According to the recent infant screening in India 5-6 infants out of 1000 born with hearing loss.
A hearing is an important ability for children to develop speech and language skills to grow. The hearing loss in an infant is difficult to identify or detect and it is detected around two years old. There are several factors that cause hearing loss in babies such as congenital or acquired Hearing loss is found in different categories such as conductive, sensorineural or mixed.
So, it is advised to have the screening for the hearing of newly born.
Congenital hearing loss:
Hearing loss at the time of birth is called congenital hearing deafness. Approximately 50% of the hearing loss caused is genetic,25% is acquired and 25% caused due to an unknown cause. Inner ear abnormality such as Mondini dysplasia with variable inheritance patterns results in 20% of the Congenital sensorineural deafness and the remaining does not have distinguishing features. It depends on 2 factors:
Genetic factors(Inherited congenital deafness)
Hearing loss from the genetic defect can be present at the time of birth or develop later in life. It causes more than 50 % of the hearing loss.
- Non-syndromic deafness- About 80% of genetic disorder is non- syndromic. It has two types, Autosomal dominant (DFNA) and Autosomal recessive (DFNB).
- Autosomal Recessive hearing loss: It occurs when a child receives a hearing loss gene from each parent. It means parents do not have hearing loss but each parent carries the recessive gene.
- Autosomal dominant hearing loss: In this on parent carry the dominant gene for hearing loss. Dominant gene passed from parents to the offspring. In this parents may not have hearing diseases but on of from them have sign or symptoms of the hearing syndrome.
- Syndromic deafness-About 20% of genetic disorder is syndromic.
- X-linked Charcot Marie Tooth (CMT)
Non-genetic factors(Non inherited congenital deafness)
It causes 20 % congenital deafness. These disorders can be linked to genetic disorders but mostly occur independently.
- The problem occurred during birth such as herpes, rubella cytomegalovirus, toxoplasmosis or another serious infection.
- Deficiency of oxygen during pregnancy.
- Premature birth: babies who have their weight less than 3 kg and require some drugs to survive. They have a risk of hearing loss.
- Nervous system or brain disorder: Some time mothers use ototoxic medicine during pregnancy such as antibiotics, aspirin that damage fetus auditory nerve or other hearing structures.
- If the mother has an infection during pregnancy that may cause hearing loss in babies.
- Due to taking alcohol and smoking during pregnancy.
- Viral syndrome– It is often connected with prenatal infections with viruses such as measles. Infants exposed to a bodily fluid such as breast milk, saliva and urine can transfer these viruses.
- Mancini and Michel dysplasia– It is caused due to membranous abnormality, a bony abnormality or a combination of both two.
- Malformation of inner auditory meatus– It is caused because of the unusually sized opening between the inner ear and the brain(inner auditory meatus) and their association with the other bone abnormality
There are others factors also such as lack of oxygen(anoxia), Maternal diabetes, complications associated with the RH factor in the blood/Jaundice, Toxemia during pregnancy etc.
Acquired hearing loss:
It is a hearing loss that appears after birth due to external environmental and physical factor such as diseases, injury and other condition.
Conditions that cause hearing loss in babies:
- Ear infections
- Ototoxic medicines
- Head injury
- Noise exposure
For a healthy and fully active life, early detection of hearing loss is a must. So, consult the doctor because congenital hearing loss requires identification as soon as possible.