HEARING CONSERVATION

Dr. G.K. Hebbar outlines a detailed method of tackling deafness and its problems in the society. Early detection is the most important aspect of this program, for it can stall the process of increasing handicap.

Even partial hearing loss is a real loss.   Millions of  persons  suffer  from  partial  loss  of  hearing  but  are  resistant  to  treatment  or  correction.   That’s because they have their indifferent attitude and continue to operate unnecessarily at a much lower  level  of  efficiency  in  their  work  and  also  their  social  and  family  life.  A  person  with  a  hearing  loss  is  severely  handicapped.  What  can  be  done  to  help  such  hard  of  the  hearing  individuals  and  also  conserve  normal  hearing  of  the  rest  of  our  population  ?

With  the  advent  of  industrialization the  population  at  large  is  exposed  to  an  unprecedented   level  of  noise,  that  was  unimaginable  a  couple  of  decades  ago.  Hearing  loss  resulting  from  such  an  over  stimulation  by  sounds  is  known  as  noise-induced  hearing  loss.  Damage  to  the  ear  and  the  concomitant  hearing  loss  depend  on  the  cumulative  exposure  to  sounds  from  all  sources – environmental,  recreational  as  well  as  occupational.  The  ear  does  not  differentiate  desirable  sound  from  an  unwanted  sound.   How  can  we  protect  our  ears  from  this  deafening  onslaught  ?

The answer to both  the  problems  lies  in the  successful  implementation  of  a  Hearing  Conservation  Programme  (HCP).

Definition of hearing conservation

If  we  define  hearing  conservation  in  the  broadest  sense,  we  must  not  confine  ourselves  to  preservation  of  normal  hearing  alone  but  also  residual  hearing.   For  such  a  HCP  to  become  successful  it  is  important  that  it  should  be  implemented  right  from  childhood.   It  also  includes  educating  laypersons  about  hearing  loss,  monitoring  workers  in  industries,  offering  suitable  medical  assistance  and  drafting  legislations  to  ensure  adequate  care  and  aid  when  a  loss  in  hearing  is  detected.

HCP in children

It  is  important  to  identify  deafness  among  children  as  early  as  possible;  the  sooner  the  better,  since,  even  partial  deafness  in  children  results  in  poor  learning  abilities  in  school,  and  psycho-social  problems.  Such  a  goal  can  only  be  achieved  by  screening  all  the  children  at  risk.   Inexpensive  table  audiometers  are  easily  available.   The  government  can  definitely  afford  to  supply  these  to  every  taluk  headquarters  hospital.

The  audiometer  does  not  require  great  expertise  to operate  operate;   the  nurses  stationed  at  the  hospital  can  be  taught  to  operate  it.   All  the  schools  in  each  taluk  can  be  systematically  covered.   Once  the  hearing  impaired  children  are  identified,  arrangements  can  be  made  to  refer  them  to  a  specialist  centre  for  further  treatment,  or  specialist  could  visit  these  hospitals.   In  the  cities  and  in  major  towns  where  more  facilities  are  available,  it  would  obviously  be  easier  to  screen  school  children.

Health  workers  and  social  workers  who cover most of the houses in the village for other purposes can also be included in the programme to enquire about the hearing abilities  and/or incidence of discharging ear among members of the family.  The  suspected cases thus identified should be referred to the taluk headquarters for audiometry and necessary action.

Public education

Increasing public awareness and concern is one of the most effective methods to promote HCP.  The public should be made to realise that hearing is a necessary function rather than an  expendable  commodity.

Unfortunately,  our  public  education programmes and school systems fail  to  emphasise the  importance of hearing and its conservation.  They also do not  realise that this type of health education is as important as learning to read and write and hence should be made a part of a child’s curriculum.

Organisations  such as  parent-teacher associations should take it upon themselves to organise regular  programmes highlighting the importance of hearing and the dangers of noise exposure.   Children  are amenable to audio-visual aids  and so with the help of these devices they could be educated regarding the handicaps and hardships caused by deafness, and about the role of nutrition and personal hygiene in preventing infections leading to deafness.

Mass  media  like  the  radio, television,  newspapers and magazines  could  educate the adult  population.

All  efforts  have  to be made to rid the general  people  of the  misconceptions    surrounding  deafness,  and  to  guide  afflicted  to  seek  professional  help.   Free  camps  should  be  conducted  by  specialists  in  remote  areas,  not  only  to  identify  deafness  but  also  to  educate  the  people  about  basic  care  of  the  ear  and  other  important  measures  to  prevent  deafness.   Service  organisation  could  take  it  upon  themselves  to  adopt  a  village  and  arrange  such  camps  at  regular  intervals.

HCP  in Industries

The  mushrooming  of  industries  around  the  metropolitan  cities  has  led  to  a  marked  increase  in  migration  of  the  rural  population  to  the  cities.   The  population  exposed  to industrial  noise  has  thus  increased  considerably.   Hence it  becomes  imperative  that  we  adhere  to  a  very  strict  HCP  in  industries.

Noise measurement is usually done for two reasons: to determine whether there is a need for a hearing conservation program and to obtain information to control noise at the source. For this, two measures are important: one the noise level in decibels (dBA) and two, the time of exposure.

If the noise level at the location is 90 dBA but the exposure time is less than eight hours, there is no need for a hearing conservation programme, 90 dBA is the maximum permissible exposure level (PEL) for an 8-hour workday.  If the exposure continues for more than eight hours, the accepted level in decibel falls accordingly.

Measurements should be made at the level of the exposed person’s ears and at the location where he/she usually works at various times of the day over a period of a month to determine an average level for that particular location.  Instruments called noise dosimeters are generally used for the purpose.  These accumulate the total dosage over an 8-hour period.  A general safe rule to follow is that, if an area is above the chosen criteria, regardless of the time of exposure, the individual should be protected.

A complete hearing conservation programme must involve some arrangements for medical direction and intervention.  Even though an  industrial hearing  conservation programme is  primarily related to prevention of hearing loss from noise exposure, it must also include provisions to determine losses from other causes.  Referrals to an otologist are made for the purpose of determining and conducting follow up action.

Conducting hearing tests but making no provisions for treatment  and follow up action is useless.  The tests merely provide the information that determines what subsequent action must be taken.  Such an action cannot be completed without medical interpretation and intervention.

Proper legislation

The key to a successful HCP is through proper legislation.  No amount of individual of organisational efforts will be fruitful, unless backed whole-heartedly by the government bodies.

Unless we make it mandatory to incorporate hearing evaluation tests in the routine yearly school health programme we will be missing the diagnosis of hearing loss in most of the children.  Most of these children can be restored to normal hearing with proper medical or surgical treatment. Such a legislation will go a long way in cutting medical expenditure and also in preventing complications secondary to the undiagnosed disease. The responsibility of conducting such evaluations, maintaining records and arranging for regular follow-ups for the children identified, as having a hearing loss should be solely with the management of the school.  Lapses or negligence should be seriously dealt with.

Similar responsibility should rest with the management in industries.  A responsible person should be delegated with the task of successfully running a programme in association with a medical consultant.  Records must be kept accurately and legibly since these records may become part of medico-legal procedures.

At present, the laws that protect employees from occupational injuries and diseases are not implemented seriously.  Existing loopholes have to be effectively sealed thus making it mandatory for industries to use feasible administrative or engineering controls to reduce workers’ exposure to noise to permissible levels.  If hazardous levels of noise persist, the affected employees have to be included in a HCP and provided with personal protective equipment.  Employees who are judged to be handicapped due to the hearing loss should be adequately compensated.  Compensation boards should be set up to authenticate each case and make recommendations.

Environmental noise pollution in our cities is totally unchecked.  Walking on the roads in any city is an ear shattering experience. Road transport authorities must take poise pollution seriously and must assist in reducing noise by banning the use of horns in buses and lorries.  More areas in the cities can be made “No Horn” zones.  The use of blaring loudspeakers in public should be banned and violators should be heavily penalized.

Unless proper steps are taken to conserve hearing, an increasing percentage of our population are going to suffer from partial or total deafness which in most cases is preventable.  We should seriously think in terms of an effective hearing conservation program suitable for our country before more damage is done.