Deafne ss Dr. Jairaj Vaishnav SR in ENT SMS Hospital
DeafnessDr. Jairaj Vaishnav SR in ENT SMS Hospital
“When you lose your vision, you lose contact with things; when you lose
your hearing, you lose contact with people.”
Helen Keller
Protection
Impedance match
Capture; Amplify mid-freqs
Vertical direction coding
Frequency analysis
Transduction
Outer, middle & inner ear
ICF Defination (WHO: 2001DDD)
Hearing impairment :refers to complete or partial loss of the ability to hear from one or both ears. The level of impairment can be mild, moderate, severe or profound;
Deafness : refers to the complete loss of ability to hear from one or both ears.
Type of Loss
Conductive Sensorineural Mixed Auditory
Processing Disorder
Quantification of Hearing Loss
Unable to hear sound at “Mild” Hearing Loss
26 – 40 dB “Moderate” Hearing Loss
41-55 dB “Severe” Hearing Loss
56- 70 dB “Profound” Hearing Loss
91 dB & greater
Degree of Hearing Loss
Minimal Mild Moderate Moderately
Severe Severe Profound
Impact of HL on Quality of Life
Physical health Emotional & mental health Other’s perceptions of a person’s
mental acuity Social skills Family relationships Self-esteem Work & school performance
Hearing Loss
Part of ear not working Includes:
outer ear middle ear inner ear hearing acoustic nerve auditory system
Types
Conductive deafness: due to defect in the conducting mechanism of the ear namely external and middle ear.
Sensori-neural deafness / Perceptive deafness: due to lesions in the labyrinth, 8th nerve & central connections. It includes psychogenic deafness.
Mixed deafness: both the above mentioned types are present.
External ear: Wax, Fungus, Otitis Externa, Foreign Bodies, Polyps,
Myringitis, Stenosis, Atresia, Tumours.
Causes of Conductive deafness
Middle Ear
Cont…..
Congenital defects of the ear drum and ossicles.
Traumatic: Barotrauma, rupture of ear drum, # of the base of the skull
Inflammation: AOM, COM, Serous OM, Adhesive OM.
Tuberculosis and syphilitic OM
Neoplasms Otosclerosis
Causes of Conductive deafness
Eustachian tube Catarrh = xcessive discharge from nose / throat / ear Eustachian catarrh
Eustachian tube dysfunction due to diseases of the nose, paranasal sinuses & pharynx
Barotrauma
Conductive Sensorineural
Causes of Sensori-neural deafness
Local causes (inner ear)
Congenital Trauma: Head injury,
surgical injury to labyrinth, loud sounds (acute or chronic acoustic trauma) producing concussion.
Infections: mumps, syphilis, tuberculous meningitis, enteric fever, labyrinthitis.
Tumours: Acoustic neuroma (Schwanoma of C8 nerve)
Meniere’s disease Ototoxic drugs:
streptomycin, Kanamycin, neomycin, salicylates, frusemide and quinine.
Causes of Sensori-neural deafness
General causes
Presbycusis CVS: atherosclerosis,
HTN CNS: disseminated
sclerosis DM Avitaminosis Hypothyroidism Smoking Alcoholism
Presbyacusis: is a progressive bilateral symmetrical age-related sensorineural hearing loss. It is also known as age-related hearing loss
Causes of Sensory-neural deafness
Psychogenic deafness: 2 types
Functional: due to emotional cause, but the patient is not aware of the cause.
Malingering: no organic or psychological cause. The patient is aware that he is pretending to be deaf for personal gains.
Trauma: Blast injury, acoustic trauma, head injury.
CSOM with labyrinthitis. Otosclerosis Senile deafness superimposed on
conductive deafness.
Causes of Mixed deafness
“The assessment, intervention, and management of communicative consequences of hearing loss”
Rehabilitation
Methods of rehabilitation
I. Instrumental devicesA. Hearing Aids
- Conventional hearing aids
- Bone anchored hearing aids
- Implantable hearing aidsB. Implants - Cochlear implants
- Auditory brainstem implants
C. Assistive devices for the deaf
II. Training A. Speech(lip) trainingB. Auditory training
C. Speech conservation
Hearing aids
Device to amplify sounds ---- 3 parts. Microphone- picks up sound and converts to electrical impulses. Amplifier- magnifies electrical impulses. Receiver-converts electrical impulses back to sound.
TypesAir conduction hearing aids Bone conduction hearing aids
Hearing Aids
Body worn types Behind the ear types Spectacles type In the ear type Canal types(ITC/CIC)
Types
Types of hearing aids
Bone anchored hearing aids
Based on the principle of bone conduction Candidacy profile
a) chronic inflammation or infection of ear canal
b) children with malformed or absent outer canals
c) unilateral deafness.
Bone anchored hearing aids
Titanium fixture, abutment, sound processor
Bone anchored hearing aids
When air conduction hearing aid can’t be used
- Canal atresia
- Chronic ear discharge
- Excessive feedback and discomfort
CoHL / Mixed hearing loss
- otosclerosis / tympanosclerosis.
Single sided hearing loss
Indications for BAHA
Implantable hearing aids
Mechanical vibration delivered directly to the ossicular chain
2 types
1) piezoelectric devices
2) electromagnetic hearing devices
.
Candidacy profile- Adults 18 yrs and older with moderate to severe SNHL- Should have an experience with hearing aids previously
Implantable hearing aids
Vibrant soundbridge device
Semi implantable device made of 2 components
Cochlear implants
Electronic device- electrical stimulation of auditory nerve
2 components external- sound processor, mic, transmitter and internal-receiver/stimulator, electrode array
Auditory brainstem implant
Stimulates the cochlear nuclear complex in the brainstem directly by placing the implant in the lateral recess of the fourth ventricle.
Used when CN VIII is severed in the surgery of vestibular schwannoma
Multi electrode array is attached to a decron mesh which is placed on the brainstem
Auditory brainstem implant
Definition
Cochlear implants are surgically placed electrical device that receive sound and transmit the resulting electrical signals to electrodes implanted in the cochlea of the ear.
The signals stimulate cochlea, allowing patient to hear.
It is also known as Bionic ear.
Parts of cochlear implant External
Microphone Speech processor Transmitter
Internal Receiver and stimulator An array of up to 22 electrodes
Mechanism
Cochlear implants bypass damaged portion of the ear & directly stimulate the auditory nerve and later the brain recognizes it as sound.
Assistive devices
Helps in special difficult situations
Warns of danger signals
3 groups
1. Assistive listening devices and systems
2. Alerting devices
3. Telecommunication devices
Training
1. Speech reading2. Auditory training3. Speech conservation
Management of rehabilitation
Parental guidance Hearing aids Speech & language therapy Education of the deaf Vocational guidance
? How a cochlear implant works.webm
"An untreated hearing loss is more noticeable than hearing aids."
Thank you for “LISTENING”