Prevention of hearing impairments 

Hearing impairments in children can be of three types :

•  neurosensorial
•  in transmission
•  mixed

1.  Neurosensorial hearing impairments

– of genetic origin :
Effective prevention consists of dissuading consanguinity which, even to a small
degree, increases the risk.  This applies especially to populations living in a closed
community.
– Infections (viral, bacterial and parasitic) of the pregnant woman (causing embryo and foetus pathologies) and of the child, can be prevented by vaccination.
– Intoxication of the pregnant woman (causing embryo and foetus pathologies) and of the child are mainly of medical and/or accidental origin.  A list of toxic agents must be kept up to date by the WHO and regularly distributed.
These toxic products shall be placed out of reach of children.
– Malnutrition and vitamin-deficiency in the pregnant woman and the child.
Health education as well as preventive and curative measures must be intensified.
– Physical agents (X-rays, ultrasonic treatment, etc.) shall be used with care and given by regularly checked equipment.
– Premature birth, which makes hearing impairments more likely through respiratory and/or central distress, shall be targeted for prevention.
– Obstetrical trauma
–  Neonatal anoxia
– Nuclear icterus.
– Childhood cranial trauma shall be the subject of a more intensive campaign concerning environmental risks.
– Childhood noise trauma, resulting from excessive exposure, shall be avoided.

2.  Hearing transmission impairmentsHearing transmission impairments may be :

– due to a congenital malformation of the outer ear or middle ear.  Where this malformation is bilateral, a hearing-aid by osseous conduction shall be fitted as soon as possible after birth.  Where the malformation is unilateral, the healthy or apparently healthy ear shall be regularly checked ;  where a hearing impairment develops, a hearing-aid will be necessary.
– due to trauma.
– due most frequently to recurrent middle-ear otitis with sero-mucous causes, complications and repercussions on hearing integration.
Appropriate treatment.

3.  Mixed hearing impairments

There may be aggravation of neuro-sensorial type hearing impairment by a transmission element or vice-versa.
Prevention includes the measures designed to avoid both neuro-sensorial hearing impairments and transmission impairments.

B.  ADULT HEARING IMPAIRMENTS

Adult hearing impairments may also be of three types :

•  neuro-sensorial
•  in transmission
•  mixed

· Adult hearing impairments may have the same causes as in the child.
· They are often an aggravation of a hearing impairment developed in infancy or childhood.
· Deafness in older people, whatever the cause, requires early fitting of a hearing-aid so that these older people do not lose the habit of surrounding noise.
· Acoustic trauma :

a)  professional :  Prevention consists of combating noise « at its source » and of making available to workers a means of individual protection.  It also consists of checking up on employees by hearing tests when they are taken on and in the course of their employment, with appropriate measures to follow.
b)  due to environmental noise pollution : Excessive exposure to noise shall be avoided.  The wearing of a protective device shall be recommended, even imposed.

· Barotrauma and other ear trauma (blasts, burns, etc.)
Appropriate prevention.
· Cranial-auricular trauma shall be the subject of a more intensive campaign concerning environmental risks, whether professional or not.
· Stapedian and/or cochlear otospongiosis causes progressive hearing impairments which must be detected and treated as early as possible.
· Central deafness.
Prevention is chiefly on the same lines as that for cardio-vascular affections.
· Causes of central deafness, especially tumours, shall be detected and treated as early as possible.

N.B. Requisites for correct prevention of hearing deficiencies :

Systematic ear, nose and throat examinations.Regular audiometric screening, more particularly for « at risk » individuals.