DEAFNESS – ITS IMPACT ON THE SOCIETY AND MANAGEMENT

Deafness means loss of hearing and it may be partial or total. Unlike blindness deafness often provokes ridicules rather than sympathy. Unable to hear what is said and unable to answer, the severely deaf person appears to be stupid. So isolated from family and friends and greeted by unsympathetic attitude he or she is often depressed and needs psychological counseling. The problem of the child deaf from the birth is quite different from that of the adult who has become completely deafened after school age or in adult life. The Hard of Hearing person whose deafness has developed slowly over the years is different again. But for all of them the handicap is the same – the handicap of the silent world, the difficulties of communicating with the hearing and speaking world. Moreover disability of deafness is invisible so deaf suffers in silence. So it really creates a great problem among thousands of deaf people and atributes to loss of manpower.
Globally 250 million people are the victims of deafness and India is in the 2nd position with 60 million hearing impaired people (6%). So we need a comprehensive management strategy at National level to fight against this.
Let us discuss the basics of hearing i.e., How we hear. At first sound goes to External Ear upto Ear Drum. This Ear Drum vibrates which in turn vibrates the ossicular chain i.e., middle ear bones malleus, incus and stapes. In this way sound wave passes to the inner ear and reaches the cochlea. From there the sound passes via auditory nerve to reach cerebral cortex and we hear. Any disruption in the pathway of sound conduction leads to partial or total deafness.

Showing Cross Section of Right Ear with External, Middle and Inner parts

Type of Deafness :

It can be divided into two major categories :–

A. Conductive deafness i.e., due to failure of sound conduction through external ear and middle ear.

B. Sensorineural deafness or Nerve Deafness i.e., problems in the inner ear, auditory nerve or brain itself.

Degree of Deafness : Mild, Moderate, Severe and profound.

Categorisation and percentage of hearing impairment recommended by Dept. of Personnel, Government of India

Category Type of impoinment Average hearing threshold for AC in dB by pure tone audiometry in 500, 1000 & 2000 Hz Speech discrimination in better ear Percentage of impoinment
I Mild 26 to 40dB 81 to 100% Less than 40%
II Moderate 41 to 55dB 51 to 80% 41 to 50%
III Severe 56 to 70dB 41 to 50% 51 to 75%
IV a) Profound
b) Near Total
c) Total
71 to 90 dB
Above 91dB
Nil
Less than 40%
No discrimination
No discrimination
76 to 100%
100%
100%

In our country mild degree of deafness can not be detected early because we, Indian people usually speak loudly and the social stigma.

Causes of Deafness :

A. Conductive type :

  • Congenital atresia of external and middle ear
  • Wax
  • Foreign Body in the External Ear like Beads, seeds etc.
  • Traumatic injuries to the ear drum and ossicular chains.
  • ASOM and CSOM with discharging ear.
  • OME i.e., collection of fluid in the middle ear.
  • Otosclerosis i.e., stiffness of the ossicle stapes.
  • Barotraumatic otitis media due to Air Travel, High Altitude climbing etc.

B. Sensorineural Type i.e., Nerve Deafness :

  • By birth i.e., congenital – genetic defect, maternal infection like rubella, cytomegallovirus, HIV etc., Taking ototoxic drugs during pregnancy etc.
  • Presbyacusis i.e., deafness of old age.
  • Meniere’s Disease.
  • Noise Induced Hearing loss in urban areas and industrial belt.
  • Ototoxic durg intake like Aminoglycoside Antibiotics, Aspirin, Quinine Freusemide etc.
  • Infection like Mumps, Measles, Meningitis and rarely syphillis.
  • Metabolic Disorder i.e., Diabetes Mellitus, Hipothyroids, Head injuries etc.
  • Rarely Acoustic Neuroma or Other Cere-bellopontine Angle Tumour.

Deafness in children :

Early diagnosis of deafness is the key to successful mangement of deaf especially in children. Deafness must be assessed soon after birth for high risk babies.

They include : Premature and low birth weight baby (below 1500 gm) delayed crying, hypoxia i.e., low O2 intake during births.
Genetic deformities.
Rhesus Disease.
During Pregnancy exposure to viral infection.
After birth jaundice, viral infection, menengitis etc.

It is important to note that without hearing a child can not develop speech and language. So the aim should be to recognise deaf child before the age of 1 year because from 1 year to 3 years onwards babies start learing the speech. Unfortunately, hearing loss is often not detected untill a child is 2, 3, or even 4 years old especially in Rural Areas due to poor awareness about deafness and its relation with sppech and language development as well as lack of infrastructure like non availability of audiologist, audiological equipments, speech therapist etc. especially at sub divisional level Govt. Hospitals in our country. Regarding the assesment of deafness mothers assessment is very much important and should be taken seriously. Parents can assess hearing of their child at home by following manner–

Shortly after Birth – Startle reflex i.e, closing of eyes on exposure to loud sound.

By 1 to 3 months – children notices sudden prolonged sound.
By 4 months – Baby turns his /her eye towards the sound.
By 7 months – Turns the head towards the familiar voice or sound from accross the room like mothers voice, cup and spoon sounds etc.
By 9 months – may babble loudly and tunefully likes Ma Ma, Ba Ba etc.
By 12 months – responds to his/her own name or other familiar sounds.
From 13th – 24th months – Articulate speech with ability to answer question.

If any abnormality found during these period, parent should not waste time and must see an ENT Specialist for proper evaluation of hearing.

Tests for Detection / Assessment of Deafness

  • Tunning Fork Tests.
  • Audiometry (in case of child Free Field).
  • Tympanometry.
  • BERA– confirms the degree of deafness.
  • In new born Otoacoustic Emission Test is done for confirmation of deafness ? it is an invaluable tool for screening deafness in new born.

All these tests are done to detect degree type of deafness and by all these measures we have to identify Bilateral hearing loss child as early as possible. Bilateral hearing Aids are recommended for use from 1 year of age keeping the fact in the mind that children develop speech mostly during the period from 1yr-3yrs. Delay in using Binaural Hearing AIDS delays speech and language development. Profound degree of SN Deafness or Total deafness may require lip reading and they generally do not inprove speech with conventional hearing aids. For them Cochlear Implant Surgery is the ideal choice by which a profound or total deaf child can learn speech and language like a normal child. It is really a boon to the compeltely deaf and dumb child. But very few can take the advantage of cochlear implantation in the ear because of its high cost (nearly 4.5 lakhs).

Management of Deafness :

Conductive deafness are mostly cured by medicine and/or microsurgery. Microsurgery can be done at doorstep hospital like SD Hospital. Those who are unfit for surgery or do not willing to do surgery may use hearing aids preferably digital one.

  • Conductive
    • Wax- by removal after softening
    • Foreign body- by removal
    • OME – by medicine – no improvement –Myringotomy and Grommet insertation
    • ASOM- by medicine
    • CSOM- by Myringoplasty / Ossicuoplasty
    • Otosclorosis – by Stapedectomy
    • Few cases who are unfit for surgery and not cured by medicine or refused surgery may use Hearing Aid

Sensorineural (SN) deafness are sometimes cured by medicine but most of them with bilateral hearing loss need hearing aids for partial deafness and cochlear implant for total deafness.

  • Sensorineurual Deafness
    • Sudden SN Deafness by medicines
    • Congenital Deafness by Hearing Aids and Cochlear Implants and auditory training
    • Chronic Deafness Hearing Aids and lip reading
    • Total Deafness Cochlear Implants

Who will benefit from cochlear implant surgery?

  • Prelingual children – With profound or total deafness since birth below the age of 6 years and above the age of 1 year without speech development.
  • Those children and adult who benefits from hearing aid earlier but later can not hear due to deterioration of Hearning.
  • Postlingual – After developing speech and languages sometimes child or adult becomes deaf completely in any part of life require Cochlear Implantation Surgery.

Rehabilitation :

(1) Education of Children

A. Schooling ? Those child who are bilaterally profoundly deaf may be admitted in deaf school for special teaching by deaf teacher. Lip reading, sign language, expression of face and body etc. will help to develop communicating skill where hearing aid will not be helpful.

B. But those who have moderate to severe degree of bilateral deafness may be admited to normal school with proper hearing aids because their speech and language development will be facilitated due to interaction with normal child and thus they will not be socially isolated.

(2) Facilities for the hearing handicapped person
As per Physically Handicapped Bill 1993 which include hearing handicapped are as follows :

  • Free education for BPL Category.
  • Students Scholorship – Stipend will be given from class I to class VIII in Government and Government Aided Schools.
  • Students Scholorship – Stipend will be given from class I to class VIII in Government and Government Aided Schools.
  • Reservation for admission in Goverment Institution and Government Jobs – 3% seats are kept reserved besides in all cases of financial subsidy. 3% will be spent for physically handicapped including deaf persons.
  • Free hearing aids – There is provision by Deptt. of Social Welfare, State Government and National Institute of Hearing Hadicapped to supply free hearing aids from their office at all State Capitals or District Head Quarters. Hearing Handicapped Certificate and monthly income statement are necessary.
  • Rebate in Income Tax.
  • Hearing Handicapped persons are entitled to get financial assistance from Deptt. of Social Welfare, State Government and Nationalised Banks for Developement of self employed projects.
  • Upper age limit for jobs in Govenrment Service is relaxed to 45 years.
  • Concession in fare as well as seat reservation in Government carriers like Train, Bus, Air.

Issue of Hearing Handicapped Certificate

Issued from Deptt. of ENT, Medical Colleges, District Hospitals and Sub-divisional Hospitals once or twice a month. Documents needed are Ration Card, Voter ID Card, Photographs, Address Proof Certificate. This certificate is valid for 10 years and renewal can be done.
Considering the enormity of the deaf population in our country (6% of total population) and lack of awareness and poor infrastructure The Association of Otolaryngologists of India, West Bengal appealed to Governor of West Bengal to take up the matter with the respective State Governments and Govt. of India with following recommendations to be considered :
a) Initiation of National Programme for Prevention and Control of Deafness.
b) Strict Implementation of Law for Controlling Sound Pollution (Crackers, Electric Horn and various devices fitted to the vehicles, industrial noise, sound emitted by the transport system).
c) Implementation of compulsory screening tests for detecting hearing disorders in all infants and neonates specially in low birthweight and high risk babies.
d) Provision of Fund for regular and periodic hearing screening test for school children.
e) Arrangement for getting high quality, easily available and economic hearing aids for the hearing handicapped population and subsidy in Cochlear Implant Surgery.
f) Trained personnel e.g. ENT Specialists, Audiologists and Social Workers must be provided at least at the level of Subdivisional Hospital for early detection of Deafness.

Treatment protocol should be in 3-tier system

Tier I : Primary Care – Awareness for prevention and early detection of Deafness and minimum intervention for treatment at the Block level hospitals.
Tier II : Secondary Care- Detection of Deafness and treatment of curable causes including microsurgery and rehabilitation as far as practicable at the Sub division and District level hospitals.
Tier III: Tertiary Care- Specialised Treatment Modality- means most modern specialised treatment modalities available-at the city hospitals (eg. Medical College Hospitals, Advanced Corporate Hospitals) for the hearing handicapped providing microsurgical facilities, availability of cochlear implantation surgery and selection and distribution of highly efficacious modern hearing aids.
So lets see them smiling with sympathetic approach, medical expertise and modern technologies but early detection of deafness is absoulately necessary to minimise deaf cases in our country.