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”