Explore Causes of Hearing Loss in more detail :
Other Causes of Hearing Loss
Non-genetic causes of permanent childhood hearing loss
Permanent hearing loss in childhood not due to genetic factors can be due to infection (either in the child themselves, or prenatally in the mother) or complications at birth. A particularly important example of an infection which leads to hearing loss is bacterial meningitis, a potentially life-threatening illness which can lead to a range of serious consequences including profound deafness. It is important to realise that there is no infection/illness that ALWAYS causes deafness, and that the likelihood of becoming deaf from infections/illness varies with condition; for example, bacterial meningitis has been found to be associated with deafness in anything from 5 to 35% of cases (see also ).
Hearing loss can also be acquired in the womb by the foetus if the mother has an infection during pregnancy. Rubella (German measles), cytomegalovirus (CMV) and herpes are examples of conditions which can lead to deafness in the baby if acquired by the pregnant mother. CMV has been the focus of much recent research to see if it is possible to screen for the condition in pregnancy and reduce the risk of consequences to the baby. Please visit this ClinicalTrials.gov website page for some further information. Alcohol or other substance abuse during pregnancy can also lead to hearing loss in the child.
Difficulties at birth that are not related to genetic factors or infection can also lead to deafness. Babies born with a very low birthweight (<1.5 kilogrammes), who are born very premature, or who experience severe lack of oxygen or other birth trauma, along with those with severe jaundice after birth, are all at greater risk of developing permanent hearing loss. Babies who develop hearing loss as a result of birth trauma or events around birth are at a greater risk of developing Auditory Neuropathy Spectrum Disorder, a particular type of hearing loss which is further discussed on this Boys Town website page.
For young children, the most common cause of hearing loss is otitis media with effusion, also known as glue ear. This condition affects at least one in four children at some time, and the majority of cases occur in children under 10. Please visit this National Health Service (NHS) - UK website page for some further information on middle ear infection (otitis media). It causes a typically reversible/temporary mild or moderate hearing loss which varies in duration and effect on hearing and how well the child functions.
Some other causes of hearing loss in adulthood
The most common type of adult onset hearing loss is age-related hearing loss (also known as presbycusis, or presbyacusis), but there are a number of less common causes of hearing loss which can affect people across the age spectrum. These include conditions which only present as hearing loss in adulthood, even though they are thought to be genetic (such as otosclerosis, a condition in which the bones of the middle ear become fused), and particular conditions that normally develop in adulthood, such as Ménière's disease. Please visit this National Health Service (NHS) - UK website page for more information on Ménière's disease. However, the remainder of this section focuses on non-genetic causes of hearing loss in children (although some of these may also affect adults).