These are the most common causes of deafness in children:

- In most cases permanent deafness is hereditary. A third of people who are deaf for genetic reasons were born deaf, a third become deaf during childhood and the other third become deaf as adults. Permanent hearing loss among children is the most common congenital disability - in developing countries this is up to five in every 1 000 babies.

- Inflammation of the middle ear (tympanitis) is the most common cause of a type of deafness known as conductive deafness. Regular ear infections can cause permanent hearing loss among children.

- German measles during pregnancy can cause permanent deafness. If a pregnant woman contracts German measles during the first eight weeks of pregnancy there is an 86 per cent chance her baby will be deaf.

- Other problems during pregnancy that can also result in deafness in the unborn baby include infection with the cytomegalo virus, Rhesus-irreconcilable blood between mother and baby, thyroid problems and diabetes in the mother.

- Permanent deafness can result if the baby suffers from a lack of oxygen during birth or has to be connected to a respirator for more than five days.

- Another risk factor is if the baby weighs less than 1,5 kg at birth.

- Injuries during birth (especially head injuries) and jaundice in babies can also be a cause.

- So can viral and bacterial infections such as meningitis in babies and toddlers.

- Certain medicines such as some antibiotics and TB drugs can also cause deafness.

(This is an extract of an article that originally appeared in YOU Pulse / Huisgenoot-POLS magazine, September 2007. Buy the latest copy, on newsstands now, for more fascinating stories from the world of health and wellness.)