Congenital hearing loss is a form of hearing loss that is assumed to have been present at the time of birth. It has been estimated that somewhere between one-quarter and a half of all hearing loss cases in the severe to profound categories have either hereditary or genetic causes, with many of those being classified as congenital.
In the UK, it is estimated that the rate at which congenital hearing loss is identified at birth is 1.33 for every 1,000 births, though that figure rises to 2.83 among children of primary school age, and 3.5 for those in adolescence, indicating that the condition can be slow to develop in some cases.
Forms of congenital hearing loss
The total number of congenital hearing loss cases is generally divided into two categories: hereditary or non-hereditary, although it is not always possible to put a case into one of these categories. Sometimes, medical professionals are unable to determine whether a child’s hearing loss is caused by the combination of recessive genes via a child’s parent or through an event that occurred during the pre-natal stage or during birth. Overall, it is estimated that genetic issues are the cause of over half of congenital hearing loss cases.
Non-hereditary congenital hearing loss
Cases of congenital hearing loss that are considered to be non-hereditary can fall into a number of categories. In fact, there are several potential causes, though some are more prevalent than others.
One of the most cited causes of this form of hearing loss is the action of teratogenic drugs. These are drugs or various substances that can potentially interfere with the development of a healthy foetus, which can, in turn, lead to birth defects. If there is maternal exposure to this form of medication, particularly during the early phases of the pregnancy, then the risk is increased as the foetus will be at particular risk of suffering some form of damage. This category of drugs includes Quinine, Reticonic and Thalidomide. Exposure to any of these drugs can lead to the presence of serious hearing loss at the time of birth.
Another potential cause of non-hereditary congenital hearing loss is a viral infection. In cases where the mother contracts a particular type of infection during the course of her pregnancy, there can be significant effects on the child. The most dangerous viruses in this category, which are the most likely to lead to mild to profound hearing loss, are Rubella, Toxoplasmosis and some Syphilis variants.
In addition, there are a number of less common potential causes of non-hereditary congenital hearing loss, including problems that develop during the period of inner ear development for the foetus, as well as potential risks occurring in the immediate post-natal period, including diseases like meningitis and neo-natal septicaemia, which can cause significant hearing loss.
Hereditary congenital hearing loss
Hereditary forms of hearing loss are categorised as those in which a loss of hearing function is due to the transmission of certain genetic information from parents. In some cases, it is important to note that the congenital hearing loss may not be present when the child is born, but may develop later in life, as partially indicated by the figures for congenital hearing loss cited above.
There are a number of conditions that can be associated with significant congenital hearing loss, including Down syndrome, Treacher Collins syndrome, Usher syndrome, Alport syndrome, Crouzon syndrome and Waardenburg syndrome. Hereditary congenital hearing loss, whether present at birth or identified later on, can occur as an isolated factor, but it also often develops in parallel to a number of other defects, which can enable doctors to identify it as associated with a particular syndrome.
Congenital hearing loss support
If parents of a child with congenital hearing loss decide a hearing aid will provide the best support for their child, the good news is that this support is usually available at an early stage. In fact, a hearing aid can be fitted at a young age, although for younger children, it is recommended that the behind the ear style of hearing aid is used as this is both more straightforward to fit and easier to adjust to take account of the child’s growth and development.
As well as the use of hearing aids, it is important that the family of a child with congenital hearing loss take steps to create a supportive and welcoming situation for the child, particularly if there are other children in the family. These steps can include the development of communication skills including sign language or lip-reading, which can make all the difference.
There is no doubt that congenital hearing loss in your child can be a difficult thing for any family to adjust to, but by adopting the best approach, backed with full professional and medical support, there is every chance of ensuring that this type of hearing loss is not a barrier as the child goes through life.