anatomic contraindications
  • Medically not contraindicated

29
Indications for Cochlear Implantation -- Children
  • 12 months or older
  • Bilateral severe-to-profound sensorineural
    hearing loss with PTA of 90 dB or greater in
    better ear
  • No appreciable benefit with hearing aids (parent
    survey when lt5 yo or 30 or less on sentence
    recognition when gt5 yo)
  • Must be able to tolerate wearing hearing aids and
    show some aided ability
  • Enrolled in aural/oral education program
  • No medical or anatomic contraindications
  • Motivated parents

30
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

31
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

32
Surgical technique
33
Surgical Technique
34
Surgical Technique
35
Postoperative Management
  • Complication rate only 5
  • Wound infection/breakdown
  • Yu, et al showed good response to Abx, ID
  • Facial nerve injury/stimulation, CSF leak,
    Meningitis
  • CDC recommendations
  • Vertigo (Steenerson reported 75)
  • Device failurere-implantation usually successful
  • Avoid MRI

36
Postoperative Rehabilitation
  • Necessary part of implantation
  • Different focus depends on patients previous
    experience with sound
  • Goal is to enable children to be able to learn
    passively from the environment
  • Program addresses receptive as well as expressive
    language skills
  • Multidisciplinary, dedicated group necessary

37
Results of Implantation
  • Wide range of outcomes
  • Improvement is long-term (Waltzman, et al. 5-15
    yr f/u)
  • Implantation is cost effectiveeven in the
    elderly (Francis, et al)
  • Research indicates recipe for success includes
  • Short length of time from deafness to
    implantation (Sharma showed lt3.5 years regain
    normal latencies within 6 mos. After 7 years,
    little plasticity remains)
  • Experience with language before onset of deafness
  • Implantation before age six for prelingually
    deafened children (Govaerts, et al showed 90 of
    children implanted lt2yo were integrated into
    mainstream vs. only 20-30 if implanted after age
    4)
  • Aural/oral education
  • Highly motivated patients/parents

38
A Look to the Future
  • Partial implants with hearing aid
  • Those with residual low-frequency hearing
  • Intraoperative mapping
  • Bilateral implantation
  • One vs. two speech processors
  • Implantation for asymmetric SNHL
  • Softip array
  • Minimally invasive implantation

39
THANK YOU
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